Add a new SDK member type java_systemserver_libs.

Similar to java_boot_libs, java_systemserver_libs only provide access
to their dex implementation jar for use by dexpreopting and do not
provide an actual implementation jar.

This is used in the subsequent CL.

Bug: 194150908
Test: m nothing
Change-Id: Ib2e7d5e6c002314a0231f46934a766f4a27e610a

java/java.go

@@ -73,6 +73,7 @@ func RegisterJavaSdkMemberTypes() {
 	android.RegisterSdkMemberType(javaHeaderLibsSdkMemberType)
 	android.RegisterSdkMemberType(javaLibsSdkMemberType)
 	android.RegisterSdkMemberType(javaBootLibsSdkMemberType)
+	android.RegisterSdkMemberType(javaSystemserverLibsSdkMemberType)
 	android.RegisterSdkMemberType(javaTestSdkMemberType)
 }
 
@@ -146,6 +147,37 @@ var (
 		onlyCopyJarToSnapshot,
 	}
 
+	// Supports adding java systemserver libraries to module_exports and sdk.
+	//
+	// The build has some implicit dependencies (via the systemserver jars configuration) on a number
+	// of modules that are part of the java systemserver classpath and which are provided by mainline
+	// modules but which are not otherwise used outside those mainline modules.
+	//
+	// As they are not needed outside the mainline modules adding them to the sdk/module-exports as
+	// either java_libs, or java_header_libs would end up exporting more information than was strictly
+	// necessary. The java_systemserver_libs property to allow those modules to be exported as part of
+	// the sdk/module_exports without exposing any unnecessary information.
+	javaSystemserverLibsSdkMemberType = &librarySdkMemberType{
+		android.SdkMemberTypeBase{
+			PropertyName: "java_systemserver_libs",
+			SupportsSdk:  true,
+		},
+		func(ctx android.SdkMemberContext, j *Library) android.Path {
+			// Java systemserver libs are only provided in the SDK to provide access to their dex
+			// implementation jar for use by dexpreopting. They do not need to provide an actual
+			// implementation jar but the java_import will need a file that exists so just copy an empty
+			// file. Any attempt to use that file as a jar will cause a build error.
+			return ctx.SnapshotBuilder().EmptyFile()
+		},
+		func(osPrefix, name string) string {
+			// Create a special name for the implementation jar to try and provide some useful information
+			// to a developer that attempts to compile against this.
+			// TODO(b/175714559): Provide a proper error message in Soong not ninja.
+			return filepath.Join(osPrefix, "java_systemserver_libs", "snapshot", "jars", "are", "invalid", name+jarFileSuffix)
+		},
+		onlyCopyJarToSnapshot,
+	}
+
 	// Supports adding java test libraries to module_exports but not sdk.
 	javaTestSdkMemberType = &testSdkMemberType{
 		SdkMemberTypeBase: android.SdkMemberTypeBase{

sdk/java_sdk_test.go

@@ -482,6 +482,71 @@ module_exports_snapshot {
 	)
 }
 
+func TestSnapshotWithJavaSystemserverLibrary(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		prepareForSdkTestWithJava,
+		android.FixtureAddFile("aidl", nil),
+		android.FixtureAddFile("resource.txt", nil),
+	).RunTestWithBp(t, `
+		module_exports {
+			name: "myexports",
+			java_systemserver_libs: ["myjavalib"],
+		}
+
+		java_library {
+			name: "myjavalib",
+			srcs: ["Test.java"],
+			java_resources: ["resource.txt"],
+			// The aidl files should not be copied to the snapshot because a java_systemserver_libs member
+			// is not intended to be used for compiling Java, only for accessing the dex implementation
+			// jar.
+			aidl: {
+				export_include_dirs: ["aidl"],
+			},
+			system_modules: "none",
+			sdk_version: "none",
+			compile_dex: true,
+			permitted_packages: ["pkg.myjavalib"],
+		}
+	`)
+
+	CheckSnapshot(t, result, "myexports", "",
+		checkUnversionedAndroidBpContents(`
+// This is auto-generated. DO NOT EDIT.
+
+java_import {
+    name: "myjavalib",
+    prefer: false,
+    visibility: ["//visibility:public"],
+    apex_available: ["//apex_available:platform"],
+    jars: ["java_systemserver_libs/snapshot/jars/are/invalid/myjavalib.jar"],
+    permitted_packages: ["pkg.myjavalib"],
+}
+`),
+		checkVersionedAndroidBpContents(`
+// This is auto-generated. DO NOT EDIT.
+
+java_import {
+    name: "myexports_myjavalib@current",
+    sdk_member_name: "myjavalib",
+    visibility: ["//visibility:public"],
+    apex_available: ["//apex_available:platform"],
+    jars: ["java_systemserver_libs/snapshot/jars/are/invalid/myjavalib.jar"],
+    permitted_packages: ["pkg.myjavalib"],
+}
+
+module_exports_snapshot {
+    name: "myexports@current",
+    visibility: ["//visibility:public"],
+    java_systemserver_libs: ["myexports_myjavalib@current"],
+}
+`),
+		checkAllCopyRules(`
+.intermediates/myexports/common_os/empty -> java_systemserver_libs/snapshot/jars/are/invalid/myjavalib.jar
+`),
+	)
+}
+
 func TestHostSnapshotWithJavaImplLibrary(t *testing.T) {
 	result := android.GroupFixturePreparers(
 		prepareForSdkTestWithJava,