Add support for the remote execution of metalava actions.

Test: built aosp crosshatch userdebug with RBE_METALAVA=1
Change-Id: I3d42d75b4522f99ff95ce8c997ead782e4322f6e
diff --git a/java/droiddoc.go b/java/droiddoc.go
index a9b5d5f..96102ff 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -24,6 +24,7 @@
 
 	"android/soong/android"
 	"android/soong/java/config"
+	"android/soong/remoteexec"
 )
 
 func init() {
@@ -1375,7 +1376,31 @@
 	srcJarList android.Path, bootclasspath, classpath classpath, sourcepaths android.Paths) *android.RuleBuilderCommand {
 	// Metalava uses lots of memory, restrict the number of metalava jobs that can run in parallel.
 	rule.HighMem()
-	cmd := rule.Command().BuiltTool(ctx, "metalava").
+	cmd := rule.Command()
+	if ctx.Config().IsEnvTrue("RBE_METALAVA") {
+		rule.Remoteable(android.RemoteRuleSupports{RBE: true})
+		execStrategy := remoteexec.LocalExecStrategy
+		if v := ctx.Config().Getenv("RBE_METALAVA_EXEC_STRATEGY"); v != "" {
+			execStrategy = v
+		}
+		pool := "metalava"
+		if v := ctx.Config().Getenv("RBE_METALAVA_POOL"); v != "" {
+			pool = v
+		}
+		inputs := []string{android.PathForOutput(ctx, "host", ctx.Config().PrebuiltOS(), "framework", "metalava.jar").String()}
+		if v := ctx.Config().Getenv("RBE_METALAVA_INPUTS"); v != "" {
+			inputs = append(inputs, strings.Split(v, ",")...)
+		}
+		cmd.Text((&remoteexec.REParams{
+			Labels:          map[string]string{"type": "compile", "lang": "java", "compiler": "metalava"},
+			ExecStrategy:    execStrategy,
+			Inputs:          inputs,
+			ToolchainInputs: []string{config.JavaCmd(ctx).String()},
+			Platform:        map[string]string{remoteexec.PoolKey: pool},
+		}).NoVarTemplate(ctx.Config()))
+	}
+
+	cmd.BuiltTool(ctx, "metalava").
 		Flag(config.JavacVmFlags).
 		FlagWithArg("-encoding ", "UTF-8").
 		FlagWithArg("-source ", javaVersion.String()).
diff --git a/remoteexec/remoteexec.go b/remoteexec/remoteexec.go
index 860db55..99e29dc 100644
--- a/remoteexec/remoteexec.go
+++ b/remoteexec/remoteexec.go
@@ -82,17 +82,31 @@
 
 func init() {
 	pctx.VariableFunc("Wrapper", func(ctx android.PackageVarContext) string {
-		if override := ctx.Config().Getenv("RBE_WRAPPER"); override != "" {
-			return override
-		}
-		return DefaultWrapperPath
+		return wrapper(ctx.Config())
 	})
 }
 
-// Generate the remote execution wrapper template to be added as a prefix to the rule's command.
-func (r *REParams) Template() string {
-	template := "${remoteexec.Wrapper}"
+func wrapper(cfg android.Config) string {
+	if override := cfg.Getenv("RBE_WRAPPER"); override != "" {
+		return override
+	}
+	return DefaultWrapperPath
+}
 
+// Template generates the remote execution wrapper template to be added as a prefix to the rule's
+// command.
+func (r *REParams) Template() string {
+	return "${remoteexec.Wrapper}" + r.wrapperArgs()
+}
+
+// NoVarTemplate generate the remote execution wrapper template without variables, to be used in
+// RuleBuilder.
+func (r *REParams) NoVarTemplate(cfg android.Config) string {
+	return wrapper(cfg) + r.wrapperArgs()
+}
+
+func (r *REParams) wrapperArgs() string {
+	args := ""
 	var kvs []string
 	labels := r.Labels
 	if len(labels) == 0 {
@@ -102,7 +116,7 @@
 		kvs = append(kvs, k+"="+v)
 	}
 	sort.Strings(kvs)
-	template += " --labels=" + strings.Join(kvs, ",")
+	args += " --labels=" + strings.Join(kvs, ",")
 
 	var platform []string
 	for k, v := range r.Platform {
@@ -116,32 +130,32 @@
 	}
 	if platform != nil {
 		sort.Strings(platform)
-		template += " --platform=\"" + strings.Join(platform, ",") + "\""
+		args += " --platform=\"" + strings.Join(platform, ",") + "\""
 	}
 
 	strategy := r.ExecStrategy
 	if strategy == "" {
 		strategy = defaultExecStrategy
 	}
-	template += " --exec_strategy=" + strategy
+	args += " --exec_strategy=" + strategy
 
 	if len(r.Inputs) > 0 {
-		template += " --inputs=" + strings.Join(r.Inputs, ",")
+		args += " --inputs=" + strings.Join(r.Inputs, ",")
 	}
 
 	if r.RSPFile != "" {
-		template += " --input_list_paths=" + r.RSPFile
+		args += " --input_list_paths=" + r.RSPFile
 	}
 
 	if len(r.OutputFiles) > 0 {
-		template += " --output_files=" + strings.Join(r.OutputFiles, ",")
+		args += " --output_files=" + strings.Join(r.OutputFiles, ",")
 	}
 
 	if len(r.ToolchainInputs) > 0 {
-		template += " --toolchain_inputs=" + strings.Join(r.ToolchainInputs, ",")
+		args += " --toolchain_inputs=" + strings.Join(r.ToolchainInputs, ",")
 	}
 
-	return template + " -- "
+	return args + " -- "
 }
 
 // StaticRules returns a pair of rules based on the given RuleParams, where the first rule is a
diff --git a/remoteexec/remoteexec_test.go b/remoteexec/remoteexec_test.go
index 30e891c..56985d3 100644
--- a/remoteexec/remoteexec_test.go
+++ b/remoteexec/remoteexec_test.go
@@ -17,6 +17,8 @@
 import (
 	"fmt"
 	"testing"
+
+	"android/soong/android"
 )
 
 func TestTemplate(t *testing.T) {
@@ -64,6 +66,22 @@
 	}
 }
 
+func TestNoVarTemplate(t *testing.T) {
+	params := &REParams{
+		Labels:      map[string]string{"type": "compile", "lang": "cpp", "compiler": "clang"},
+		Inputs:      []string{"$in"},
+		OutputFiles: []string{"$out"},
+		Platform: map[string]string{
+			ContainerImageKey: DefaultImage,
+			PoolKey:           "default",
+		},
+	}
+	want := fmt.Sprintf("prebuilts/remoteexecution-client/live/rewrapper --labels=compiler=clang,lang=cpp,type=compile --platform=\"Pool=default,container-image=%s\" --exec_strategy=local --inputs=$in --output_files=$out -- ", DefaultImage)
+	if got := params.NoVarTemplate(android.NullConfig("")); got != want {
+		t.Errorf("NoVarTemplate() returned\n%s\nwant\n%s", got, want)
+	}
+}
+
 func TestTemplateDeterminism(t *testing.T) {
 	r := &REParams{
 		Labels:      map[string]string{"type": "compile", "lang": "cpp", "compiler": "clang"},