Merge "Add sdk_version:"none" to replace no_standard_libs:true"
diff --git a/android/arch.go b/android/arch.go
index f4a3c06..46e582c 100644
--- a/android/arch.go
+++ b/android/arch.go
@@ -713,7 +713,7 @@
 // If host is supported for the module, the Host and HostCross OsClasses are selected.  If device is supported
 // for the module, the Device OsClass is selected.
 // Within each selected OsClass, the multilib selection is determined by:
-//    - The compile_multilib property if it set (which may be overriden by target.android.compile_multlib or
+//    - The compile_multilib property if it set (which may be overridden by target.android.compile_multilib or
 //      target.host.compile_multilib).
 //    - The default multilib passed to InitAndroidArchModule if compile_multilib was not set.
 // Valid multilib values include:
diff --git a/apex/apex.go b/apex/apex.go
index 11b433c..84e5497 100644
--- a/apex/apex.go
+++ b/apex/apex.go
@@ -61,7 +61,7 @@
 			`--key ${key} ${opt_flags} ${image_dir} ${out} `,
 		CommandDeps: []string{"${apexer}", "${avbtool}", "${e2fsdroid}", "${merge_zips}",
 			"${mke2fs}", "${resize2fs}", "${sefcontext_compile}",
-			"${soong_zip}", "${zipalign}", "${aapt2}"},
+			"${soong_zip}", "${zipalign}", "${aapt2}", "prebuilts/sdk/current/public/android.jar"},
 		Description: "APEX ${image_dir} => ${out}",
 	}, "tool_path", "image_dir", "copy_commands", "manifest", "file_contexts", "canned_fs_config", "key", "opt_flags")
 
@@ -1062,6 +1062,10 @@
 		Description: "signapk",
 		Output:      a.outputFiles[apexType],
 		Input:       unsignedOutputFile,
+		Implicits: []android.Path{
+			a.container_certificate_file,
+			a.container_private_key_file,
+		},
 		Args: map[string]string{
 			"certificates": a.container_certificate_file.String() + " " + a.container_private_key_file.String(),
 			"flags":        "-a 4096", //alignment
diff --git a/cc/rs.go b/cc/rs.go
index 5421b92..fbc6bfb 100644
--- a/cc/rs.go
+++ b/cc/rs.go
@@ -72,11 +72,12 @@
 	stampFile := android.PathForModuleGen(ctx, "rs", "rs.stamp")
 	depFiles := make(android.WritablePaths, 0, len(rsFiles))
 	genFiles := make(android.WritablePaths, 0, 2*len(rsFiles))
+	headers := make(android.Paths, 0, len(rsFiles))
 	for _, rsFile := range rsFiles {
 		depFiles = append(depFiles, rsGeneratedDepFile(ctx, rsFile))
-		genFiles = append(genFiles,
-			rsGeneratedCppFile(ctx, rsFile),
-			rsGeneratedHFile(ctx, rsFile))
+		headerFile := rsGeneratedHFile(ctx, rsFile)
+		genFiles = append(genFiles, rsGeneratedCppFile(ctx, rsFile), headerFile)
+		headers = append(headers, headerFile)
 	}
 
 	ctx.Build(pctx, android.BuildParams{
@@ -92,7 +93,7 @@
 		},
 	})
 
-	return android.Paths{stampFile}
+	return headers
 }
 
 func rsFlags(ctx ModuleContext, flags Flags, properties *BaseCompilerProperties) Flags {
diff --git a/cmd/multiproduct_kati/main.go b/cmd/multiproduct_kati/main.go
index 330c5dd..1171a65 100644
--- a/cmd/multiproduct_kati/main.go
+++ b/cmd/multiproduct_kati/main.go
@@ -156,10 +156,12 @@
 }
 
 func main() {
-	writer := terminal.NewWriter(terminal.StdioImpl{})
-	defer writer.Finish()
+	stdio := terminal.StdioImpl{}
 
-	log := logger.New(writer)
+	output := terminal.NewStatusOutput(stdio.Stdout(), "",
+		build.OsEnvironment().IsEnvTrue("ANDROID_QUIET_BUILD"))
+
+	log := logger.New(output)
 	defer log.Cleanup()
 
 	flag.Parse()
@@ -172,8 +174,7 @@
 
 	stat := &status.Status{}
 	defer stat.Finish()
-	stat.AddOutput(terminal.NewStatusOutput(writer, "",
-		build.OsEnvironment().IsEnvTrue("ANDROID_QUIET_BUILD")))
+	stat.AddOutput(output)
 
 	var failures failureCount
 	stat.AddOutput(&failures)
@@ -188,7 +189,7 @@
 		Context: ctx,
 		Logger:  log,
 		Tracer:  trace,
-		Writer:  writer,
+		Writer:  output,
 		Status:  stat,
 	}}
 
@@ -341,7 +342,7 @@
 	} else if failures > 1 {
 		log.Fatalf("%d failures", failures)
 	} else {
-		writer.Print("Success")
+		fmt.Fprintln(output, "Success")
 	}
 }
 
@@ -386,7 +387,7 @@
 		Context: mpctx.Context,
 		Logger:  log,
 		Tracer:  mpctx.Tracer,
-		Writer:  terminal.NewWriter(terminal.NewCustomStdio(nil, f, f)),
+		Writer:  f,
 		Thread:  mpctx.Tracer.NewThread(product),
 		Status:  &status.Status{},
 	}}
@@ -466,3 +467,8 @@
 }
 
 func (f *failureCount) Flush() {}
+
+func (f *failureCount) Write(p []byte) (int, error) {
+	// discard writes
+	return len(p), nil
+}
diff --git a/cmd/soong_ui/main.go b/cmd/soong_ui/main.go
index 5f9bd01..f5276c3 100644
--- a/cmd/soong_ui/main.go
+++ b/cmd/soong_ui/main.go
@@ -109,10 +109,10 @@
 		os.Exit(1)
 	}
 
-	writer := terminal.NewWriter(c.stdio())
-	defer writer.Finish()
+	output := terminal.NewStatusOutput(c.stdio().Stdout(), os.Getenv("NINJA_STATUS"),
+		build.OsEnvironment().IsEnvTrue("ANDROID_QUIET_BUILD"))
 
-	log := logger.New(writer)
+	log := logger.New(output)
 	defer log.Cleanup()
 
 	ctx, cancel := context.WithCancel(context.Background())
@@ -125,8 +125,7 @@
 
 	stat := &status.Status{}
 	defer stat.Finish()
-	stat.AddOutput(terminal.NewStatusOutput(writer, os.Getenv("NINJA_STATUS"),
-		build.OsEnvironment().IsEnvTrue("ANDROID_QUIET_BUILD")))
+	stat.AddOutput(output)
 	stat.AddOutput(trace.StatusTracer())
 
 	build.SetupSignals(log, cancel, func() {
@@ -140,7 +139,7 @@
 		Logger:  log,
 		Metrics: met,
 		Tracer:  trace,
-		Writer:  writer,
+		Writer:  output,
 		Status:  stat,
 	}}
 
@@ -312,13 +311,13 @@
 func make(ctx build.Context, config build.Config, _ []string, logsDir string) {
 	if config.IsVerbose() {
 		writer := ctx.Writer
-		writer.Print("! The argument `showcommands` is no longer supported.")
-		writer.Print("! Instead, the verbose log is always written to a compressed file in the output dir:")
-		writer.Print("!")
-		writer.Print(fmt.Sprintf("!   gzip -cd %s/verbose.log.gz | less -R", logsDir))
-		writer.Print("!")
-		writer.Print("! Older versions are saved in verbose.log.#.gz files")
-		writer.Print("")
+		fmt.Fprintln(writer, "! The argument `showcommands` is no longer supported.")
+		fmt.Fprintln(writer, "! Instead, the verbose log is always written to a compressed file in the output dir:")
+		fmt.Fprintln(writer, "!")
+		fmt.Fprintf(writer, "!   gzip -cd %s/verbose.log.gz | less -R\n", logsDir)
+		fmt.Fprintln(writer, "!")
+		fmt.Fprintln(writer, "! Older versions are saved in verbose.log.#.gz files")
+		fmt.Fprintln(writer, "")
 		time.Sleep(5 * time.Second)
 	}
 
diff --git a/java/config/kotlin.go b/java/config/kotlin.go
index 7cea042..fd8e3db 100644
--- a/java/config/kotlin.go
+++ b/java/config/kotlin.go
@@ -32,6 +32,7 @@
 	pctx.SourcePathVariable("KotlinScriptRuntimeJar", "external/kotlinc/lib/kotlin-script-runtime.jar")
 	pctx.SourcePathVariable("KotlinTrove4jJar", "external/kotlinc/lib/trove4j.jar")
 	pctx.SourcePathVariable("KotlinKaptJar", "external/kotlinc/lib/kotlin-annotation-processing.jar")
+	pctx.SourcePathVariable("KotlinAnnotationJar", "external/kotlinc/lib/annotations-13.0.jar")
 	pctx.SourcePathVariable("KotlinStdlibJar", KotlinStdlibJar)
 
 	// These flags silence "Illegal reflective access" warnings when running kotlinc in OpenJDK9
diff --git a/java/kotlin.go b/java/kotlin.go
index 33167ba..8306907 100644
--- a/java/kotlin.go
+++ b/java/kotlin.go
@@ -44,6 +44,7 @@
 			"${config.KotlinScriptRuntimeJar}",
 			"${config.KotlinStdlibJar}",
 			"${config.KotlinTrove4jJar}",
+			"${config.KotlinAnnotationJar}",
 			"${config.GenKotlinBuildFileCmd}",
 			"${config.SoongZipCmd}",
 			"${config.ZipSyncCmd}",
diff --git a/ui/build/config.go b/ui/build/config.go
index c298f00..6df9529 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -61,6 +61,28 @@
 
 const srcDirFileCheck = "build/soong/root.bp"
 
+type BuildAction uint
+
+const (
+	// Builds all of the modules and their dependencies of a specified directory, relative to the root
+	// directory of the source tree.
+	BUILD_MODULES_IN_A_DIRECTORY BuildAction = iota
+
+	// Builds all of the modules and their dependencies of a list of specified directories. All specified
+	// directories are relative to the root directory of the source tree.
+	BUILD_MODULES_IN_DIRECTORIES
+)
+
+// checkTopDir validates that the current directory is at the root directory of the source tree.
+func checkTopDir(ctx Context) {
+	if _, err := os.Stat(srcDirFileCheck); err != nil {
+		if os.IsNotExist(err) {
+			ctx.Fatalf("Current working directory must be the source tree. %q not found.", srcDirFileCheck)
+		}
+		ctx.Fatalln("Error verifying tree state:", err)
+	}
+}
+
 func NewConfig(ctx Context, args ...string) Config {
 	ret := &configImpl{
 		environ: OsEnvironment(),
@@ -154,12 +176,7 @@
 	ret.environ.Set("TMPDIR", absPath(ctx, ret.TempDir()))
 
 	// Precondition: the current directory is the top of the source tree
-	if _, err := os.Stat(srcDirFileCheck); err != nil {
-		if os.IsNotExist(err) {
-			log.Fatalf("Current working directory must be the source tree. %q not found", srcDirFileCheck)
-		}
-		log.Fatalln("Error verifying tree state:", err)
-	}
+	checkTopDir(ctx)
 
 	if srcDir := absPath(ctx, "."); strings.ContainsRune(srcDir, ' ') {
 		log.Println("You are building in a directory whose absolute path contains a space character:")
@@ -229,6 +246,203 @@
 	return Config{ret}
 }
 
