Add support for native header outputs to JavaBuilder

Add a --native_header_output flag which, if set, causes JavaBuilder to set
the equivalent of `javac -h`, and then collect all generated headers and
write them to a jar archive at the given path.

PiperOrigin-RevId: 180954084

6 files changed, 105 insertions, 60 deletions

diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/BUILD b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/BUILD
index 64d8fa649c..5690a38298 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/BUILD
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/BUILD
@@ -23,6 +23,7 @@ java_library(
     deps = [
         ":JarOwner",
         "//third_party:guava",
+        "//third_party:jsr305",
     ],
 )
 
diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/JavaLibraryBuildRequest.java b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/JavaLibraryBuildRequest.java
index c0ba8d976a..0a45152647 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/JavaLibraryBuildRequest.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/JavaLibraryBuildRequest.java
@@ -60,6 +60,7 @@ public final class JavaLibraryBuildRequest {
   private final List<String> processorNames;
 
   private final Path outputJar;
+  private final Path nativeHeaderOutput;
 
   private final Path classDir;
   private final Path tempDir;
@@ -170,6 +171,7 @@ public final class JavaLibraryBuildRequest {
     this.classDir = asPath(firstNonNull(optionsParser.getClassDir(), "classes"));
     this.tempDir = asPath(firstNonNull(optionsParser.getTempDir(), "_tmp"));
     this.outputJar = asPath(optionsParser.getOutputJar());
+    this.nativeHeaderOutput = asPath(optionsParser.getNativeHeaderOutput());
     for (Entry<String, List<String>> entry : optionsParser.getPostProcessors().entrySet()) {
       switch (entry.getKey()) {
         case "jacoco":
@@ -253,6 +255,10 @@ public final class JavaLibraryBuildRequest {
     return outputJar;
   }
 
+  public Path getNativeHeaderOutput() {
+    return nativeHeaderOutput;
+  }
+
   public Path getClassDir() {
     return classDir;
   }
@@ -261,6 +267,10 @@ public final class JavaLibraryBuildRequest {
     return tempDir;
   }
 
+  public Path getNativeHeaderDir() {
+    return getTempDir().resolve("native_headers");
+  }
+
   public JacocoInstrumentationProcessor getJacocoInstrumentationProcessor() {
     return jacocoInstrumentationProcessor;
   }
@@ -282,22 +292,26 @@ public final class JavaLibraryBuildRequest {
   }
 
   public BlazeJavacArguments toBlazeJavacArguments(ImmutableList<Path> classPath) {
-    return BlazeJavacArguments.builder()
-        .classPath(classPath)
-        .classOutput(getClassDir())
-        .bootClassPath(
-            ImmutableList.<Path>builder()
-                .addAll(getBootClassPath())
-                .addAll(getExtClassPath())
-                .build())
-        .javacOptions(makeJavacArguments())
-        .sourceFiles(ImmutableList.copyOf(getSourceFiles()))
-        .processors(null)
-        .sourcePath(getSourcePath())
-        .sourceOutput(getSourceGenDir())
-        .processorPath(getProcessorPath())
-        .plugins(getPlugins())
-        .build();
+    BlazeJavacArguments.Builder builder =
+        BlazeJavacArguments.builder()
+            .classPath(classPath)
+            .classOutput(getClassDir())
+            .bootClassPath(
+                ImmutableList.<Path>builder()
+                    .addAll(getBootClassPath())
+                    .addAll(getExtClassPath())
+                    .build())
+            .javacOptions(makeJavacArguments())
+            .sourceFiles(ImmutableList.copyOf(getSourceFiles()))
+            .processors(null)
+            .sourcePath(getSourcePath())
+            .sourceOutput(getSourceGenDir())
+            .processorPath(getProcessorPath())
+            .plugins(getPlugins());
+    if (getNativeHeaderOutput() != null) {
+      builder.nativeHeaderOutput(getNativeHeaderDir());
+    }
+    return builder.build();
   }
 
