Add sandbox property to the javadoc rule.

The sandbox property indicates whether metalava should only read
inputs explicitly specified on the command line. This CL adds the
property and sets the appropriate configuration for RBE depending
on whether the sandbox is set or not.

Test: built aosp_crosshatch-userdebug with/without RBE_METALAVA.
Change-Id: I7256d29f18e0af18dbe65d1c7dbbf62fd3d65f4c
diff --git a/android/rule_builder.go b/android/rule_builder.go
index 6226548..afb5f4e 100644
--- a/android/rule_builder.go
+++ b/android/rule_builder.go
@@ -172,7 +172,7 @@
 
 	inputs := make(map[string]Path)
 	for _, c := range r.commands {
-		for _, input := range c.inputs {
+		for _, input := range append(c.inputs, c.implicits...) {
 			inputStr := input.String()
 			if _, isOutput := outputs[inputStr]; !isOutput {
 				if _, isDepFile := depFiles[inputStr]; !isDepFile {
@@ -480,6 +480,7 @@
 type RuleBuilderCommand struct {
 	buf           strings.Builder
 	inputs        Paths
+	implicits     Paths
 	orderOnlys    Paths
 	outputs       WritablePaths
 	depFiles      WritablePaths
@@ -503,6 +504,16 @@
 	return path.String()
 }
 
+func (c *RuleBuilderCommand) addImplicit(path Path) string {
+	if c.sbox {
+		if rel, isRel, _ := maybeRelErr(c.sboxOutDir.String(), path.String()); isRel {
+			return "__SBOX_OUT_DIR__/" + rel
+		}
+	}
+	c.implicits = append(c.implicits, path)
+	return path.String()
+}
+
 func (c *RuleBuilderCommand) addOrderOnly(path Path) {
 	c.orderOnlys = append(c.orderOnlys, path)
 }
@@ -623,7 +634,7 @@
 // Implicit adds the specified input path to the dependencies returned by RuleBuilder.Inputs without modifying the
 // command line.
 func (c *RuleBuilderCommand) Implicit(path Path) *RuleBuilderCommand {
-	c.addInput(path)
+	c.addImplicit(path)
 	return c
 }
 
@@ -631,11 +642,16 @@
 // command line.
 func (c *RuleBuilderCommand) Implicits(paths Paths) *RuleBuilderCommand {
 	for _, path := range paths {
-		c.addInput(path)
+		c.addImplicit(path)
 	}
 	return c
 }
 
+// GetImplicits returns the command's implicit inputs.
+func (c *RuleBuilderCommand) GetImplicits() Paths {
+	return c.implicits
+}
+
 // OrderOnly adds the specified input path to the dependencies returned by RuleBuilder.OrderOnlys
 // without modifying the command line.
 func (c *RuleBuilderCommand) OrderOnly(path Path) *RuleBuilderCommand {
diff --git a/java/droiddoc.go b/java/droiddoc.go
index 68cfe9f..8675424 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -121,6 +121,10 @@
 
 	// names of the output files used in args that will be generated
 	Out []string
+
+	// If set, metalava is sandboxed to only read files explicitly specified on the command
+	// line. Defaults to false.
+	Sandbox *bool
 }
 