+// NewBuildActionConfig returns a build configuration based on the build action. The arguments are
+// processed based on the build action and extracts any arguments that belongs to the build action.
+func NewBuildActionConfig(action BuildAction, dir string, buildDependencies bool, ctx Context, args ...string) Config {
+	return NewConfig(ctx, getConfigArgs(action, dir, buildDependencies, ctx, args)...)
+}
+
+// getConfigArgs processes the command arguments based on the build action and creates a set of new
+// arguments to be accepted by Config.
+func getConfigArgs(action BuildAction, dir string, buildDependencies bool, ctx Context, args []string) []string {
+	// The next block of code verifies that the current directory is the root directory of the source
+	// tree. It then finds the relative path of dir based on the root directory of the source tree
+	// and verify that dir is inside of the source tree.
+	checkTopDir(ctx)
+	topDir, err := os.Getwd()
+	if err != nil {
+		ctx.Fatalf("Error retrieving top directory: %v", err)
+	}
+	dir, err = filepath.Abs(dir)
+	if err != nil {
+		ctx.Fatalf("Unable to find absolute path %s: %v", dir, err)
+	}
+	relDir, err := filepath.Rel(topDir, dir)
+	if err != nil {
+		ctx.Fatalf("Unable to find relative path %s of %s: %v", relDir, topDir, err)
+	}
+	// If there are ".." in the path, it's not in the source tree.
+	if strings.Contains(relDir, "..") {
+		ctx.Fatalf("Directory %s is not under the source tree %s", dir, topDir)
+	}
+
+	configArgs := args[:]
+
+	// If the arguments contains GET-INSTALL-PATH, change the target name prefix from MODULES-IN- to
+	// GET-INSTALL-PATH-IN- to extract the installation path instead of building the modules.
+	targetNamePrefix := "MODULES-IN-"
+	if inList("GET-INSTALL-PATH", configArgs) {
+		targetNamePrefix = "GET-INSTALL-PATH-IN-"
+		configArgs = removeFromList("GET-INSTALL-PATH", configArgs)
+	}
+
+	var buildFiles []string
+	var targets []string
+
+	switch action {
+	case BUILD_MODULES_IN_A_DIRECTORY:
+		// If dir is the root source tree, all the modules are built of the source tree are built so
+		// no need to find the build file.
+		if topDir == dir {
+			break
+		}
+		// Find the build file from the directory where the build action was triggered by traversing up
+		// the source tree. If a blank build filename is returned, simply use the directory where the build
+		// action was invoked.
+		buildFile := findBuildFile(ctx, relDir)
+		if buildFile == "" {
+			buildFile = filepath.Join(relDir, "Android.mk")
+		}
+		buildFiles = []string{buildFile}
+		targets = []string{convertToTarget(filepath.Dir(buildFile), targetNamePrefix)}
+	case BUILD_MODULES_IN_DIRECTORIES:
+		newConfigArgs, dirs := splitArgs(configArgs)
+		configArgs = newConfigArgs
+		targets, buildFiles = getTargetsFromDirs(ctx, relDir, dirs, targetNamePrefix)
+	}
+
+	// This is to support building modules without building their dependencies. Soon, this will be
+	// deprecated.
+	if !buildDependencies && len(buildFiles) > 0 {
+		if err := os.Setenv("ONE_SHOT_MAKEFILE", strings.Join(buildFiles, " ")); err != nil {
+			ctx.Fatalf("Unable to set ONE_SHOT_MAKEFILE environment variable: %v", err)
+		}
+	}
+
+	// Tidy only override all other specified targets.
+	tidyOnly := os.Getenv("WITH_TIDY_ONLY")
+	if tidyOnly == "true" || tidyOnly == "1" {
+		configArgs = append(configArgs, "tidy_only")
+	} else {
+		configArgs = append(configArgs, targets...)
+	}
+
+	return configArgs
+}
+
+// convertToTarget replaces "/" to "-" in dir and pre-append the targetNamePrefix to the target name.
+func convertToTarget(dir string, targetNamePrefix string) string {
+	return targetNamePrefix + strings.ReplaceAll(dir, "/", "-")
+}
+
+// findBuildFile finds a build file (makefile or blueprint file) by looking at dir first. If not
+// found, go up one level and repeat again until one is found and the path of that build file
+// relative to the root directory of the source tree is returned. The returned filename of build
+// file is "Android.mk". If one was not found, a blank string is returned.
+func findBuildFile(ctx Context, dir string) string {
+	// If the string is empty, assume it is top directory of the source tree.
+	if dir == "" {
+		return ""
+	}
+
+	for ; dir != "."; dir = filepath.Dir(dir) {
+		for _, buildFile := range []string{"Android.bp", "Android.mk"} {
+			_, err := os.Stat(filepath.Join(dir, buildFile))
+			if err == nil {
+				// Returning the filename Android.mk as it might be used for ONE_SHOT_MAKEFILE variable.
+				return filepath.Join(dir, "Android.mk")
+			}
+			if !os.IsNotExist(err) {
+				ctx.Fatalf("Error retrieving the build file stats: %v", err)
+			}
+		}
+	}
+
+	return ""
+}
+
+// splitArgs iterates over the arguments list and splits into two lists: arguments and directories.
+func splitArgs(args []string) (newArgs []string, dirs []string) {
+	specialArgs := map[string]bool{
+		"showcommands": true,
+		"snod":         true,
+		"dist":         true,
+		"checkbuild":   true,
+	}
+
+	newArgs = []string{}
+	dirs = []string{}
+
+	for _, arg := range args {
+		// It's a dash argument if it starts with "-" or it's a key=value pair, it's not a directory.
+		if strings.IndexRune(arg, '-') == 0 || strings.IndexRune(arg, '=') != -1 {
+			newArgs = append(newArgs, arg)
+			continue
+		}
+
+		if _, ok := specialArgs[arg]; ok {
+			newArgs = append(newArgs, arg)
+			continue
+		}
+
+		dirs = append(dirs, arg)
+	}
+
+	return newArgs, dirs
+}
+
+// getTargetsFromDirs iterates over the dirs list and creates a list of targets to build. If a
+// directory from the dirs list does not exist, a fatal error is raised. relDir is related to the
+// source root tree where the build action command was invoked. Each directory is validated if the
+// build file can be found and follows the format "dir1:target1,target2,...". Target is optional.
+func getTargetsFromDirs(ctx Context, relDir string, dirs []string, targetNamePrefix string) (targets []string, buildFiles []string) {
+	for _, dir := range dirs {
+		// The directory may have specified specific modules to build. ":" is the separator to separate
+		// the directory and the list of modules.
+		s := strings.Split(dir, ":")
+		l := len(s)
+		if l > 2 { // more than one ":" was specified.
+			ctx.Fatalf("%s not in proper directory:target1,target2,... format (\":\" was specified more than once)", dir)
+		}
+
+		dir = filepath.Join(relDir, s[0])
+		if _, err := os.Stat(dir); err != nil {
+			ctx.Fatalf("couldn't find directory %s", dir)
+		}
+
+		// Verify that if there are any targets specified after ":". Each target is separated by ",".
+		var newTargets []string
+		if l == 2 && s[1] != "" {
+			newTargets = strings.Split(s[1], ",")
+			if inList("", newTargets) {
+				ctx.Fatalf("%s not in proper directory:target1,target2,... format", dir)
+			}
+		}
+
+		buildFile := findBuildFile(ctx, dir)
+		if buildFile == "" {
+			ctx.Fatalf("Build file not found for %s directory", dir)
+		}
+		buildFileDir := filepath.Dir(buildFile)
+
+		// If there are specified targets, find the build file in the directory. If dir does not
+		// contain the build file, bail out as it is required for one shot build. If there are no
+		// target specified, build all the modules in dir (or the closest one in the dir path).
+		if len(newTargets) > 0 {
+			if buildFileDir != dir {
+				ctx.Fatalf("Couldn't locate a build file from %s directory", dir)
+			}
+		} else {
+			newTargets = []string{convertToTarget(buildFileDir, targetNamePrefix)}
+		}
+
+		buildFiles = append(buildFiles, buildFile)
+		targets = append(targets, newTargets...)
+	}
+
+	return targets, buildFiles
+}
+
 func (c *configImpl) parseArgs(ctx Context, args []string) {
 	for i := 0; i < len(args); i++ {
 		arg := strings.TrimSpace(args[i])
diff --git a/ui/build/config_test.go b/ui/build/config_test.go
index 242e3af..1ef5456 100644
--- a/ui/build/config_test.go
+++ b/ui/build/config_test.go
@@ -17,19 +17,22 @@
 import (
 	"bytes"
 	"context"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
 	"reflect"
 	"strings"
 	"testing"
 
 	"android/soong/ui/logger"
-	"android/soong/ui/terminal"
 )
 
 func testContext() Context {
 	return Context{&ContextImpl{
 		Context: context.Background(),
 		Logger:  logger.New(&bytes.Buffer{}),
-		Writer:  terminal.NewWriter(terminal.NewCustomStdio(&bytes.Buffer{}, &bytes.Buffer{}, &bytes.Buffer{})),
+		Writer:  &bytes.Buffer{},
 	}}
 }
 
