misc/genjsdeps: command to generate closure deps

reusing code from pkg/server/ui.go

Change-Id: I56b8d4b42df2fbcbbe3d654261036cdb907f9f27

pkg/misc/genjsdeps/genjsdeps.go

@@ -0,0 +1,150 @@
+/*
+Copyright 2013 The Camlistore Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// The genjsdeps command, similarly to the closure depswriter.py tool,
+// outputs to os.Stdout for each .js file, which namespaces
+// it provides, and the namespaces it requires, hence allowing
+// the closure library to resolve dependencies between those files.
+package main
+
+import (
+	"bufio"
+	"bytes"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"sync"
+	"time"
+)
+
+// TODO(mpl): make a library and a separate command which uses
+// that library.
+// http://camlistore.org/issue/142
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "Usage: genjsdeps <dir>\n")
+	os.Exit(1)
+}
+
+func main() {
+	flag.Parse()
+	args := flag.Args()
+	if len(args) != 1 {
+		usage()
+	}
+	dir := path.Clean(args[0])
+	fi, err := os.Stat(dir)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if !fi.IsDir() {
+		log.Fatalf("%v not a dir", dir)
+	}
+	var buf bytes.Buffer
+	err = filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if !strings.HasSuffix(path, ".js") {
+			return nil
+		}
+		suffix := path[len(dir)+1:]
+		prov, req, err := parseProvidesRequires(info, path)
+		if err != nil {
+			return err
+		}
+		if len(prov) > 0 {
+			fmt.Fprintf(&buf, "goog.addDependency(%q, %v, %v);\n", "../../"+suffix, jsList(prov), jsList(req))
+		}
+		return nil
+	})
+	if err != nil {
+		log.Fatalf("Error walking %d generating deps.js: %v", dir, err)
+	}
+	io.Copy(os.Stdout, &buf)
+}
+
+var provReqRx = regexp.MustCompile(`^goog\.(provide|require)\(['"]([\w\.]+)['"]\)`)
+
+type depCacheItem struct {
+	modTime            time.Time
+	provides, requires []string
+}
+
+var (
+	depCacheMu sync.Mutex
+	depCache   = map[string]depCacheItem{}
+)
+
+func parseProvidesRequires(fi os.FileInfo, path string) (provides, requires []string, err error) {
+	mt := fi.ModTime()
+	depCacheMu.Lock()
+	defer depCacheMu.Unlock()
+	if ci := depCache[path]; ci.modTime.Equal(mt) {
+		return ci.provides, ci.requires, nil
+	}
+
+	f, err := os.Open(path)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+	br := bufio.NewReader(f)
+	for {
+		l, err := br.ReadString('\n')
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, nil, err
+		}
+		if !strings.HasPrefix(l, "goog.") {
+			continue
+		}
+		m := provReqRx.FindStringSubmatch(l)
+		if m != nil {
+			if m[1] == "provide" {
+				provides = append(provides, m[2])
+			} else {
+				requires = append(requires, m[2])
+			}
+		}
+	}
+	depCache[path] = depCacheItem{provides: provides, requires: requires, modTime: mt}
+	return provides, requires, nil
+}
+
+// jsList prints a list of strings as JavaScript list.
+type jsList []string
+
+func (s jsList) String() string {
+	var buf bytes.Buffer
+	buf.WriteByte('[')
+	for i, v := range s {
+		if i > 0 {
+			buf.WriteString(", ")
+		}
+		fmt.Fprintf(&buf, "%q", v)
+	}
+	buf.WriteByte(']')
+	return buf.String()
+}