code:
<?php
// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Database schema for MariaDB
 *
 * @category  Database
 * @package   GNUsocial
 * @author    Evan Prodromou <evan@status.net>
 * @copyright 2019 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */

defined('GNUSOCIAL') || die();

/**
 * Class representing the database schema for MariaDB
 *
 * A class representing the database schema. Can be used to
 * manipulate the schema -- especially for plugins and upgrade
 * utilities.
 *
 * @copyright 2019 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */
class MysqlSchema extends Schema
{
    public static $_single = null;

    /**
     * Main public entry point. Use this to get
     * the singleton object.
     *
     * @param object|null $conn
     * @param string|null dummy param
     * @return Schema the (single) Schema object
     */
    public static function get($conn = null, $_ = 'mysql')
    {
        if (empty(self::$_single)) {
            self::$_single = new Schema($conn, 'mysql');
        }
        return self::$_single;
    }

    /**
     * Returns a TableDef object for the table
     * in the schema with the given name.
     *
     * Throws an exception if the table is not found.
     *
     * @param string $table Name of the table to get
     *
     * @return array of tabledef for that table.
     * @throws PEAR_Exception
     * @throws SchemaTableMissingException
     */
    public function getTableDef($table)
    {
        $def = [];
        $hasKeys = false;

        // Pull column data from INFORMATION_SCHEMA
        $columns = $this->fetchMetaInfo($table, 'COLUMNS', 'ORDINAL_POSITION');
        if (count($columns) == 0) {
            throw new SchemaTableMissingException("No such table: $table");
        }

        foreach ($columns as $row) {
            $name = $row['COLUMN_NAME'];
            $field = [];

            $type = $field['type'] = $row['DATA_TYPE'];

            switch ($type) {
                case 'char':
                case 'varchar':
                    if (!is_null($row['CHARACTER_MAXIMUM_LENGTH'])) {
                        $field['length'] = (int) $row['CHARACTER_MAXIMUM_LENGTH'];
                    }
                    break;
                case 'decimal':
                    // Other int types may report these values, but they're irrelevant.
                    // Just ignore them!
                    if (!is_null($row['NUMERIC_PRECISION'])) {
                        $field['precision'] = (int) $row['NUMERIC_PRECISION'];
                    }
                    if (!is_null($row['NUMERIC_SCALE'])) {
                        $field['scale'] = (int) $row['NUMERIC_SCALE'];
                    }
                    break;
                case 'enum':
                    $enum = preg_replace("/^enum\('(.+)'\)$/", '\1', $row['COLUMN_TYPE']);
                    $field['enum'] = explode("','", $enum);
                    break;
            }

            if ($row['IS_NULLABLE'] == 'NO') {
                $field['not null'] = true;
            }
            $col_default = $row['COLUMN_DEFAULT'];
            if (!is_null($col_default) && $col_default !== 'NULL') {
                if ($this->isNumericType($field)) {
                    $field['default'] = (int) $col_default;
                } elseif ($col_default === 'CURRENT_TIMESTAMP'
                          || $col_default === 'current_timestamp()') {
                    // A hack for "datetime" fields
                    // Skip "timestamp" as they get a CURRENT_TIMESTAMP default implicitly
                    if ($type !== 'timestamp') {
                        $field['default'] = 'CURRENT_TIMESTAMP';
                    }
                } else {
                    $match = "/^'(.*)'$/";
                    if (preg_match($match, $col_default)) {
                        $field['default'] = preg_replace($match, '\1', $col_default);
                    } else {
                        $field['default'] = $col_default;
                    }
                }
            }
            if ($row['COLUMN_KEY'] !== null) {
                // We'll need to look up key info...
                $hasKeys = true;
            }
            if ($row['COLUMN_COMMENT'] !== null && $row['COLUMN_COMMENT'] != '') {
                $field['description'] = $row['COLUMN_COMMENT'];
            }

            $extra = $row['EXTRA'];
            if ($extra) {
                if (preg_match('/(^|\s)auto_increment(\s|$)/i', $extra)) {
                    $field['auto_increment'] = true;
                }
            }

            if (!empty($row['COLLATION_NAME'])) {
                $field['collate'] = $row['COLLATION_NAME'];
            }

            $def['fields'][$name] = $field;
        }

        if ($hasKeys) {
            $key_info = $this->fetchKeyInfo($table);

            foreach ($key_info as $row) {
                $key_name = $row['key_name'];
                $cols = $row['cols'];

                switch ($row['key_type']) {
                    case 'PRIMARY':
                        $def['primary key'] = $cols;
                        break;
                    case 'UNIQUE':
                        $def['unique keys'][$key_name] = $cols;
                        break;
                    case 'FULLTEXT':
                        $def['fulltext indexes'][$key_name] = $cols;
                        break;
                    default:
                        $def['indexes'][$key_name] = $cols;
                }
            }
        }

        $foreign_key_info = $this->fetchForeignKeyInfo($table);

        foreach ($foreign_key_info as $row) {
            $key_name = $row['key_name'];
            $cols = $row['cols'];
            $ref_table = $row['ref_table'];

            $def['foreign keys'][$key_name] = [$ref_table, $cols];
        }
        return $def;
    }

    /**
     * Pull the given table properties from INFORMATION_SCHEMA.
     * Most of the good stuff is MySQL extensions.
     *
     * @param $table
     * @param $props
     * @return array
     * @throws PEAR_Exception
     * @throws SchemaTableMissingException
     */
    public function getTableProperties($table, $props)
    {
        $data = $this->fetchMetaInfo($table, 'TABLES');
        if ($data) {
            return $data[0];
        } else {
            throw new SchemaTableMissingException("No such table: $table");
        }
    }

    /**
     * Pull some INFORMATION.SCHEMA data for the given table.
     *
     * @param string $table
     * @param $infoTable
     * @param null $orderBy
     * @return array of arrays
     * @throws PEAR_Exception
     */
    public function fetchMetaInfo($table, $infoTable, $orderBy = null)
    {
        $schema = $this->conn->getDatabase();
        $info = $this->fetchQueryData(sprintf(
            <<<'END'
            SELECT * FROM INFORMATION_SCHEMA.%1$s
              WHERE TABLE_SCHEMA = '%2$s' AND TABLE_NAME = '%3$s'%4$s;
            END,
            $this->quoteIdentifier($infoTable),
            $schema,
            $table,
            ($orderBy ? " ORDER BY {$orderBy}" : '')
        ));

        return array_map(function (array $cols): array {
            return array_change_key_case($cols, CASE_UPPER);
        }, $info);
    }

    /**
     * Pull index and keys information for the given table.
     *
     * @param string $table
     * @return array of arrays
     * @throws PEAR_Exception
     */
    private function fetchKeyInfo(string $table): array
    {
        $schema = $this->conn->getDatabase();
        $data = $this->fetchQueryData(
            <<<EOT
            SELECT INDEX_NAME AS `key_name`,
                CASE
                  WHEN INDEX_NAME = 'PRIMARY' THEN 'PRIMARY'
                  WHEN NON_UNIQUE IS NOT TRUE THEN 'UNIQUE'
                  ELSE INDEX_TYPE
                END AS `key_type`,
                COLUMN_NAME AS `col`,
                SUB_PART AS `col_length`
              FROM INFORMATION_SCHEMA.STATISTICS
              WHERE TABLE_SCHEMA = '{$schema}' AND TABLE_NAME = '{$table}'
              ORDER BY `key_name`, `key_type`, SEQ_IN_INDEX;
            EOT
        );

        $rows = [];
        foreach ($data as $row) {
            $name = $row['key_name'];

            if (!is_null($row['col_length'])) {
                $row['col'] = [$row['col'], (int) $row['col_length']];
            }
            unset($row['col_length']);

            if (!array_key_exists($name, $rows)) {
                $row['cols'] = [$row['col']];

                unset($row['col']);
                $rows[$name] = $row;
            } else {
                $rows[$name]['cols'][] = $row['col'];
            }
        }

        return array_values($rows);
    }

    /**
     * Pull foreign key information for the given table.
     *
     * @param string $table
     * @return array array of arrays
     * @throws PEAR_Exception
     */
    private function fetchForeignKeyInfo(string $table): array
    {
        $schema = $this->conn->getDatabase();
        $data = $this->fetchQueryData(
            <<<END
            SELECT CONSTRAINT_NAME AS `key_name`,
                COLUMN_NAME AS `col`,
                REFERENCED_TABLE_NAME AS `ref_table`,
                REFERENCED_COLUMN_NAME AS `ref_col`
              FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
              WHERE TABLE_SCHEMA = '{$schema}'
              AND TABLE_NAME = '{$table}'
              AND REFERENCED_TABLE_SCHEMA = '{$schema}'
              ORDER BY `key_name`, ORDINAL_POSITION;
            END
        );

        $rows = [];
        foreach ($data as $row) {
            $name = $row['key_name'];

            if (!array_key_exists($name, $rows)) {
                $row['cols'] = [$row['col'] => $row['ref_col']];

                unset($row['col']);
                unset($row['ref_col']);
                $rows[$name] = $row;
            } else {
                $rows[$name]['cols'][$row['col']] = $row['ref_col'];
            }
        }

        return array_values($rows);
    }

    /**
     * Append an SQL statement with an index definition for a full-text search
     * index over one or more columns on a table.
     *
     * @param array $statements
     * @param string $table
     * @param string $name
     * @param array $def
     */
    public function appendCreateFulltextIndex(array &$statements, $table, $name, array $def)
    {
        $statements[] = "CREATE FULLTEXT INDEX $name ON $table " . $this->buildIndexList($def);
    }

    /**
     * Append an SQL statement with an index definition for an advisory
     * index over one or more columns on a table.
     *
     * @param array $statements
     * @param string $table
     * @param string $name
     * @param array $def
     */
    public function appendCreateIndex(array &$statements, $table, $name, array $def)
    {
        $statements[] = "ALTER TABLE {$this->quoteIdentifier($table)} "
                      . "ADD INDEX {$name} {$this->buildIndexList($def)}";
    }