@@ -173,3 +176,877 @@
 		})
 	}
 }
+
+func TestConfigCheckTopDir(t *testing.T) {
+	ctx := testContext()
+	buildRootDir := filepath.Dir(srcDirFileCheck)
+	expectedErrStr := fmt.Sprintf("Current working directory must be the source tree. %q not found.", srcDirFileCheck)
+
+	tests := []struct {
+		// ********* Setup *********
+		// Test description.
+		description string
+
+		// ********* Action *********
+		// If set to true, the build root file is created.
+		rootBuildFile bool
+
+		// The current path where Soong is being executed.
+		path string
+
+		// ********* Validation *********
+		// Expecting error and validate the error string against expectedErrStr.
+		wantErr bool
+	}{{
+		description:   "current directory is the root source tree",
+		rootBuildFile: true,
+		path:          ".",
+		wantErr:       false,
+	}, {
+		description:   "one level deep in the source tree",
+		rootBuildFile: true,
+		path:          "1",
+		wantErr:       true,
+	}, {
+		description:   "very deep in the source tree",
+		rootBuildFile: true,
+		path:          "1/2/3/4/5/6/7/8/9/1/2/3/4/5/6/7/8/9/1/2/3/4/5/6/7/8/9/1/2/3/4/5/6/7",
+		wantErr:       true,
+	}, {
+		description:   "outside of source tree",
+		rootBuildFile: false,
+		path:          "1/2/3/4/5",
+		wantErr:       true,
+	}}
+
+	for _, tt := range tests {
+		t.Run(tt.description, func(t *testing.T) {
+			defer logger.Recover(func(err error) {
+				if !tt.wantErr {
+					t.Fatalf("Got unexpected error: %v", err)
+				}
+				if expectedErrStr != err.Error() {
+					t.Fatalf("expected %s, got %s", expectedErrStr, err.Error())
+				}
+			})
+
+			// Create the root source tree.
+			rootDir, err := ioutil.TempDir("", "")
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer os.RemoveAll(rootDir)
+
+			// Create the build root file. This is to test if topDir returns an error if the build root
+			// file does not exist.
+			if tt.rootBuildFile {
+				dir := filepath.Join(rootDir, buildRootDir)
+				if err := os.MkdirAll(dir, 0755); err != nil {
+					t.Errorf("failed to create %s directory: %v", dir, err)
+				}
+				f := filepath.Join(rootDir, srcDirFileCheck)
+				if err := ioutil.WriteFile(f, []byte{}, 0644); err != nil {
+					t.Errorf("failed to create file %s: %v", f, err)
+				}
+			}
+
+			// Next block of code is to set the current directory.
+			dir := rootDir
+			if tt.path != "" {
+				dir = filepath.Join(dir, tt.path)
+				if err := os.MkdirAll(dir, 0755); err != nil {
+					t.Errorf("failed to create %s directory: %v", dir, err)
+				}
+			}
+			curDir, err := os.Getwd()
+			if err != nil {
+				t.Fatalf("failed to get the current directory: %v", err)
+			}
+			defer func() { os.Chdir(curDir) }()
+
+			if err := os.Chdir(dir); err != nil {
+				t.Fatalf("failed to change directory to %s: %v", dir, err)
+			}
+
+			checkTopDir(ctx)
+		})
+	}
+}
+
+func TestConfigConvertToTarget(t *testing.T) {
+	tests := []struct {
+		// ********* Setup *********
+		// Test description.
+		description string
+
+		// ********* Action *********
+		// The current directory where Soong is being executed.
+		dir string
+
+		// The current prefix string to be pre-appended to the target.
+		prefix string
+
+		// ********* Validation *********
+		// The expected target to be invoked in ninja.
+		expectedTarget string
+	}{{
+		description:    "one level directory in source tree",
+		dir:            "test1",
+		prefix:         "MODULES-IN-",
+		expectedTarget: "MODULES-IN-test1",
+	}, {
+		description:    "multiple level directories in source tree",
+		dir:            "test1/test2/test3/test4",
+		prefix:         "GET-INSTALL-PATH-IN-",
+		expectedTarget: "GET-INSTALL-PATH-IN-test1-test2-test3-test4",
+	}}
+	for _, tt := range tests {
+		t.Run(tt.description, func(t *testing.T) {
+			target := convertToTarget(tt.dir, tt.prefix)
+			if target != tt.expectedTarget {
+				t.Errorf("expected %s, got %s for target", tt.expectedTarget, target)
+			}
+		})
+	}
+}
+
+func setTop(t *testing.T, dir string) func() {
+	curDir, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("failed to get current directory: %v", err)
+	}
+	if err := os.Chdir(dir); err != nil {
+		t.Fatalf("failed to change directory to top dir %s: %v", dir, err)
+	}
+	return func() { os.Chdir(curDir) }
+}
+
+func createBuildFiles(t *testing.T, topDir string, buildFiles []string) {
+	for _, buildFile := range buildFiles {
+		buildFile = filepath.Join(topDir, buildFile)
+		if err := ioutil.WriteFile(buildFile, []byte{}, 0644); err != nil {
+			t.Errorf("failed to create file %s: %v", buildFile, err)
+		}
+	}
+}
+
+func createDirectories(t *testing.T, topDir string, dirs []string) {
+	for _, dir := range dirs {
+		dir = filepath.Join(topDir, dir)
+		if err := os.MkdirAll(dir, 0755); err != nil {
+			t.Errorf("failed to create %s directory: %v", dir, err)
+		}
+	}
+}
+
+func TestConfigGetTargets(t *testing.T) {
+	ctx := testContext()
+	tests := []struct {
+		// ********* Setup *********
+		// Test description.
+		description string
+
+		// Directories that exist in the source tree.
+		dirsInTrees []string
+
+		// Build files that exists in the source tree.
+		buildFiles []string
+
+		// ********* Action *********
+		// Directories passed in to soong_ui.
+		dirs []string
+
+		// Current directory that the user executed the build action command.
+		curDir string
+
+		// ********* Validation *********
+		// Expected targets from the function.
+		expectedTargets []string
+
+		// Expected build from the build system.
+		expectedBuildFiles []string
+
+		// Expecting error from running test case.
+		errStr string
+	}{{
+		description:        "one target dir specified",
+		dirsInTrees:        []string{"0/1/2/3"},
+		buildFiles:         []string{"0/1/2/3/Android.bp"},
+		dirs:               []string{"1/2/3"},
+		curDir:             "0",
+		expectedTargets:    []string{"MODULES-IN-0-1-2-3"},
+		expectedBuildFiles: []string{"0/1/2/3/Android.mk"},
+	}, {
+		description: "one target dir specified, build file does not exist",
+		dirsInTrees: []string{"0/1/2/3"},
+		buildFiles:  []string{},
+		dirs:        []string{"1/2/3"},
+		curDir:      "0",
+		errStr:      "Build file not found for 0/1/2/3 directory",
+	}, {
+		description: "one target dir specified, invalid targets specified",
+		dirsInTrees: []string{"0/1/2/3"},
+		buildFiles:  []string{},
+		dirs:        []string{"1/2/3:t1:t2"},
+		curDir:      "0",
+		errStr:      "1/2/3:t1:t2 not in proper directory:target1,target2,... format (\":\" was specified more than once)",
+	}, {
+		description:        "one target dir specified, no targets specified but has colon",
+		dirsInTrees:        []string{"0/1/2/3"},
+		buildFiles:         []string{"0/1/2/3/Android.bp"},
+		dirs:               []string{"1/2/3:"},
+		curDir:             "0",
+		expectedTargets:    []string{"MODULES-IN-0-1-2-3"},
+		expectedBuildFiles: []string{"0/1/2/3/Android.mk"},
+	}, {
+		description:        "one target dir specified, two targets specified",
+		dirsInTrees:        []string{"0/1/2/3"},
+		buildFiles:         []string{"0/1/2/3/Android.bp"},
+		dirs:               []string{"1/2/3:t1,t2"},
+		curDir:             "0",
+		expectedTargets:    []string{"t1", "t2"},
+		expectedBuildFiles: []string{"0/1/2/3/Android.mk"},
+	}, {
+		description: "one target dir specified, no targets and has a comma",
+		dirsInTrees: []string{"0/1/2/3"},
+		buildFiles:  []string{"0/1/2/3/Android.bp"},
+		dirs:        []string{"1/2/3:,"},
+		curDir:      "0",
+		errStr:      "0/1/2/3 not in proper directory:target1,target2,... format",
+	}, {
+		description: "one target dir specified, improper targets defined",
+		dirsInTrees: []string{"0/1/2/3"},
+		buildFiles:  []string{"0/1/2/3/Android.bp"},
+		dirs:        []string{"1/2/3:,t1"},
+		curDir:      "0",
+		errStr:      "0/1/2/3 not in proper directory:target1,target2,... format",
+	}, {
+		description: "one target dir specified, blank target",
+		dirsInTrees: []string{"0/1/2/3"},
+		buildFiles:  []string{"0/1/2/3/Android.bp"},
+		dirs:        []string{"1/2/3:t1,"},
+		curDir:      "0",
+		errStr:      "0/1/2/3 not in proper directory:target1,target2,... format",
+	}, {
+		description:        "one target dir specified, many targets specified",
+		dirsInTrees:        []string{"0/1/2/3"},
+		buildFiles:         []string{"0/1/2/3/Android.bp"},
+		dirs:               []string{"1/2/3:t1,t2,t3,t4,t5,t6,t7,t8,t9,t10"},
+		curDir:             "0",
+		expectedTargets:    []string{"t1", "t2", "t3", "t4", "t5", "t6", "t7", "t8", "t9", "t10"},
+		expectedBuildFiles: []string{"0/1/2/3/Android.mk"},
+	}, {
+		description: "one target dir specified, one target specified, build file does not exist",
+		dirsInTrees: []string{"0/1/2/3"},
+		buildFiles:  []string{},
+		dirs:        []string{"1/2/3:t1"},
+		curDir:      "0",
+		errStr:      "Build file not found for 0/1/2/3 directory",
+	}, {
+		description: "one target dir specified, one target specified, build file not in target dir",
+		dirsInTrees: []string{"0/1/2/3"},
+		buildFiles:  []string{"0/1/2/Android.mk"},
+		dirs:        []string{"1/2/3:t1"},
+		curDir:      "0",
+		errStr:      "Couldn't locate a build file from 0/1/2/3 directory",
+	}, {
+		description:        "one target dir specified, build file not in target dir",
+		dirsInTrees:        []string{"0/1/2/3"},
+		buildFiles:         []string{"0/1/2/Android.mk"},
+		dirs:               []string{"1/2/3"},
+		curDir:             "0",
+		expectedTargets:    []string{"MODULES-IN-0-1-2"},
+		expectedBuildFiles: []string{"0/1/2/Android.mk"},
+	}, {
+		description:        "multiple targets dir specified, targets specified",
+		dirsInTrees:        []string{"0/1/2/3", "0/3/4"},
+		buildFiles:         []string{"0/1/2/3/Android.bp", "0/3/4/Android.mk"},
+		dirs:               []string{"1/2/3:t1,t2", "3/4:t3,t4,t5"},
+		curDir:             "0",
+		expectedTargets:    []string{"t1", "t2", "t3", "t4", "t5"},
+		expectedBuildFiles: []string{"0/1/2/3/Android.mk", "0/3/4/Android.mk"},
+	}, {
+		description:        "multiple targets dir specified, one directory has targets specified",
+		dirsInTrees:        []string{"0/1/2/3", "0/3/4"},
+		buildFiles:         []string{"0/1/2/3/Android.bp", "0/3/4/Android.mk"},
+		dirs:               []string{"1/2/3:t1,t2", "3/4"},
+		curDir:             "0",
+		expectedTargets:    []string{"t1", "t2", "MODULES-IN-0-3-4"},
+		expectedBuildFiles: []string{"0/1/2/3/Android.mk", "0/3/4/Android.mk"},
+	}, {
+		description: "two dirs specified, only one dir exist",
+		dirsInTrees: []string{"0/1/2/3"},
+		buildFiles:  []string{"0/1/2/3/Android.mk"},
+		dirs:        []string{"1/2/3:t1", "3/4"},
+		curDir:      "0",
+		errStr:      "couldn't find directory 0/3/4",
+	}, {
+		description:        "multiple targets dirs specified at root source tree",
+		dirsInTrees:        []string{"0/1/2/3", "0/3/4"},
+		buildFiles:         []string{"0/1/2/3/Android.bp", "0/3/4/Android.mk"},
+		dirs:               []string{"0/1/2/3:t1,t2", "0/3/4"},
+		curDir:             ".",
+		expectedTargets:    []string{"t1", "t2", "MODULES-IN-0-3-4"},
+		expectedBuildFiles: []string{"0/1/2/3/Android.mk", "0/3/4/Android.mk"},
+	}, {
+		description: "no directories specified",
+		dirsInTrees: []string{"0/1/2/3", "0/3/4"},
+		buildFiles:  []string{"0/1/2/3/Android.bp", "0/3/4/Android.mk"},
+		dirs:        []string{},
+		curDir:      ".",
+	}}
+	for _, tt := range tests {
+		t.Run(tt.description, func(t *testing.T) {
+			defer logger.Recover(func(err error) {
+				if tt.errStr == "" {
+					t.Fatalf("Got unexpected error: %v", err)
+				}
+				if tt.errStr != err.Error() {
+					t.Errorf("expected %s, got %s", tt.errStr, err.Error())
+				}
+			})
+
+			// Create the root source tree.
+			topDir, err := ioutil.TempDir("", "")
+			if err != nil {
+				t.Fatalf("failed to create temp dir: %v", err)
+			}
+			defer os.RemoveAll(topDir)
+
+			createDirectories(t, topDir, tt.dirsInTrees)
+			createBuildFiles(t, topDir, tt.buildFiles)
+			r := setTop(t, topDir)
+			defer r()
+
+			targets, buildFiles := getTargetsFromDirs(ctx, tt.curDir, tt.dirs, "MODULES-IN-")
+			if !reflect.DeepEqual(targets, tt.expectedTargets) {
+				t.Errorf("expected %v, got %v for targets", tt.expectedTargets, targets)
+			}
+			if !reflect.DeepEqual(buildFiles, tt.expectedBuildFiles) {
+				t.Errorf("expected %v, got %v for build files", tt.expectedBuildFiles, buildFiles)
+			}
+
+			// If the execution reached here and there was an expected error code, the unit test case failed.
+			if tt.errStr != "" {
+				t.Errorf("expecting error %s", tt.errStr)
+			}
+		})
+	}
+}
+
+func TestConfigFindBuildFile(t *testing.T) {
+	ctx := testContext()
+
+	tests := []struct {
+		// ********* Setup *********
+		// Test description.
+		description string
+
+		// Array of build files to create in dir.
+		buildFiles []string
+
+		// ********* Action *********
+		// Directory to create, also the base directory is where findBuildFile is invoked.
+		dir string
+
+		// ********* Validation *********
+		// Expected build file path to find.
+		expectedBuildFile string
+	}{{
+		description:       "build file exists at leaf directory",
+		buildFiles:        []string{"1/2/3/Android.bp"},
+		dir:               "1/2/3",
+		expectedBuildFile: "1/2/3/Android.mk",
+	}, {
+		description:       "build file exists in all directory paths",
+		buildFiles:        []string{"1/Android.mk", "1/2/Android.mk", "1/2/3/Android.mk"},
+		dir:               "1/2/3",
+		expectedBuildFile: "1/2/3/Android.mk",
+	}, {
+		description:       "build file does not exist in all directory paths",
+		buildFiles:        []string{},
+		dir:               "1/2/3",
+		expectedBuildFile: "",
+	}, {
+		description:       "build file exists only at top directory",
+		buildFiles:        []string{"Android.bp"},
+		dir:               "1/2/3",
+		expectedBuildFile: "",
+	}, {
+		description:       "build file exist in a subdirectory",
+		buildFiles:        []string{"1/2/Android.bp"},
+		dir:               "1/2/3",
+		expectedBuildFile: "1/2/Android.mk",
+	}, {
+		description:       "build file exists in a subdirectory",
+		buildFiles:        []string{"1/Android.mk"},
+		dir:               "1/2/3",
+		expectedBuildFile: "1/Android.mk",
+	}, {
+		description:       "top directory",
+		buildFiles:        []string{"Android.bp"},
+		dir:               ".",
+		expectedBuildFile: "",
+	}}
+
+	for _, tt := range tests {
+		t.Run(tt.description, func(t *testing.T) {
+			defer logger.Recover(func(err error) {
+				t.Fatalf("Got unexpected error: %v", err)
+			})
+
+			topDir, err := ioutil.TempDir("", "")
+			if err != nil {
+				t.Fatalf("failed to create temp dir: %v", err)
+			}
+			defer os.RemoveAll(topDir)
+
+			if tt.dir != "" {
+				createDirectories(t, topDir, []string{tt.dir})
+			}
+
+			createBuildFiles(t, topDir, tt.buildFiles)
+
+			curDir, err := os.Getwd()
+			if err != nil {
+				t.Fatalf("Could not get working directory: %v", err)
+			}
+			defer func() { os.Chdir(curDir) }()
+			if err := os.Chdir(topDir); err != nil {
+				t.Fatalf("Could not change top dir to %s: %v", topDir, err)
+			}
+
+			buildFile := findBuildFile(ctx, tt.dir)
+			if buildFile != tt.expectedBuildFile {
