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// Copyright 2015 Google Inc. 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.buildjar.genclass;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.ImmutableSet;
import com.google.devtools.build.buildjar.JarCreator;
import com.google.devtools.build.buildjar.proto.JavaCompilation.CompilationUnit;
import com.google.devtools.build.buildjar.proto.JavaCompilation.Manifest;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
/**
* GenClass post-processes the output of a Java compilation, and produces
* a jar containing only the class files for sources that were generated
* by annotation processors.
*/
public class GenClass {
public static void main(String[] args) throws IOException {
GenClassOptions options = GenClassOptionsParser.parse(Arrays.asList(args));
Manifest manifest = readManifest(options.manifest());
extractGeneratedClasses(options.classJar(), manifest, options.tempDir());
writeOutputJar(options);
}
/**
* Reads the compilation manifest.
*/
private static Manifest readManifest(Path path) throws IOException {
Manifest manifest;
try (InputStream inputStream = Files.newInputStream(path)) {
manifest = Manifest.parseFrom(inputStream);
}
return manifest;
}
/**
* For each top-level class in the compilation, determine the path prefix
* of classes corresponding to that compilation unit.
*
* <p>Prefixes are used to correctly handle inner classes, e.g. the top-level
* class "c.g.Foo" may correspond to "c/g/Foo.class" and also
* "c/g/Foo$Inner.class" or "c/g/Foo$0.class".
*/
@VisibleForTesting
static ImmutableSet<String> getGeneratedPrefixes(Manifest manifest) {
ImmutableSet.Builder<String> prefixes = ImmutableSet.builder();
for (CompilationUnit unit : manifest.getCompilationUnitList()) {
if (!unit.getGeneratedByAnnotationProcessor()) {
continue;
}
String pkg;
if (unit.hasPkg()) {
pkg = unit.getPkg().replace('.', '/') + "/";
} else {
pkg = "";
}
for (String toplevel : unit.getTopLevelList()) {
prefixes.add(pkg + toplevel);
}
}
return prefixes.build();
}
/**
* Unzip all the class files that correspond to annotation processor-
* generated sources into the temporary directory.
*/
private static void extractGeneratedClasses(Path classJar, Manifest manifest, Path tempDir)
throws IOException {
ImmutableSet<String> generatedPrefixes = getGeneratedPrefixes(manifest);
try (JarFile jar = new JarFile(classJar.toFile())) {
Enumeration<JarEntry> entries = jar.entries();
while (entries.hasMoreElements()) {
JarEntry entry = entries.nextElement();
String name = entry.getName();
if (!name.endsWith(".class")) {
continue;
}
String prefix = name.substring(0, name.length() - ".class".length());
int idx = prefix.indexOf('$');
if (idx > 0) {
prefix = prefix.substring(0, idx);
}
if (generatedPrefixes.contains(prefix)) {
Files.createDirectories(tempDir.resolve(name).getParent());
Files.copy(jar.getInputStream(entry), tempDir.resolve(name));
}
}
}
}
/** Writes the generated class files to the output jar. */
private static void writeOutputJar(GenClassOptions options) throws IOException {
JarCreator output = new JarCreator(options.outputJar().toString());
output.setCompression(true);
output.setNormalize(true);
output.addDirectory(options.tempDir().toString());
output.execute();
}
}
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