Add support for sysprop description files to Java

From now on, a java shared library can be built only with adding
".sysprop" description file to srcs. Sysprop library generator will
automatically generate a .java file, and soong will wrap it into .srcjar
file which will finally be contained in the java library. For the schema
of description file, see system/tools/sysprop/sysprop.proto.

Bug: 80125326
Test: 1) write a .sysprop description file.
2) create java_library and add description file to srcs.
3) create a test app, link against library of 2), and call generated
sysprop methods.
4) see compile succeeded.

Change-Id: I3ff87bc0a20f5a1aa126ef6d0f4d874a2ff4af8d
diff --git a/java/gen.go b/java/gen.go
index a993829..993e6d1 100644
--- a/java/gen.go
+++ b/java/gen.go
@@ -26,6 +26,7 @@
 
 func init() {
 	pctx.HostBinToolVariable("aidlCmd", "aidl")
+	pctx.HostBinToolVariable("syspropCmd", "sysprop_java")
 	pctx.SourcePathVariable("logtagsCmd", "build/tools/java-event-log-tags.py")
 	pctx.SourcePathVariable("mergeLogtagsCmd", "build/tools/merge-event-log-tags.py")
 }
@@ -49,6 +50,17 @@
 			Command:     "$mergeLogtagsCmd -o $out $in",
 			CommandDeps: []string{"$mergeLogtagsCmd"},
 		})
+
+	sysprop = pctx.AndroidStaticRule("sysprop",
+		blueprint.RuleParams{
+			Command: `rm -rf $out.tmp && mkdir -p $out.tmp && ` +
+				`$syspropCmd --java-output-dir $out.tmp $in && ` +
+				`${config.SoongZipCmd} -jar -o $out -C $out.tmp -D $out.tmp && rm -rf $out.tmp`,
+			CommandDeps: []string{
+				"$syspropCmd",
+				"${config.SoongZipCmd}",
+			},
+		})
 )
 
 func genAidl(ctx android.ModuleContext, aidlFile android.Path, aidlFlags string) android.Path {
@@ -82,6 +94,19 @@
 	return javaFile
 }
 
+func genSysprop(ctx android.ModuleContext, syspropFile android.Path) android.Path {
+	srcJarFile := android.GenPathWithExt(ctx, "sysprop", syspropFile, "srcjar")
+
+	ctx.Build(pctx, android.BuildParams{
+		Rule:        sysprop,
+		Description: "sysprop_java " + syspropFile.Rel(),
+		Output:      srcJarFile,
+		Input:       syspropFile,
+	})
+
+	return srcJarFile
+}
+
 func (j *Module) genSources(ctx android.ModuleContext, srcFiles android.Paths,
 	flags javaBuilderFlags) android.Paths {
 
@@ -99,6 +124,9 @@
 		case ".proto":
 			srcJarFile := genProto(ctx, srcFile, flags)
 			outSrcFiles = append(outSrcFiles, srcJarFile)
+		case ".sysprop":
+			srcJarFile := genSysprop(ctx, srcFile)
+			outSrcFiles = append(outSrcFiles, srcJarFile)
 		default:
 			outSrcFiles = append(outSrcFiles, srcFile)
 		}