+				t.Errorf("expected %q, got %q for build file", tt.expectedBuildFile, buildFile)
+			}
+		})
+	}
+}
+
+func TestConfigSplitArgs(t *testing.T) {
+	tests := []struct {
+		// ********* Setup *********
+		// Test description.
+		description string
+
+		// ********* Action *********
+		// Arguments passed in to soong_ui.
+		args []string
+
+		// ********* Validation *********
+		// Expected newArgs list after extracting the directories.
+		expectedNewArgs []string
+
+		// Expected directories
+		expectedDirs []string
+	}{{
+		description:     "flags but no directories specified",
+		args:            []string{"showcommands", "-j", "-k"},
+		expectedNewArgs: []string{"showcommands", "-j", "-k"},
+		expectedDirs:    []string{},
+	}, {
+		description:     "flags and one directory specified",
+		args:            []string{"snod", "-j", "dir:target1,target2"},
+		expectedNewArgs: []string{"snod", "-j"},
+		expectedDirs:    []string{"dir:target1,target2"},
+	}, {
+		description:     "flags and directories specified",
+		args:            []string{"dist", "-k", "dir1", "dir2:target1,target2"},
+		expectedNewArgs: []string{"dist", "-k"},
+		expectedDirs:    []string{"dir1", "dir2:target1,target2"},
+	}, {
+		description:     "only directories specified",
+		args:            []string{"dir1", "dir2", "dir3:target1,target2"},
+		expectedNewArgs: []string{},
+		expectedDirs:    []string{"dir1", "dir2", "dir3:target1,target2"},
+	}}
+	for _, tt := range tests {
+		t.Run(tt.description, func(t *testing.T) {
+			args, dirs := splitArgs(tt.args)
+			if !reflect.DeepEqual(tt.expectedNewArgs, args) {
+				t.Errorf("expected %v, got %v for arguments", tt.expectedNewArgs, args)
+			}
+			if !reflect.DeepEqual(tt.expectedDirs, dirs) {
+				t.Errorf("expected %v, got %v for directories", tt.expectedDirs, dirs)
+			}
+		})
+	}
+}
+
+type envVar struct {
+	name  string
+	value string
+}
+
+type buildActionTestCase struct {
+	// ********* Setup *********
+	// Test description.
+	description string
+
+	// Directories that exist in the source tree.
+	dirsInTrees []string
+
+	// Build files that exists in the source tree.
+	buildFiles []string
+
+	// ********* Action *********
+	// Arguments passed in to soong_ui.
+	args []string
+
+	// Directory where the build action was invoked.
+	curDir string
+
+	// WITH_TIDY_ONLY environment variable specified.
+	tidyOnly string
+
+	// ********* Validation *********
+	// Expected arguments to be in Config instance.
+	expectedArgs []string
+
+	// Expected environment variables to be set.
+	expectedEnvVars []envVar
+}
+
+func testGetConfigArgs(t *testing.T, tt buildActionTestCase, action BuildAction, buildDependencies bool) {
+	ctx := testContext()
+
+	// Environment variables to set it to blank on every test case run.
+	resetEnvVars := []string{
+		"ONE_SHOT_MAKEFILE",
+		"WITH_TIDY_ONLY",
+	}
+
+	for _, name := range resetEnvVars {
+		if err := os.Unsetenv(name); err != nil {
+			t.Fatalf("failed to unset environment variable %s: %v", name, err)
+		}
+	}
+	if tt.tidyOnly != "" {
+		if err := os.Setenv("WITH_TIDY_ONLY", tt.tidyOnly); err != nil {
+			t.Errorf("failed to set WITH_TIDY_ONLY to %s: %v", tt.tidyOnly, err)
+		}
+	}
+
+	// Create the root source tree.
+	topDir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatalf("failed to create temp dir: %v", err)
+	}
+	defer os.RemoveAll(topDir)
+
+	createDirectories(t, topDir, tt.dirsInTrees)
+	createBuildFiles(t, topDir, tt.buildFiles)
+
+	r := setTop(t, topDir)
+	defer r()
+
+	// The next block is to create the root build file.
+	rootBuildFileDir := filepath.Dir(srcDirFileCheck)
+	if err := os.MkdirAll(rootBuildFileDir, 0755); err != nil {
+		t.Fatalf("Failed to create %s directory: %v", rootBuildFileDir, err)
+	}
+
+	if err := ioutil.WriteFile(srcDirFileCheck, []byte{}, 0644); err != nil {
+		t.Fatalf("failed to create %s file: %v", srcDirFileCheck, err)
+	}
+
+	args := getConfigArgs(action, tt.curDir, buildDependencies, ctx, tt.args)
+	if !reflect.DeepEqual(tt.expectedArgs, args) {
+		t.Fatalf("expected %v, got %v for config arguments", tt.expectedArgs, args)
+	}
+
+	for _, env := range tt.expectedEnvVars {
+		if val := os.Getenv(env.name); val != env.value {
+			t.Errorf("expecting %s, got %s for environment variable %s", env.value, val, env.name)
+		}
+	}
+}
+
+// TODO: Remove this test case once mm shell build command has been deprecated.
+func TestGetConfigArgsBuildModulesInDirecotoryNoDeps(t *testing.T) {
+	tests := []buildActionTestCase{{
+		description:  "normal execution in a directory",
+		dirsInTrees:  []string{"0/1/2"},
+		buildFiles:   []string{"0/1/2/Android.mk"},
+		args:         []string{"-j", "-k", "showcommands", "fake-module"},
+		curDir:       "0/1/2",
+		tidyOnly:     "",
+		expectedArgs: []string{"-j", "-k", "showcommands", "fake-module", "MODULES-IN-0-1-2"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: "0/1/2/Android.mk"}},
+	}, {
+		description:  "makefile in parent directory",
+		dirsInTrees:  []string{"0/1/2"},
+		buildFiles:   []string{"0/1/Android.mk"},
+		args:         []string{},
+		curDir:       "0/1/2",
+		tidyOnly:     "",
+		expectedArgs: []string{"MODULES-IN-0-1"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: "0/1/Android.mk"}},
+	}, {
+		description:  "build file not found",
+		dirsInTrees:  []string{"0/1/2"},
+		buildFiles:   []string{},
+		args:         []string{},
+		curDir:       "0/1/2",
+		tidyOnly:     "",
+		expectedArgs: []string{"MODULES-IN-0-1-2"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: "0/1/2/Android.mk"}},
+	}, {
+		description:  "build action executed at root directory",
+		dirsInTrees:  []string{},
+		buildFiles:   []string{},
+		args:         []string{},
+		curDir:       ".",
+		tidyOnly:     "",
+		expectedArgs: []string{},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: ""}},
+	}, {
+		description:  "GET-INSTALL-PATH specified,",
+		dirsInTrees:  []string{"0/1/2"},
+		buildFiles:   []string{"0/1/Android.mk"},
+		args:         []string{"GET-INSTALL-PATH"},
+		curDir:       "0/1/2",
+		tidyOnly:     "",
+		expectedArgs: []string{"GET-INSTALL-PATH-IN-0-1"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: "0/1/Android.mk"}},
+	}, {
+		description:  "tidy only environment variable specified,",
+		dirsInTrees:  []string{"0/1/2"},
+		buildFiles:   []string{"0/1/Android.mk"},
+		args:         []string{"GET-INSTALL-PATH"},
+		curDir:       "0/1/2",
+		tidyOnly:     "true",
+		expectedArgs: []string{"tidy_only"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: "0/1/Android.mk"}},
+	}}
+	for _, tt := range tests {
+		t.Run("build action BUILD_MODULES_IN_DIR without their dependencies, "+tt.description, func(t *testing.T) {
+			testGetConfigArgs(t, tt, BUILD_MODULES_IN_A_DIRECTORY, false)
+		})
+	}
+}
+
+func TestGetConfigArgsBuildModulesInDirectory(t *testing.T) {
+	tests := []buildActionTestCase{{
+		description:     "normal execution in a directory",
+		dirsInTrees:     []string{"0/1/2"},
+		buildFiles:      []string{"0/1/2/Android.mk"},
+		args:            []string{"fake-module"},
+		curDir:          "0/1/2",
+		tidyOnly:        "",
+		expectedArgs:    []string{"fake-module", "MODULES-IN-0-1-2"},
+		expectedEnvVars: []envVar{},
+	}, {
+		description:     "build file in parent directory",
+		dirsInTrees:     []string{"0/1/2"},
+		buildFiles:      []string{"0/1/Android.mk"},
+		args:            []string{},
+		curDir:          "0/1/2",
+		tidyOnly:        "",
+		expectedArgs:    []string{"MODULES-IN-0-1"},
+		expectedEnvVars: []envVar{},
+	},
+		{
+			description:     "build file in parent directory, multiple module names passed in",
+			dirsInTrees:     []string{"0/1/2"},
+			buildFiles:      []string{"0/1/Android.mk"},
+			args:            []string{"fake-module1", "fake-module2", "fake-module3"},
+			curDir:          "0/1/2",
+			tidyOnly:        "",
+			expectedArgs:    []string{"fake-module1", "fake-module2", "fake-module3", "MODULES-IN-0-1"},
+			expectedEnvVars: []envVar{},
+		}, {
+			description:     "build file in 2nd level parent directory",
+			dirsInTrees:     []string{"0/1/2"},
+			buildFiles:      []string{"0/Android.bp"},
+			args:            []string{},
+			curDir:          "0/1/2",
+			tidyOnly:        "",
+			expectedArgs:    []string{"MODULES-IN-0"},
+			expectedEnvVars: []envVar{},
+		}, {
+			description:     "build action executed at root directory",
+			dirsInTrees:     []string{},
+			buildFiles:      []string{},
+			args:            []string{},
+			curDir:          ".",
+			tidyOnly:        "",
+			expectedArgs:    []string{},
+			expectedEnvVars: []envVar{},
+		}, {
+			description:     "build file not found - no error is expected to return",
+			dirsInTrees:     []string{"0/1/2"},
+			buildFiles:      []string{},
+			args:            []string{},
+			curDir:          "0/1/2",
+			tidyOnly:        "",
+			expectedArgs:    []string{"MODULES-IN-0-1-2"},
+			expectedEnvVars: []envVar{},
+		}, {
+			description:     "GET-INSTALL-PATH specified,",
+			dirsInTrees:     []string{"0/1/2"},
+			buildFiles:      []string{"0/1/Android.mk"},
+			args:            []string{"GET-INSTALL-PATH", "-j", "-k", "GET-INSTALL-PATH"},
+			curDir:          "0/1/2",
+			tidyOnly:        "",
+			expectedArgs:    []string{"-j", "-k", "GET-INSTALL-PATH-IN-0-1"},
+			expectedEnvVars: []envVar{},
+		}, {
+			description:     "tidy only environment variable specified,",
+			dirsInTrees:     []string{"0/1/2"},
+			buildFiles:      []string{"0/1/Android.mk"},
+			args:            []string{"GET-INSTALL-PATH"},
+			curDir:          "0/1/2",
+			tidyOnly:        "true",
+			expectedArgs:    []string{"tidy_only"},
+			expectedEnvVars: []envVar{},
+		}, {
+			description:     "normal execution in root directory with args",
+			dirsInTrees:     []string{},
+			buildFiles:      []string{},
+			args:            []string{"-j", "-k", "fake_module"},
+			curDir:          "",
+			tidyOnly:        "",
+			expectedArgs:    []string{"-j", "-k", "fake_module"},
+			expectedEnvVars: []envVar{},
+		}}
+	for _, tt := range tests {
+		t.Run("build action BUILD_MODULES_IN_DIR, "+tt.description, func(t *testing.T) {
+			testGetConfigArgs(t, tt, BUILD_MODULES_IN_A_DIRECTORY, true)
+		})
+	}
+}
+
+// TODO: Remove this test case once mmm shell build command has been deprecated.
+func TestGetConfigArgsBuildModulesInDirectoriesNoDeps(t *testing.T) {
+	tests := []buildActionTestCase{{
+		description:  "normal execution in a directory",
+		dirsInTrees:  []string{"0/1/2/3.1", "0/1/2/3.2", "0/1/2/3.3"},
+		buildFiles:   []string{"0/1/2/3.1/Android.bp", "0/1/2/3.2/Android.bp", "0/1/2/3.3/Android.bp"},
+		args:         []string{"3.1/:t1,t2", "3.2/:t3,t4", "3.3/:t5,t6"},
+		curDir:       "0/1/2",
+		tidyOnly:     "",
+		expectedArgs: []string{"t1", "t2", "t3", "t4", "t5", "t6"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: "0/1/2/3.1/Android.mk 0/1/2/3.2/Android.mk 0/1/2/3.3/Android.mk"}},
+	}, {
+		description:  "GET-INSTALL-PATH specified",
+		dirsInTrees:  []string{"0/1/2/3.1", "0/1/2/3.2", "0/1/2/3.3"},
+		buildFiles:   []string{"0/1/2/3.1/Android.bp", "0/1/2/3.2/Android.bp", "0/1/2/3.3/Android.bp"},
+		args:         []string{"GET-INSTALL-PATH", "3.1/", "3.2/", "3.3/:t6"},
+		curDir:       "0/1/2",
+		tidyOnly:     "",
+		expectedArgs: []string{"GET-INSTALL-PATH-IN-0-1-2-3.1", "GET-INSTALL-PATH-IN-0-1-2-3.2", "t6"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: "0/1/2/3.1/Android.mk 0/1/2/3.2/Android.mk 0/1/2/3.3/Android.mk"}},
+	}, {
+		description:  "tidy only environment variable specified",
+		dirsInTrees:  []string{"0/1/2/3.1", "0/1/2/3.2", "0/1/2/3.3"},
+		buildFiles:   []string{"0/1/2/3.1/Android.bp", "0/1/2/3.2/Android.bp", "0/1/2/3.3/Android.bp"},
+		args:         []string{"GET-INSTALL-PATH", "3.1/", "3.2/", "3.3/:t6"},
+		curDir:       "0/1/2",
+		tidyOnly:     "1",
+		expectedArgs: []string{"tidy_only"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: "0/1/2/3.1/Android.mk 0/1/2/3.2/Android.mk 0/1/2/3.3/Android.mk"}},
+	}, {
+		description:  "normal execution from top dir directory",
+		dirsInTrees:  []string{"0/1/2/3.1", "0/1/2/3.2", "0/1/2/3.3"},
+		buildFiles:   []string{"0/1/2/3.1/Android.bp", "0/1/2/3.2/Android.bp", "0/1/2/3.3/Android.bp"},
+		args:         []string{"0/1/2/3.1", "0/1/2/3.2/:t3,t4", "0/1/2/3.3/:t5,t6"},
+		curDir:       ".",
+		tidyOnly:     "",
+		expectedArgs: []string{"MODULES-IN-0-1-2-3.1", "t3", "t4", "t5", "t6"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: "0/1/2/3.1/Android.mk 0/1/2/3.2/Android.mk 0/1/2/3.3/Android.mk"}},
+	}}
+	for _, tt := range tests {
+		t.Run("build action BUILD_MODULES_IN_DIRS_NO_DEPS, "+tt.description, func(t *testing.T) {
+			testGetConfigArgs(t, tt, BUILD_MODULES_IN_DIRECTORIES, false)
+		})
+	}
+}
+
+func TestGetConfigArgsBuildModulesInDirectories(t *testing.T) {
+	tests := []buildActionTestCase{{
+		description:  "normal execution in a directory",
+		dirsInTrees:  []string{"0/1/2/3.1", "0/1/2/3.2", "0/1/2/3.3"},
+		buildFiles:   []string{"0/1/2/3.1/Android.bp", "0/1/2/3.2/Android.bp", "0/1/2/3.3/Android.bp"},
+		args:         []string{"3.1/", "3.2/", "3.3/"},
+		curDir:       "0/1/2",
+		tidyOnly:     "",
+		expectedArgs: []string{"MODULES-IN-0-1-2-3.1", "MODULES-IN-0-1-2-3.2", "MODULES-IN-0-1-2-3.3"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: ""}},
+	}, {
+		description:  "GET-INSTALL-PATH specified",
+		dirsInTrees:  []string{"0/1/2/3.1", "0/1/2/3.2", "0/1/3"},
+		buildFiles:   []string{"0/1/2/3.1/Android.bp", "0/1/2/3.2/Android.bp", "0/1/Android.bp"},
+		args:         []string{"GET-INSTALL-PATH", "2/3.1/", "2/3.2", "3"},
+		curDir:       "0/1",
+		tidyOnly:     "",
+		expectedArgs: []string{"GET-INSTALL-PATH-IN-0-1-2-3.1", "GET-INSTALL-PATH-IN-0-1-2-3.2", "GET-INSTALL-PATH-IN-0-1"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: ""}},
+	}, {
+		description:  "tidy only environment variable specified",
+		dirsInTrees:  []string{"0/1/2/3.1", "0/1/2/3.2", "0/1/2/3.3"},
+		buildFiles:   []string{"0/1/2/3.1/Android.bp", "0/1/2/3.2/Android.bp", "0/1/2/3.3/Android.bp"},
+		args:         []string{"GET-INSTALL-PATH", "3.1/", "3.2/", "3.3"},
+		curDir:       "0/1/2",
+		tidyOnly:     "1",
+		expectedArgs: []string{"tidy_only"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: ""}},
+	}, {
+		description:  "normal execution from top dir directory",
+		dirsInTrees:  []string{"0/1/2/3.1", "0/1/2/3.2", "0/1/3", "0/2"},
+		buildFiles:   []string{"0/1/2/3.1/Android.bp", "0/1/2/3.2/Android.bp", "0/1/3/Android.bp", "0/2/Android.bp"},
+		args:         []string{"0/1/2/3.1", "0/1/2/3.2", "0/1/3", "0/2"},
+		curDir:       ".",
+		tidyOnly:     "",
+		expectedArgs: []string{"MODULES-IN-0-1-2-3.1", "MODULES-IN-0-1-2-3.2", "MODULES-IN-0-1-3", "MODULES-IN-0-2"},
+		expectedEnvVars: []envVar{
+			envVar{
+				name:  "ONE_SHOT_MAKEFILE",
+				value: ""}},
+	}}
+	for _, tt := range tests {
+		t.Run("build action BUILD_MODULES_IN_DIRS, "+tt.description, func(t *testing.T) {
+			testGetConfigArgs(t, tt, BUILD_MODULES_IN_DIRECTORIES, true)
+		})
+	}
+}
diff --git a/ui/build/context.go b/ui/build/context.go
index 249e898..7ff98ef 100644
--- a/ui/build/context.go
+++ b/ui/build/context.go
@@ -16,12 +16,12 @@
 