    /**
     * Close out a 'create table' SQL statement.
     *
     * @param string $name
     * @param array $def
     *
     * @return string
     */
    public function endCreateTable($name, array $def)
    {
        $engine = self::storageEngine($def);
        $charset = self::charset();
        return ") ENGINE '{$engine}' "
             . "DEFAULT CHARACTER SET '{$charset}' "
             . "DEFAULT COLLATE '{$charset}_bin'";
    }

    /**
     * Returns the character set of choice for MariaDB.
     * Overrides default standard "UTF8".
     *
     * @return string
     */
    public static function charset(): string
    {
        return 'utf8mb4';
    }

    /**
     * Returns the storage engine of choice for the supplied definition.
     *
     * @param array $def
     * @return string
     */
    protected static function storageEngine(array $def): string
    {
        return 'InnoDB';
    }

    /**
     * Append phrase(s) to an array of partial ALTER TABLE chunks in order
     * to alter the given column from its old state to a new one.
     *
     * @param array $phrase
     * @param string $columnName
     * @param array $old previous column definition as found in DB
     * @param array $cd current column definition
     */
    public function appendAlterModifyColumn(
        array &$phrase,
        string $columnName,
        array  $old,
        array  $cd
    ): void {
        $phrase[] = 'MODIFY COLUMN ' . $this->quoteIdentifier($columnName)
                  . ' ' . $this->columnSql($columnName, $cd);
    }

    /**
     * MySQL doesn't take 'DROP CONSTRAINT', need to treat primary keys as
     * if they were indexes here, but can use 'PRIMARY KEY' special name.
     *
     * @param array $phrase
     */
    public function appendAlterDropPrimary(array &$phrase, string $tableName)
    {
        $phrase[] = 'DROP PRIMARY KEY';
    }

    /**
     * MySQL doesn't take 'DROP CONSTRAINT', need to treat unique keys as
     * if they were indexes here.
     *
     * @param array $phrase
     * @param string $keyName MySQL
     */
    public function appendAlterDropUnique(array &$phrase, $keyName)
    {
        $phrase[] = 'DROP INDEX ' . $keyName;
    }

    public function appendAlterDropForeign(array &$phrase, $keyName)
    {
        $phrase[] = 'DROP FOREIGN KEY ' . $keyName;
    }

    /**
     * Throw some table metadata onto the ALTER TABLE if we have a mismatch
     * in expected type, collation.
     * @param array $phrase
     * @param $tableName
     * @param array $def
     * @throws Exception
     */
    public function appendAlterExtras(array &$phrase, $tableName, array $def)
    {
        // Check for table properties: make sure we are using sane
        // storage engine, character set and collation.
        $oldProps = $this->getTableProperties($tableName, ['ENGINE', 'TABLE_COLLATION']);
        $engine = self::storageEngine($def);
        $charset = self::charset();
        if (mb_strtolower($oldProps['ENGINE']) !== mb_strtolower($engine)) {
            $phrase[] = "ENGINE '{$engine}'";
        }
        if (strtolower($oldProps['TABLE_COLLATION']) !== "{$charset}_bin") {
            $phrase[] = "CONVERT TO CHARACTER SET '{$charset} COLLATE '{$charset}_bin'";
            $phrase[] = "DEFAULT CHARACTER SET '{$charset}'";
            $phrase[] = "DEFAULT COLLATE '{$charset}_bin'";
        }
    }

    /**
     * Append an SQL statement to drop an index from a table.
     * Note that in MariaDB index names are relation-specific.
     *
     * @param array $statements
     * @param string $table
     * @param string $name
     */
    public function appendDropIndex(array &$statements, $table, $name)
    {
        $statements[] = "ALTER TABLE {$this->quoteIdentifier($table)} "
                      . "DROP INDEX {$name}";
    }

    private function isNumericType(array $cd): bool
    {
        $ints = array_map(
            function ($s) {
                return $s . 'int';
            },
            ['tiny', 'small', 'medium', 'big']
        );
        $ints = array_merge($ints, ['int', 'numeric', 'serial']);
        return in_array(strtolower($cd['type']), $ints);
    }

    /**
     * Return the proper SQL for creating or
     * altering a column.
     *
     * Appropriate for use in CREATE TABLE or
     * ALTER TABLE statements.
     *
     * @param string $name column name to create
     * @param array $cd column to create
     *
     * @return string correct SQL for that column
     */
    public function columnSql(string $name, array $cd)
    {
        $line = [];
        $line[] = parent::columnSql($name, $cd);

        // This'll have been added from our transform of "serial" type
        if (!empty($cd['auto_increment'])) {
            $line[] = 'AUTO_INCREMENT';
        }

        if (!empty($cd['description'])) {
            $line[] = 'COMMENT';
            $line[] = $this->quoteValue($cd['description']);
        }

        return implode(' ', $line);
    }

    public function mapType($column)
    {
        $map = [
            'integer' => 'int',
            'numeric' => 'decimal',
            'blob'    => 'longblob',
        ];

        $type = $column['type'];
        if (array_key_exists($type, $map)) {
            $type = $map[$type];
        }

        $size = $column['size'] ?? null;
        switch ($type) {
            case 'int':
                if (in_array($size, ['tiny', 'small', 'medium', 'big'])) {
                    $type = $size . $type;
                }
                break;
            case 'float':
                if ($size === 'big') {
                    $type = 'double';
                }
                break;
            case 'text':
                if (in_array($size, ['tiny', 'medium', 'long'])) {
                    $type = $size . $type;
                }
                break;
        }

        return $type;
    }

    /**
     * Collation in MariaDB format from our format
     *
     * @param string $collate
     * @return string
     */
    protected function collationToMySQL(string $collate): string
    {
        if (!in_array($collate, [
            'utf8_bin',
            'utf8_general_cs',
            'utf8_general_ci',
        ])) {
            common_log(
                LOG_ERR,
                'Collation not supported: "' . $collate . '"'
            );
            $collate = 'utf8_bin';
        }

        if (substr($collate, 0, 13) === 'utf8_general_') {
            $collate = 'utf8mb4_unicode_' . substr($collate, 13);
        } elseif (substr($collate, 0, 5) === 'utf8_') {
            $collate = 'utf8mb4_' . substr($collate, 5);
        }
        return $collate;
    }

    public function typeAndSize(string $name, array $column)
    {
        if ($column['type'] === 'enum') {
            $vals = [];
            foreach ($column['enum'] as &$val) {
                $vals[] = "'{$val}'";
            }
            return 'ENUM(' . implode(',', $vals) . ')';
        } elseif ($this->isStringType($column)) {
            $col = parent::typeAndSize($name, $column);
            if (!empty($column['collate'])) {
                $col .= " COLLATE '{$column['collate']}'";
            }
            return $col;
        } else {
            return parent::typeAndSize($name, $column);
        }
    }

    /**
     * Filter the given table definition array to match features available
     * in this database.
     *
     * This lets us strip out unsupported things like comments, foreign keys,
     * or type variants that we wouldn't get back from getTableDef().
     *
     * @param string $tableName
     * @param array $tableDef
     * @return array
     */
    public function filterDef(string $tableName, array $tableDef)
    {
        $tableDef = parent::filterDef($tableName, $tableDef);

        foreach ($tableDef['fields'] as $name => &$col) {
            switch ($col['type']) {
                case 'serial':
                    $col['type'] = 'int';
                    $col['auto_increment'] = true;
                    break;
                case 'bool':
                    $col['type'] = 'int';
                    $col['size'] = 'tiny';
                    $col['default'] = (int) $col['default'];
                    break;
            }

            if (!empty($col['collate'])) {
                $col['collate'] = $this->collationToMySQL($col['collate']);
            }

            $col['type'] = $this->mapType($col);
            unset($col['size']);
        }
        return $tableDef;
    }
}


code:
<?php
// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Database schema for PostgreSQL
 *
 * @category  Database
 * @package   GNUsocial
 * @author    Evan Prodromou <evan@status.net>
 * @author    Brenda Wallace <shiny@cpan.org>
 * @author    Brion Vibber <brion@status.net>
 * @copyright 2019 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */

defined('GNUSOCIAL') || die();

/**
 * Class representing the database schema for PostgreSQL
 *
 * A class representing the database schema. Can be used to
 * manipulate the schema -- especially for plugins and upgrade
 * utilities.
 *
 * @copyright 2019 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */
class PgsqlSchema extends Schema
{
    public static $_single = null;

    /**
     * Main public entry point. Use this to get
     * the singleton object.
     *
     * @param object|null $conn
     * @param string|null dummy param
     * @return Schema the (single) Schema object
     */
    public static function get($conn = null, $_ = 'pgsql')
    {
        if (empty(self::$_single)) {
            self::$_single = new Schema($conn, 'pgsql');
        }
        return self::$_single;
    }

    /**
     * Returns a table definition array for the table
     * in the schema with the given name.
     *
     * Throws an exception if the table is not found.
     *
     * @param string $table Name of the table to get
     *
     * @return array tabledef for that table.
     * @throws SchemaTableMissingException
     */
    public function getTableDef($table)
    {
        $def = [];
        $hasKeys = false;

        // Pull column data from INFORMATION_SCHEMA
        $columns = $this->fetchMetaInfo($table, 'columns', 'ordinal_position');
        if (count($columns) == 0) {
            throw new SchemaTableMissingException("No such table: $table");
        }

        // Get information on the emulated "enum" type
        $enum_info = $this->fetchEnumInfo($table);

        foreach ($columns as $row) {
            $name = $row['column_name'];

