soong_jar: Implement symlinks, fix directories

Ensure that we only create one directory entry, not one with a / at the
end and another without. Clean incoming paths to prevent other similar
duplicates.

When adding directories specified directly as inputs, use the relative
path just like files, not the full path.

Instead of traversing symlinks, addg them to the zip file directly.

Present an error instead of crashing when an input does not exist.

Change-Id: Id6d6561fe12c28398f6096bf9bcae602bb7aa491

cmd/soong_jar/soong_jar.go

@@ -41,7 +41,7 @@ func (l *fileArgs) Set(s string) error {
 		return fmt.Errorf("must pass -C before -f")
 	}
 
-	*l = append(*l, fileArg{*relativeRoot, s})
+	*l = append(*l, fileArg{filepath.Clean(*relativeRoot), s})
 	return nil
 }
 
@@ -162,6 +162,8 @@ func (z *zipWriter) writeListFile(listFile fileArg) error {
 }
 
 func (z *zipWriter) writeRelFile(root, file string) error {
+	file = filepath.Clean(file)
+
 	rel, err := filepath.Rel(root, file)
 	if err != nil {
 		return err
@@ -176,11 +178,17 @@ func (z *zipWriter) writeRelFile(root, file string) error {
 }
 
 func (z *zipWriter) writeFile(rel, file string) error {
-	if s, _ := os.Stat(file); s.IsDir() {
+	if s, err := os.Lstat(file); err != nil {
+		return err
+	} else if s.IsDir() {
 		if z.directories {
-			return z.writeDirectory(file)
+			return z.writeDirectory(rel)
 		}
 		return nil
+	} else if s.Mode()&os.ModeSymlink != 0 {
+		return z.writeSymlink(rel, file)
+	} else if !s.Mode().IsRegular() {
+		return fmt.Errorf("%s is not a file, directory, or symlink", file)
 	}
 
 	if z.directories {
@@ -217,13 +225,17 @@ func (z *zipWriter) writeFile(rel, file string) error {
 }
 
 func (z *zipWriter) writeDirectory(dir string) error {
-	for dir != "" && !z.createdDirs[dir] {
+	if dir != "" && !strings.HasSuffix(dir, "/") {
+		dir = dir + "/"
+	}
+
+	for dir != "" && dir != "./" && !z.createdDirs[dir] {
 		z.createdDirs[dir] = true
 
 		dirHeader := &zip.FileHeader{
 			Name: dir,
 		}
-		dirHeader.SetMode(os.ModeDir)
+		dirHeader.SetMode(0700 | os.ModeDir)
 		dirHeader.SetModTime(z.time)
 
 		_, err := z.w.CreateHeader(dirHeader)
@@ -236,3 +248,31 @@ func (z *zipWriter) writeDirectory(dir string) error {
 
 	return nil
 }
+
+func (z *zipWriter) writeSymlink(rel, file string) error {
+	if z.directories {
+		dir, _ := filepath.Split(rel)
+		if err := z.writeDirectory(dir); err != nil {
+			return err
+		}
+	}
+
+	fileHeader := &zip.FileHeader{
+		Name: rel,
+	}
+	fileHeader.SetModTime(z.time)
+	fileHeader.SetMode(0700 | os.ModeSymlink)
+
+	out, err := z.w.CreateHeader(fileHeader)
+	if err != nil {
+		return err
+	}
+
+	dest, err := os.Readlink(file)
+	if err != nil {
+		return err
+	}
+
+	_, err = io.WriteString(out, dest)
+	return err
+}