Generate runtime stubs in droidstubs

Similar to how the exportable stubs are generated in droidstubs, this
change adds the rule to generate the runtime stubs in droidstubs. Unlike
the exportable stubs, which the artifacts are dist'ed during the sdk
build, the runtime stubs will only used in the hiddenapi flags
generation. Therefore, only the stubs are generated and no other
artifacts are generated during the "runtime" metalava invocation. When
`aconfig_declarations` property is not defined (i.e. no flags are
enabled, thus the exportable and the runtime stubs are identical), the
runtime stubs are simple copied from the exportable stubs.

Note that the runtime stubs are not a dependency of `droid` as of now.
The dependency of the hiddenapi flags will be replaced to the runtime
stubs in the child CL.

Test: m nothing --no-skip-soong-tests && m api-stubs-docs-non-updatable
Bug: 319162970
Change-Id: I14928b7b5619522c4caab1dfc795bc9c7e929639

3 files changed, 85 insertions, 9 deletions

diff --git a/java/droiddoc.go b/java/droiddoc.go
index 6a66f45ec..df40d016c 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -222,6 +222,8 @@ type Javadoc struct {
 	stubsSrcJar android.WritablePath
 
 	exportableStubsSrcJar android.WritablePath
+
+	runtimeStubsSrcJar android.WritablePath
 }
 
 func (j *Javadoc) OutputFiles(tag string) (android.Paths, error) {
diff --git a/java/droidstubs.go b/java/droidstubs.go
index 6ca59d1db..b1126146c 100644
--- a/java/droidstubs.go
+++ b/java/droidstubs.go
@@ -214,6 +214,7 @@ type currentApiTimestampProvider interface {
 type annotationFlagsParams struct {
 	migratingNullability    bool
 	validatingNullability   bool
+	extractAnnotations      bool
 	nullabilityWarningsFile android.WritablePath
 	annotationsZip          android.WritablePath
 }
@@ -241,6 +242,7 @@ type stubsCommandConfigParams struct {
 	validatingNullability       bool
 	annotationsEnabled          bool
 	apiLevelsAnnotationsEnabled bool
+	extractAnnotations          bool
 }
 
 // droidstubs passes sources files through Metalava to generate stub .java files that only contain the API to be
@@ -525,7 +527,9 @@ func (d *Droidstubs) annotationsFlags(ctx android.ModuleContext, cmd *android.Ru
 		cmd.FlagWithOutput("--nullability-warnings-txt ", params.nullabilityWarningsFile)
 	}
 
-	cmd.FlagWithOutput("--extract-annotations ", params.annotationsZip)
+	if params.extractAnnotations {
+		cmd.FlagWithOutput("--extract-annotations ", params.annotationsZip)
+	}
 
 	if len(d.properties.Merge_annotations_dirs) != 0 {
 		d.mergeAnnoDirFlags(ctx, cmd)
@@ -571,7 +575,9 @@ func (d *Droidstubs) apiLevelsAnnotationsFlags(ctx android.ModuleContext, cmd *a
 				} else if stubsType == Exportable {
 					apiVersions = s.exportableArtifacts.apiVersionsXml
 				} else {
-					ctx.ModuleErrorf("%s stubs type does not generate api-versions.xml file", stubsType.String())
+					// if the stubs type does not generate api-versions.xml file, default to using the
+					// everything artifacts
+					apiVersions = s.everythingArtifacts.apiVersionsXml
 				}
 			} else {
 				ctx.PropertyErrorf("api_levels_module",
@@ -805,6 +811,7 @@ func (d *Droidstubs) commonMetalavaStubCmd(ctx android.ModuleContext, rule *andr
 	annotationParams := annotationFlagsParams{
 		migratingNullability:    params.stubConfig.migratingNullability,
 		validatingNullability:   params.stubConfig.validatingNullability,
+		extractAnnotations:      params.stubConfig.extractAnnotations,
 		nullabilityWarningsFile: params.nullabilityWarningsFile,
 		annotationsZip:          params.annotationsZip,
 	}
@@ -1053,6 +1060,38 @@ func (d *Droidstubs) exportableStubCmd(ctx android.ModuleContext, params stubsCo
 	d.optionalStubCmd(ctx, optionalCmdParams)
 }
 
+// Sandbox rule for generating runtime stubs
+func (d *Droidstubs) runtimeStubCmd(ctx android.ModuleContext, params stubsCommandConfigParams) {
+
+	// We are only interested in generating the stubs srcjar,
+	// not other artifacts for the runtime stubs
+	params.checkApi = false
+	params.writeSdkValues = false
+	params.validatingNullability = false
+	params.extractAnnotations = false
+	params.apiLevelsAnnotationsEnabled = false
+
+	optionalCmdParams := stubsCommandParams{
+		stubConfig: params,
+	}
+
+	d.Javadoc.runtimeStubsSrcJar = android.PathForModuleOut(ctx, params.stubsType.String(), ctx.ModuleName()+"-"+"stubs.srcjar")
+	optionalCmdParams.stubsSrcJar = d.Javadoc.runtimeStubsSrcJar
+
+	// If aconfig_declarations property is not defined, all flagged apis symbols are stripped
+	// as no aconfig flags are enabled. In such case, the runtime stubs are identical to the
+	// exportable stubs, thus no additional metalava invocation is needed.
+	if len(d.properties.Aconfig_declarations) == 0 {
+		rule := android.NewRuleBuilder(pctx, ctx)
+		rule.Command().
+			Text("cp").Flag("-f").
+			Input(d.exportableStubsSrcJar).Output(d.runtimeStubsSrcJar)
+		rule.Build(fmt.Sprintf("metalava_%s", params.stubsType.String()), "metalava merged")
+	} else {
+		d.optionalStubCmd(ctx, optionalCmdParams)
+	}
+}
+
 func (d *Droidstubs) optionalStubCmd(ctx android.ModuleContext, params stubsCommandParams) {
 
 	params.srcJarDir = android.PathForModuleOut(ctx, params.stubConfig.stubsType.String(), "srcjars")
@@ -1124,6 +1163,8 @@ func (d *Droidstubs) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 
 	annotationsEnabled := Bool(d.properties.Annotations_enabled)
 
