| // Copyright 2016 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.android.desugar; |
| |
| import static com.google.common.base.Preconditions.checkArgument; |
| |
| import com.google.common.collect.ImmutableMap; |
| import com.google.common.collect.Iterators; |
| import java.io.IOException; |
| import java.lang.invoke.MethodHandle; |
| import java.nio.file.Files; |
| import java.nio.file.Path; |
| import java.util.ArrayList; |
| import java.util.LinkedHashMap; |
| import java.util.Map; |
| import java.util.function.Predicate; |
| import java.util.stream.Stream; |
| |
| class LambdaClassMaker { |
| |
| static final String LAMBDA_METAFACTORY_DUMPER_PROPERTY = "jdk.internal.lambda.dumpProxyClasses"; |
| |
| private final Path rootDirectory; |
| private final Map<Path, LambdaInfo> generatedClasses = new LinkedHashMap<>(); |
| |
| public LambdaClassMaker(Path rootDirectory) { |
| checkArgument(Files.isDirectory(rootDirectory)); |
| this.rootDirectory = rootDirectory; |
| } |
| |
| public void generateLambdaClass(String invokerInternalName, LambdaInfo lambdaInfo, |
| MethodHandle bootstrapMethod, ArrayList<Object> bsmArgs) throws IOException { |
| // Invoking the bootstrap method will dump the generated class |
| try { |
| bootstrapMethod.invokeWithArguments(bsmArgs); |
| } catch (Throwable e) { |
| throw new IllegalStateException("Failed to generate lambda class for class " |
| + invokerInternalName + " using " + bootstrapMethod + " with arguments " + bsmArgs, e); |
| } |
| |
| Path generatedClassFile = findOnlyUnprocessed(invokerInternalName + "$$Lambda$"); |
| generatedClasses.put(generatedClassFile, lambdaInfo); |
| } |
| |
| /** |
| * Returns absolute paths to .class files generated since the last call to this method together |
| * with a string descriptor of the factory method. |
| */ |
| public ImmutableMap<Path, LambdaInfo> drain() { |
| ImmutableMap<Path, LambdaInfo> result = ImmutableMap.copyOf(generatedClasses); |
| generatedClasses.clear(); |
| return result; |
| } |
| |
| private Path findOnlyUnprocessed(String pathPrefix) throws IOException { |
| // pathPrefix is an internal class name prefix containing '/', but paths obtained on Windows |
| // will not contain '/' and searches will fail. So, construct an absolute path from the given |
| // string and use its string representation to find the file we need regardless of host |
| // system's file system |
| Path rootPathPrefix = rootDirectory.resolve(pathPrefix); |
| final String rootPathPrefixStr = rootPathPrefix.toString(); |
| |
| // TODO(bazel-team): This could be much nicer with lambdas |
| try (Stream<Path> paths = |
| Files.list(rootPathPrefix.getParent()) |
| .filter( |
| new Predicate<Path>() { |
| @Override |
| public boolean test(Path path) { |
| return path.toString().startsWith(rootPathPrefixStr) |
| && !generatedClasses.containsKey(path); |
| } |
| })) { |
| return Iterators.getOnlyElement(paths.iterator()); |
| } |
| } |
| } |