            $field = [];
            $field['type'] = $type = $row['udt_name'];

            if (in_array($type, ['char', 'bpchar', 'varchar'])) {
                if ($row['character_maximum_length'] !== null) {
                    $field['length'] = intval($row['character_maximum_length']);
                }
            }
            if ($type == 'numeric') {
                // Other int types may report these values, but they're irrelevant.
                // Just ignore them!
                if ($row['numeric_precision'] !== null) {
                    $field['precision'] = intval($row['numeric_precision']);
                }
                if ($row['numeric_scale'] !== null) {
                    $field['scale'] = intval($row['numeric_scale']);
                }
            }
            if ($row['is_nullable'] == 'NO') {
                $field['not null'] = true;
            }
            $col_default = $row['column_default'];
            if (!is_null($col_default)) {
                if ($this->isNumericType($field)) {
                    $field['default'] = (int) $col_default;
                } elseif ($type === 'bool') {
                    $field['default'] = ($col_default === 'true') ? true : false;
                } else {
                    $match = "/^'(.*)'(::.+)*$/";
                    if (preg_match($match, $col_default)) {
                        $field['default'] = preg_replace(
                            $match,
                            '\1',
                            $col_default
                        );
                    } else {
                        $field['default'] = $col_default;
                    }
                }
            }
            if (
                $row['is_identity'] === 'YES'
                && $row['identity_generation'] = 'BY DEFAULT'
            ) {
                $field['auto_increment'] = true;
            } elseif (array_key_exists($name, $enum_info)) {
                $field['enum'] = $enum_info[$name];
            }

            if (!empty($row['collation_name'])) {
                $field['collate'] = $row['collation_name'];
            }

            $def['fields'][$name] = $field;
        }

        $key_info = $this->fetchKeyInfo($table);

        foreach ($key_info as $row) {
            $key_name = $row['key_name'];
            $cols = $row['cols'];

            switch ($row['key_type']) {
                case 'primary':
                    $def['primary key'] = $cols;
                    break;
                case 'unique':
                    $def['unique keys'][$key_name] = $cols;
                    break;
                case 'gin':
                    // @fixme Way too magical.
                    $cols = array_values(preg_grep(
                        '/^(.+(\(|\)).+|\s*)$/',
                        preg_split('(COALESCE\(|,)', $cols[0]),
                        PREG_GREP_INVERT
                    ));
                    $def['fulltext indexes'][$key_name] = $cols;
                    break;
                default:
                    $def['indexes'][$key_name] = $cols;
            }
        }

        $foreign_key_info = $this->fetchForeignKeyInfo($table);

        foreach ($foreign_key_info as $row) {
            $key_name = $row['key_name'];
            $cols = $row['cols'];
            $ref_table = $row['ref_table'];

            $def['foreign keys'][$key_name] = [$ref_table, $cols];
        }

        return $def;
    }

    /**
     * Pull some INFORMATION.SCHEMA data for the given table.
     *
     * @param string $table
     * @param $infoTable
     * @param null $orderBy
     * @return array of arrays
     * @throws PEAR_Exception
     */
    public function fetchMetaInfo($table, $infoTable, $orderBy = null)
    {
        $catalog = $this->conn->getDatabase();
        $info = $this->fetchQueryData(sprintf(
            <<<'END'
            SELECT * FROM information_schema.%1$s
              WHERE table_catalog = '%2$s' AND table_name = '%3$s'%4$s;
            END,
            $this->quoteIdentifier($infoTable),
            $catalog,
            $table,
            ($orderBy ? " ORDER BY {$orderBy}" : '')
        ));

        return array_map(function (array $cols): array {
            return array_change_key_case($cols, CASE_LOWER);
        }, $info);
    }

    /**
     * Pull index and keys information for the given table.
     *
     * @param string $table
     * @return array of arrays
     * @throws PEAR_Exception
     */
    private function fetchKeyInfo(string $table): array
    {
        $data = $this->fetchQueryData(sprintf(
            <<<'EOT'
            SELECT "rel"."relname" AS "key_name",
                CASE
                  WHEN "idx"."indisprimary" IS TRUE THEN 'primary'
                  WHEN "idx"."indisunique"  IS TRUE THEN 'unique'
                  ELSE "am"."amname"
                END AS "key_type",
                CASE
                  WHEN "cols"."attname" IS NOT NULL THEN "cols"."attname"
                  ELSE pg_get_indexdef("idx"."indexrelid",
                                       CAST("col_nums"."pos" AS INTEGER),
                                       TRUE)
                END AS "col"
              FROM pg_index AS "idx"
              CROSS JOIN LATERAL unnest("idx"."indkey")
              WITH ORDINALITY AS "col_nums" ("num", "pos")
              INNER JOIN pg_class AS "rel"
              ON "idx"."indexrelid" = "rel".oid
              LEFT JOIN pg_attribute AS "cols"
              ON "idx"."indrelid" = "cols"."attrelid"
              AND "col_nums"."num" = "cols"."attnum"
              LEFT JOIN pg_am AS "am"
              ON "rel"."relam" = "am".oid
              WHERE "idx"."indrelid" = CAST('%s' AS REGCLASS)
              ORDER BY "key_type", "key_name", "col_nums"."pos";
            EOT,
            $table
        ));

        $rows = [];
        foreach ($data as $row) {
            $name = $row['key_name'];

            if (!array_key_exists($name, $rows)) {
                $row['cols'] = [$row['col']];

                unset($row['col']);
                $rows[$name] = $row;
            } else {
                $rows[$name]['cols'][] = $row['col'];
            }
        }

        return array_values($rows);
    }

    /**
     * Pull foreign key information for the given table.
     *
     * @param string $table
     * @return array array of arrays
     * @throws PEAR_Exception
     */
    private function fetchForeignKeyInfo(string $table): array
    {
        $data = $this->fetchQueryData(sprintf(
            <<<'END'
            SELECT "con"."conname" AS "key_name",
                "cols"."attname" AS "col",
                "ref_rel"."relname" AS "ref_table",
                "ref_cols"."attname" AS "ref_col"
              FROM pg_constraint AS "con"
              CROSS JOIN LATERAL unnest("con"."conkey", "con"."confkey")
              WITH ORDINALITY AS "col_nums" ("num", "ref_num", "pos")
              LEFT JOIN pg_attribute AS "cols"
              ON "con"."conrelid" = "cols"."attrelid"
              AND "col_nums"."num" = "cols"."attnum"
              LEFT JOIN pg_class AS "ref_rel"
              ON "con"."confrelid" = "ref_rel".oid
              LEFT JOIN pg_attribute AS "ref_cols"
              ON "con"."confrelid" = "ref_cols"."attrelid"
              AND "col_nums"."ref_num" = "ref_cols"."attnum"
              WHERE "con"."contype" = 'f'
              AND "con"."conrelid" = CAST('%s' AS REGCLASS)
              ORDER BY "key_name", "col_nums"."pos";
            END,
            $table
        ));

        $rows = [];
        foreach ($data as $row) {
            $name = $row['key_name'];

            if (!array_key_exists($name, $rows)) {
                $row['cols'] = [$row['col'] => $row['ref_col']];

                unset($row['col']);
                unset($row['ref_col']);
                $rows[$name] = $row;
            } else {
                $rows[$name]['cols'][$row['col']] = $row['ref_col'];
            }
        }

        return array_values($rows);
    }

    /**
     * Pull information about the emulated enum columns
     *
     * @param string $table
     * @return array of arrays
     * @throws PEAR_Exception
     */
    private function fetchEnumInfo($table)
    {
        $data = $this->fetchQueryData(
            <<<END
            SELECT "cols"."attname" AS "col", "con"."consrc" AS "check"
              FROM pg_constraint AS "con"
              INNER JOIN pg_attribute AS "cols"
              ON "con"."conrelid" = "cols"."attrelid"
              AND "con"."conkey"[1] = "cols"."attnum"
              WHERE "cols".atttypid = CAST('text' AS REGTYPE)
              AND "con"."contype" = 'c'
              AND cardinality("con"."conkey") = 1
              AND "con"."conrelid" = CAST('{$table}' AS REGCLASS);
            END
        );

        $rows = [];
        foreach ($data as $row) {
            // PostgreSQL can show either
            $name_regex = '(' . preg_quote($this->quoteIdentifier($row['col']))
                        . '|' . preg_quote($row['col']) . ')';

            $enum = explode("'::text, '", preg_replace(
                "/^\({$name_regex} = ANY \(ARRAY\['(.+)'::text]\)\)$/D",
                '\2',
                $row['check']
            ));
            $rows[$row['col']] = $enum;
        }
        return $rows;
    }

    private function isNumericType(array $cd): bool
    {
        $ints = ['int', 'numeric', 'serial'];
        return in_array(strtolower($cd['type']), $ints);
    }

    /**
     * Return the proper SQL for creating or
     * altering a column.
     *
     * Appropriate for use in CREATE TABLE or
     * ALTER TABLE statements.
     *
     * @param string $name column name to create
     * @param array $cd column to create
     *
     * @return string correct SQL for that column
     */
    public function columnSql(string $name, array $cd)
    {
        $line = [];
        $line[] = parent::columnSql($name, $cd);

        // This'll have been added from our transform of 'serial' type
        if (!empty($cd['auto_increment'])) {
            $line[] = 'GENERATED BY DEFAULT AS IDENTITY';
        } elseif (!empty($cd['enum'])) {
            foreach ($cd['enum'] as &$val) {
                $vals[] = "'" . $val . "'";
            }
            $line[] = 'CHECK (' . $name . ' IN (' . implode(',', $vals) . '))';
        }

        return implode(' ', $line);
    }

    public function appendAlterDropPrimary(array &$phrase, string $tableName)
    {
        // name hack -- is this reliable?
        $phrase[] = 'DROP CONSTRAINT ' . $this->quoteIdentifier($tableName . '_pkey');
    }

    public function buildFulltextIndexList($table, array $def)
    {
        foreach ($def as &$val) {
            $cols[] = $this->buildFulltextIndexItem($table, $val);
        }

        return "(to_tsvector('english', " . implode(" || ' ' || ", $cols) . '))';
    }

    public function buildFulltextIndexItem($table, $def)
    {
        return sprintf(
            "COALESCE(%s.%s, '')",
            $this->quoteIdentifier($table),
            $def
        );
    }

    public function mapType($column)
    {
        $map = [
            'integer'  => 'int',
            'char'     => 'bpchar',
            'datetime' => 'timestamp',
            'enum'     => 'text',
            'blob'     => 'bytea'
        ];