+	extractAnnotations := annotationsEnabled
+
 	migratingNullability := annotationsEnabled && String(d.properties.Previous_api) != ""
 	validatingNullability := annotationsEnabled && (strings.Contains(String(d.Javadoc.properties.Args), "--validate-nullability-from-merged-stubs") ||
 		String(d.properties.Validate_nullability_from_list) != "")
@@ -1145,17 +1186,26 @@ func (d *Droidstubs) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 		validatingNullability:       validatingNullability,
 		annotationsEnabled:          annotationsEnabled,
 		apiLevelsAnnotationsEnabled: apiLevelsAnnotationsEnabled,
+		extractAnnotations:          extractAnnotations,
 	}
 	stubCmdParams.stubsType = Everything
 	// Create default (i.e. "everything" stubs) rule for metalava
 	d.everythingStubCmd(ctx, stubCmdParams)
 
-	// The module generates "exportable" (and "runtime" eventually) stubs regardless of whether
+	// The module generates "exportable" stubs regardless of whether
 	// aconfig_declarations property is defined or not. If the property is not defined, the module simply
 	// strips all flagged apis to generate the "exportable" stubs
 	stubCmdParams.stubsType = Exportable
 	d.exportableStubCmd(ctx, stubCmdParams)
 
+	// "runtime" stubs do not generate any other artifacts than the stubs.
+	// Therefore, metalava does not have to run for "runtime" configuration
+	// when the module does not generate stubs.
+	if stubCmdParams.generateStubs {
+		stubCmdParams.stubsType = Runtime
+		d.runtimeStubCmd(ctx, stubCmdParams)
+	}
+
 	if apiCheckEnabled(ctx, d.properties.Check_api.Current, "current") {
 
 		if len(d.Javadoc.properties.Out) > 0 {
diff --git a/java/droidstubs_test.go b/java/droidstubs_test.go
index e5ffd2847..ca34e0ef1 100644
--- a/java/droidstubs_test.go
+++ b/java/droidstubs_test.go
@@ -396,23 +396,47 @@ func TestAconfigDeclarations(t *testing.T) {
 			"bar",
 		],
 	}
+	droidstubs {
+		name: "baz",
+		srcs: ["a/A.java"],
+		api_surface: "public",
+		check_api: {
+			current: {
+				api_file: "a/current.txt",
+				removed_api_file: "a/removed.txt",
+			}
+		},
+	}
 	`)
 
 	// Check that droidstubs depend on aconfig_declarations
 	android.AssertBoolEquals(t, "foo expected to depend on bar",
 		CheckModuleHasDependency(t, result.TestContext, "foo", "android_common", "bar"), true)
 
-	m := result.ModuleForTests("foo", "android_common")
+	fooModule := result.ModuleForTests("foo", "android_common")
 	android.AssertStringDoesContain(t, "foo generates revert annotations file",
-		strings.Join(m.AllOutputs(), ""), "revert-annotations-exportable.txt")
+		strings.Join(fooModule.AllOutputs(), ""), "revert-annotations-exportable.txt")
 
 	// revert-annotations.txt passed to exportable stubs generation metalava command
-	manifest := m.Output("metalava_exportable.sbox.textproto")
-	cmdline := String(android.RuleBuilderSboxProtoForTests(t, result.TestContext, manifest).Commands[0].Command)
-	android.AssertStringDoesContain(t, "flagged api hide command not included", cmdline, "revert-annotations-exportable.txt")
+	exportableManifest := fooModule.Output("metalava_exportable.sbox.textproto")
+	exportableCmdline := String(android.RuleBuilderSboxProtoForTests(t, result.TestContext, exportableManifest).Commands[0].Command)
+	android.AssertStringDoesContain(t, "flagged api hide command not included", exportableCmdline, "revert-annotations-exportable.txt")
 
 	android.AssertStringDoesContain(t, "foo generates exportable stubs jar",
-		strings.Join(m.AllOutputs(), ""), "exportable/foo-stubs.srcjar")
+		strings.Join(fooModule.AllOutputs(), ""), "exportable/foo-stubs.srcjar")
+
+	// revert-annotations.txt passed to runtime stubs generation metalava command
+	runtimeManifest := fooModule.Output("metalava_runtime.sbox.textproto")
+	runtimeCmdline := String(android.RuleBuilderSboxProtoForTests(t, result.TestContext, runtimeManifest).Commands[0].Command)
+	android.AssertStringDoesContain(t, "flagged api hide command not included", runtimeCmdline, "revert-annotations-runtime.txt")
+
+	android.AssertStringDoesContain(t, "foo generates runtime stubs jar",
+		strings.Join(fooModule.AllOutputs(), ""), "runtime/foo-stubs.srcjar")
+
+	// If aconfig_declarations property is not defined, the runtime stubs is a copy of the exportable stubs
+	bazModule := result.ModuleForTests("baz", "android_common")
+	bazRuntimeCmdline := bazModule.Rule("metalava_runtime").RuleParams.Command
+	android.AssertStringDoesContain(t, "copy command should include the input stub", bazRuntimeCmdline, "exportable/baz-stubs.srcjar")
 }
 
 func TestReleaseExportRuntimeApis(t *testing.T) {