Mojom formatter incorporated in the mojom binary.

mojom/mojom_parser/fmt_cmd.go

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file contains fmtCmd which formats a .mojom file and outputs the
+// formatted mojom file to stdout.
+// The fmt command is invoked as follows:
+//
+//              mojom fmt [-w] <mojom_file>
+//
+//      If -w is specified and the formatted file is different from the original,
+//      the file is overwritten with the formatted version.
+package main
+
+import (
+        "flag"
+        "fmt"
+        "io/ioutil"
+        "mojom/mojom_parser/formatter"
+        "os"
+        "path/filepath"
+)
+
+// fmtCmd implements the fmt command for the mojom tool.
+// The slice of strings |args| is the list of arguments passed on the command
+// line starting with the program name and followed by the invoked command.
+func fmtCmd(args []string) {
+        flagSet := flag.NewFlagSet("fmt_cmd", flag.PanicOnError)
+        var overwrite bool
+        flagSet.BoolVar(&overwrite, "w", false,
+                "Overwrite the specified file with the formatted version if it is different from the original.")
+
+        printUsage := func() {
+                fmt.Fprintf(os.Stderr, "Usage: %s fmt [-w] <mojom_file>\n\n", filepath.Base(args[0]))
+                flagSet.PrintDefaults()
+        }
+
+        if err := flagSet.Parse(args[2:]); err != nil {
+                fmt.Fprintln(os.Stderr, err.Error())
+                printUsage()
+                os.Exit(1)
+        }
+
+        inputFileName := flagSet.Arg(0)
+        if inputFileName == "" {
+                fmt.Fprintln(os.Stderr, "No .mojom file given.")
+                printUsage()
+                os.Exit(1)
+        }
+
+        originalBytes, err := ioutil.ReadFile(inputFileName)
+        if err != nil {
+                ErrorExit(err.Error())
+        }
+
+        original := string(originalBytes[:])
+
+        var formatted string
+        formatted, err = formatter.FormatMojom(inputFileName, original)
+        if err != nil {
+                ErrorExit(err.Error())
+        }
+
+        if overwrite {
+                if formatted != original {
+                        if err := ioutil.WriteFile(inputFileName, []byte(formatted), 0); err != nil {
+                                ErrorExit(err.Error())
+                        }
+                }
+        } else {
+                fmt.Print(formatted)
+        }
+}