 import (
 	"context"
+	"io"
 
 	"android/soong/ui/logger"
 	"android/soong/ui/metrics"
 	"android/soong/ui/metrics/metrics_proto"
 	"android/soong/ui/status"
-	"android/soong/ui/terminal"
 	"android/soong/ui/tracer"
 )
 
@@ -35,7 +35,7 @@
 
 	Metrics *metrics.Metrics
 
-	Writer terminal.Writer
+	Writer io.Writer
 	Status *status.Status
 
 	Thread tracer.Thread
diff --git a/ui/build/dumpvars.go b/ui/build/dumpvars.go
index 4335667..266130f 100644
--- a/ui/build/dumpvars.go
+++ b/ui/build/dumpvars.go
@@ -249,7 +249,7 @@
 	env := config.Environment()
 	// Print the banner like make does
 	if !env.IsEnvTrue("ANDROID_QUIET_BUILD") {
-		ctx.Writer.Print(Banner(make_vars))
+		fmt.Fprintln(ctx.Writer, Banner(make_vars))
 	}
 
 	// Populate the environment
diff --git a/ui/build/util.go b/ui/build/util.go
index 0676a86..75e6753 100644
--- a/ui/build/util.go
+++ b/ui/build/util.go
@@ -44,6 +44,17 @@
 	return indexList(s, list) != -1
 }
 
+// removeFromlist removes all occurrences of the string in list.
+func removeFromList(s string, list []string) []string {
+	filteredList := make([]string, 0, len(list))
+	for _, ls := range list {
+		if s != ls {
+			filteredList = append(filteredList, ls)
+		}
+	}
+	return filteredList
+}
+
 // ensureDirectoriesExist is a shortcut to os.MkdirAll, sending errors to the ctx logger.
 func ensureDirectoriesExist(ctx Context, dirs ...string) {
 	for _, dir := range dirs {
diff --git a/ui/status/log.go b/ui/status/log.go
index 921aa44..7badac7 100644
--- a/ui/status/log.go
+++ b/ui/status/log.go
@@ -71,6 +71,11 @@
 	fmt.Fprintf(v.w, "%s%s\n", level.Prefix(), message)
 }
 
+func (v *verboseLog) Write(p []byte) (int, error) {
+	fmt.Fprint(v.w, string(p))
+	return len(p), nil
+}
+
 type errorLog struct {
 	w io.WriteCloser
 
@@ -134,3 +139,8 @@
 
 	fmt.Fprintf(e.w, "error: %s\n", message)
 }
+
+func (e *errorLog) Write(p []byte) (int, error) {
+	fmt.Fprint(e.w, string(p))
+	return len(p), nil
+}
diff --git a/ui/status/status.go b/ui/status/status.go
index 46ec72e..3d8cd7a 100644
--- a/ui/status/status.go
+++ b/ui/status/status.go
@@ -173,6 +173,9 @@
 	// Flush is called when your outputs should be flushed / closed. No
 	// output is expected after this call.
 	Flush()
+
+	// Write lets StatusOutput implement io.Writer
+	Write(p []byte) (n int, err error)
 }
 
 // Status is the multiplexer / accumulator between ToolStatus instances (via
diff --git a/ui/status/status_test.go b/ui/status/status_test.go
index e62785f..9494582 100644
--- a/ui/status/status_test.go
+++ b/ui/status/status_test.go
@@ -27,6 +27,11 @@
 func (c counterOutput) Message(level MsgLevel, msg string) {}
 func (c counterOutput) Flush()                             {}
 
+func (c counterOutput) Write(p []byte) (int, error) {
+	// Discard writes
+	return len(p), nil
+}
+
 func (c counterOutput) Expect(t *testing.T, counts Counts) {
 	if Counts(c) == counts {
 		return
diff --git a/ui/terminal/Android.bp b/ui/terminal/Android.bp
index 7104a50..b533b0d 100644
--- a/ui/terminal/Android.bp
+++ b/ui/terminal/Android.bp
@@ -17,11 +17,15 @@
     pkgPath: "android/soong/ui/terminal",
     deps: ["soong-ui-status"],
     srcs: [
+        "dumb_status.go",
+        "format.go",
+        "smart_status.go",
         "status.go",
-        "writer.go",
+        "stdio.go",
         "util.go",
     ],
     testSrcs: [
+        "status_test.go",
         "util_test.go",
     ],
     darwin: {
diff --git a/ui/terminal/dumb_status.go b/ui/terminal/dumb_status.go
new file mode 100644
index 0000000..201770f
--- /dev/null
+++ b/ui/terminal/dumb_status.go
@@ -0,0 +1,71 @@
+// Copyright 2019 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package terminal
+
+import (
+	"fmt"
+	"io"
+
+	"android/soong/ui/status"
+)
+
+type dumbStatusOutput struct {
+	writer    io.Writer
+	formatter formatter
+}
+
+// NewDumbStatusOutput returns a StatusOutput that represents the
+// current build status similarly to Ninja's built-in terminal
+// output.
+func NewDumbStatusOutput(w io.Writer, formatter formatter) status.StatusOutput {
+	return &dumbStatusOutput{
+		writer:    w,
+		formatter: formatter,
+	}
+}
+
+func (s *dumbStatusOutput) Message(level status.MsgLevel, message string) {
+	if level >= status.StatusLvl {
+		fmt.Fprintln(s.writer, s.formatter.message(level, message))
+	}
+}
+
+func (s *dumbStatusOutput) StartAction(action *status.Action, counts status.Counts) {
+}
+
+func (s *dumbStatusOutput) FinishAction(result status.ActionResult, counts status.Counts) {
+	str := result.Description
+	if str == "" {
+		str = result.Command
+	}
+
+	progress := s.formatter.progress(counts) + str
+
+	output := s.formatter.result(result)
+	output = string(stripAnsiEscapes([]byte(output)))
+
+	if output != "" {
+		fmt.Fprint(s.writer, progress, "\n", output)
+	} else {
+		fmt.Fprintln(s.writer, progress)
+	}
+}
+
+func (s *dumbStatusOutput) Flush() {}
+
+func (s *dumbStatusOutput) Write(p []byte) (int, error) {
+	fmt.Fprint(s.writer, string(p))
+	return len(p), nil
+}
diff --git a/ui/terminal/format.go b/ui/terminal/format.go
new file mode 100644
index 0000000..4205bdc
--- /dev/null
+++ b/ui/terminal/format.go
@@ -0,0 +1,123 @@
+// Copyright 2019 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package terminal
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	"android/soong/ui/status"
+)
+
+type formatter struct {
+	format string
+	quiet  bool
+	start  time.Time
+}
+
+// newFormatter returns a formatter for formatting output to
+// the terminal in a format similar to Ninja.
+// format takes nearly all the same options as NINJA_STATUS.
+// %c is currently unsupported.
+func newFormatter(format string, quiet bool) formatter {
+	return formatter{
+		format: format,
+		quiet:  quiet,
+		start:  time.Now(),
+	}
+}
+
+func (s formatter) message(level status.MsgLevel, message string) string {
+	if level >= status.ErrorLvl {
+		return fmt.Sprintf("FAILED: %s", message)
+	} else if level > status.StatusLvl {
+		return fmt.Sprintf("%s%s", level.Prefix(), message)
+	} else if level == status.StatusLvl {
+		return message
+	}
+	return ""
+}
+
+func (s formatter) progress(counts status.Counts) string {
+	if s.format == "" {
+		return fmt.Sprintf("[%3d%% %d/%d] ", 100*counts.FinishedActions/counts.TotalActions, counts.FinishedActions, counts.TotalActions)
+	}
+
+	buf := &strings.Builder{}
+	for i := 0; i < len(s.format); i++ {
+		c := s.format[i]
+		if c != '%' {
+			buf.WriteByte(c)
+			continue
+		}
+
+		i = i + 1
+		if i == len(s.format) {
+			buf.WriteByte(c)
+			break
+		}
+
+		c = s.format[i]
+		switch c {
+		case '%':
+			buf.WriteByte(c)
+		case 's':
+			fmt.Fprintf(buf, "%d", counts.StartedActions)
+		case 't':
+			fmt.Fprintf(buf, "%d", counts.TotalActions)
+		case 'r':
+			fmt.Fprintf(buf, "%d", counts.RunningActions)
+		case 'u':
+			fmt.Fprintf(buf, "%d", counts.TotalActions-counts.StartedActions)
+		case 'f':
+			fmt.Fprintf(buf, "%d", counts.FinishedActions)
+		case 'o':
+			fmt.Fprintf(buf, "%.1f", float64(counts.FinishedActions)/time.Since(s.start).Seconds())
+		case 'c':
+			// TODO: implement?
+			buf.WriteRune('?')
+		case 'p':
+			fmt.Fprintf(buf, "%3d%%", 100*counts.FinishedActions/counts.TotalActions)
+		case 'e':
+			fmt.Fprintf(buf, "%.3f", time.Since(s.start).Seconds())
+		default:
+			buf.WriteString("unknown placeholder '")
+			buf.WriteByte(c)
+			buf.WriteString("'")
+		}
+	}
+	return buf.String()
+}
+
+func (s formatter) result(result status.ActionResult) string {
+	var ret string
+	if result.Error != nil {
+		targets := strings.Join(result.Outputs, " ")
+		if s.quiet || result.Command == "" {
+			ret = fmt.Sprintf("FAILED: %s\n%s", targets, result.Output)
+		} else {
+			ret = fmt.Sprintf("FAILED: %s\n%s\n%s", targets, result.Command, result.Output)
+		}
+	} else if result.Output != "" {
+		ret = result.Output
+	}
+
+	if len(ret) > 0 && ret[len(ret)-1] != '\n' {
+		ret += "\n"
+	}
+
+	return ret
+}
diff --git a/ui/terminal/smart_status.go b/ui/terminal/smart_status.go
new file mode 100644
index 0000000..8fa9eff
--- /dev/null
+++ b/ui/terminal/smart_status.go
@@ -0,0 +1,158 @@
+// Copyright 2019 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package terminal
+
+import (
+	"fmt"
+	"io"
+	"strings"
+	"sync"
+
+	"android/soong/ui/status"
+)
+
+type smartStatusOutput struct {
+	writer    io.Writer
+	formatter formatter
+
+	lock sync.Mutex
+
+	haveBlankLine bool
+}
+
+// NewSmartStatusOutput returns a StatusOutput that represents the
+// current build status similarly to Ninja's built-in terminal
+// output.
+func NewSmartStatusOutput(w io.Writer, formatter formatter) status.StatusOutput {
+	return &smartStatusOutput{
+		writer:    w,
+		formatter: formatter,
+
+		haveBlankLine: true,
+	}
+}
+
+func (s *smartStatusOutput) Message(level status.MsgLevel, message string) {
+	if level < status.StatusLvl {
+		return
+	}
+
+	str := s.formatter.message(level, message)
+
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	if level > status.StatusLvl {
+		s.print(str)
+	} else {
+		s.statusLine(str)
+	}
+}
+
+func (s *smartStatusOutput) StartAction(action *status.Action, counts status.Counts) {
+	str := action.Description
+	if str == "" {
+		str = action.Command
+	}
+
+	progress := s.formatter.progress(counts)
+
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.statusLine(progress + str)
+}
+
+func (s *smartStatusOutput) FinishAction(result status.ActionResult, counts status.Counts) {
+	str := result.Description
+	if str == "" {
+		str = result.Command
+	}
+
+	progress := s.formatter.progress(counts) + str
+
+	output := s.formatter.result(result)
+
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	if output != "" {
+		s.statusLine(progress)
+		s.requestLine()
+		s.print(output)
+	} else {
+		s.statusLine(progress)
+	}
+}
+
+func (s *smartStatusOutput) Flush() {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.requestLine()
+}
+
+func (s *smartStatusOutput) Write(p []byte) (int, error) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+	s.print(string(p))
+	return len(p), nil
+}
+
+func (s *smartStatusOutput) requestLine() {
+	if !s.haveBlankLine {
+		fmt.Fprintln(s.writer)
+		s.haveBlankLine = true
+	}
+}
+
+func (s *smartStatusOutput) print(str string) {
+	if !s.haveBlankLine {
+		fmt.Fprint(s.writer, "\r", "\x1b[K")
+		s.haveBlankLine = true
+	}
+	fmt.Fprint(s.writer, str)
+	if len(str) == 0 || str[len(str)-1] != '\n' {
+		fmt.Fprint(s.writer, "\n")
+	}
+}
+
+func (s *smartStatusOutput) statusLine(str string) {
+	idx := strings.IndexRune(str, '\n')
+	if idx != -1 {
+		str = str[0:idx]
+	}
+
+	// Limit line width to the terminal width, otherwise we'll wrap onto
+	// another line and we won't delete the previous line.
+	//
+	// Run this on every line in case the window has been resized while
+	// we're printing. This could be optimized to only re-run when we get
+	// SIGWINCH if it ever becomes too time consuming.
+	if max, ok := termWidth(s.writer); ok {
+		if len(str) > max {
+			// TODO: Just do a max. Ninja elides the middle, but that's
+			// more complicated and these lines aren't that important.
+			str = str[:max]
+		}
+	}
+
+	// Move to the beginning on the line, turn on bold, print the output,
+	// turn off bold, then clear the rest of the line.
+	start := "\r\x1b[1m"
+	end := "\x1b[0m\x1b[K"
+	fmt.Fprint(s.writer, start, str, end)
+	s.haveBlankLine = false
+}
diff --git a/ui/terminal/status.go b/ui/terminal/status.go
index 2445c5b..69a2a09 100644
--- a/ui/terminal/status.go
+++ b/ui/terminal/status.go
@@ -15,131 +15,23 @@
 package terminal
 
 import (
-	"fmt"
-	"strings"
-	"time"
+	"io"
 
 	"android/soong/ui/status"
 )
 
-type statusOutput struct {
-	writer Writer
-	format string
-
-	start time.Time
-	quiet bool
-}
-
 // NewStatusOutput returns a StatusOutput that represents the
 // current build status similarly to Ninja's built-in terminal
 // output.
 //
 // statusFormat takes nearly all the same options as NINJA_STATUS.
 // %c is currently unsupported.
-func NewStatusOutput(w Writer, statusFormat string, quietBuild bool) status.StatusOutput {
-	return &statusOutput{
-		writer: w,
-		format: statusFormat,
+func NewStatusOutput(w io.Writer, statusFormat string, quietBuild bool) status.StatusOutput {
+	formatter := newFormatter(statusFormat, quietBuild)
 
-		start: time.Now(),
-		quiet: quietBuild,
-	}
-}
-
-func (s *statusOutput) Message(level status.MsgLevel, message string) {
-	if level >= status.ErrorLvl {
-		s.writer.Print(fmt.Sprintf("FAILED: %s", message))
-	} else if level > status.StatusLvl {
-		s.writer.Print(fmt.Sprintf("%s%s", level.Prefix(), message))
-	} else if level == status.StatusLvl {
-		s.writer.StatusLine(message)
-	}
-}
-
-func (s *statusOutput) StartAction(action *status.Action, counts status.Counts) {
-	if !s.writer.isSmartTerminal() {
-		return
-	}
-
-	str := action.Description
-	if str == "" {
-		str = action.Command
-	}
-
-	s.writer.StatusLine(s.progress(counts) + str)
-}
-
-func (s *statusOutput) FinishAction(result status.ActionResult, counts status.Counts) {
-	str := result.Description
-	if str == "" {
-		str = result.Command
-	}
-
-	progress := s.progress(counts) + str
-
-	if result.Error != nil {
-		targets := strings.Join(result.Outputs, " ")
-		if s.quiet || result.Command == "" {
-			s.writer.StatusAndMessage(progress, fmt.Sprintf("FAILED: %s\n%s", targets, result.Output))
-		} else {
-			s.writer.StatusAndMessage(progress, fmt.Sprintf("FAILED: %s\n%s\n%s", targets, result.Command, result.Output))
-		}
-	} else if result.Output != "" {
-		s.writer.StatusAndMessage(progress, result.Output)
+	if isSmartTerminal(w) {
+		return NewSmartStatusOutput(w, formatter)
 	} else {
-		s.writer.StatusLine(progress)
+		return NewDumbStatusOutput(w, formatter)
 	}
 }
-
-func (s *statusOutput) Flush() {}
-
-func (s *statusOutput) progress(counts status.Counts) string {
-	if s.format == "" {
-		return fmt.Sprintf("[%3d%% %d/%d] ", 100*counts.FinishedActions/counts.TotalActions, counts.FinishedActions, counts.TotalActions)
-	}
-
-	buf := &strings.Builder{}
-	for i := 0; i < len(s.format); i++ {
-		c := s.format[i]
-		if c != '%' {
-			buf.WriteByte(c)
-			continue
-		}
-
-		i = i + 1
-		if i == len(s.format) {
-			buf.WriteByte(c)
-			break
-		}
-
-		c = s.format[i]
-		switch c {
-		case '%':
-			buf.WriteByte(c)
-		case 's':
-			fmt.Fprintf(buf, "%d", counts.StartedActions)
-		case 't':
-			fmt.Fprintf(buf, "%d", counts.TotalActions)
-		case 'r':
-			fmt.Fprintf(buf, "%d", counts.RunningActions)
-		case 'u':
-			fmt.Fprintf(buf, "%d", counts.TotalActions-counts.StartedActions)
-		case 'f':
-			fmt.Fprintf(buf, "%d", counts.FinishedActions)
-		case 'o':
-			fmt.Fprintf(buf, "%.1f", float64(counts.FinishedActions)/time.Since(s.start).Seconds())
-		case 'c':
-			// TODO: implement?
-			buf.WriteRune('?')
-		case 'p':
-			fmt.Fprintf(buf, "%3d%%", 100*counts.FinishedActions/counts.TotalActions)
-		case 'e':
-			fmt.Fprintf(buf, "%.3f", time.Since(s.start).Seconds())
-		default:
-			buf.WriteString("unknown placeholder '")
-			buf.WriteByte(c)
-			buf.WriteString("'")
-		}
-	}
-	return buf.String()
-}
diff --git a/ui/terminal/status_test.go b/ui/terminal/status_test.go
new file mode 100644
index 0000000..a87a7f0
--- /dev/null
+++ b/ui/terminal/status_test.go
@@ -0,0 +1,272 @@
+// Copyright 2018 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package terminal
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+
+	"android/soong/ui/status"
+)
+
+func TestStatusOutput(t *testing.T) {
+	tests := []struct {
+		name  string
+		calls func(stat status.StatusOutput)
+		smart string
+		dumb  string
+	}{
+		{
+			name:  "two actions",
+			calls: twoActions,
+			smart: "\r\x1b[1m[  0% 0/2] action1\x1b[0m\x1b[K\r\x1b[1m[ 50% 1/2] action1\x1b[0m\x1b[K\r\x1b[1m[ 50% 1/2] action2\x1b[0m\x1b[K\r\x1b[1m[100% 2/2] action2\x1b[0m\x1b[K\n",
+			dumb:  "[ 50% 1/2] action1\n[100% 2/2] action2\n",
+		},
+		{
+			name:  "two parallel actions",
+			calls: twoParallelActions,
+			smart: "\r\x1b[1m[  0% 0/2] action1\x1b[0m\x1b[K\r\x1b[1m[  0% 0/2] action2\x1b[0m\x1b[K\r\x1b[1m[ 50% 1/2] action1\x1b[0m\x1b[K\r\x1b[1m[100% 2/2] action2\x1b[0m\x1b[K\n",
+			dumb:  "[ 50% 1/2] action1\n[100% 2/2] action2\n",
+		},
+		{
+			name:  "action with output",
+			calls: actionsWithOutput,
+			smart: "\r\x1b[1m[  0% 0/3] action1\x1b[0m\x1b[K\r\x1b[1m[ 33% 1/3] action1\x1b[0m\x1b[K\r\x1b[1m[ 33% 1/3] action2\x1b[0m\x1b[K\r\x1b[1m[ 66% 2/3] action2\x1b[0m\x1b[K\noutput1\noutput2\n\r\x1b[1m[ 66% 2/3] action3\x1b[0m\x1b[K\r\x1b[1m[100% 3/3] action3\x1b[0m\x1b[K\n",
+			dumb:  "[ 33% 1/3] action1\n[ 66% 2/3] action2\noutput1\noutput2\n[100% 3/3] action3\n",
+		},
+		{
+			name:  "action with output without newline",
+			calls: actionsWithOutputWithoutNewline,
+			smart: "\r\x1b[1m[  0% 0/3] action1\x1b[0m\x1b[K\r\x1b[1m[ 33% 1/3] action1\x1b[0m\x1b[K\r\x1b[1m[ 33% 1/3] action2\x1b[0m\x1b[K\r\x1b[1m[ 66% 2/3] action2\x1b[0m\x1b[K\noutput1\noutput2\n\r\x1b[1m[ 66% 2/3] action3\x1b[0m\x1b[K\r\x1b[1m[100% 3/3] action3\x1b[0m\x1b[K\n",
+			dumb:  "[ 33% 1/3] action1\n[ 66% 2/3] action2\noutput1\noutput2\n[100% 3/3] action3\n",
+		},
+		{
+			name:  "action with error",
+			calls: actionsWithError,
+			smart: "\r\x1b[1m[  0% 0/3] action1\x1b[0m\x1b[K\r\x1b[1m[ 33% 1/3] action1\x1b[0m\x1b[K\r\x1b[1m[ 33% 1/3] action2\x1b[0m\x1b[K\r\x1b[1m[ 66% 2/3] action2\x1b[0m\x1b[K\nFAILED: f1 f2\ntouch f1 f2\nerror1\nerror2\n\r\x1b[1m[ 66% 2/3] action3\x1b[0m\x1b[K\r\x1b[1m[100% 3/3] action3\x1b[0m\x1b[K\n",
+			dumb:  "[ 33% 1/3] action1\n[ 66% 2/3] action2\nFAILED: f1 f2\ntouch f1 f2\nerror1\nerror2\n[100% 3/3] action3\n",
+		},
+		{
+			name:  "action with empty description",
+			calls: actionWithEmptyDescription,
+			smart: "\r\x1b[1m[  0% 0/1] command1\x1b[0m\x1b[K\r\x1b[1m[100% 1/1] command1\x1b[0m\x1b[K\n",
+			dumb:  "[100% 1/1] command1\n",
+		},
+		{
+			name:  "messages",
+			calls: actionsWithMessages,
+			smart: "\r\x1b[1m[  0% 0/2] action1\x1b[0m\x1b[K\r\x1b[1m[ 50% 1/2] action1\x1b[0m\x1b[K\r\x1b[1mstatus\x1b[0m\x1b[K\r\x1b[Kprint\nFAILED: error\n\r\x1b[1m[ 50% 1/2] action2\x1b[0m\x1b[K\r\x1b[1m[100% 2/2] action2\x1b[0m\x1b[K\n",
+			dumb:  "[ 50% 1/2] action1\nstatus\nprint\nFAILED: error\n[100% 2/2] action2\n",
+		},
+		{
+			name:  "action with long description",
+			calls: actionWithLongDescription,
+			smart: "\r\x1b[1m[  0% 0/2] action with very long descrip\x1b[0m\x1b[K\r\x1b[1m[ 50% 1/2] action with very long descrip\x1b[0m\x1b[K\n",
+			dumb:  "[ 50% 1/2] action with very long description to test eliding\n",
+		},
+		{
+			name:  "action with output with ansi codes",
+			calls: actionWithOuptutWithAnsiCodes,
+			smart: "\r\x1b[1m[  0% 0/1] action1\x1b[0m\x1b[K\r\x1b[1m[100% 1/1] action1\x1b[0m\x1b[K\n\x1b[31mcolor\x1b[0m\n",
+			dumb:  "[100% 1/1] action1\ncolor\n",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Run("smart", func(t *testing.T) {
+				smart := &fakeSmartTerminal{termWidth: 40}
+				stat := NewStatusOutput(smart, "", false)
+				tt.calls(stat)
+				stat.Flush()
+
+				if g, w := smart.String(), tt.smart; g != w {
+					t.Errorf("want:\n%q\ngot:\n%q", w, g)
+				}
+			})
+
+			t.Run("dumb", func(t *testing.T) {
+				dumb := &bytes.Buffer{}
+				stat := NewStatusOutput(dumb, "", false)
+				tt.calls(stat)
+				stat.Flush()
+
+				if g, w := dumb.String(), tt.dumb; g != w {
+					t.Errorf("want:\n%q\ngot:\n%q", w, g)
+				}
+			})
+		})
+	}
+}
+
+type runner struct {
+	counts status.Counts
+	stat   status.StatusOutput
+}
+
+func newRunner(stat status.StatusOutput, totalActions int) *runner {
+	return &runner{
+		counts: status.Counts{TotalActions: totalActions},
+		stat:   stat,
+	}
+}
+
+func (r *runner) startAction(action *status.Action) {
+	r.counts.StartedActions++
+	r.counts.RunningActions++
+	r.stat.StartAction(action, r.counts)
+}
+
+func (r *runner) finishAction(result status.ActionResult) {
+	r.counts.FinishedActions++
+	r.counts.RunningActions--
+	r.stat.FinishAction(result, r.counts)
+}
+
+func (r *runner) finishAndStartAction(result status.ActionResult, action *status.Action) {
+	r.counts.FinishedActions++
+	r.stat.FinishAction(result, r.counts)
+
+	r.counts.StartedActions++
+	r.stat.StartAction(action, r.counts)
+}
+
+var (
+	action1 = &status.Action{Description: "action1"}
+	result1 = status.ActionResult{Action: action1}
+	action2 = &status.Action{Description: "action2"}
+	result2 = status.ActionResult{Action: action2}
+	action3 = &status.Action{Description: "action3"}
+	result3 = status.ActionResult{Action: action3}
+)
+
+func twoActions(stat status.StatusOutput) {
+	runner := newRunner(stat, 2)
+	runner.startAction(action1)
+	runner.finishAction(result1)
+	runner.startAction(action2)
+	runner.finishAction(result2)
+}
+
+func twoParallelActions(stat status.StatusOutput) {
+	runner := newRunner(stat, 2)
+	runner.startAction(action1)
+	runner.startAction(action2)
+	runner.finishAction(result1)
+	runner.finishAction(result2)
+}
+
+func actionsWithOutput(stat status.StatusOutput) {
+	result2WithOutput := status.ActionResult{Action: action2, Output: "output1\noutput2\n"}
+
+	runner := newRunner(stat, 3)
+	runner.startAction(action1)
+	runner.finishAction(result1)
+	runner.startAction(action2)
+	runner.finishAction(result2WithOutput)
+	runner.startAction(action3)
+	runner.finishAction(result3)
+}
+
+func actionsWithOutputWithoutNewline(stat status.StatusOutput) {
+	result2WithOutputWithoutNewline := status.ActionResult{Action: action2, Output: "output1\noutput2"}
+
+	runner := newRunner(stat, 3)
+	runner.startAction(action1)
+	runner.finishAction(result1)
+	runner.startAction(action2)
+	runner.finishAction(result2WithOutputWithoutNewline)
+	runner.startAction(action3)
+	runner.finishAction(result3)
+}
+
+func actionsWithError(stat status.StatusOutput) {
+	action2WithError := &status.Action{Description: "action2", Outputs: []string{"f1", "f2"}, Command: "touch f1 f2"}
+	result2WithError := status.ActionResult{Action: action2WithError, Output: "error1\nerror2\n", Error: fmt.Errorf("error1")}
+
+	runner := newRunner(stat, 3)
+	runner.startAction(action1)
+	runner.finishAction(result1)
+	runner.startAction(action2WithError)
+	runner.finishAction(result2WithError)
+	runner.startAction(action3)
+	runner.finishAction(result3)
+}
+
+func actionWithEmptyDescription(stat status.StatusOutput) {
+	action1 := &status.Action{Command: "command1"}
+	result1 := status.ActionResult{Action: action1}
+
+	runner := newRunner(stat, 1)
+	runner.startAction(action1)
+	runner.finishAction(result1)
+}
+
+func actionsWithMessages(stat status.StatusOutput) {
+	runner := newRunner(stat, 2)
+
+	runner.startAction(action1)
+	runner.finishAction(result1)
+
+	stat.Message(status.VerboseLvl, "verbose")
+	stat.Message(status.StatusLvl, "status")
+	stat.Message(status.PrintLvl, "print")
+	stat.Message(status.ErrorLvl, "error")
+
+	runner.startAction(action2)
+	runner.finishAction(result2)
+}
+
+func actionWithLongDescription(stat status.StatusOutput) {
+	action1 := &status.Action{Description: "action with very long description to test eliding"}
+	result1 := status.ActionResult{Action: action1}
+
+	runner := newRunner(stat, 2)
+
+	runner.startAction(action1)
+
+	runner.finishAction(result1)
+}
+
+func actionWithOuptutWithAnsiCodes(stat status.StatusOutput) {
+	result1WithOutputWithAnsiCodes := status.ActionResult{Action: action1, Output: "\x1b[31mcolor\x1b[0m"}
+
+	runner := newRunner(stat, 1)
+	runner.startAction(action1)
+	runner.finishAction(result1WithOutputWithAnsiCodes)
+}
+
+func TestSmartStatusOutputWidthChange(t *testing.T) {
+	smart := &fakeSmartTerminal{termWidth: 40}
+	stat := NewStatusOutput(smart, "", false)
+
+	runner := newRunner(stat, 2)
+
+	action := &status.Action{Description: "action with very long description to test eliding"}
+	result := status.ActionResult{Action: action}
+
+	runner.startAction(action)
+	smart.termWidth = 30
+	runner.finishAction(result)
+
+	stat.Flush()
+
+	w := "\r\x1b[1m[  0% 0/2] action with very long descrip\x1b[0m\x1b[K\r\x1b[1m[ 50% 1/2] action with very lo\x1b[0m\x1b[K\n"
+
+	if g := smart.String(); g != w {
+		t.Errorf("want:\n%q\ngot:\n%q", w, g)
+	}
+}
diff --git a/ui/terminal/stdio.go b/ui/terminal/stdio.go
new file mode 100644
index 0000000..dec2963
--- /dev/null
+++ b/ui/terminal/stdio.go
@@ -0,0 +1,55 @@
+// Copyright 2018 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package terminal provides a set of interfaces that can be used to interact
+// with the terminal (including falling back when the terminal is detected to
+// be a redirect or other dumb terminal)
+package terminal
+
+import (
+	"io"
+	"os"
+)
+
+// StdioInterface represents a set of stdin/stdout/stderr Reader/Writers
+type StdioInterface interface {
+	Stdin() io.Reader
+	Stdout() io.Writer
+	Stderr() io.Writer
+}
+
+// StdioImpl uses the OS stdin/stdout/stderr to implement StdioInterface
+type StdioImpl struct{}
+
+func (StdioImpl) Stdin() io.Reader  { return os.Stdin }
+func (StdioImpl) Stdout() io.Writer { return os.Stdout }
+func (StdioImpl) Stderr() io.Writer { return os.Stderr }
+
+var _ StdioInterface = StdioImpl{}
+
+type customStdio struct {
+	stdin  io.Reader
+	stdout io.Writer
+	stderr io.Writer
+}
+
+func NewCustomStdio(stdin io.Reader, stdout, stderr io.Writer) StdioInterface {
+	return customStdio{stdin, stdout, stderr}
+}
+
+func (c customStdio) Stdin() io.Reader  { return c.stdin }
+func (c customStdio) Stdout() io.Writer { return c.stdout }
+func (c customStdio) Stderr() io.Writer { return c.stderr }
+
+var _ StdioInterface = customStdio{}
diff --git a/ui/terminal/util.go b/ui/terminal/util.go
index a85a517..3a11b79 100644
--- a/ui/terminal/util.go
+++ b/ui/terminal/util.go
@@ -22,13 +22,15 @@
 	"unsafe"
 )
 
