Propagate the dex jar path as an OptionalPath which is either valid or
invalid with a message.

This will allow propagating any error from the deapexer module for
prebuilt APEXes to the location where the dex jars get used. It's only
at those points that we can raise errors about not being able to
extract files from the deapexer modules if they are invalid, and this
way we avoid encoding knowledge there about why they may be invalid.

To keep the refactoring limited it intentionally does not change any of
the existing logic for when dexJarFiles are set or not (non-nil vs nil
prior to this change), although there may be opportunity to use this
for more conditions when dex jars aren't available.

The refactoring is also not extended to
dexpreopt.ClassLoaderContextMap.

Test: m nothing
Bug: 192006406
Change-Id: I68986dccd9a9b3fee4d24caa1947ea17a36caedc
diff --git a/java/sdk_library.go b/java/sdk_library.go
index 2d8aef7..0fcce17 100644
--- a/java/sdk_library.go
+++ b/java/sdk_library.go
@@ -540,7 +540,7 @@
 	// The dex jar for the stubs.
 	//
 	// This is not the implementation jar, it still only contains stubs.
-	stubsDexJarPath android.Path
+	stubsDexJarPath OptionalDexJarPath
 
 	// The API specification file, e.g. system_current.txt.
 	currentApiFilePath android.OptionalPath
@@ -906,10 +906,10 @@
 }
 
 // to satisfy SdkLibraryDependency interface
-func (c *commonToSdkLibraryAndImport) SdkApiStubDexJar(ctx android.BaseModuleContext, kind android.SdkKind) android.Path {
+func (c *commonToSdkLibraryAndImport) SdkApiStubDexJar(ctx android.BaseModuleContext, kind android.SdkKind) OptionalDexJarPath {
 	paths := c.selectScopePaths(ctx, kind)
 	if paths == nil {
-		return nil
+		return makeUnsetDexJarPath()
 	}
 
 	return paths.stubsDexJarPath
@@ -1035,7 +1035,7 @@
 
 	// SdkApiStubDexJar returns the dex jar for the stubs. It is needed by the hiddenapi processing
 	// tool which processes dex files.
-	SdkApiStubDexJar(ctx android.BaseModuleContext, kind android.SdkKind) android.Path
+	SdkApiStubDexJar(ctx android.BaseModuleContext, kind android.SdkKind) OptionalDexJarPath
 
 	// SdkRemovedTxtFile returns the optional path to the removed.txt file for the specified sdk kind.
 	SdkRemovedTxtFile(ctx android.BaseModuleContext, kind android.SdkKind) android.OptionalPath
@@ -1929,7 +1929,7 @@
 	xmlPermissionsFileModule *sdkLibraryXml
 
 	// Build path to the dex implementation jar obtained from the prebuilt_apex, if any.
-	dexJarFile android.Path
+	dexJarFile OptionalDexJarPath
 
 	// Expected install file path of the source module(sdk_library)
 	// or dex implementation jar obtained from the prebuilt_apex, if any.
@@ -2220,11 +2220,12 @@
 			// Get the path of the dex implementation jar from the `deapexer` module.
 			di := ctx.OtherModuleProvider(deapexerModule, android.DeapexerProvider).(android.DeapexerInfo)
 			if dexOutputPath := di.PrebuiltExportPath(apexRootRelativePathToJavaLib(module.BaseModuleName())); dexOutputPath != nil {
-				module.dexJarFile = dexOutputPath
+				dexJarFile := makeDexJarPathFromPath(dexOutputPath)
+				module.dexJarFile = dexJarFile
 				installPath := android.PathForModuleInPartitionInstall(
 					ctx, "apex", ai.ApexVariationName, apexRootRelativePathToJavaLib(module.BaseModuleName()))
 				module.installFile = installPath
-				module.initHiddenAPI(ctx, dexOutputPath, module.findScopePaths(apiScopePublic).stubsImplPath[0], nil)
+				module.initHiddenAPI(ctx, dexJarFile, module.findScopePaths(apiScopePublic).stubsImplPath[0], nil)
 
 				// Dexpreopting.
 				module.dexpreopter.installPath = module.dexpreopter.getInstallPath(ctx, installPath)
@@ -2269,14 +2270,14 @@
 }
 
 // to satisfy UsesLibraryDependency interface
-func (module *SdkLibraryImport) DexJarBuildPath() android.Path {
+func (module *SdkLibraryImport) DexJarBuildPath() OptionalDexJarPath {
 	// The dex implementation jar extracted from the .apex file should be used in preference to the
 	// source.
-	if module.dexJarFile != nil {
+	if module.dexJarFile.IsSet() {
 		return module.dexJarFile
 	}
 	if module.implLibraryModule == nil {
-		return nil
+		return makeUnsetDexJarPath()
 	} else {
 		return module.implLibraryModule.DexJarBuildPath()
 	}