        $type = $column['type'];
        if (array_key_exists($type, $map)) {
            $type = $map[$type];
        }

        $size = $column['size'] ?? null;
        switch ($type) {
            case 'int':
                if (in_array($size, ['tiny', 'small'])) {
                    $type = 'int2';
                } elseif ($size === 'big') {
                    $type = 'int8';
                } else {
                    $type = 'int4';
                }
                break;
            case 'float':
                $type = ($size !== 'big') ? 'float4' : 'float8';
                break;
        }

        return $type;
    }

    /**
     * Collation in PostgreSQL format from our format
     *
     * @param string $collate
     * @return string
     */
    protected function collationToPostgreSQL(string $collate): string
    {
        if (!in_array($collate, [
            'utf8_bin',
            'utf8_general_cs',
            'utf8_general_ci',
        ])) {
            common_log(
                LOG_ERR,
                'Collation not supported: "' . $collate . '"'
            );
            $collate = 'utf8_bin';
        }

        // @fixme No case-insensitivity support
        if (substr($collate, 0, 13) === 'utf8_general_') {
            $collate = 'und-x-icu';
        } elseif (substr($collate, 0, 8) === 'utf8_bin') {
            $collate = 'C';
        }

        return $collate;
    }

    public function typeAndSize(string $name, array $column)
    {
        $col = parent::typeAndSize($name, $column);

        if ($this->isStringType($column)) {
            if (!empty($column['collate'])) {
                $col .= ' COLLATE "' . $column['collate'] . '"';
            }
        }

        return $col;
    }

    /**
     * Append an SQL statement with an index definition for a full-text search
     * index over one or more columns on a table.
     *
     * @param array $statements
     * @param string $table
     * @param string $name
     * @param array $def
     */
    public function appendCreateFulltextIndex(array &$statements, $table, $name, array $def)
    {
        $statements[] = "CREATE INDEX {$name} ON {$table} USING gin "
                      . $this->buildFulltextIndexList($table, $def);
    }

    /**
     * Filter the given table definition array to match features available
     * in this database.
     *
     * This lets us strip out unsupported things like comments, foreign keys,
     * or type variants that we wouldn't get back from getTableDef().
     *
     * @param string $tableName
     * @param array $tableDef
     * @return array
     */
    public function filterDef(string $tableName, array $tableDef)
    {
        $tableDef = parent::filterDef($tableName, $tableDef);

        foreach ($tableDef['fields'] as $name => &$col) {
            // No convenient support for field descriptions
            unset($col['description']);

            if ($col['type'] === 'serial') {
                $col['type'] = 'int';
                $col['auto_increment'] = true;
            }

            if (!empty($col['collate'])) {
                $col['collate'] = $this->collationToPostgreSQL($col['collate']);
            }

            $col['type'] = $this->mapType($col);
            unset($col['size']);
        }

        if (!empty($tableDef['primary key'])) {
            $tableDef['primary key'] = $this->filterKeyDef($tableDef['primary key']);
        }
        foreach (['unique keys', 'indexes'] as $type) {
            if (!empty($tableDef[$type])) {
                foreach ($tableDef[$type] as $k => $def) {
                    $tableDef[$type][$k] = $this->filterKeyDef($def);
                }
            }
        }
        return $tableDef;
    }

    /**
     * Filter the given key/index definition to match features available
     * in this database.
     *
     * @param array $def
     * @return array
     */
    public function filterKeyDef(array $def)
    {
        // PostgreSQL doesn't like prefix lengths specified on keys...?
        foreach ($def as $i => $item) {
            if (is_array($item)) {
                $def[$i] = $item[0];
            }
        }
        return $def;
    }
}

repo_name: ksuudilla/gnu

license: mit


code:
<?php
// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Database schema
 *
 * @category  Database
 * @package   GNUsocial
 * @author    Evan Prodromou <evan@status.net>
 * @author    Brion Vibber <brion@status.net>
 * @copyright 2019 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */

defined('GNUSOCIAL') || die();

/**
 * Class representing the database schema
 *
 * A class representing the database schema. Can be used to
 * manipulate the schema -- especially for plugins and upgrade
 * utilities.
 *
 * @copyright 2019 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */
class Schema
{
    public static $_static = null;
    protected $conn = null;

    /**
     * Constructor. Only run once for singleton object.
     * @param null $conn
     */
    protected function __construct($conn = null)
    {
        if (is_null($conn)) {
            // XXX: there should be an easier way to do this.
            $user = new User();
            $conn = $user->getDatabaseConnection();
            $user->free();
            unset($user);
        }

        $this->conn = $conn;
    }

    /**
     * Main public entry point. Use this to get
     * the schema object.
     *
     * @param object|null $conn
     * @param string|null Force a database type (necessary for installation purposes in which we don't have a config.php)
     * @return Schema the Schema object for the connection
     */
    public static function get($conn = null, $dbtype = null)
    {
        if (is_null($conn)) {
            $key = 'default';
        } else {
            $key = hash('md5', $conn->getDSN('string'));
        }

        if (is_null($dbtype)) {
            $dbtype = common_config('db', 'type');
        }
        if (empty(self::$_static[$key])) {
            $schemaClass = ucfirst($dbtype) . 'Schema';
            self::$_static[$key] = new $schemaClass($conn);
        }
        return self::$_static[$key];
    }

    /**
     * Gets a ColumnDef object for a single column.
     *
     * Throws an exception if the table is not found.
     *
     * @param string $table name of the table
     * @param string $column name of the column
     *
     * @return ColumnDef definition of the column or null
     *                   if not found.
     */
    public function getColumnDef($table, $column)
    {
        $td = $this->getTableDef($table);

        if (!empty($td) && !empty($td->columns)) {
            foreach ($td->columns as $cd) {
                if ($cd->name == $column) {
                    return $cd;
                }
            }
        }

        return null;
    }

    /**
     * Creates a table with the given names and columns.
     *
     * @param string $tableName Name of the table
     * @param array $def Table definition array listing fields and indexes.
     *
     * @return bool success flag
     * @throws PEAR_Exception
     */
    public function createTable($tableName, $def)
    {
        $statements = $this->buildCreateTable($tableName, $def);
        return $this->runSqlSet($statements);
    }

    /**
     * Build a set of SQL statements to create a table with the given
     * name and columns.
     *
     * @param string $name Name of the table
     * @param array $def Table definition array
     *
     * @return array success flag
     * @throws Exception
     */
    public function buildCreateTable($name, $def)
    {
        $def = $this->validateDef($name, $def);
        $def = $this->filterDef($name, $def);
        $sql = [];

        foreach ($def['fields'] as $col => $colDef) {
            $this->appendColumnDef($sql, $col, $colDef);
        }

        // Primary, unique, and foreign keys are constraints, so go within
        // the CREATE TABLE statement normally.
        if (!empty($def['primary key'])) {
            $this->appendPrimaryKeyDef($sql, $def['primary key']);
        }

        if (!empty($def['unique keys'])) {
            foreach ($def['unique keys'] as $col => $colDef) {
                $this->appendUniqueKeyDef($sql, $col, $colDef);
            }
        }

        if (!empty($def['foreign keys'])) {
            foreach ($def['foreign keys'] as $keyName => $keyDef) {
                $this->appendForeignKeyDef($sql, $keyName, $keyDef);
            }
        }

        // Wrap the CREATE TABLE around the main body chunks...
        $statements = [];
        $statements[] = $this->startCreateTable($name, $def) . "\n" .
            implode(",\n", $sql) . "\n" .
            $this->endCreateTable($name, $def);

        // Multi-value indexes are advisory and for best portability
        // should be created as separate statements.
        if (!empty($def['indexes'])) {
            foreach ($def['indexes'] as $col => $colDef) {
                $this->appendCreateIndex($statements, $name, $col, $colDef);
            }
        }
        if (!empty($def['fulltext indexes'])) {
            foreach ($def['fulltext indexes'] as $col => $colDef) {
                $this->appendCreateFulltextIndex($statements, $name, $col, $colDef);
            }
        }

        return $statements;
    }

    /**
     * Set up a 'create table' SQL statement.
     *
     * @param string $name table name
     * @param array $def table definition
     * @return string
     */
    public function startCreateTable($name, array $def)
    {
        return 'CREATE TABLE ' . $this->quoteIdentifier($name) . ' (';
    }

    /**
     * Close out a 'create table' SQL statement.
     *
     * @param string $name table name
     * @param array $def table definition
     * @return string
     */
    public function endCreateTable($name, array $def)
    {
        return ')';
    }

    /**
     * Append an SQL fragment with a column definition in a CREATE TABLE statement.
     *
     * @param array $sql
     * @param string $name
     * @param array $def
     */
    public function appendColumnDef(array &$sql, string $name, array $def)
    {
        $sql[] = $name . ' ' . $this->columnSql($name, $def);
    }

    /**
     * Append an SQL fragment with a constraint definition for a primary
     * key in a CREATE TABLE statement.
     *
     * @param array $sql
     * @param array $def
     */
    public function appendPrimaryKeyDef(array &$sql, array $def)
    {
        $sql[] = "PRIMARY KEY " . $this->buildIndexList($def);
    }

    /**
     * Append an SQL fragment with a constraint definition for a unique
     * key in a CREATE TABLE statement.
     *
     * @param array $sql
     * @param string $name
     * @param array $def
     */
    public function appendUniqueKeyDef(array &$sql, $name, array $def)
    {
        $sql[] = "CONSTRAINT $name UNIQUE " . $this->buildIndexList($def);
    }

    /**
     * Append an SQL fragment with a constraint definition for a foreign
     * key in a CREATE TABLE statement.
     *
     * @param array $sql
     * @param string $name
     * @param array $def
     * @throws Exception
     */
    public function appendForeignKeyDef(array &$sql, $name, array $def)
    {
        if (count($def) != 2) {
            throw new Exception("Invalid foreign key def for $name: " . var_export($def, true));
        }
        list($refTable, $map) = $def;
        $srcCols = array_keys($map);
        $refCols = array_values($map);
        $sql[] = 'CONSTRAINT ' . $this->quoteIdentifier($name) . ' FOREIGN KEY ' .
            $this->buildIndexList($srcCols) .
            ' REFERENCES ' .
            $this->quoteIdentifier($refTable) .
            ' ' .
            $this->buildIndexList($refCols);
    }