 type ApiToCheck struct {
@@ -1419,41 +1423,25 @@
 }
 
 func metalavaCmd(ctx android.ModuleContext, rule *android.RuleBuilder, javaVersion javaVersion, srcs android.Paths,
-	srcJarList android.Path, bootclasspath, classpath classpath, sourcepaths android.Paths, implicits android.Paths) *android.RuleBuilderCommand {
+	srcJarList android.Path, bootclasspath, classpath classpath, sourcepaths android.Paths, implicitsRsp android.WritablePath, sandbox bool) *android.RuleBuilderCommand {
 	// Metalava uses lots of memory, restrict the number of metalava jobs that can run in parallel.
 	rule.HighMem()
 	cmd := rule.Command()
-
-	var implicitsRsp android.WritablePath
-	if len(implicits) > 0 {
-		implicitsRsp = android.PathForModuleOut(ctx, ctx.ModuleName()+"-"+"implicits.rsp")
-		impRule := android.NewRuleBuilder()
-		impCmd := impRule.Command()
-		// A dummy action that copies the ninja generated rsp file to a new location. This allows us to
-		// add a large number of inputs to a file without exceeding bash command length limits (which
-		// would happen if we use the WriteFile rule). The cp is needed because RuleBuilder sets the
-		// rsp file to be ${output}.rsp.
-		impCmd.Text("cp").FlagWithRspFileInputList("", implicits).Output(implicitsRsp)
-		impRule.Build(pctx, ctx, "implicitsGen", "implicits generation")
-		cmd.Implicits(implicits)
-		cmd.Implicit(implicitsRsp)
-	}
 	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
+		pool := ctx.Config().GetenvWithDefault("RBE_METALAVA_POOL", "metalava")
+		execStrategy := ctx.Config().GetenvWithDefault("RBE_METALAVA_EXEC_STRATEGY", remoteexec.LocalExecStrategy)
+		labels := map[string]string{"type": "compile", "lang": "java", "compiler": "metalava"}
+		if !sandbox {
+			execStrategy = remoteexec.LocalExecStrategy
+			labels["shallow"] = "true"
 		}
 		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", "shallow": "true"},
+			Labels:          labels,
 			ExecStrategy:    execStrategy,
 			Inputs:          inputs,
 			RSPFile:         implicitsRsp.String(),
@@ -1467,8 +1455,17 @@
 		FlagWithArg("-encoding ", "UTF-8").
 		FlagWithArg("-source ", javaVersion.String()).
 		FlagWithRspFileInputList("@", srcs).
-		FlagWithInput("@", srcJarList).
-		FlagWithOutput("--strict-input-files:warn ", android.PathForModuleOut(ctx, ctx.ModuleName()+"-"+"violations.txt"))
+		FlagWithInput("@", srcJarList)
+
+	if javaHome := ctx.Config().Getenv("ANDROID_JAVA_HOME"); javaHome != "" {
+		cmd.Implicit(android.PathForSource(ctx, javaHome))
+	}
+
+	if sandbox {
+		cmd.FlagWithOutput("--strict-input-files ", android.PathForModuleOut(ctx, ctx.ModuleName()+"-"+"violations.txt"))
+	} else {
+		cmd.FlagWithOutput("--strict-input-files:warn ", android.PathForModuleOut(ctx, ctx.ModuleName()+"-"+"violations.txt"))
+	}
 
 	if implicitsRsp != nil {
 		cmd.FlagWithArg("--strict-input-files-exempt ", "@"+implicitsRsp.String())
@@ -1518,8 +1515,12 @@
 
 	srcJarList := zipSyncCmd(ctx, rule, srcJarDir, d.Javadoc.srcJars)
 
+	implicitsRsp := android.PathForModuleOut(ctx, ctx.ModuleName()+"-"+"implicits.rsp")
+
 	cmd := metalavaCmd(ctx, rule, javaVersion, d.Javadoc.srcFiles, srcJarList,
-		deps.bootClasspath, deps.classpath, d.Javadoc.sourcepaths, d.Javadoc.implicits)
+		deps.bootClasspath, deps.classpath, d.Javadoc.sourcepaths, implicitsRsp,
+		Bool(d.Javadoc.properties.Sandbox))
+	cmd.Implicits(d.Javadoc.implicits)
 
 	d.stubsFlags(ctx, cmd, stubsDir)
 
@@ -1638,6 +1639,16 @@
 		cmd.FlagWithArg("--error-message:compatibility:released ", msg)
 	}
 
+	impRule := android.NewRuleBuilder()
+	impCmd := impRule.Command()
+	// A dummy action that copies the ninja generated rsp file to a new location. This allows us to
+	// add a large number of inputs to a file without exceeding bash command length limits (which
+	// would happen if we use the WriteFile rule). The cp is needed because RuleBuilder sets the
+	// rsp file to be ${output}.rsp.
+	impCmd.Text("cp").FlagWithRspFileInputList("", cmd.GetImplicits()).Output(implicitsRsp)
+	impRule.Build(pctx, ctx, "implicitsGen", "implicits generation")
+	cmd.Implicit(implicitsRsp)
+
 	if generateStubs {
 		rule.Command().
 			BuiltTool(ctx, "soong_zip").