/*
 * Copyright (C) 2013 Google, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.google.testing.compile;

import com.google.common.base.CharMatcher;
import com.google.common.base.MoreObjects;
import com.google.common.base.Optional;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.collect.ImmutableList;
import com.google.common.io.ByteSource;

import java.io.ByteArrayOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;
import java.net.URI;
import java.nio.charset.Charset;
import java.util.Map.Entry;

import javax.tools.FileObject;
import javax.tools.ForwardingJavaFileManager;
import javax.tools.JavaFileManager;
import javax.tools.JavaFileObject;
import javax.tools.JavaFileObject.Kind;
import javax.tools.SimpleJavaFileObject;
import javax.tools.StandardLocation;

/**
 * A file manager implementation that stores all output in memory.
 *
 * @author Gregory Kick
 */
// TODO(gak): under java 1.7 this could all be done with a PathFileManager
final class InMemoryJavaFileManager extends ForwardingJavaFileManager<JavaFileManager> {
  private final LoadingCache<URI, JavaFileObject> inMemoryFileObjects =
      CacheBuilder.newBuilder().build(new CacheLoader<URI, JavaFileObject>() {
        @Override
        public JavaFileObject load(URI key) {
          return new InMemoryJavaFileObject(key);
        }
      });

  InMemoryJavaFileManager(JavaFileManager fileManager) {
    super(fileManager);
  }

  private static URI uriForFileObject(Location location, String packageName, String relativeName) {
    return URI.create(
        "mem:///" + location.getName() + '/' + CharMatcher.is('.').replaceFrom(packageName, '/')
            + '/' + relativeName);
  }

  private static URI uriForJavaFileObject(Location location, String className, Kind kind) {
    return URI.create(
        "mem:///" + location.getName() + '/' + CharMatcher.is('.').replaceFrom(className, '/')
            + kind.extension);
  }

  @Override
  public boolean isSameFile(FileObject a, FileObject b) {
    if (a instanceof SimpleJavaFileObject) {
      if (b instanceof SimpleJavaFileObject) {
        return ((SimpleJavaFileObject) a).toUri().equals(((SimpleJavaFileObject) b).toUri());
      }
    }
    if (b instanceof SimpleJavaFileObject) {
      return false;
    }
    return super.isSameFile(a, b);
  }

  @Override
  public FileObject getFileForInput(Location location, String packageName,
      String relativeName) throws IOException {
    if (location.isOutputLocation()) {
      return inMemoryFileObjects.getIfPresent(
          uriForFileObject(location, packageName, relativeName));
    } else {
      return super.getFileForInput(location, packageName, relativeName);
    }
  }

  @Override
  public JavaFileObject getJavaFileForInput(Location location, String className, Kind kind)
      throws IOException {
    if (location.isOutputLocation()) {
      return inMemoryFileObjects.getIfPresent(uriForJavaFileObject(location, className, kind));
    } else {
      return super.getJavaFileForInput(location, className, kind);
    }
  }

  @Override
  public FileObject getFileForOutput(Location location, String packageName,
      String relativeName, FileObject sibling) throws IOException {
    URI uri = uriForFileObject(location, packageName, relativeName);
    return inMemoryFileObjects.getUnchecked(uri);
  }

  @Override
  public JavaFileObject getJavaFileForOutput(Location location, String className, final Kind kind,
      FileObject sibling) throws IOException {
    URI uri = uriForJavaFileObject(location, className, kind);
    return inMemoryFileObjects.getUnchecked(uri);
  }

  ImmutableList<JavaFileObject> getGeneratedSources() {
    ImmutableList.Builder<JavaFileObject> result = ImmutableList.builder();
    for (Entry<URI, JavaFileObject> entry : inMemoryFileObjects.asMap().entrySet()) {
      if (entry.getKey().getPath().startsWith("/" + StandardLocation.SOURCE_OUTPUT.name())
          && (entry.getValue().getKind() == Kind.SOURCE)) {
        result.add(entry.getValue());
      }
    }
    return result.build();
  }

  ImmutableList<JavaFileObject> getOutputFiles() {
    return ImmutableList.copyOf(inMemoryFileObjects.asMap().values());
  }

  private static final class InMemoryJavaFileObject extends SimpleJavaFileObject
      implements JavaFileObject {
    private long lastModified = 0L;
    private Optional<ByteSource> data = Optional.absent();

    InMemoryJavaFileObject(URI uri) {
      super(uri, JavaFileObjects.deduceKind(uri));
    }

    @Override
    public InputStream openInputStream() throws IOException {
      if (data.isPresent()) {
        return data.get().openStream();
      } else {
        throw new FileNotFoundException();
      }
    }

    @Override
    public OutputStream openOutputStream() throws IOException {
      return new ByteArrayOutputStream() {
        @Override
        public void close() throws IOException {
          super.close();
          data = Optional.of(ByteSource.wrap(toByteArray()));
          lastModified = System.currentTimeMillis();
        }
      };
    }

    @Override
    public Reader openReader(boolean ignoreEncodingErrors) throws IOException {
      if (data.isPresent()) {
        return data.get().asCharSource(Charset.defaultCharset()).openStream();
      } else {
        throw new FileNotFoundException();
      }
    }

    @Override
    public CharSequence getCharContent(boolean ignoreEncodingErrors)
        throws IOException {
      if (data.isPresent()) {
        return data.get().asCharSource(Charset.defaultCharset()).read();
      } else {
        throw new FileNotFoundException();
      }
    }

    @Override
    public Writer openWriter() throws IOException {
      return new StringWriter() {
        @Override
        public void close() throws IOException {
          super.close();
          data =
              Optional.of(ByteSource.wrap(toString().getBytes(Charset.defaultCharset())));
          lastModified = System.currentTimeMillis();
        }
      };
    }

    @Override
    public long getLastModified() {
      return lastModified;
    }

    @Override
    public boolean delete() {
      this.data = Optional.absent();
      this.lastModified = 0L;
      return true;
    }

    @Override
    public String toString() {
      return MoreObjects.toStringHelper(this)
          .add("uri", toUri())
          .add("kind", kind)
          .toString();
    }
  }
}

@@ -2783,307 +2783,423 @@
     
-if (a instanceof SimpleJavaFileObject) %7B%0A      if (b instanceof Si
+/* This check is less strict than what is typically done by the normal co
 mp
+i
 le
-JavaFileObject) %7B%0A        return ((Simple
+r file managers%0A     * (e.g. 
 Java
+c
 File
-Object) a).toUri().equals(((SimpleJavaFileObject) b).toUri());%0A      %7D%0A    %7D%0A    if (b instanceof Si
+Manager), but is actually the moral equivalent of what most of the%0A     * implementations do anyway. We use this check rather than just delegating to the co
 mp
+i
 le
-JavaFileO
+r's%0A     * file manager because file o
 bject
-) %7B%0A      return false;%0A    %7D%0A    return super.isSameFile(a, b
+s for tests generally cause IllegalArgumentExceptions. */%0A    return a.toUri().equals(b.toUri()
 );%0A 

Update InMemoryJavaFileManager to be even more lenient about which FileObject implementations it considers for isSameFile. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=111507236