    /**
     * Append an SQL statement with an index definition for an advisory
     * index over one or more columns on a table.
     *
     * @param array $statements
     * @param string $table
     * @param string $name
     * @param array $def
     */
    public function appendCreateIndex(array &$statements, $table, $name, array $def)
    {
        $statements[] = 'CREATE INDEX ' . $name . ' ON ' .
                        $this->quoteIdentifier($table) . ' ' . $this->buildIndexList($def);
    }

    /**
     * Append an SQL statement with an index definition for a full-text search
     * index over one or more columns on a table.
     *
     * @param array $statements
     * @param string $table
     * @param string $name
     * @param array $def
     * @throws Exception
     */
    public function appendCreateFulltextIndex(array &$statements, $table, $name, array $def)
    {
        throw new Exception("Fulltext index not supported in this database");
    }

    /**
     * Append an SQL statement to drop an index from a table.
     *
     * @param array $statements
     * @param string $table
     * @param string $name
     */
    public function appendDropIndex(array &$statements, $table, $name)
    {
        $statements[] = "DROP INDEX {$name}";
    }

    public function buildIndexList(array $def)
    {
        // @fixme
        return '(' . implode(',', array_map([$this, 'buildIndexItem'], $def)) . ')';
    }

    public function buildIndexItem($def)
    {
        if (is_array($def)) {
            list($name, $size) = $def;
            return $this->quoteIdentifier($name) . '(' . intval($size) . ')';
        }
        return $this->quoteIdentifier($def);
    }

    /**
     * Drops a table from the schema
     *
     * Throws an exception if the table is not found.
     *
     * @param string $name Name of the table to drop
     *
     * @return bool success flag
     * @throws PEAR_Exception
     */
    public function dropTable($name)
    {
        global $_PEAR;

        $res = $this->conn->exec('DROP TABLE ' . $this->quoteIdentifier($name));

        if ($_PEAR->isError($res)) {
            PEAR_ErrorToPEAR_Exception($res);
        }

        return true;
    }

    /**
     * Adds an index to a table.
     *
     * If no name is provided, a name will be made up based
     * on the table name and column names.
     *
     * Throws an exception on database error, esp. if the table
     * does not exist.
     *
     * @param string $table Name of the table
     * @param array $columnNames Name of columns to index
     * @param string $name (Optional) name of the index
     *
     * @return bool success flag
     * @throws PEAR_Exception
     */
    public function createIndex($table, $columnNames, $name = null)
    {
        global $_PEAR;

        $statements = [];

        if (!is_array($columnNames)) {
            $columnNames = [$columnNames];
        }

        if (empty($name)) {
            $name = "{$table}_" . implode("_", $columnNames) . "_idx";
        }

        $this->appendCreateIndex($statements, $table, $name, $columnNames);

        $this->conn->beginTransaction();

        foreach ($statements as $sql) {
            $res = $this->conn->exec($sql);

            if ($_PEAR->isError($res)) {
                $this->conn->rollback();
                PEAR_ErrorToPEAR_Exception($res);
            }
        }

        $this->conn->commit();
        return true;
    }

    /**
     * Drops a named index from a table.
     *
     * @param string $table name of the table the index is on.
     * @param string $name name of the index
     *
     * @return bool success flag
     * @throws PEAR_Exception
     */
    public function dropIndex($table, $name)
    {
        global $_PEAR;

        $statements = [];
        $this->appendDropIndex($statements, $table, $name);

        $this->conn->beginTransaction();

        foreach ($statements as $sql) {
            $res = $this->conn->exec($sql);

            if ($_PEAR->isError($res)) {
                $this->conn->rollback();
                PEAR_ErrorToPEAR_Exception($res);
            }
        }

        $this->conn->commit();
        return true;
    }

    /**
     * Adds a column to a table
     *
     * @param string $table name of the table
     * @param ColumnDef $columndef Definition of the new
     *                             column.
     *
     * @return bool success flag
     * @throws PEAR_Exception
     */
    public function addColumn($table, $columndef)
    {
        global $_PEAR;

        $sql = 'ALTER TABLE ' . $this->quoteIdentifier($table) .
               ' ADD COLUMN ' . $this->columnSql($name, $columndef);

        $res = $this->conn->exec($sql);

        if ($_PEAR->isError($res)) {
            PEAR_ErrorToPEAR_Exception($res);
        }

        return true;
    }

    /**
     * Returns the character set of choice for this DBMS (in practice, UTF-8).
     *
     * @return string
     */
    public static function charset(): string
    {
        return 'UTF8';
    }

    /**
     * Modifies a column in the schema.
     *
     * The name must match an existing column and table.
     * @fixme Relies on MODIFY COLUMN, which is specific to MariaDB/MySQL
     *
     * @param string $table name of the table
     * @param ColumnDef $columndef new definition of the column.
     *
     * @return bool success flag
     * @throws PEAR_Exception
     */
    public function modifyColumn($table, $columndef)
    {
        global $_PEAR;

        $sql = 'ALTER TABLE ' . $this->quoteIdentifier($table) .
               ' MODIFY COLUMN ' . $this->columnSql($name, $columndef);

        $res = $this->conn->exec($sql);

        if ($_PEAR->isError($res)) {
            PEAR_ErrorToPEAR_Exception($res);
        }

        return true;
    }

    /**
     * Drops a column from a table
     *
     * The name must match an existing column.
     *
     * @param string $table name of the table
     * @param string $columnName name of the column to drop
     *
     * @return bool success flag
     * @throws PEAR_Exception
     */
    public function dropColumn($table, $columnName)
    {
        global $_PEAR;

        $sql = 'ALTER TABLE ' . $this->quoteIdentifier($table) .
               ' DROP COLUMN ' . $columnName;

        $res = $this->conn->exec($sql);

        if ($_PEAR->isError($res)) {
            PEAR_ErrorToPEAR_Exception($res);
        }

        return true;
    }

    /**
     * Ensures that a table exists with the given
     * name and the given column definitions.
     *
     * If the table does not yet exist, it will
     * create the table. If it does exist, it will
     * alter the table to match the column definitions.
     *
     * @param string $tableName name of the table
     * @param array $def Table definition array
     *
     * @return bool success flag
     * @throws PEAR_Exception
     */
    public function ensureTable($tableName, $def)
    {
        $statements = $this->buildEnsureTable($tableName, $def);
        return $this->runSqlSet($statements);
    }

    /**
     * Run a given set of SQL commands on the connection in sequence.
     * Empty input is ok.
     *
     * @fixme if multiple statements, wrap in a transaction?
     * @param array $statements
     * @return bool success flag
     * @throws PEAR_Exception
     */
    public function runSqlSet(array $statements)
    {
        global $_PEAR;

        $this->conn->beginTransaction();

        foreach ($statements as $sql) {
            if (defined('DEBUG_INSTALLER')) {
                echo "" . htmlspecialchars($sql) . "
\n";
            }

            $res = $this->conn->exec($sql);

            if ($_PEAR->isError($res)) {
                $this->conn->rollback();
                common_debug('PEAR exception on query: ' . $sql);
                PEAR_ErrorToPEAR_Exception($res);
            }
        }

        $this->conn->commit();
        return true;
    }

    /**
     * Check a table's status, and if needed build a set
     * of SQL statements which change it to be consistent
     * with the given table definition.
     *
     * If the table does not yet exist, statements will
     * be returned to create the table. If it does exist,
     * statements will be returned to alter the table to
     * match the column definitions.
     *
     * @param string $tableName name of the table
     * @param array $def
     * @return array of SQL statements
     * @throws Exception
     */
    public function buildEnsureTable($tableName, array $def)
    {
        try {
            $old = $this->getTableDef($tableName);
        } catch (SchemaTableMissingException $e) {
            return $this->buildCreateTable($tableName, $def);
        }

        // Filter the DB-independent table definition to match the current
        // database engine's features and limitations.
        $def = $this->validateDef($tableName, $def);
        $def = $this->filterDef($tableName, $def);

        $statements = [];
        $fields = $this->diffArrays($old, $def, 'fields');
        $uniques = $this->diffArrays($old, $def, 'unique keys');
        $indexes = $this->diffArrays($old, $def, 'indexes');
        $foreign = $this->diffArrays($old, $def, 'foreign keys');
        $fulltext = $this->diffArrays($old, $def, 'fulltext indexes');

        // Drop any obsolete or modified indexes ahead...
        foreach ($indexes['del'] + $indexes['mod'] as $indexName) {
            $this->appendDropIndex($statements, $tableName, $indexName);
        }

        // Drop any obsolete or modified fulltext indexes ahead...
        foreach ($fulltext['del'] + $fulltext['mod'] as $indexName) {
            $this->appendDropIndex($statements, $tableName, $indexName);
        }

        // For efficiency, we want this all in one
        // query, instead of using our methods.

