Support mechanism to select a specific version of module sdk prebuilt

This CL is the java_system_modules_import equivalent of aosp/2928483.

With trunk stable, we will have multiple versions of art prebuilt apex
in the tree. Each art apex will contribute its own module sdk, i.e. its
own prebuilt system_modules to the build. This CL introduces a mechanism
to selelect a specific version of prebuilt system modules using
apex_contributions.

Implementation details: Create a new source_module_name property to
identify the root module. rdeps referring to the root module will get
redirected if necessary.

Bug: 322175508

Test: Added a unit test
Change-Id: I9f885ffa5afea96d2e6ce077264d3b207ed7e80d

java/system_modules.go

@@ -19,6 +19,7 @@ import (
 	"strings"
 
 	"github.com/google/blueprint"
+	"github.com/google/blueprint/proptools"
 
 	"android/soong/android"
 )
@@ -210,7 +211,7 @@ func (system *SystemModules) AndroidMk() android.AndroidMkData {
 // type and the one to use is selected at runtime.
 func systemModulesImportFactory() android.Module {
 	module := &systemModulesImport{}
-	module.AddProperties(&module.properties)
+	module.AddProperties(&module.properties, &module.prebuiltProperties)
 	android.InitPrebuiltModule(module, &module.properties.Libs)
 	android.InitAndroidArchModule(module, android.HostAndDeviceSupported, android.MultilibCommon)
 	android.InitDefaultableModule(module)
@@ -219,13 +220,39 @@ func systemModulesImportFactory() android.Module {
 
 type systemModulesImport struct {
 	SystemModules
-	prebuilt android.Prebuilt
+	prebuilt           android.Prebuilt
+	prebuiltProperties prebuiltSystemModulesProperties
+}
+
+type prebuiltSystemModulesProperties struct {
+	// Name of the source soong module that gets shadowed by this prebuilt
+	// If unspecified, follows the naming convention that the source module of
+	// the prebuilt is Name() without "prebuilt_" prefix
+	Source_module_name *string
 }
 
 func (system *systemModulesImport) Name() string {
 	return system.prebuilt.Name(system.ModuleBase.Name())
 }
 
+// BaseModuleName returns the source module that will get shadowed by this prebuilt
+// e.g.
+//
+//	java_system_modules_import {
+//	   name: "my_system_modules.v1",
+//	   source_module_name: "my_system_modules",
+//	}
+//
+//	java_system_modules_import {
+//	   name: "my_system_modules.v2",
+//	   source_module_name: "my_system_modules",
+//	}
+//
+// `BaseModuleName` for both will return `my_system_modules`
+func (system *systemModulesImport) BaseModuleName() string {
+	return proptools.StringDefault(system.prebuiltProperties.Source_module_name, system.ModuleBase.Name())
+}
+
 func (system *systemModulesImport) Prebuilt() *android.Prebuilt {
 	return &system.prebuilt
 }

java/system_modules_test.go

@@ -15,6 +15,7 @@
 package java
 
 import (
+	"fmt"
 	"testing"
 
 	"android/soong/android"
@@ -111,3 +112,85 @@ func TestJavaSystemModulesMixSourceAndPrebuilt(t *testing.T) {
 	expectedPrebuiltPaths := getModuleHeaderJarsAsRelativeToTopPaths(result, "prebuilt_system-module1", "prebuilt_system-module2")
 	android.AssertArrayString(t, "prebuilt system modules inputs", expectedPrebuiltPaths, prebuiltInputs.RelativeToTop().Strings())
 }
+
+func TestMultipleSystemModulesPrebuilts(t *testing.T) {
+	bp := `
+		// an rdep
+		java_library {
+			name: "foo",
+			sdk_version: "none",
+			system_modules: "my_system_modules",
+		}
+
+		// multiple variations of java_system_modules
+		// source
+		java_system_modules {
+			name: "my_system_modules",
+			libs: ["bar"],
+		}
+		java_library {
+			name: "bar",
+			srcs: ["bar.java"],
+		}
+		// prebuilt "v1"
+		java_system_modules_import {
+			name: "my_system_modules.v1",
+			source_module_name: "my_system_modules",
+			libs: ["bar.v1"],
+		}
+		java_import {
+			name: "bar.v1",
+			source_module_name: "bar",
+			jars: ["bar.v1.jar"],
+		}
+		// prebuilt "v2"
+		java_system_modules_import {
+			name: "my_system_modules.v2",
+			source_module_name: "my_system_modules",
+			libs: ["bar.v2"],
+		}
+		java_import {
+			name: "bar.v2",
+			source_module_name: "bar",
+			jars: ["bar.v2.jar"],
+		}
+
+		// selectors
+		apex_contributions {
+			name: "myapex_contributions",
+			contents: ["%v"],
+		}
+	`
+	testCases := []struct {
+		desc                   string
+		selectedDependencyName string
+	}{
+		{
+			desc:                   "Source system_modules is selected using apex_contributions",
+			selectedDependencyName: "my_system_modules",
+		},
+		{
+			desc:                   "Prebuilt system_modules v1 is selected using apex_contributions",
+			selectedDependencyName: "prebuilt_my_system_modules.v1",
+		},
+		{
+			desc:                   "Prebuilt system_modules v2 is selected using apex_contributions",
+			selectedDependencyName: "prebuilt_my_system_modules.v2",
+		},
+	}
+
+	for _, tc := range testCases {
+		res := android.GroupFixturePreparers(
+			prepareForJavaTest,
+			android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
+				variables.BuildFlags = map[string]string{
+					"RELEASE_APEX_CONTRIBUTIONS_ADSERVICES": "myapex_contributions",
+				}
+			}),
+		).RunTestWithBp(t, fmt.Sprintf(bp, tc.selectedDependencyName))
+
+		// check that rdep gets the correct variation of system_modules
+		hasDep := CheckModuleHasDependency(t, res.TestContext, "foo", "android_common", tc.selectedDependencyName)
+		android.AssertBoolEquals(t, fmt.Sprintf("expected dependency from foo to %s\n", tc.selectedDependencyName), true, hasDep)
+	}
+}