cache template

spin.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"fmt"
+	"os"
+	"path/filepath"
 
 	"github.com/egoist/spin/utils"
 	"gopkg.in/alecthomas/kingpin.v2"
@@ -13,23 +15,35 @@ func main() {
 
 	kingpin.Parse()
 
-	if utils.FileExists(*target) {
+	if utils.PathExists(*target) {
 		isEmpty, _ := utils.IsEmpty(*target)
 		if !isEmpty {
 			fmt.Println("Output directory already exists and is not empty")
 			return
 		}
 	}
 
-	url := fmt.Sprintf("https://github.com/%s/archive/master/archive.zip", *repo)
+	homedir, _ := os.UserHomeDir()
+	cacheDir := filepath.Join(homedir, fmt.Sprintf(".spin/templates/github/%s", *repo))
 
-	outFile, err := utils.DownloadFile(url)
+	if !utils.PathExists(cacheDir) {
+		url := fmt.Sprintf("https://github.com/%s/archive/master/archive.zip", *repo)
 
-	if err != nil {
+		zipFile, err := utils.DownloadFile(url)
+
+		if err != nil {
+			fmt.Println("error", err)
+			return
+		}
+
+		utils.Unzip(zipFile.Name(), cacheDir)
+	}
+
+	if err := utils.Copy(cacheDir, *target); err != nil {
 		fmt.Println("error", err)
-	} else {
-		fmt.Printf("Creating new project in %s\n", *target)
-		utils.Unzip(outFile.Name(), *target)
-		fmt.Println("Success!")
+		return
 	}
+
+	fmt.Printf("Creating new project in %s\n", *target)
+	fmt.Println("Success!")
 }

utils/copy.go

@@ -0,0 +1,175 @@
+package utils
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+const (
+	// tmpPermissionForDirectory makes the destination directory writable,
+	// so that stuff can be copied recursively even if any original directory is NOT writable.
+	// See https://github.com/otiai10/copy/pull/9 for more information.
+	tmpPermissionForDirectory = os.FileMode(0755)
+)
+
+// Copy copies src to dest, doesn't matter if src is a directory or a file.
+func Copy(src, dest string, opt ...Options) error {
+	info, err := os.Lstat(src)
+	if err != nil {
+		return err
+	}
+	return copy(src, dest, info, assure(opt...))
+}
+
+// copy dispatches copy-funcs according to the mode.
+// Because this "copy" could be called recursively,
+// "info" MUST be given here, NOT nil.
+func copy(src, dest string, info os.FileInfo, opt Options) error {
+
+	if opt.Skip(src) {
+		return nil
+	}
+
+	if info.Mode()&os.ModeSymlink != 0 {
+		return onsymlink(src, dest, info, opt)
+	}
+
+	if info.IsDir() {
+		return dcopy(src, dest, info, opt)
+	}
+	return fcopy(src, dest, info, opt)
+}
+
+// fcopy is for just a file,
+// with considering existence of parent directory
+// and file permission.
+func fcopy(src, dest string, info os.FileInfo, opt Options) (err error) {
+
+	if err = os.MkdirAll(filepath.Dir(dest), os.ModePerm); err != nil {
+		return
+	}
+
+	f, err := os.Create(dest)
+	if err != nil {
+		return
+	}
+	defer fclose(f, &err)
+
+	if err = os.Chmod(f.Name(), info.Mode()|opt.AddPermission); err != nil {
+		return
+	}
+
+	s, err := os.Open(src)
+	if err != nil {
+		return
+	}
+	defer fclose(s, &err)
+
+	if _, err = io.Copy(f, s); err != nil {
+		return
+	}
+
+	if opt.Sync {
+		err = f.Sync()
+	}
+
+	return
+}
+
+// dcopy is for a directory,
+// with scanning contents inside the directory
+// and pass everything to "copy" recursively.
+func dcopy(srcdir, destdir string, info os.FileInfo, opt Options) (err error) {
+
+	originalMode := info.Mode()
+
+	// Make dest dir with 0755 so that everything writable.
+	if err = os.MkdirAll(destdir, tmpPermissionForDirectory); err != nil {
+		return
+	}
+	// Recover dir mode with original one.
+	defer chmod(destdir, originalMode|opt.AddPermission, &err)
+
+	contents, err := ioutil.ReadDir(srcdir)
+	if err != nil {
+		return
+	}
+
+	for _, content := range contents {
+		cs, cd := filepath.Join(srcdir, content.Name()), filepath.Join(destdir, content.Name())
+		if err = copy(cs, cd, content, opt); err != nil {
+			// If any error, exit immediately
+			return
+		}
+	}
+
+	return
+}
+
+func onsymlink(src, dest string, info os.FileInfo, opt Options) error {
+
+	switch opt.OnSymlink(src) {
+	case Shallow:
+		return lcopy(src, dest)
+	case Deep:
+		orig, err := os.Readlink(src)
+		if err != nil {
+			return err
+		}
+		info, err = os.Lstat(orig)
+		if err != nil {
+			return err
+		}
+		return copy(orig, dest, info, opt)
+	case Skip:
+		fallthrough
+	default:
+		return nil // do nothing
+	}
+}
+
+// lcopy is for a symlink,
+// with just creating a new symlink by replicating src symlink.
+func lcopy(src, dest string) error {
+	src, err := os.Readlink(src)
+	if err != nil {
+		return err
+	}
+	return os.Symlink(src, dest)
+}
+
+// fclose ANYHOW closes file,
+// with asiging error raised during Close,
+// BUT respecting the error already reported.
+func fclose(f *os.File, reported *error) {
+	if err := f.Close(); *reported == nil {
+		*reported = err
+	}
+}
+
+// chmod ANYHOW changes file mode,
+// with asiging error raised during Chmod,
+// BUT respecting the error already reported.
+func chmod(dir string, mode os.FileMode, reported *error) {
+	if err := os.Chmod(dir, mode); *reported == nil {
+		*reported = err
+	}
+}
+
+// assure Options struct, should be called only once.
+// All optional values MUST NOT BE nil/zero after assured.
+func assure(opts ...Options) Options {
+	if len(opts) == 0 {
+		return getDefaultOptions()
+	}
+	defopt := getDefaultOptions()
+	if opts[0].OnSymlink == nil {
+		opts[0].OnSymlink = defopt.OnSymlink
+	}
+	if opts[0].Skip == nil {
+		opts[0].Skip = defopt.Skip
+	}
+	return opts[0]
+}

