aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/main/java/com/google/devtools/build/lib/analysis/SkylarkProviders.java
blob: 6ed41d9009cef1ae89a163abd56db53ffa6a7733 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
// 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.analysis;

import com.google.common.base.Function;
import com.google.common.collect.ImmutableCollection;
import com.google.common.collect.ImmutableMap;
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.SkylarkApiProvider;
import com.google.devtools.build.lib.syntax.EvalException;
import com.google.devtools.build.lib.syntax.SkylarkType;
import com.google.devtools.build.lib.util.Preconditions;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * A helper class for transitive infos provided by Skylark rule implementations.
 */
@Immutable
public final class SkylarkProviders implements TransitiveInfoProvider {
  private final ImmutableMap<SkylarkClassObjectConstructor.Key, SkylarkClassObject>
      declaredProviders;
  private final ImmutableMap<String, Object> skylarkProviders;

  SkylarkProviders(
      ImmutableMap<String, Object> skylarkProviders,
      ImmutableMap<SkylarkClassObjectConstructor.Key, SkylarkClassObject> declaredProviders) {
    this.declaredProviders = Preconditions.checkNotNull(declaredProviders);
    this.skylarkProviders = Preconditions.checkNotNull(skylarkProviders);
  }

  public void init(ConfiguredTarget target) {
    for (Object o : skylarkProviders.values()) {
      if (o instanceof SkylarkApiProvider) {
        ((SkylarkApiProvider) o).init(target);
      }
    }
  }

  /**
   * Returns the keys for the Skylark providers.
   */
  public ImmutableCollection<String> getKeys() {
    return skylarkProviders.keySet();
  }

  /**
   * Returns a Skylark provider; "key" must be one from {@link #getKeys()}.
   */
  public Object getValue(String key) {
    return skylarkProviders.get(key);
  }

  /**
   * Returns a Skylark provider and try to cast it into the specified type
   */
  public <TYPE> TYPE getValue(String key, Class<TYPE> type) throws EvalException {
    Object obj = skylarkProviders.get(key);
    if (obj == null) {
      return null;
    }
    SkylarkType.checkType(obj, type, key);
    return type.cast(obj);
  }

  public SkylarkClassObject getDeclaredProvider(SkylarkClassObjectConstructor.Key key) {
    return declaredProviders.get(key);
  }


  private static final Function<SkylarkProviders, Map<String, Object>>
      SKYLARK_PROVIDERS_MAP_FUNCTION = new Function<SkylarkProviders, Map<String, Object>>() {
        @Override
        public Map<String, Object> apply(SkylarkProviders skylarkProviders) {
          return skylarkProviders.skylarkProviders;
        }
      };

  public static final Function<SkylarkProviders,
                               Map<SkylarkClassObjectConstructor.Key, SkylarkClassObject>>
      DECLARED_PROVIDERS_MAP_FUNCTION =
      new Function<SkylarkProviders, Map<SkylarkClassObjectConstructor.Key, SkylarkClassObject>>() {
        @Override
        public Map<SkylarkClassObjectConstructor.Key, SkylarkClassObject> apply(
            SkylarkProviders skylarkProviders) {
          return skylarkProviders.declaredProviders;
        }
      };

  /**
   * Merges skylark providers. The set of providers must be disjoint.
   *
   * @param providers providers to merge {@code this} with.
   */
  public static SkylarkProviders merge(List<SkylarkProviders> providers) {
    if (providers.size() == 0) {
      return null;
    }
    if (providers.size() == 1) {
      return providers.get(0);
    }

    ImmutableMap<String, Object> skylarkProviders = mergeMaps(providers,
        SKYLARK_PROVIDERS_MAP_FUNCTION);
    ImmutableMap<SkylarkClassObjectConstructor.Key, SkylarkClassObject> declaredProviders =
        mergeMaps(providers, DECLARED_PROVIDERS_MAP_FUNCTION);

    return new SkylarkProviders(skylarkProviders, declaredProviders);
  }

  private static <K, V> ImmutableMap<K, V> mergeMaps(List<SkylarkProviders> providers,
      Function<SkylarkProviders, Map<K, V>> mapGetter) {
    ImmutableMap.Builder<K, V> resultBuilder = new ImmutableMap.Builder<>();
    Set<K> seenKeys = new HashSet<>();
    for (SkylarkProviders provider : providers) {
      Map<K, V> map = mapGetter.apply(provider);
      for (K key : map.keySet()) {
        if (!seenKeys.add(key)) {
          // TODO(dslomov): add better diagnostics.
          throw new IllegalStateException("Skylark provider " + key + " provided twice");
        }

        resultBuilder.put(key, map.get(key));
      }
    }
    return resultBuilder.build();
  }
}