Consolidate the code to resolve a deapexer module dependency.

It will get more logic in upcoming CLs.

Add a property to DeapexerInfo for the APEX name, for use in error
messages.

Test: m nothing
Bug: 192006406
Change-Id: I957f3df8b34543a38cde38768dac93e78132d672

7 files changed, 60 insertions, 56 deletions

diff --git a/android/deapexer.go b/android/deapexer.go
index 9290481d4..bed657464 100644
--- a/android/deapexer.go
+++ b/android/deapexer.go
@@ -69,6 +69,8 @@ import (
 
 // The information exported by the `deapexer` module, access it using `DeapxerInfoProvider`.
 type DeapexerInfo struct {
+	apexModuleName string
+
 	// map from the name of an exported file from a prebuilt_apex to the path to that file. The
 	// exported file name is the apex relative path, e.g. javalib/core-libart.jar.
 	//
@@ -76,6 +78,11 @@ type DeapexerInfo struct {
 	exports map[string]WritablePath
 }
 
+// ApexModuleName returns the name of the APEX module that provided the info.
+func (i DeapexerInfo) ApexModuleName() string {
+	return i.apexModuleName
+}
+
 // PrebuiltExportPath provides the path, or nil if not available, of a file exported from the
 // prebuilt_apex that created this ApexInfo.
 //
@@ -95,9 +102,10 @@ var DeapexerProvider = blueprint.NewProvider(DeapexerInfo{})
 // for use with a prebuilt_apex module.
 //
 // See apex/deapexer.go for more information.
-func NewDeapexerInfo(exports map[string]WritablePath) DeapexerInfo {
+func NewDeapexerInfo(apexModuleName string, exports map[string]WritablePath) DeapexerInfo {
 	return DeapexerInfo{
-		exports: exports,
+		apexModuleName: apexModuleName,
+		exports:        exports,
 	}
 }
 
@@ -133,3 +141,20 @@ type RequiresFilesFromPrebuiltApexTag interface {
 	// Method that differentiates this interface from others.
 	RequiresFilesFromPrebuiltApex()
 }
+
+// FindDeapexerProviderForModule searches through the direct dependencies of the current context
+// module for a DeapexerTag dependency and returns its DeapexerInfo. If there is an error then it is
+// reported with ctx.ModuleErrorf and nil is returned.
+func FindDeapexerProviderForModule(ctx ModuleContext) *DeapexerInfo {
+	var di *DeapexerInfo
+	ctx.VisitDirectDepsWithTag(DeapexerTag, func(m Module) {
+		p := ctx.OtherModuleProvider(m, DeapexerProvider).(DeapexerInfo)
+		di = &p
+	})
+	if di != nil {
+		return di
+	}
+	ai := ctx.Provider(ApexInfoProvider).(ApexInfo)
+	ctx.ModuleErrorf("No prebuilt APEX provides a deapexer module for APEX variant %s", ai.ApexVariationName)
+	return nil
+}
diff --git a/apex/apex_test.go b/apex/apex_test.go
index 1f9bd5a2e..420489e68 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -4859,8 +4859,11 @@ func TestPrebuiltExportDexImplementationJars(t *testing.T) {
 		// Make sure that dexpreopt can access dex implementation files from the prebuilt.
 		ctx := testDexpreoptWithApexes(t, bp, "", transform)
 
+		deapexerName := deapexerModuleName("myapex")
+		android.AssertStringEquals(t, "APEX module name from deapexer name", "myapex", apexModuleName(deapexerName))
+
 		// Make sure that the deapexer has the correct input APEX.
-		deapexer := ctx.ModuleForTests("myapex.deapexer", "android_common")
+		deapexer := ctx.ModuleForTests(deapexerName, "android_common")
 		rule := deapexer.Rule("deapexer")
 		if expected, actual := []string{"myapex-arm64.apex"}, android.NormalizePathsForTesting(rule.Implicits); !reflect.DeepEqual(expected, actual) {
 			t.Errorf("expected: %q, found: %q", expected, actual)
diff --git a/apex/deapexer.go b/apex/deapexer.go
index 2c1835aa4..8c9030a85 100644
--- a/apex/deapexer.go
+++ b/apex/deapexer.go
@@ -15,6 +15,8 @@
 package apex
 
 import (
+	"strings"
+
 	"android/soong/android"
 )
 