-func isTerminal(w io.Writer) bool {
+func isSmartTerminal(w io.Writer) bool {
 	if f, ok := w.(*os.File); ok {
 		var termios syscall.Termios
 		_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, f.Fd(),
 			ioctlGetTermios, uintptr(unsafe.Pointer(&termios)),
 			0, 0, 0)
 		return err == 0
+	} else if _, ok := w.(*fakeSmartTerminal); ok {
+		return true
 	}
 	return false
 }
@@ -43,6 +45,8 @@
 			syscall.TIOCGWINSZ, uintptr(unsafe.Pointer(&winsize)),
 			0, 0, 0)
 		return int(winsize.ws_column), err == 0
+	} else if f, ok := w.(*fakeSmartTerminal); ok {
+		return f.termWidth, true
 	}
 	return 0, false
 }
@@ -99,3 +103,8 @@
 
 	return input
 }
+
+type fakeSmartTerminal struct {
+	bytes.Buffer
+	termWidth int
+}
diff --git a/ui/terminal/writer.go b/ui/terminal/writer.go
deleted file mode 100644
index ebe4b2a..0000000
--- a/ui/terminal/writer.go
+++ /dev/null
@@ -1,229 +0,0 @@
-// Copyright 2018 Google Inc. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// Package terminal provides a set of interfaces that can be used to interact
-// with the terminal (including falling back when the terminal is detected to
-// be a redirect or other dumb terminal)
-package terminal
-
-import (
-	"fmt"
-	"io"
-	"os"
-	"strings"
-	"sync"
-)
-
-// Writer provides an interface to write temporary and permanent messages to
-// the terminal.
-//
-// The terminal is considered to be a dumb terminal if TERM==dumb, or if a
-// terminal isn't detected on stdout/stderr (generally because it's a pipe or
-// file). Dumb terminals will strip out all ANSI escape sequences, including
-// colors.
-type Writer interface {
-	// Print prints the string to the terminal, overwriting any current
-	// status being displayed.
-	//
-	// On a dumb terminal, the status messages will be kept.
-	Print(str string)
-
-	// Status prints the first line of the string to the terminal,
-	// overwriting any previous status line. Strings longer than the width
-	// of the terminal will be cut off.
-	//
-	// On a dumb terminal, previous status messages will remain, and the
-	// entire first line of the string will be printed.
-	StatusLine(str string)
-
-	// StatusAndMessage prints the first line of status to the terminal,
-	// similarly to StatusLine(), then prints the full msg below that. The
-	// status line is retained.
-	//
-	// There is guaranteed to be no other output in between the status and
-	// message.
-	StatusAndMessage(status, msg string)
-
-	// Finish ensures that the output ends with a newline (preserving any
-	// current status line that is current displayed).
-	//
-	// This does nothing on dumb terminals.
-	Finish()
-
-	// Write implements the io.Writer interface. This is primarily so that
-	// the logger can use this interface to print to stderr without
-	// breaking the other semantics of this interface.
-	//
-	// Try to use any of the other functions if possible.
-	Write(p []byte) (n int, err error)
-
-	isSmartTerminal() bool
-}
-
-// NewWriter creates a new Writer based on the stdio and the TERM
-// environment variable.
-func NewWriter(stdio StdioInterface) Writer {
-	w := &writerImpl{
-		stdio: stdio,
-
-		haveBlankLine: true,
-	}
-
-	if term, ok := os.LookupEnv("TERM"); ok && term != "dumb" {
-		w.smartTerminal = isTerminal(stdio.Stdout())
-	}
-	w.stripEscapes = !w.smartTerminal
-
-	return w
-}
-
-type writerImpl struct {
-	stdio StdioInterface
-
-	haveBlankLine bool
-
-	// Protecting the above, we assume that smartTerminal and stripEscapes
-	// does not change after initial setup.
-	lock sync.Mutex
-
-	smartTerminal bool
-	stripEscapes  bool
-}
-
-func (w *writerImpl) isSmartTerminal() bool {
-	return w.smartTerminal
-}
-
-func (w *writerImpl) requestLine() {
-	if !w.haveBlankLine {
-		fmt.Fprintln(w.stdio.Stdout())
-		w.haveBlankLine = true
-	}
-}
-
-func (w *writerImpl) Print(str string) {
-	if w.stripEscapes {
-		str = string(stripAnsiEscapes([]byte(str)))
-	}
-
-	w.lock.Lock()
-	defer w.lock.Unlock()
-	w.print(str)
-}
-
-func (w *writerImpl) print(str string) {
-	if !w.haveBlankLine {
-		fmt.Fprint(w.stdio.Stdout(), "\r", "\x1b[K")
-		w.haveBlankLine = true
-	}
-	fmt.Fprint(w.stdio.Stdout(), str)
-	if len(str) == 0 || str[len(str)-1] != '\n' {
-		fmt.Fprint(w.stdio.Stdout(), "\n")
-	}
-}
-
-func (w *writerImpl) StatusLine(str string) {
-	w.lock.Lock()
-	defer w.lock.Unlock()
-
-	w.statusLine(str)
-}
-
-func (w *writerImpl) statusLine(str string) {
-	if !w.smartTerminal {
-		fmt.Fprintln(w.stdio.Stdout(), str)
-		return
-	}
-
-	idx := strings.IndexRune(str, '\n')
-	if idx != -1 {
-		str = str[0:idx]
-	}
-
-	// Limit line width to the terminal width, otherwise we'll wrap onto
-	// another line and we won't delete the previous line.
-	//
-	// Run this on every line in case the window has been resized while
-	// we're printing. This could be optimized to only re-run when we get
-	// SIGWINCH if it ever becomes too time consuming.
-	if max, ok := termWidth(w.stdio.Stdout()); ok {
-		if len(str) > max {
-			// TODO: Just do a max. Ninja elides the middle, but that's
-			// more complicated and these lines aren't that important.
-			str = str[:max]
-		}
-	}
-
-	// Move to the beginning on the line, print the output, then clear
-	// the rest of the line.
-	fmt.Fprint(w.stdio.Stdout(), "\r", str, "\x1b[K")
-	w.haveBlankLine = false
-}
-
-func (w *writerImpl) StatusAndMessage(status, msg string) {
-	if w.stripEscapes {
-		msg = string(stripAnsiEscapes([]byte(msg)))
-	}
-
-	w.lock.Lock()
-	defer w.lock.Unlock()
-
-	w.statusLine(status)
-	w.requestLine()
-	w.print(msg)
-}
-
-func (w *writerImpl) Finish() {
-	w.lock.Lock()
-	defer w.lock.Unlock()
-
-	w.requestLine()
-}
-
-func (w *writerImpl) Write(p []byte) (n int, err error) {
-	w.Print(string(p))
-	return len(p), nil
-}
-
-// StdioInterface represents a set of stdin/stdout/stderr Reader/Writers
-type StdioInterface interface {
-	Stdin() io.Reader
-	Stdout() io.Writer
-	Stderr() io.Writer
-}
-
-// StdioImpl uses the OS stdin/stdout/stderr to implement StdioInterface
-type StdioImpl struct{}
-
-func (StdioImpl) Stdin() io.Reader  { return os.Stdin }
-func (StdioImpl) Stdout() io.Writer { return os.Stdout }
-func (StdioImpl) Stderr() io.Writer { return os.Stderr }
-
-var _ StdioInterface = StdioImpl{}
-
-type customStdio struct {
-	stdin  io.Reader
-	stdout io.Writer
-	stderr io.Writer
-}
-
-func NewCustomStdio(stdin io.Reader, stdout, stderr io.Writer) StdioInterface {
-	return customStdio{stdin, stdout, stderr}
-}
-
-func (c customStdio) Stdin() io.Reader  { return c.stdin }
-func (c customStdio) Stdout() io.Writer { return c.stdout }
-func (c customStdio) Stderr() io.Writer { return c.stderr }
-
-var _ StdioInterface = customStdio{}
diff --git a/ui/tracer/status.go b/ui/tracer/status.go
index af50e2d..c831255 100644
--- a/ui/tracer/status.go
+++ b/ui/tracer/status.go
@@ -85,3 +85,8 @@
 
 func (s *statusOutput) Flush()                                        {}
 func (s *statusOutput) Message(level status.MsgLevel, message string) {}
+
+func (s *statusOutput) Write(p []byte) (int, error) {
+	// Discard writes
+	return len(p), nil
+}