// Copyright 2014 The Bazel Authors. All rights reserved.
//
// 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.devtools.build.lib.rules.cpp;

import com.google.common.base.Function;
import com.google.common.collect.ImmutableMap;
import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
import com.google.devtools.build.lib.analysis.TransitiveInfoProvider;
import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
import com.google.devtools.build.lib.packages.SkylarkClassObject;
import com.google.devtools.build.lib.packages.SkylarkClassObjectConstructor;
import com.google.devtools.build.lib.rules.cpp.CcLinkParamsStore.CcLinkParamsStoreImpl;

/** A target that provides C linker parameters. */
@Immutable
public final class CcLinkParamsProvider extends SkylarkClassObject
    implements TransitiveInfoProvider {
  public static final SkylarkClassObjectConstructor CC_LINK_PARAMS =
      SkylarkClassObjectConstructor.createNative("link_params");
  public static final Function<TransitiveInfoCollection, CcLinkParamsStore> TO_LINK_PARAMS =
      new Function<TransitiveInfoCollection, CcLinkParamsStore>() {
        @Override
        public CcLinkParamsStore apply(TransitiveInfoCollection input) {
          CcLinkParamsProvider provider = input.getProvider(
              CcLinkParamsProvider.class);
          return provider == null ? null : provider.getCcLinkParamsStore();
        }
      };

  private final CcLinkParamsStoreImpl store;

  public CcLinkParamsProvider(CcLinkParamsStore store) {
    super(CC_LINK_PARAMS, ImmutableMap.<String, Object>of());
    this.store = new CcLinkParamsStoreImpl(store);
  }

  /** Returns the link params store. */
  public CcLinkParamsStore getCcLinkParamsStore() {
    return store;
  }

  /**
   * Returns link parameters given static / shared linking settings.
   */
  public CcLinkParams getCcLinkParams(boolean linkingStatically, boolean linkShared) {
    return store.get(linkingStatically, linkShared);
  }
}

@@ -1743,24 +1743,57 @@
 on input) %7B%0A
+          // Try native first...%0A
           Cc
@@ -1844,23 +1844,8 @@
 der(
-%0A              
 CcLi
@@ -1866,16 +1866,230 @@
 er.class
+);%0A          if (provider != null) %7B%0A            return provider.getCcLinkParamsStore();%0A          %7D%0A%0A          // ... then try Skylark.%0A          provider = (CcLinkParamsProvider) input.get(CC_LINK_PARAMS.getKey()
 );%0A     
@@ -2085,39 +2085,36 @@
 y());%0A          
-return 
+if (
 provider == null
@@ -2110,24 +2110,37 @@
 der 
-=
+!
 = null
- ? null :
+) %7B%0A            return
  pro
@@ -2161,32 +2161,67 @@
 kParamsStore();%0A
+          %7D%0A          return null;%0A
         %7D%0A      

Allow rules to consume CcLinkParamsProviders provided by Skylark rules.