JavaBuilder can run as a Blaze worker process now.

--
MOS_MIGRATED_REVID=95527889

2 files changed, 89 insertions, 10 deletions

diff --git a/src/java_tools/buildjar/BUILD b/src/java_tools/buildjar/BUILD
index eabf9d53b1..5e41759ba1 100644
--- a/src/java_tools/buildjar/BUILD
+++ b/src/java_tools/buildjar/BUILD
@@ -6,6 +6,7 @@ java_binary(
     main_class = "com.google.devtools.build.buildjar.BazelJavaBuilder",
     deps = [
         "//src/main/protobuf:proto_deps",
+        "//src/main/protobuf:proto_worker_protocol",
         "//third_party:error_prone",
         "//third_party:guava",
         "//third_party:jsr305",
@@ -176,7 +177,10 @@ bootstrap_java_library(
         "//third_party:protobuf-jars",
     ],
     neverlink_jars = ["//tools/defaults:java_langtools"],
-    srcjars = ["//src/main/protobuf:proto_deps_srcjar"],
+    srcjars = [
+        "//src/main/protobuf:proto_deps_srcjar",
+        "//src/main/protobuf:proto_worker_protocol_srcjar",
+    ],
 )
 
 bootstrap_java_binary(
diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/BazelJavaBuilder.java b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/BazelJavaBuilder.java
index 4531098a77..0ba15cd4fd 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/BazelJavaBuilder.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/BazelJavaBuilder.java
@@ -20,9 +20,14 @@ import com.google.devtools.build.buildjar.javac.plugins.BlazeJavaCompilerPlugin;
 import com.google.devtools.build.buildjar.javac.plugins.dependency.DependencyModule;
 import com.google.devtools.build.buildjar.javac.plugins.errorprone.ErrorProneOptionsPlugin;
 import com.google.devtools.build.buildjar.javac.plugins.filemanager.FileManagerInitializationPlugin;
+import com.google.devtools.build.lib.worker.WorkerProtocol.WorkRequest;
+import com.google.devtools.build.lib.worker.WorkerProtocol.WorkResponse;
 
+import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.io.PrintStream;
 import java.util.Arrays;
+import java.util.List;
 
 /**
  * The JavaBuilder main called by bazel.
@@ -35,22 +40,92 @@ public abstract class BazelJavaBuilder {
    * The main method of the BazelJavaBuilder.
    */
   public static void main(String[] args) {
+    if (args.length == 1 && args[0].equals("--persistent_worker")) {
+      System.exit(runPersistentWorker());
+    } else {
+      // This is a single invocation of JavaBuilder that exits after it processed the request.
+      System.exit(processRequest(Arrays.asList(args)));
+    }
+  }
+
+  private static int runPersistentWorker() {
+    PrintStream originalStdOut = System.out;
+    PrintStream originalStdErr = System.err;
+
+    while (true) {
+      try {
+        WorkRequest request = WorkRequest.parseDelimitedFrom(System.in);
+
+        if (request == null) {
+          break;
+        }
+
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        PrintStream ps = new PrintStream(baos, true);
+        // Make sure that we exit nonzero in case an exception occurs during processRequest.
+        int exitCode = 1;
+        // TODO(philwo) - change this so that a PrintWriter can be passed in and will be used
+        // instead of redirect stdout / stderr.
+        System.setOut(ps);
+        System.setErr(ps);
+        try {
+          exitCode = processRequest(request.getArgumentsList());
+        } finally {
+          System.setOut(originalStdOut);
+          System.setErr(originalStdErr);
+        }
+
+        WorkResponse.newBuilder()
+            .setOutput(baos.toString())
+            .setExitCode(exitCode)
+            .build()
+            .writeDelimitedTo(System.out);
+        System.out.flush();
+      } catch (IOException e) {
+        e.printStackTrace();
+        return 1;
+      } finally {
+        // JavaBuilder doesn't close certain file handles. We have to migrate to using the real
+        // Jsr199 API instead of just calling the Main method of Javac in order to fix this, for
+        // now let's just invoke GC.
+        System.gc();
+      }
+    }
+
+    return 0;
+  }
+
+  private static int processRequest(List<String> args) {
     try {
-      ImmutableList<BlazeJavaCompilerPlugin> plugins =
-          ImmutableList.<BlazeJavaCompilerPlugin>of(
-              new FileManagerInitializationPlugin(),
-              new ErrorProneOptionsPlugin());
-      JavaLibraryBuildRequest build =
-          new JavaLibraryBuildRequest(
-              Arrays.asList(args), plugins, new DependencyModule.Builder());
-      build.setJavacOpts(JavacOptions.normalizeOptions(build.getJavacOpts()));
+      JavaLibraryBuildRequest build = parse(args);
       AbstractJavaBuilder builder = build.getDependencyModule().reduceClasspath()
           ? new ReducedClasspathJavaLibraryBuilder()
           : new SimpleJavaLibraryBuilder();
       builder.run(build, System.err);
     } catch (IOException | InvalidCommandLineException e) {
       System.err.println(CMDNAME + " threw exception : " + e.getMessage());
-      System.exit(1);
+      return 1;
     }
+    return 0;
+  }
+
+  /**
+   * Parses the list of arguments into a {@link JavaLibraryBuildRequest}. The returned
+   * {@link JavaLibraryBuildRequest} object can be then used to configure the compilation itself.
+   *
+   * @throws IOException if the argument list contains a file (with the @ prefix) and reading that
+   *         file failed
+   * @throws InvalidCommandLineException on any command line error
+   */
+  private static JavaLibraryBuildRequest parse(List<String> args) throws IOException,
+      InvalidCommandLineException {
+    ImmutableList<BlazeJavaCompilerPlugin> plugins =
+        ImmutableList.<BlazeJavaCompilerPlugin>of(
+            new FileManagerInitializationPlugin(),
+            new ErrorProneOptionsPlugin());
+    JavaLibraryBuildRequest build =
+        new JavaLibraryBuildRequest(args, plugins, new DependencyModule.Builder());
+    build.setJavacOpts(JavacOptions.normalizeOptions(build.getJavacOpts()));
+    return build;
   }
 }