A mojom .d generator.

mojom/mojom_parser/generators/common/cli.go

Index: mojom/mojom_parser/generators/common/cli.go
diff --git a/mojom/mojom_parser/generators/common/cli.go b/mojom/mojom_parser/generators/common/cli.go
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+// 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.
+
+// cli.go implements logic to create a generator config object from command
+// line arguments.
+
+package common
+
+import (
+	"flag"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+
+	"mojo/public/go/bindings"
+	"mojom/mojom_parser/generated/mojom_files"
+)
+
+// GetConfig provides the primary interface for generators.
+// By calling GetConfig, a generator implements the command line interface
+// that is used by all generators.
+func GetCliConfig(args []string) GeneratorConfig {
+	config := new(generatorCliConfig)
+	flagSet := flag.NewFlagSet("Generator Common Flag Set", flag.ExitOnError)
+
+	var fileGraphFile string
+	flagSet.StringVar(&fileGraphFile, "file-graph", "-",
+		"Location of the parser output. \"-\" for stdin. (default \"-\")")
+	flagSet.StringVar(&config.outputDir, "output-dir", ".",
+		"output directory for generated files.")
+	flagSet.StringVar(&config.srcRootPath, "src-root-path", ".",
+		"relative path to the root of the source tree.")
+	flagSet.BoolVar(&config.noGenImports, "no-gen-imports", false,
+		"Generate code only for the files that are specified on the command line. "+
+			"By default, code is generated for all specified files and their transitive imports.")
+
+	flagSet.Parse(args[1:])
+
+	// Compute the absolute path for the source root and the output directory.
+	var err error
+	config.srcRootPath, err = filepath.Abs(config.srcRootPath)
+	if err != nil {
+		log.Fatalln(err.Error())
+	}
+
+	config.outputDir, err = filepath.Abs(config.outputDir)
+	if err != nil {
+		log.Fatalln(err.Error())
+	}
+
+	// Read the file graph either from standard in or the specified file.
+	var fileGraphReader io.Reader
+	if fileGraphFile == "-" {
+		fileGraphReader = os.Stdin
+	} else {
+		var err error
+		if fileGraphReader, err = os.Open(fileGraphFile); err != nil {
+			log.Fatalln(err.Error())
+		}
+	}
+
+	config.fileGraph = decodeFileGraph(fileGraphReader)
+	return config
+}
+
+// decodeFileGraph decodes a serialized MojomFileGraph.
+func decodeFileGraph(in io.Reader) (fileGraph *mojom_files.MojomFileGraph) {
+	inputBytes, err := ioutil.ReadAll(in)
+	if err != nil {
+		log.Fatalf("Failed to read: %v\n", err)
+	}
+
+	decoder := bindings.NewDecoder(inputBytes, nil)
+	fileGraph = new(mojom_files.MojomFileGraph)
+	if err := fileGraph.Decode(decoder); err != nil {
+		log.Fatalf("Failed to decode file graph: %v\n", err)
+	}
+
+	return
+}
+
+// generatorCliConfig implements GeneratorConfig.
+type generatorCliConfig struct {
+	fileGraph    *mojom_files.MojomFileGraph
+	outputDir    string
+	srcRootPath  string
+	noGenImports bool
+}
+
+// See GeneratorConfig.
+func (c *generatorCliConfig) FileGraph() *mojom_files.MojomFileGraph {
+	return c.fileGraph
+}
+
+// See GeneratorConfig.
+func (c *generatorCliConfig) OutputDir() string {
+	return c.outputDir
+}
+
+// See GeneratorConfig.
+func (c *generatorCliConfig) SrcRootPath() string {
+	return c.srcRootPath
+}
+
+// See GeneratorConfig.
+func (c *generatorCliConfig) GenImports() bool {
+	return !c.noGenImports
+}