        $phrase = [];

        foreach ($foreign['del'] + $foreign['mod'] as $keyName) {
            $this->appendAlterDropForeign($phrase, $keyName);
        }

        foreach ($uniques['del'] + $uniques['mod'] as $keyName) {
            $this->appendAlterDropUnique($phrase, $keyName);
        }

        if (isset($old['primary key']) && (!isset($def['primary key']) || $def['primary key'] != $old['primary key'])) {
            $this->appendAlterDropPrimary($phrase, $tableName);
        }

        foreach ($fields['add'] as $columnName) {
            $this->appendAlterAddColumn(
                $phrase,
                $columnName,
                $def['fields'][$columnName]
            );
        }

        foreach ($fields['mod'] as $columnName) {
            $this->appendAlterModifyColumn(
                $phrase,
                $columnName,
                $old['fields'][$columnName],
                $def['fields'][$columnName]
            );
        }

        foreach ($fields['del'] as $columnName) {
            $this->appendAlterDropColumn($phrase, $columnName);
        }

        if (isset($def['primary key']) && (!isset($old['primary key']) || $old['primary key'] != $def['primary key'])) {
            $this->appendAlterAddPrimary($phrase, $def['primary key']);
        }

        foreach ($uniques['mod'] + $uniques['add'] as $keyName) {
            $this->appendAlterAddUnique($phrase, $keyName, $def['unique keys'][$keyName]);
        }

        foreach ($foreign['mod'] + $foreign['add'] as $keyName) {
            $this->appendAlterAddForeign($phrase, $keyName, $def['foreign keys'][$keyName]);
        }

        $this->appendAlterExtras($phrase, $tableName, $def);

        if (count($phrase) > 0) {
            $sql = 'ALTER TABLE ' . $this->quoteIdentifier($tableName) .
                   ' ' . implode(",\n", $phrase);
            $statements[] = $sql;
        }

        // Now create any indexes...
        foreach ($indexes['mod'] + $indexes['add'] as $indexName) {
            $this->appendCreateIndex($statements, $tableName, $indexName, $def['indexes'][$indexName]);
        }

        foreach ($fulltext['mod'] + $fulltext['add'] as $indexName) {
            $colDef = $def['fulltext indexes'][$indexName];
            $this->appendCreateFulltextIndex($statements, $tableName, $indexName, $colDef);
        }

        /*
         * Merges all consecutive ALTER TABLE's into one statement.
         * This is necessary in MariaDB as foreign keys can disallow removal of
         * an index if a replacement isn't provided instantly.
         */
        [$stmts_orig, $statements] = [$statements, []];
        foreach ($stmts_orig as $stmt) {
            $prev = array_slice($statements, -1)[0] ?? '';
            $prefix = "ALTER TABLE {$this->quoteIdentifier($tableName)} ";
            if (mb_substr($stmt, 0, mb_strlen($prefix)) === $prefix
                && mb_substr($prev, 0, mb_strlen($prefix)) === $prefix) {
                $statements[] = array_pop($statements) . ', '
                              . mb_substr($stmt, mb_strlen($prefix));
            } else {
                $statements[] = $stmt;
            }
        }

        return $statements;
    }

    public function diffArrays($oldDef, $newDef, $section, $compareCallback = null)
    {
        $old = isset($oldDef[$section]) ? $oldDef[$section] : [];
        $new = isset($newDef[$section]) ? $newDef[$section] : [];

        $oldKeys = array_keys($old);
        $newKeys = array_keys($new);

        $toadd = array_diff($newKeys, $oldKeys);
        $todrop = array_diff($oldKeys, $newKeys);
        $same = array_intersect($newKeys, $oldKeys);
        $tomod = [];
        $tokeep = [];

        // Find which fields have actually changed definition
        // in a way that we need to tweak them for this DB type.
        foreach ($same as $name) {
            if ($compareCallback) {
                $same = call_user_func($compareCallback, $old[$name], $new[$name]);
            } else {
                $same = ($old[$name] == $new[$name]);
            }
            if ($same) {
                $tokeep[] = $name;
                continue;
            }
            $tomod[] = $name;
        }
        return [
            'add' => $toadd,
            'del' => $todrop,
            'mod' => $tomod,
            'keep' => $tokeep,
            'count' => count($toadd) + count($todrop) + count($tomod)
        ];
    }

    /**
     * Append phrase(s) to an array of partial ALTER TABLE chunks in order
     * to add the given column definition to the table.
     *
     * @param array $phrase
     * @param string $columnName
     * @param array $cd
     */
    public function appendAlterAddColumn(array &$phrase, string $columnName, array $cd)
    {
        $phrase[] = 'ADD COLUMN ' .
            $this->quoteIdentifier($columnName) .
            ' ' .
            $this->columnSql($columnName, $cd);
    }

    /**
     * Append phrase(s) to an array of partial ALTER TABLE chunks in order
     * to alter the given column from its old state to a new one.
     *
     * @param array $phrase
     * @param string $columnName
     * @param array $old previous column definition as found in DB
     * @param array $cd current column definition
     */
    public function appendAlterModifyColumn(
        array &$phrase,
        string $columnName,
        array  $old,
        array  $cd
    ): void {
        $prefix = 'ALTER COLUMN ' . $this->quoteIdentifier($columnName);

        // @fixme TYPE is a PostgreSQL extension
        $oldType = $this->typeAndSize($columnName, $old);
        $newType = $this->typeAndSize($columnName, $cd);
        if ($oldType !== $newType) {
            $phrase[] = $prefix . ' TYPE ' . $newType;
        }

        if (!($old['not null'] ?? false) && ($cd['not null'] ?? false)) {
            $phrase[] = $prefix . ' SET NOT NULL';
        } elseif (($old['not null'] ?? false) && !($cd['not null'] ?? false)) {
            $phrase[] = $prefix . ' DROP NOT NULL';
        }

        if (!is_null($old['default'] ?? null) && is_null($cd['default'] ?? null)) {
            $phrase[] = $prefix . ' DROP DEFAULT';
        } elseif (($old['default'] ?? null) !== ($cd['default'] ?? null)) {
            $phrase[] = $prefix . ' SET DEFAULT ' . $this->quoteDefaultValue($cd);
        }
    }

    /**
     * Append phrase(s) to an array of partial ALTER TABLE chunks in order
     * to drop the given column definition from the table.
     *
     * @param array $phrase
     * @param string $columnName
     */
    public function appendAlterDropColumn(array &$phrase, $columnName)
    {
        $phrase[] = 'DROP COLUMN ' . $this->quoteIdentifier($columnName);
    }

    public function appendAlterAddUnique(array &$phrase, $keyName, array $def)
    {
        $sql = [];
        $sql[] = 'ADD';
        $this->appendUniqueKeyDef($sql, $keyName, $def);
        $phrase[] = implode(' ', $sql);
    }

    public function appendAlterAddForeign(array &$phrase, $keyName, array $def)
    {
        $sql = [];
        $sql[] = 'ADD';
        $this->appendForeignKeyDef($sql, $keyName, $def);
        $phrase[] = implode(' ', $sql);
    }

    public function appendAlterAddPrimary(array &$phrase, array $def)
    {
        $sql = [];
        $sql[] = 'ADD';
        $this->appendPrimaryKeyDef($sql, $def);
        $phrase[] = implode(' ', $sql);
    }

    public function appendAlterDropPrimary(array &$phrase, string $tableName)
    {
        $phrase[] = 'DROP CONSTRAINT PRIMARY KEY';
    }

    public function appendAlterDropUnique(array &$phrase, $keyName)
    {
        $phrase[] = 'DROP CONSTRAINT ' . $keyName;
    }

    public function appendAlterDropForeign(array &$phrase, $keyName)
    {
        $phrase[] = 'DROP CONSTRAINT ' . $keyName;
    }

    public function appendAlterExtras(array &$phrase, $tableName, array $def)
    {
        // no-op
    }

    /**
     * Quote a db/table/column identifier if necessary.
     *
     * @param string $name
     * @return string
     */
    public function quoteIdentifier($name)
    {
        return $this->conn->quoteIdentifier($name);
    }

    public function quoteDefaultValue($cd)
    {
        if (in_array($cd['type'], ['datetime', 'timestamp']) && $cd['default'] === 'CURRENT_TIMESTAMP') {
            return $cd['default'];
        } else {
            return $this->quoteValue($cd['default']);
        }
    }

    public function quoteValue($val)
    {
        // MDB2_Driver_Common::quote changes empty strings to "NULL".
        if ($val === '') {
            return '';
        }
        return $this->conn->quote($val);
    }

    /**
     * Returns the array of names from an array of
     * ColumnDef objects.
     *
     * @param array $cds array of ColumnDef objects
     *
     * @return array strings for name values
     */
    protected function _names($cds)
    {
        $names = [];

        foreach ($cds as $cd) {
            $names[] = $cd->name;
        }

        return $names;
    }

    /**
     * Get a ColumnDef from an array matching
     * name.
     *
     * @param array $cds Array of ColumnDef objects
     * @param string $name Name of the column
     *
     * @return ColumnDef matching item or null if no match.
     */
    protected function _byName($cds, $name)
    {
        foreach ($cds as $cd) {
            if ($cd->name == $name) {
                return $cd;
            }
        }

        return null;
    }

    /**
     * Is this column a string type?
     *
     * @param array $cd
     * @return bool
     */
    protected function isStringType(array $cd): bool
    {
        $strings = ['char', 'varchar', 'text'];
        $strings[] = 'bpchar';  // PostgreSQL
        $strings[] = 'enum';    // MariaDB
        return in_array(strtolower($cd['type']), $strings);
    }

    /**
     * Collation in our format from MariaDB format
     *
     * @param string $collate
     * @return string
     */
    protected function collationFromMySQL(string $collate): string
    {
        if (substr($collate, 0, 8) === 'utf8mb4_') {
            $collate = 'utf8_' . substr($collate, 8);
        }
        if (substr($collate, 0, 13) === 'utf8_unicode_') {
            $collate = 'utf8_general_' . substr($collate, 13);
        }
        if (!in_array($collate, [
            'utf8_bin',
            'utf8_general_cs',
            'utf8_general_ci',
        ])) {
            common_log(
                LOG_ERR,
                'Collation not supported: "' . $collate . '"'
            );
            $collate = 'utf8_bin';
        }
        return $collate;
    }