utils/copy_options.go

@@ -0,0 +1,46 @@
+package utils
+
+import "os"
+
+// Options specifies optional actions on copying.
+type Options struct {
+	// OnSymlink can specify what to do on symlink
+	OnSymlink func(src string) SymlinkAction
+	// Skip can specify which files should be skipped
+	Skip func(src string) bool
+	// AddPermission to every entities,
+	// NO MORE THAN 0777
+	AddPermission os.FileMode
+	// Sync file after copy.
+	// Useful in case when file must be on the disk
+	// (in case crash happens, for example),
+	// at the expense of some performance penalty
+	Sync bool
+}
+
+// SymlinkAction represents what to do on symlink.
+type SymlinkAction int
+
+const (
+	// Deep creates hard-copy of contents.
+	Deep SymlinkAction = iota
+	// Shallow creates new symlink to the dest of symlink.
+	Shallow
+	// Skip does nothing with symlink.
+	Skip
+)
+
+// getDefaultOptions provides default options,
+// which would be modified by usage-side.
+func getDefaultOptions() Options {
+	return Options{
+		OnSymlink: func(string) SymlinkAction {
+			return Shallow // Do shallow copy
+		},
+		Skip: func(string) bool {
+			return false // Don't skip
+		},
+		AddPermission: 0,     // Add nothing
+		Sync:          false, // Do not sync
+	}
+}

utils/fs.go

@@ -5,8 +5,8 @@ import (
 	"os"
 )
 
-// FileExists checks if a file exists
-func FileExists(name string) bool {
+// PathExists checks if a file exists
+func PathExists(name string) bool {
 	if _, err := os.Stat(name); err != nil {
 		if os.IsNotExist(err) {
 			return false