   /** Constructs a command line that can be used for a javac invocation. */
diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/OptionsParser.java b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/OptionsParser.java
index 9a7cc7d807..8df2d2d718 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/OptionsParser.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/OptionsParser.java
@@ -35,6 +35,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.NoSuchElementException;
 import java.util.Set;
+import javax.annotation.Nullable;
 
 /**
  * Parses options that the {@link JavaLibraryBuildRequest} needs to construct a build request from
@@ -71,6 +72,7 @@ public final class OptionsParser {
   private final List<String> processorNames = new ArrayList<>();
 
   private String outputJar;
+  private @Nullable String nativeHeaderOutput;
 
   private String classDir;
   private String tempDir;
@@ -184,6 +186,9 @@ public final class OptionsParser {
         case "--output":
           outputJar = getArgument(argQueue, arg);
           break;
+        case "--native_header_output":
+          nativeHeaderOutput = getArgument(argQueue, arg);
+          break;
         case "--classdir":
           classDir = getArgument(argQueue, arg);
           break;
@@ -419,6 +424,11 @@ public final class OptionsParser {
     return outputJar;
   }
 
+  @Nullable
+  public String getNativeHeaderOutput() {
+    return nativeHeaderOutput;
+  }
+
   public String getClassDir() {
     return classDir;
   }
diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/SimpleJavaLibraryBuilder.java b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/SimpleJavaLibraryBuilder.java
index 7f461c0c7a..d5dd08688d 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/SimpleJavaLibraryBuilder.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/SimpleJavaLibraryBuilder.java
@@ -33,6 +33,7 @@ import java.nio.file.SimpleFileVisitor;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.util.HashMap;
 import java.util.Map;
+import javax.annotation.Nullable;
 
 /** An implementation of the JavaBuilder that uses in-process javac to compile java files. */
 public class SimpleJavaLibraryBuilder implements Closeable {
@@ -49,30 +50,45 @@ public class SimpleJavaLibraryBuilder implements Closeable {
   }
 
   protected void prepareSourceCompilation(JavaLibraryBuildRequest build) throws IOException {
-    Path classDirectory = build.getClassDir();
-    if (Files.exists(classDirectory)) {
-      try {
-        // Necessary for local builds in order to discard previous outputs
-        cleanupDirectory(classDirectory);
-      } catch (IOException e) {
-        throw new IOException("Cannot clean output directory '" + classDirectory + "'", e);
-      }
-    }
-    Files.createDirectories(classDirectory);
+    cleanupDirectory(build.getClassDir());
 
     setUpSourceJars(build);
+    cleanupDirectory(build.getSourceGenDir());
+    cleanupDirectory(build.getNativeHeaderDir());
+  }
 
-    // Create sourceGenDir if necessary.
-    if (build.getSourceGenDir() != null) {
-      Path sourceGenDir = build.getSourceGenDir();
-      if (Files.exists(sourceGenDir)) {
-        try {
-          cleanupDirectory(sourceGenDir);
-        } catch (IOException e) {
-          throw new IOException("Cannot clean output directory '" + sourceGenDir + "'", e);
-        }
-      }
-      Files.createDirectories(sourceGenDir);
+  // Necessary for local builds in order to discard previous outputs
+  private static void cleanupDirectory(@Nullable Path directory) throws IOException {
+    if (directory == null) {
+      return;
+    }
+    if (!Files.exists(directory)) {
+      Files.createDirectories(directory);
+      return;
+    }
+    try {
+      // TODO(b/27069912): handle symlinks
+      Files.walkFileTree(
+          directory,
+          new SimpleFileVisitor<Path>() {
+            @Override
+            public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
+                throws IOException {
+              Files.delete(file);
+              return FileVisitResult.CONTINUE;
+            }
+
+            @Override
+            public FileVisitResult postVisitDirectory(Path dir, IOException exc)
+                throws IOException {
+              if (!dir.equals(directory)) {
+                Files.delete(dir);
+              }
+              return FileVisitResult.CONTINUE;
+            }
+          });
+    } catch (IOException e) {
+      throw new IOException("Cannot clean '" + directory + "'", e);
     }
   }
 