    /**
     * Return the proper SQL for creating or
     * altering a column.
     *
     * Appropriate for use in CREATE TABLE or
     * ALTER TABLE statements.
     *
     * @param string $name column name to create
     * @param array $cd column to create
     *
     * @return string correct SQL for that column
     */
    public function columnSql(string $name, array $cd)
    {
        $line = [];
        $line[] = $this->typeAndSize($name, $cd);

        if (isset($cd['default'])) {
            $line[] = 'default';
            $line[] = $this->quoteDefaultValue($cd);
        }
        if (!empty($cd['not null'])) {
            $line[] = 'NOT NULL';
        } else {
            $line[] = 'NULL';
        }

        return implode(' ', $line);
    }

    /**
     *
     * @param string $column canonical type name in defs
     * @return string native DB type name
     */
    public function mapType($column)
    {
        return $column;
    }

    public function typeAndSize(string $name, array $column)
    {
        //$type = $this->mapType($column)['type'];
        $type = $column['type'];
        if (isset($column['size'])) {
            $type = $column['size'] . $type;
        }
        $lengths = [];

        if (isset($column['precision'])) {
            $lengths[] = $column['precision'];
            if (isset($column['scale'])) {
                $lengths[] = $column['scale'];
            }
        } elseif (isset($column['length'])) {
            $lengths[] = $column['length'];
        }

        if ($lengths) {
            return $type . '(' . implode(',', $lengths) . ')';
        } else {
            return $type;
        }
    }

    /**
     * Convert an old-style set of ColumnDef objects into the current
     * Drupal-style schema definition array, for backwards compatibility
     * with plugins written for 0.9.x.
     *
     * @param string $tableName
     * @param array $defs : array of ColumnDef objects
     * @return array
     */
    protected function oldToNew($tableName, array $defs)
    {
        $table = [];
        $prefixes = [
            'tiny',
            'small',
            'medium',
            'big',
        ];
        foreach ($defs as $cd) {
            $column = [];
            $column['type'] = $cd->type;
            foreach ($prefixes as $prefix) {
                if (substr($cd->type, 0, strlen($prefix)) == $prefix) {
                    $column['type'] = substr($cd->type, strlen($prefix));
                    $column['size'] = $prefix;
                    break;
                }
            }

            if ($cd->size) {
                if ($cd->type == 'varchar' || $cd->type == 'char') {
                    $column['length'] = $cd->size;
                }
            }
            if (!$cd->nullable) {
                $column['not null'] = true;
            }
            if ($cd->auto_increment) {
                $column['type'] = 'serial';
            }
            if ($cd->default) {
                $column['default'] = $cd->default;
            }
            $table['fields'][$cd->name] = $column;

            if ($cd->key == 'PRI') {
                // If multiple columns are defined as primary key,
                // we'll pile them on in sequence.
                if (!isset($table['primary key'])) {
                    $table['primary key'] = [];
                }
                $table['primary key'][] = $cd->name;
            } elseif ($cd->key === 'MUL') {
                // Individual multiple-value indexes are only per-column
                // using the old ColumnDef syntax.
                $idx = "{$tableName}_{$cd->name}_idx";
                $table['indexes'][$idx] = [$cd->name];
            } elseif ($cd->key === 'UNI') {
                // Individual unique-value indexes are only per-column
                // using the old ColumnDef syntax.
                $idx = "{$tableName}_{$cd->name}_idx";
                $table['unique keys'][$idx] = [$cd->name];
            }
        }

        return $table;
    }

    /**
     * Filter the given table definition array to match features available
     * in this database.
     *
     * This lets us strip out unsupported things like comments, foreign keys,
     * or type variants that we wouldn't get back from getTableDef().
     *
     * @param string $tableName
     * @param array $tableDef
     * @return array
     */
    public function filterDef(string $tableName, array $tableDef)
    {
        foreach ($tableDef['fields'] as $name => &$col) {
            switch ($col['type']) {
                case 'timestamp':
                    $col['type'] = 'datetime';
                    if (!array_key_exists('default', $col)) {
                        $col['default'] = 'CURRENT_TIMESTAMP';
                    }
                    // no break
                case 'datetime':
                    // Replace archaic MariaDB-specific "zero dates" with NULL
                    if (($col['default'] ?? null) === '0000-00-00 00:00:00') {
                        $col['default'] = null;
                        $col['not null'] = false;
                    }
                    break;
            }
            if (array_key_exists('default', $col) && is_null($col['default'])) {
                unset($col['default']);
            }
            if (array_key_exists('not null', $col) && $col['not null'] !== true) {
                unset($col['not null']);
            }

            if ($this->isStringType($col)) {
                // Default collation
                if (empty($col['collate'])) {
                    $col['collate'] = 'utf8_bin';
                }
                // Migration from direct MariaDB collations
                $col['collate'] = $this->collationFromMySQL($col['collate']);
            }
        }

        if (common_config('search', 'type') !== 'fulltext') {
            unset($tableDef['fulltext indexes']);
        }
        if (!common_config('db', 'foreign_keys')) {
            unset($tableDef['foreign keys']);
        }

        return $tableDef;
    }

    /**
     * Validate a table definition array, checking for basic structure.
     *
     * If necessary, converts from an old-style array of ColumnDef objects.
     *
     * @param string $tableName
     * @param array $def : table definition array
     * @return array validated table definition array
     *
     * @throws Exception on wildly invalid input
     */
    public function validateDef($tableName, array $def)
    {
        if (isset($def[0]) && $def[0] instanceof ColumnDef) {
            $def = $this->oldToNew($tableName, $def);
        }

        // A few quick checks :D
        if (!array_key_exists('fields', $def)) {
            throw new ServerException(
                "Invalid table definition for {$tableName}: no fields."
            );
        }

        // Invalidate foreign key definitions that lack a specified index
        if (array_key_exists('foreign keys', $def)) {
            foreach ($def['foreign keys'] as $fkey_name => $fkey_def) {
                $fkey_cols = array_keys($fkey_def[1]);

                // A list of all keys/indices
                $keys = array_values(array_merge(
                    ($def['unique keys'] ?? []),
                    ($def['indexes'] ?? [])
                ));
                if (array_key_exists('primary key', $def)) {
                    $keys[] = $def['primary key'];
                }

                $indexed = false;
                foreach ($keys as $key_cols) {
                    // Only the beginning of a key counts
                    $cols = array_slice($key_cols, 0, count($fkey_cols));

                    if ($cols == $fkey_cols) {
                        $indexed = true;
                        break;
                    }
                }

                if (!$indexed) {
                    throw new ServerException(
                        "Invalid table definition for {$tableName}: "
                        . "foreign key {$fkey_name} is not indexed."
                    );
                }
            }
        }

        return $def;
    }

    /**
     * Pull info from the query into a fun-fun array of dooooom
     *
     * @param string $sql
     * @return array of arrays
     * @throws PEAR_Exception
     */
    protected function fetchQueryData(string $sql): array
    {
        global $_PEAR;

        $res = $this->conn->query($sql);
        if ($_PEAR->isError($res)) {
            PEAR_ErrorToPEAR_Exception($res);
        }

        $out = [];
        while (!empty($row = $res->fetchRow(MDB2_FETCHMODE_ASSOC))) {
            $out[] = $row;
        }
        $res->free();

        return $out;
    }

    public function renameTable(string $old_name, string $new_name) : bool
    {
        try {
            $this->getTableDef($old_name);
            try {
                $this->getTableDef($new_name);
                // New table exists, can't work
                throw new ServerException("Both table {$old_name} and {$new_name} exist. You're on your own.");
            } catch (SchemaTableMissingException $e) {
                // New table doesn't exist, carry on
            }
        } catch (SchemaTableMissingException $e) {
            // Already renamed, or no previous table, so we're done
            return true;
        }
        return $this->runSqlSet([
            'ALTER TABLE ' . $this->quoteIdentifier($old_name) .
            ' RENAME TO '  . $this->quoteIdentifier($new_name) . ';',
        ]);
    }
}

class SchemaTableMissingException extends Exception
{
    // no-op
}


code:
<?php
// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Database schema utilities
 *
 * @category  Database
 * @package   GNUsocial
 * @author    Evan Prodromou <evan@status.net>
 * @copyright 2009 StatusNet, Inc.
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */

defined('GNUSOCIAL') || die();

class SchemaUpdater
{
    public function __construct($schema)
    {
        $this->schema = $schema;
        $this->checksums = $this->getChecksums();
    }

    /**
     * @param string $tableName
     * @param array $tableDef
     */
    public function register($tableName, array $tableDef)
    {
        // Check if the table we're registering is related to a Managed_DataObject
        if (is_a(ucfirst($tableName), 'Managed_DataObject', true)) {
            call_user_func("{$tableName}::beforeSchemaUpdate");
        }

        $this->tables[$tableName] = $tableDef;
    }

    /**
     * Go ping em!
     *
     * @fixme handle tables that belong on different database servers...?
     */
    public function checkSchema()
    {
        $checksums = $this->checksums;
        foreach ($this->tables as $table => $def) {
            $checksum = $this->checksum($def);
            if (empty($checksums[$table])) {
                common_log(LOG_DEBUG, "No previous schema_version for $table: updating to $checksum");
            } elseif ($checksums[$table] === $checksum) {
                common_log(LOG_DEBUG, "Last schema_version for $table up to date: $checksum");
                continue;
            } else {
                common_log(LOG_DEBUG, "Last schema_version for $table is {$checksums[$table]}: updating to $checksum");
            }
            //$this->conn->query('START TRANSACTION');
            $this->schema->ensureTable($table, $def);
            $this->saveChecksum($table, $checksum);
            //$this->conn->commit();
        }
    }

    /**
     * Calculate a checksum for this table definition array.
     *
     * @param array $def
     * @return string
     */
    public function checksum(array $def)
    {
        $flat = serialize($def);
        return hash('sha3-256', $flat);
    }

