Use one writer for generating R.java source files

RELNOTES: None
PiperOrigin-RevId: 156205544

1 files changed, 100 insertions, 0 deletions

diff --git a/src/tools/android/java/com/google/devtools/build/android/resources/RSourceGenerator.java b/src/tools/android/java/com/google/devtools/build/android/resources/RSourceGenerator.java
new file mode 100644
index 0000000000..e2d19b1c73
--- /dev/null
+++ b/src/tools/android/java/com/google/devtools/build/android/resources/RSourceGenerator.java
@@ -0,0 +1,100 @@
+// Copyright 2017 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.resources;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.android.SdkConstants;
+import com.android.resources.ResourceType;
+import com.google.common.collect.Iterables;
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Collection;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+/** Writes out an R.java source. */
+public class RSourceGenerator {
+
+  public static RSourceGenerator with(
+      Path outputBasePath, FieldInitializers initializers, boolean finalFields) {
+    return new RSourceGenerator(outputBasePath, initializers, finalFields);
+  }
+
+  private final Path outputBasePath;
+  private final FieldInitializers values;
+  private final boolean finalFields;
+
+  private RSourceGenerator(
+      Path outputBasePath, FieldInitializers initializers, boolean finalFields) {
+    this.outputBasePath = outputBasePath;
+    this.values = initializers;
+    this.finalFields = finalFields;
+  }
+
+  /** Writes the java source with the writer values to the specified package and derived dir. */
+  public void write(String packageName) throws IOException {
+    write(packageName, values);
+  }
+
+  /**
+   * Writes the java source with the passed subset of the writer values.
+   *
+   * @param packageName The package and the dir to write the R java source to under the output
+   *     path.
+   * @param symbolsToWrite A map of ResourceType to resource name that will be written. If the map
+   *     specifies a resource that does not exist in the writer values, it will be ignored.
+   */
+  public void write(String packageName, Map<ResourceType, Set<String>> symbolsToWrite)
+      throws IOException {
+    write(packageName, values.filter(symbolsToWrite));
+  }
+
+  private void write(
+      String packageName,
+      Iterable<Entry<ResourceType, Collection<FieldInitializer>>> initializersToWrite)
+      throws IOException {
+    String packageDir = packageName.replace('.', '/');
+    Path packagePath = outputBasePath.resolve(packageDir);
+    Path rJavaPath = packagePath.resolve(SdkConstants.FN_RESOURCE_CLASS);
+    Files.createDirectories(rJavaPath.getParent());
+
+    if (Iterables.isEmpty(initializersToWrite)) {
+      return;
+    }
+
+    try (BufferedWriter writer = Files.newBufferedWriter(rJavaPath, UTF_8)) {
+      writer.write("/* AUTO-GENERATED FILE.  DO NOT MODIFY.\n");
+      writer.write(" *\n");
+      writer.write(" * This class was automatically generated by the\n");
+      writer.write(" * bazel tool from the resource data it found.  It\n");
+      writer.write(" * should not be modified by hand.\n");
+      writer.write(" */\n");
+      writer.write(String.format("package %s;\n", packageName));
+      writer.write("public final class R {\n");
+      for (Entry<ResourceType, Collection<FieldInitializer>> entry : initializersToWrite) {
+        writer.write(
+            String.format("    public static final class %s {\n", entry.getKey().getName()));
+        for (FieldInitializer field : entry.getValue()) {
+          field.writeInitSource(writer, finalFields);
+        }
+        writer.write("    }\n");
+      }
+      writer.write("}");
+    }
+  }
+}