@@ -116,6 +132,7 @@ public class SimpleJavaLibraryBuilder implements Closeable {
       result = compileJavaLibrary(build);
       if (result.isOk()) {
         buildJar(build);
+        nativeHeaderOutput(build);
       }
       if (!build.getProcessors().isEmpty()) {
         if (build.getGeneratedSourcesOutputJar() != null) {
@@ -144,6 +161,20 @@ public class SimpleJavaLibraryBuilder implements Closeable {
     }
   }
 
+  public void nativeHeaderOutput(JavaLibraryBuildRequest build) throws IOException {
+    if (build.getNativeHeaderOutput() == null) {
+      return;
+    }
+    JarCreator jar = new JarCreator(build.getNativeHeaderOutput());
+    try {
+      jar.setNormalize(true);
+      jar.setCompression(build.compressJar());
+      jar.addDirectory(build.getNativeHeaderDir());
+    } finally {
+      jar.execute();
+    }
+  }
+
   /**
    * Extracts the all source jars from the build request into the temporary directory specified in
    * the build request. Empties the temporary directory, if it exists.
@@ -151,9 +182,7 @@ public class SimpleJavaLibraryBuilder implements Closeable {
   private void setUpSourceJars(JavaLibraryBuildRequest build) throws IOException {
     Path sourcesDir = build.getTempDir();
 
-    if (Files.exists(sourcesDir)) {
-      cleanupDirectory(sourcesDir);
-    }
+    cleanupDirectory(sourcesDir);
 
     if (build.getSourceJars().isEmpty()) {
       return;
@@ -198,26 +227,6 @@ public class SimpleJavaLibraryBuilder implements Closeable {
     return fs;
   }
 
-  // TODO(b/27069912): handle symlinks
-  private static void cleanupDirectory(Path dir) throws IOException {
-    Files.walkFileTree(
-        dir,
-        new SimpleFileVisitor<Path>() {
-          @Override
-          public FileVisitResult visitFile(Path file, BasicFileAttributes attrs)
-              throws IOException {
-            Files.delete(file);
-            return FileVisitResult.CONTINUE;
-          }
-
-          @Override
-          public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
-            Files.delete(dir);
-            return FileVisitResult.CONTINUE;
-          }
-        });
-  }
-
   @Override
   public void close() throws IOException {
     for (FileSystem fs : filesystems.values()) {
diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacArguments.java b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacArguments.java
index f4da51ca7a..c187b2a396 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacArguments.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacArguments.java
@@ -61,6 +61,10 @@ public abstract class BlazeJavacArguments {
   /** The class output directory (-d). */
   public abstract Path classOutput();
 
+  /** The native header output directory (-h). */
+  @Nullable
+  public abstract Path nativeHeaderOutput();
+
   /** The generated source output directory (-s). */
   @Nullable
   public abstract Path sourceOutput();
@@ -85,6 +89,8 @@ public abstract class BlazeJavacArguments {
 
     Builder classOutput(Path classOutput);
 
+    Builder nativeHeaderOutput(Path nativeHeaderOutput);
+
     Builder bootClassPath(ImmutableList<Path> bootClassPath);
 
     Builder javacOptions(ImmutableList<String> javacOptions);
diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacMain.java b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacMain.java
index 1be5335f59..74059d2e4e 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacMain.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/buildjar/javac/BlazeJavacMain.java
@@ -172,6 +172,11 @@ public class BlazeJavacMain {
       fileManager.setLocationFromPaths(StandardLocation.CLASS_PATH, arguments.classPath());
       fileManager.setLocationFromPaths(
           StandardLocation.CLASS_OUTPUT, ImmutableList.of(arguments.classOutput()));
+      if (arguments.nativeHeaderOutput() != null) {
+        fileManager.setLocationFromPaths(
+            StandardLocation.NATIVE_HEADER_OUTPUT,
+            ImmutableList.of(arguments.nativeHeaderOutput()));
+      }
       fileManager.setLocationFromPaths(StandardLocation.SOURCE_PATH, arguments.sourcePath());
       // TODO(cushon): require an explicit bootclasspath
       Collection<Path> bootClassPath = arguments.bootClassPath();