@@ -75,6 +77,17 @@ type Deapexer struct {
 	inputApex android.Path
 }
 
+// Returns the name of the deapexer module corresponding to an APEX module with the given name.
+func deapexerModuleName(apexModuleName string) string {
+	return apexModuleName + ".deapexer"
+}
+
+// Returns the name of the APEX module corresponding to an deapexer module with
+// the given name. This reverses deapexerModuleName.
+func apexModuleName(deapexerModuleName string) string {
+	return strings.TrimSuffix(deapexerModuleName, ".deapexer")
+}
+
 func privateDeapexerFactory() android.Module {
 	module := &Deapexer{}
 	module.AddProperties(&module.properties, &module.selectedApexProperties)
@@ -113,7 +126,8 @@ func (p *Deapexer) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	// apex relative path to extracted file path available for other modules.
 	if len(exports) > 0 {
 		// Make the information available for other modules.
-		ctx.SetProvider(android.DeapexerProvider, android.NewDeapexerInfo(exports))
+		di := android.NewDeapexerInfo(apexModuleName(ctx.ModuleName()), exports)
+		ctx.SetProvider(android.DeapexerProvider, di)
 
 		// Create a sorted list of the files that this exports.
 		exportedPaths = android.SortedUniquePaths(exportedPaths)
@@ -131,6 +145,6 @@ func (p *Deapexer) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 		for _, p := range exportedPaths {
 			command.Output(p.(android.WritablePath))
 		}
-		builder.Build("deapexer", "deapex "+ctx.ModuleName())
+		builder.Build("deapexer", "deapex "+apexModuleName(ctx.ModuleName()))
 	}
 }
diff --git a/apex/prebuilt.go b/apex/prebuilt.go
index d7be9a9e1..d59f8bfec 100644
--- a/apex/prebuilt.go
+++ b/apex/prebuilt.go
@@ -631,10 +631,6 @@ func createDeapexerModuleIfNeeded(ctx android.TopDownMutatorContext, deapexerNam
 	)
 }
 
-func deapexerModuleName(baseModuleName string) string {
-	return baseModuleName + ".deapexer"
-}
-
 func apexSelectorModuleName(baseModuleName string) string {
 	return baseModuleName + ".apex.selector"
 }
diff --git a/java/bootclasspath_fragment.go b/java/bootclasspath_fragment.go
index b13e2dba4..79c73ca87 100644
--- a/java/bootclasspath_fragment.go
+++ b/java/bootclasspath_fragment.go
@@ -954,23 +954,11 @@ func (module *prebuiltBootclasspathFragmentModule) produceBootImageFiles(ctx and
 		return nil
 	}
 
-	var deapexerModule android.Module
-	ctx.VisitDirectDeps(func(module android.Module) {
-		tag := ctx.OtherModuleDependencyTag(module)
-		// Save away the `deapexer` module on which this depends, if any.
-		if tag == android.DeapexerTag {
-			deapexerModule = module
-		}
-	})
-
-	if deapexerModule == nil {
-		// This should never happen as a variant for a prebuilt_apex is only created if the
-		// deapexer module has been configured to export the dex implementation jar for this module.
-		ctx.ModuleErrorf("internal error: module does not depend on a `deapexer` module")
-		return nil
+	di := android.FindDeapexerProviderForModule(ctx)
+	if di == nil {
+		return nil // An error has been reported by FindDeapexerProviderForModule.
 	}
 
-	di := ctx.OtherModuleProvider(deapexerModule, android.DeapexerProvider).(android.DeapexerInfo)
 	files := bootImageFilesByArch{}
 	for _, variant := range imageConfig.apexVariants() {
 		arch := variant.target.Arch.ArchType
diff --git a/java/java.go b/java/java.go
index cfed1c893..b2c199992 100644
--- a/java/java.go
+++ b/java/java.go
@@ -1319,7 +1319,6 @@ func (j *Import) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	j.classLoaderContexts = make(dexpreopt.ClassLoaderContextMap)
 
 	var flags javaBuilderFlags
-	var deapexerModule android.Module
 
 	ctx.VisitDirectDeps(func(module android.Module) {
 		tag := ctx.OtherModuleDependencyTag(module)
@@ -1340,11 +1339,6 @@ func (j *Import) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 		}
 
 		addCLCFromDep(ctx, module, j.classLoaderContexts)
-
-		// Save away the `deapexer` module on which this depends, if any.
-		if tag == android.DeapexerTag {
-			deapexerModule = module
-		}
 	})
 
