main.go

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path"
	"path/filepath"
	"strings"

	"github.com/karrick/golf"
	"github.com/pscn/file2go/encode"
	"github.com/pscn/file2go/template"
)

//go:generate file2go -v -d -t -o template/files.go template/*.tmpl

var (
	output = golf.StringP('o', "output", "", "the target file name")
	test   = golf.BoolP('t', "test", false, "create a test file")
	pkg    = golf.StringP('p', "package", "",
		"package name to use, defaults to the base directory of target")
	verbose = golf.BoolP('v', "verbose", false, "be more verbose")
	devel   = golf.BoolP('d', "devel", false, "internal → use the template files, "+
		"not the ones generated by file2go\n"+
		"\tonly required when compiling the templates themselves")
)

// Usage shows a short usage summary on stderr
func Usage(msg string) {
	if msg != "" {
		fmt.Fprintf(os.Stderr, "%s\n", msg)
	}
	fmt.Fprintf(os.Stderr, "Usage of file2go:\n")
	fmt.Fprintf(os.Stderr, "\tfile2go -o target/file.go -p mypkg file1 file2 file3\n")
	golf.Usage()
}

// FlagUsage shows a short usage summary on stderr
func FlagUsage() {
	Usage("")
}

func main() {
	log.SetFlags(0) // log.LstdFlags | log.Lshortfile)
	log.SetPrefix("file2go: ")
	golf.Parse()
	if len(golf.Args()) == 0 {
		Usage("please specify one or more files")
		os.Exit(2)
	}
	if *output == "" {
		Usage("please specify output")
		os.Exit(2)
	}
	if *pkg == "" {
		*pkg = path.Base(path.Dir(*output))
	}

	files := make([]string, 0)
	for _, pattern := range golf.Args() {
		matches, err := filepath.Glob(pattern)
		if err != nil {
			log.Fatal(err)
		}
		if len(matches) == 0 {
			log.Fatalf("no files match pattern: %s", pattern)
		}
		files = append(files, matches...)
	}

	container := make([]template.File, len(files))
	for i, filename := range files {
		container[i] = template.File{Name: filepath.ToSlash(filename)}
		content, err := encode.File(filename)
		if err != nil {
			log.Fatalf("failed to encode file: filename=%s, error=%s", filename, err)
		}
		container[i].Content = content
	}

	todo := map[string]string{*output: "template/files.tmpl"}
	if *test {
		tmpName := string((*output)[:len(*output)-3])
		todo[tmpName+"_test.go"] = "template/files_test.tmpl"
	}
	for target, tmplName := range todo {
		tmpl, err := template.Parse(tmplName, &container,
			strings.Join(os.Args[1:], " "), *pkg, *devel)
		if err != nil {
			log.Fatalf("failed to generate code: %s\n", err)
		}

		if _, err := os.Stat(target); err == nil { // file exists
			data, err := ioutil.ReadFile(target)
			if err != nil {
				log.Fatalf("failed to read old file: %s; error=%s", target, err)
			}
			if string(data) == string(*tmpl) {
				if *verbose {
					log.Printf("already up to date: %s", target)
					continue
				}
			}
		}
		file, err := os.Create(target)
		if err != nil {
			log.Fatalf("failed to open file: %s\n", err)
		}
		defer file.Close()
		_, err = file.Write(*tmpl)
		if err != nil {
			log.Fatalf("failed to write code to file: %s; error=%s", target, err)
		}
	}
}