1 // Copyright 2017 The Bazel Authors. All rights reserved.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //    http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 package com.google.devtools.build.android.desugar;
15 
16 import static com.google.common.base.Preconditions.checkNotNull;
17 import static com.google.common.base.Preconditions.checkState;
18 
19 import com.google.devtools.build.android.desugar.io.BitFlags;
20 import java.util.HashMap;
21 import javax.annotation.Nullable;
22 import org.objectweb.asm.ClassReader;
23 
24 /**
25  * Simple memoizer for whether types are classes or interfaces.
26  */
27 class ClassVsInterface {
28   /** Map from internal names to whether they are an interface ({@code false} thus means class). */
29   private final HashMap<String, Boolean> known = new HashMap<>();
30   private final ClassReaderFactory classpath;
31 
ClassVsInterface(ClassReaderFactory classpath)32   public ClassVsInterface(ClassReaderFactory classpath) {
33     this.classpath = classpath;
34   }
35 
addKnownClass(@ullable String internalName)36   public ClassVsInterface addKnownClass(@Nullable String internalName) {
37     if (internalName != null) {
38       Boolean previous = known.put(internalName, false);
39       checkState(previous == null || !previous, "Already recorded as interface: %s", internalName);
40     }
41     return this;
42   }
43 
addKnownInterfaces(String... internalNames)44   public ClassVsInterface addKnownInterfaces(String... internalNames) {
45     for (String internalName : internalNames) {
46       Boolean previous = known.put(internalName, true);
47       checkState(previous == null || previous, "Already recorded as class: %s", internalName);
48     }
49     return this;
50   }
51 
isOuterInterface(String outerName, String innerName)52   public boolean isOuterInterface(String outerName, String innerName) {
53     Boolean result = known.get(outerName);
54     if (result == null) {
55       // We could just load the outer class here, but this tolerates incomplete classpaths better.
56       // Note the outer class should be in the Jar we're desugaring, so it should always be there.
57       ClassReader outerClass = checkNotNull(classpath.readIfKnown(outerName),
58           "Couldn't find outer class %s of %s", outerName, innerName);
59       result = BitFlags.isInterface(outerClass.getAccess());
60       known.put(outerName, result);
61     }
62     return result;
63   }
64 }
65