    /**
     * Pull all known table checksums into an array for easy lookup.
     *
     * @return array: associative array of table names to checksum strings
     */
    protected function getChecksums()
    {
        $checksums = array();

        try {
            $sv = new Schema_version();
            $sv->find();
            while ($sv->fetch()) {
                $checksums[$sv->table_name] = $sv->checksum;
            }

            return $checksums;
        } catch (Exception $e) {
            // no dice!
            common_log(LOG_DEBUG, "Possibly schema_version table doesn't exist yet.");
        }

        return $checksums;
    }

    /**
     * Save or update current available checksums.
     *
     * @param string $table
     * @param string $checksum
     */
    protected function saveChecksum($table, $checksum)
    {
        try {
            $sv = new Schema_version();
            $sv->table_name = $table;
            $sv->checksum = $checksum;
            $sv->modified = common_sql_now();
            if (isset($this->checksums[$table])) {
                $sv->update();
            } else {
                $sv->insert();
            }
        } catch (Exception $e) {
            // no dice!
            common_log(LOG_DEBUG, "Possibly schema_version table doesn't exist yet.");
        }
        $this->checksums[$table] = $checksum;
    }
}


code:
<?php
/**
 * StatusNet, the distributed open-source microblogging tool
 *
 * Database schema utilities
 *
 * PHP version 5
 *
 * LICENCE: This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @category  Database
 * @package   StatusNet
 * @author    Evan Prodromou <evan@status.net>
 * @copyright 2009 StatusNet, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      http://status.net/
 */

if (!defined('STATUSNET')) {
    exit(1);
}

/**
 * A class encapsulating the structure of a table.
 *
 * @category Database
 * @package  StatusNet
 * @author   Evan Prodromou <evan@status.net>
 * @license  http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link     http://status.net/
 */

class TableDef
{
    /** name of the table */
    public $name;
    /** array of ColumnDef objects for the columns. */
    public $columns;

    /**
     * Constructor.
     *
     * @param string  $name     name of the table
     * @param array   $columns  columns in the table
     */

    function __construct($name=null,$columns=null)
    {
        $this->name = $name;
        $this->columns = $columns;
    }
}


code:
<?php
/**
 * GNU social - a federating social network
 * Copyright (C) 2014, Free Software Foundation, Inc.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

if (!defined('GNUSOCIAL')) { exit(1); }

/**
 * Parent class for an exception when trying to do something that was
 * probably already done.
 *
 * This is a common case for example when remote sites are not up to
 * date with our database. For example subscriptions, where a remote
 * user may be unsubscribed from our user, but they request it anyway.
 *
 * This exception is usually caught in a manner that lets the execution
 * continue _as if_ the desired action did what it was supposed to do.
 *
 * @category Exception
 * @package  GNUsocial
 * @author   Mikael Nordfeldth <mmn@hethane.se>
 * @license  http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
 * @link     http://gnu.io/
 */

class AlreadyFulfilledException extends ServerException
{
    public function __construct($msg=null)
    {
        if ($msg === null) {
            // TRANS: Exception text when attempting to perform something which seems already done.
            $msg = _('Trying to do something that was already done.');
        }

        parent::__construct($msg, 409);
    }
}


code:
<?php
// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.
/**
 * Class for exception thrown when something was already handled.
 * Useful to use as a lock when handling a same something in different queues and only one should be attended
 *
 * @category  Exception
 * @author    Diogo Cordeiro <diogo@fc.up.pt>
 * @copyright 2020 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */

defined('GNUSOCIAL') || die();

/**
 * Exception thrown when something was already handled.
 *
 * @copyright 2019 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */
class AlreadyHandledException extends ServerException
{
    public function __construct($msg)
    {
        parent::__construct($msg, 202);
    }
}


code:
<?php
/**
 * StatusNet - the distributed open-source microblogging tool
 * Copyright (C) 2011, StatusNet, Inc.
 *
 * An exception for authorization errors
 *
 * PHP version 5
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @category  Exception
 * @package   StatusNet
 * @author    Evan Prodromou <evan@status.net>
 * @copyright 2011 StatusNet, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
 * @link      http://status.net/
 */

if (!defined('STATUSNET')) {
    // This check helps protect against security problems;
    // your code file can't be executed directly from the web.
    exit(1);
}

/**
 * An exception for authorization issues
 *
 * @category  Exception
 * @package   StatusNet
 * @author    Evan Prodromou <evan@status.net>
 * @copyright 2011 StatusNet, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
 * @link      http://status.net/
 */

class AuthorizationException extends ClientException
{
    /**
     * Constructor
     *
     * @param string $message Message for the exception
     */
    public function __construct($message=null)
    {
        parent::__construct($message, 403);
    }
}


code:
<?php
// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Class for a client exception (user error)
 *
 * @category  Exception
 * @package   GNUsocial
 * @author    Evan Prodromou <evan@status.net>
 * @copyright 2008 StatusNet, Inc.
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */

defined('GNUSOCIAL') || die();

/**
 * Class for client exceptions
 *
 * Subclass of PHP Exception for user errors.
 *
 * @category  Exception
 * @package   GNUsocial
 * @author    Evan Prodromou <evan@status.net>
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */
class ClientException extends Exception
{
    public function __construct(
        string $message = '',
        int $code = 500,
        Throwable $previous = null
    ) {
        parent::__construct($message, $code, $previous);
    }

    // custom string representation of object
    public function __toString()
    {
        return __CLASS__ . ": [{$this->code}]: {$this->message}\n";
    }
}


code:
<?php

if (!defined('GNUSOCIAL')) { exit(1); }

/**
 * Class for configuration exceptions
 *
 * Subclass of ServerException for when the site's configuration is malformed.
 *
 * @category Exception
 * @package  GNUsocial
 * @author   Mikael Nordfeldth <mmn@hethane.se>
 * @license  https://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link     https://gnu.io/social
 */

class ConfigException extends ServerException
{
    public function __construct($message=null) {
        parent::__construct($message, 500);
    }
}


code:
<?php
/**
 * StatusNet, the distributed open-source microblogging tool
 *
 * Class for an exception when there is something wrong with sending email
 *
 * PHP version 5
 *
 * LICENCE: This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @category  Exception
 * @package   GNUsocial
 * @author    Mikael Nordfeldth <mmn@hethane.se>
 * @copyright 2016 Free Software Foundation, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
 * @link      http://www.gnu.org/software/social/
 */

if (!defined('GNUSOCIAL')) { exit(1); }

class EmailException extends Exception
{
}


code:
<?php
/**
 * StatusNet, the distributed open-source microblogging tool
 *
 * Class for an exception when a database lookup returns no results
 *
 * PHP version 5
 *
 * LICENCE: This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @category  Exception
 * @package   GNUsocial
 * @author    Mikael Nordfeldth <mmn@hethane.se>
 * @copyright 2013 Free Software Foundation, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
 * @link      http://www.gnu.org/software/social/
 */

if (!defined('GNUSOCIAL')) { exit(1); }

class EmptyPkeyValueException extends ServerException
{
    public function __construct($called_class, $key=null)
    {
        // FIXME: translate the 'not specified' case?
        parent::__construct(sprintf(_('Empty primary key (%1$s) value was given to query for a "%2$s" object'),
                                        is_null($key) ? 'not specified' : _ve($key),
                                        $called_class));
    }
}


code:
<?php
/**
 * StatusNet, the distributed open-source microblogging tool
 *
 * Class for an exception when a database lookup returns no results
 *
 * PHP version 5
 *
 * LICENCE: This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @category  Exception
 * @package   GNUsocial
 * @author    Mikael Nordfeldth <mmn@hethane.se>
 * @copyright 2013 Free Software Foundation, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
 * @link      http://www.gnu.org/software/social/
 */

if (!defined('GNUSOCIAL')) { exit(1); }

class FileNotFoundException extends ServerException
{
    public $path = null;

    public function __construct($path)
    {
        $this->path = $path;
        common_debug('File not found exception for: '._ve($this->path));
        parent::__construct(_('File not found in filesystem.'), 404);
    }
}


code:
<?php

if (!defined('GNUSOCIAL')) { exit(1); }

class FileNotStoredLocallyException extends ServerException
{
    public $file = null;

    public function __construct(File $file)
    {
        $this->file = $file;
        common_debug('Requested local URL for a file that is not stored locally with id=='._ve($this->file->getID()));
        parent::__construct(_('Requested local URL for a file that is not stored locally.'));
    }
}


code:
<?php
/**
 * StatusNet, the distributed open-source microblogging tool
 *
 * Class for an exception when the group profile is missing
 *
 * PHP version 5
 *
 * LICENCE: This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @category  Exception
 * @package   StatusNet
 * @author    Evan Prodromou <evan@status.net>
 * @copyright 2010 StatusNet, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
 * @link      http://status.net/
 */

if (!defined('GNUSOCIAL')) { exit(1); }

/**
 * Class for an exception when the group profile is missing
 *
 * @category Exception
 * @package  StatusNet
 * @author   Evan Prodromou <evan@status.net>
 * @license  http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
 * @link     http://status.net/
 */

class GroupNoProfileException extends NoProfileException
{
    protected $group = null;

    /**
     * constructor
     *
     * @param User_group $user User_group that's missing a profile
     */

    public function __construct(User_group $group)
    {
        $this->group = $group;

        // TRANS: Exception text shown when no profile can be found for a group.
        // TRANS: %1$s is a group nickname, $2$d is a group profile_id (number).
        $message = sprintf(_('Group "%1$s" (%2$d) has no profile record.'),
                           $group->nickname, $group->getID());

        parent::__construct($group->profile_id, $message);
    }

    /**
     * Accessor for user
     *
     * @return User_group the group that triggered this exception
     */

    public function getGroup()
    {
        return $this->group;
    }
}


code:
<?php
/**
 * StatusNet, the distributed open-source microblogging tool
 *
 * Class for an exception when a filename is invalid
 *
 * PHP version 5
 *
 * LICENCE: This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @category  Exception
 * @package   StatusNet
 * @author    Mikael Nordfeldth <mmn@hethane.se>
 * @copyright 2016 Free Software Foundation, Inc.
 * @license   https://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
 * @link      https://gnu.io/social
 */

if (!defined('GNUSOCIAL')) { exit(1); }

/**
 * Class for an exception when a filename is invalid
 *
 * @category Exception
 * @package  GNUsocial
 * @author   Mikael Nordfeldth <mmn@hethane.se>
 * @license  https://www.fsf.org/licensing/licenses/agpl-3.0.html AGPLv3
 * @link     https://gnu.io/social
 */

class InvalidFilenameException extends ServerException
{
    public $filename = null;

    public function __construct($filename)
    {
        $this->filename = $filename;
        // We could log an entry here with the search parameters
        parent::__construct(_('Invalid filename.'));
    }
}