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// 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 static com.google.common.collect.Iterables.getOnlyElement;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
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.HashSet;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;
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<>();
private final Set<Path> existingPaths = new HashSet<>();
public LambdaClassMaker(Path rootDirectory) {
checkArgument(
Files.isDirectory(rootDirectory), "The argument '%s' is not a directory.", 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. Ignore any pre-existing
// matching files, which can come from desugar's implementation using classes being desugared.
existingPaths.addAll(findUnprocessed(invokerInternalName + "$$Lambda$"));
try {
bootstrapMethod.invokeWithArguments(bsmArgs);
} catch (Throwable e) {
throw new IllegalStateException("Failed to generate lambda class for class "
+ invokerInternalName + " using " + bootstrapMethod + " with arguments " + bsmArgs, e);
}
Path generatedClassFile = getOnlyElement(findUnprocessed(invokerInternalName + "$$Lambda$"));
generatedClasses.put(generatedClassFile, lambdaInfo);
existingPaths.add(generatedClassFile);
}
/**
* 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 ImmutableList<Path> findUnprocessed(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();
if (!Files.exists(rootPathPrefix.getParent())) {
return ImmutableList.of();
}
try (Stream<Path> paths = Files.list(rootPathPrefix.getParent())) {
return paths
.filter(
path ->
path.toString().startsWith(rootPathPrefixStr) && !existingPaths.contains(path))
.collect(ImmutableList.toImmutableList());
}
}
}
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