 	if Bool(j.properties.Installable) {
@@ -1359,16 +1353,11 @@ func (j *Import) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 		// obtained from the associated deapexer module.
 		ai := ctx.Provider(android.ApexInfoProvider).(android.ApexInfo)
 		if ai.ForPrebuiltApex {
-			if deapexerModule == nil {
-				// This should never happen as a variant for a prebuilt_apex is only created if the
-				// deapexer module has been configured to export the dex implementation jar for this module.
-				ctx.ModuleErrorf("internal error: module %q does not depend on a `deapexer` module for prebuilt_apex %q",
-					j.Name(), ai.ApexVariationName)
-				return
-			}
-
 			// Get the path of the dex implementation jar from the `deapexer` module.
-			di := ctx.OtherModuleProvider(deapexerModule, android.DeapexerProvider).(android.DeapexerInfo)
+			di := android.FindDeapexerProviderForModule(ctx)
+			if di == nil {
+				return // An error has been reported by FindDeapexerProviderForModule.
+			}
 			if dexOutputPath := di.PrebuiltExportPath(apexRootRelativePathToJavaLib(j.BaseModuleName())); dexOutputPath != nil {
 				dexJarFile := makeDexJarPathFromPath(dexOutputPath)
 				j.dexJarFile = dexJarFile
@@ -1379,7 +1368,7 @@ func (j *Import) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 			} else {
 				// This should never happen as a variant for a prebuilt_apex is only created if the
 				// prebuilt_apex has been configured to export the java library dex file.
-				ctx.ModuleErrorf("internal error: no dex implementation jar available from prebuilt_apex %q", deapexerModule.Name())
+				ctx.ModuleErrorf("internal error: no dex implementation jar available from prebuilt APEX %s", di.ApexModuleName())
 			}
 		} else if Bool(j.dexProperties.Compile_dex) {
 			sdkDep := decodeSdkDep(ctx, android.SdkContext(j))
diff --git a/java/sdk_library.go b/java/sdk_library.go
index 0fcce1752..0c61f94fd 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -2157,8 +2157,6 @@ func (module *SdkLibraryImport) OutputFiles(tag string) (android.Paths, error) {
 func (module *SdkLibraryImport) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	module.generateCommonBuildActions(ctx)
 
-	var deapexerModule android.Module
-
 	// Assume that source module(sdk_library) is installed in /<sdk_library partition>/framework
 	module.installFile = android.PathForModuleInstall(ctx, "framework", module.Stem()+".jar")
 
@@ -2187,11 +2185,6 @@ func (module *SdkLibraryImport) GenerateAndroidBuildActions(ctx android.ModuleCo
 				ctx.ModuleErrorf("xml permissions file module must be of type *sdkLibraryXml but was %T", to)
 			}
 		}
-
-		// Save away the `deapexer` module on which this depends, if any.
-		if tag == android.DeapexerTag {
-			deapexerModule = to
-		}
 	})
 
 	// Populate the scope paths with information from the properties.
@@ -2210,15 +2203,11 @@ func (module *SdkLibraryImport) GenerateAndroidBuildActions(ctx android.ModuleCo
 		// obtained from the associated deapexer module.
 		ai := ctx.Provider(android.ApexInfoProvider).(android.ApexInfo)
 		if ai.ForPrebuiltApex {
-			if deapexerModule == nil {
-				// This should never happen as a variant for a prebuilt_apex is only created if the
-				// deapxer module has been configured to export the dex implementation jar for this module.
-				ctx.ModuleErrorf("internal error: module %q does not depend on a `deapexer` module for prebuilt_apex %q",
-					module.Name(), ai.ApexVariationName)
-			}
-
 			// Get the path of the dex implementation jar from the `deapexer` module.
-			di := ctx.OtherModuleProvider(deapexerModule, android.DeapexerProvider).(android.DeapexerInfo)
+			di := android.FindDeapexerProviderForModule(ctx)
+			if di == nil {
+				return // An error has been reported by FindDeapexerProviderForModule.
+			}
 			if dexOutputPath := di.PrebuiltExportPath(apexRootRelativePathToJavaLib(module.BaseModuleName())); dexOutputPath != nil {
 				dexJarFile := makeDexJarPathFromPath(dexOutputPath)
 				module.dexJarFile = dexJarFile
@@ -2235,7 +2224,7 @@ func (module *SdkLibraryImport) GenerateAndroidBuildActions(ctx android.ModuleCo
 			} else {
 				// This should never happen as a variant for a prebuilt_apex is only created if the
 				// prebuilt_apex has been configured to export the java library dex file.
-				ctx.ModuleErrorf("internal error: no dex implementation jar available from prebuilt_apex %q", deapexerModule.Name())
+				ctx.ModuleErrorf("internal error: no dex implementation jar available from prebuilt APEX %s", di.ApexModuleName())
 			}
 		}
 	}