cmd/ebitenmobile: Clean the temporary directory up after the execution

Closes #1668

cmd/ebitenmobile/gomobile.go

@@ -51,6 +51,16 @@ func runCommand(command string, args []string, env []string) error {
 	return nil
 }
 
+func removeAll(path string) error {
+	if buildX || buildN {
+		fmt.Printf("rm -rf %s\n", path)
+	}
+	if buildN {
+		return nil
+	}
+	return os.RemoveAll(path)
+}
+
 func runGo(args ...string) error {
 	env := []string{
 		"GO111MODULE=on",
@@ -67,10 +77,10 @@ func exe(filename string) string {
 	return filename
 }
 
-func prepareGomobileCommands() error {
+func prepareGomobileCommands() (string, error) {
 	tmp, err := ioutil.TempDir("", "ebitenmobile-")
 	if err != nil {
-		return err
+		return "", err
 	}
 
 	newpath := filepath.Join(tmp, "bin")
@@ -86,7 +96,7 @@ func prepareGomobileCommands() error {
 
 	pwd, err := os.Getwd()
 	if err != nil {
-		return err
+		return tmp, err
 	}
 
 	// cd
@@ -94,7 +104,7 @@ func prepareGomobileCommands() error {
 		fmt.Printf("cd %s\n", tmp)
 	}
 	if err := os.Chdir(tmp); err != nil {
-		return err
+		return tmp, err
 	}
 	defer func() {
 		os.Chdir(pwd)
@@ -102,7 +112,7 @@ func prepareGomobileCommands() error {
 
 	const modname = "ebitenmobiletemporary"
 	if err := runGo("mod", "init", modname); err != nil {
-		return err
+		return tmp, err
 	}
 	if err := ioutil.WriteFile("tools.go", []byte(fmt.Sprintf(`// +build tools
 
@@ -113,47 +123,47 @@ import (
 	_ "golang.org/x/mobile/cmd/gomobile"
 )
 `, modname)), 0644); err != nil {
-		return err
+		return tmp, err
 	}
 
 	// To record gomobile to go.sum for Go 1.16 and later, go-get gomobile instaed of golang.org/x/mobile (#1487).
 	// This also records gobind as gomobile depends on gobind indirectly.
 	// Using `...` doesn't work on Windows since mobile/internal/mobileinit cannot be compiled on Windows w/o Cgo (#1493).
 	if err := runGo("get", "golang.org/x/mobile/cmd/gomobile@"+gomobileHash); err != nil {
-		return err
+		return tmp, err
 	}
 	if localgm := os.Getenv("EBITENMOBILE_GOMOBILE"); localgm != "" {
 		if !filepath.IsAbs(localgm) {
 			localgm = filepath.Join(pwd, localgm)
 		}
 		if err := runGo("mod", "edit", "-replace=golang.org/x/mobile="+localgm); err != nil {
-			return err
+			return tmp, err
 		}
 	}
 	if err := runGo("mod", "tidy"); err != nil {
-		return err
+		return tmp, err
 	}
 	if err := runGo("build", "-o", exe(filepath.Join("bin", "gomobile")), "golang.org/x/mobile/cmd/gomobile"); err != nil {
-		return err
+		return tmp, err
 	}
 	if err := runGo("build", "-o", exe(filepath.Join("bin", "gobind-original")), "golang.org/x/mobile/cmd/gobind"); err != nil {
-		return err
+		return tmp, err
 	}
 
 	if err := os.Mkdir("src", 0755); err != nil {
-		return err
+		return tmp, err
 	}
 	if err := ioutil.WriteFile(filepath.Join("src", "gobind.go"), gobindsrc, 0644); err != nil {
-		return err
+		return tmp, err
 	}
 
 	if err := runGo("build", "-o", exe(filepath.Join("bin", "gobind")), "-tags", "ebitenmobilegobind", filepath.Join("src", "gobind.go")); err != nil {
-		return err
+		return tmp, err
 	}
 
 	if err := runCommand("gomobile", []string{"init"}, nil); err != nil {
-		return err
+		return tmp, err
 	}
 
-	return nil
+	return tmp, nil
 }

cmd/ebitenmobile/main.go

@@ -115,27 +115,33 @@ func main() {
 
 	flagset.Parse(args[1:])
 
-	os, err := osFromBuildTarget(buildTarget)
+	buildTarget, err := osFromBuildTarget(buildTarget)
 	if err != nil {
 		log.Fatal(err)
 	}
 
 	// Add ldflags to suppress linker errors (#932).
 	// See https://github.com/golang/go/issues/17807
-	if os == "android" {
+	if buildTarget == "android" {
 		if buildLdflags != "" {
 			buildLdflags += " "
 		}
 		buildLdflags += "-extldflags=-Wl,-soname,libgojni.so"
 	}
 
-	if err := prepareGomobileCommands(); err != nil {
+	dir, err := prepareGomobileCommands()
+	defer func() {
+		if dir != "" && !buildWork {
+			removeAll(dir)
+		}
+	}()
+	if err != nil {
 		log.Fatal(err)
 	}
 
 	switch args[0] {
 	case "bind":
-		if err := doBind(args, &flagset, os); err != nil {
+		if err := doBind(args, &flagset, buildTarget); err != nil {
 			log.Fatal(err)
 		}
 	default: