Add assets support to aar_import.

Fixes https://github.com/bazelbuild/bazel/issues/4439.

Empty assets are handled by writing out an empty file named "assets/empty_asset_generated_by_bazel~", which will silently be ignored by AAPT.

RELNOTES: aar_import now supports assets.
PiperOrigin-RevId: 182110400

2 files changed, 22 insertions, 26 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/AarImport.java b/src/main/java/com/google/devtools/build/lib/rules/android/AarImport.java
index 2d696d28e4..9617d95063 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/AarImport.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/AarImport.java
@@ -17,7 +17,6 @@ import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.actions.Action;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
-import com.google.devtools.build.lib.analysis.FileProvider;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTargetFactory;
 import com.google.devtools.build.lib.analysis.RuleContext;
@@ -27,7 +26,6 @@ import com.google.devtools.build.lib.analysis.actions.CustomCommandLine;
 import com.google.devtools.build.lib.analysis.actions.SpawnAction;
 import com.google.devtools.build.lib.analysis.configuredtargets.RuleConfiguredTarget.Mode;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
-import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.rules.java.JavaCommon;
 import com.google.devtools.build.lib.rules.java.JavaCompilationArgsProvider;
 import com.google.devtools.build.lib.rules.java.JavaCompilationArtifacts;
@@ -83,23 +81,20 @@ public class AarImport implements RuleConfiguredTargetFactory {
             ruleContext, aar, ANDROID_MANIFEST, androidManifestArtifact));
 
     Artifact resources = createAarTreeArtifact(ruleContext, "resources");
-    ruleContext.registerAction(createAarResourcesExtractorActions(ruleContext, aar, resources));
+    Artifact assets = createAarTreeArtifact(ruleContext, "assets");
+    ruleContext.registerAction(
+        createAarResourcesExtractorActions(ruleContext, aar, resources, assets));
 
     ApplicationManifest androidManifest =
         ApplicationManifest.fromExplicitManifest(ruleContext, androidManifestArtifact);
 
-    FileProvider resourcesProvider =
-        new FileProvider(
-            new NestedSetBuilder<Artifact>(Order.NAIVE_LINK_ORDER).add(resources).build());
-
     Artifact resourcesZip =
         ruleContext.getImplicitOutputArtifact(AndroidRuleClasses.ANDROID_RESOURCES_ZIP);
 
     ResourceApk resourceApk =
         androidManifest.packAarWithDataAndResources(
             ruleContext,
-            LocalResourceContainer.forResourceFileProvider(
-                ruleContext, resourcesProvider, "resources"),
+            LocalResourceContainer.forAssetsAndResourcesDirectories(assets, resources),
             ResourceDependencies.fromRuleDeps(ruleContext, JavaCommon.isNeverLink(ruleContext)),
             ruleContext.getImplicitOutputArtifact(AndroidRuleClasses.ANDROID_R_TXT),
             ruleContext.getImplicitOutputArtifact(AndroidRuleClasses.ANDROID_LOCAL_SYMBOLS),
@@ -195,7 +190,7 @@ public class AarImport implements RuleConfiguredTargetFactory {
   }
 
   private static Action[] createAarResourcesExtractorActions(
-      RuleContext ruleContext, Artifact aar, Artifact outputTree) {
+      RuleContext ruleContext, Artifact aar, Artifact resourcesDir, Artifact assetsDir) {
     return new SpawnAction.Builder()
         .useDefaultShellEnvironment()
         .setExecutable(
@@ -203,11 +198,13 @@ public class AarImport implements RuleConfiguredTargetFactory {
                 AarImportBaseRule.AAR_RESOURCES_EXTRACTOR, Mode.HOST))
         .setMnemonic("AarResourcesExtractor")
         .addInput(aar)
-        .addOutput(outputTree)
+        .addOutput(resourcesDir)
+        .addOutput(assetsDir)
         .addCommandLine(
             CustomCommandLine.builder()
                 .addExecPath("--input_aar", aar)
-                .addExecPath("--output_res_dir", outputTree)
+                .addExecPath("--output_res_dir", resourcesDir)
+                .addExecPath("--output_assets_dir", assetsDir)
                 .build())
         .build(ruleContext);
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/LocalResourceContainer.java b/src/main/java/com/google/devtools/build/lib/rules/android/LocalResourceContainer.java
index d0da13d2bb..f11cd1835a 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/LocalResourceContainer.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/LocalResourceContainer.java
@@ -16,6 +16,7 @@ package com.google.devtools.build.lib.rules.android;
 import com.android.resources.ResourceFolderType;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Joiner;
+import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.actions.Artifact;
@@ -165,27 +166,25 @@ public final class LocalResourceContainer {
   }
 
   /**
-   * Creates a {@link LocalResourceContainer} containing the resources included in a {@link
-   * FileProvider}.
+   * Creates a {@link LocalResourceContainer} containing all the resources and assets in directory
+   * artifacts.
    *
    * <p>In general, {@link #forAssetsAndResources(RuleContext, String, PathFragment, String)} should
    * be used instead. No assets or transitive resources will be included in the container produced
    * by this method.
    *
-   * @param ruleContext the current context
-   * @param resourceFileProvider the provider containing resources
-   * @param resourcesAttr the attribute used to refer to resource files in this target.
+   * @param assetsDir the tree artifact containing a {@code assets/} directory
+   * @param resourcesDir the tree artifact containing a {@code res/} directory
    */
-  public static LocalResourceContainer forResourceFileProvider(
-      RuleContext ruleContext, FileProvider resourceFileProvider, String resourcesAttr)
-      throws RuleErrorException {
-    ImmutableList<Artifact> resources = getResources(ImmutableList.of(resourceFileProvider));
-
+  static LocalResourceContainer forAssetsAndResourcesDirectories(
+      Artifact assetsDir, Artifact resourcesDir) {
+    Preconditions.checkArgument(resourcesDir.isTreeArtifact());
+    Preconditions.checkArgument(assetsDir.isTreeArtifact());
     return new LocalResourceContainer(
-        resources,
-        getResourceRoots(ruleContext, resources, resourcesAttr),
-        ImmutableList.of(),
-        ImmutableList.of());
+        ImmutableList.of(resourcesDir),
+        ImmutableList.of(resourcesDir.getExecPath().getChild("res")),
+        ImmutableList.of(assetsDir),
+        ImmutableList.of(assetsDir.getExecPath().getChild("assets")));
   }
 
   private static ImmutableList<Artifact> getResources(Iterable<FileProvider> targets) {