Initial commit

cas/dir-store.go

@@ -0,0 +1,112 @@
+package cas
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sync"
+)
+
+// NewDirStore create a new store backed by the given directory.
+func NewDir(path string) *DirStore {
+	return &DirStore{
+		path: path,
+	}
+}
+
+// DirStore is a Store backed by a directory.
+type DirStore struct {
+	path  string
+	mutex sync.Mutex
+}
+
+var _ Store = &DirStore{}
+
+// GetOrCreate is part of the Store interface.
+func (s *DirStore) GetOrCreate(tag, item string, create func(io.Writer) error) (content Content, meta Meta, err error) {
+	fullPath := filepath.Join(s.path, tag, item)
+
+	f, err := os.Open(fullPath)
+	if err != nil {
+		s.mutex.Lock()
+		defer s.mutex.Unlock()
+
+		f, err = os.Open(fullPath)
+	}
+
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return
+		}
+
+		err = os.MkdirAll(filepath.Dir(fullPath), 0700)
+		if err != nil {
+			return
+		}
+
+		var out *os.File
+		out, err = os.OpenFile(fullPath+".part", os.O_CREATE|os.O_TRUNC|os.O_WRONLY|os.O_EXCL, 0600)
+		if err != nil {
+			return
+		}
+
+		err = create(out)
+
+		out.Close()
+
+		if err != nil {
+			os.Remove(fullPath + ".part")
+			return
+		}
+
+		if err = os.Rename(fullPath+".part", fullPath); err != nil {
+			return
+		}
+
+		f, err = os.Open(fullPath)
+		if err != nil {
+			return
+		}
+	}
+
+	stat, err := os.Stat(fullPath)
+	if err != nil {
+		return
+	}
+
+	return f, stat, nil
+}
+
+// Tags is part of the Store interface.
+func (s *DirStore) Tags() (tags []string, err error) {
+	entries, err := ioutil.ReadDir(s.path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return []string{}, nil
+		}
+		return
+	}
+
+	tags = make([]string, 0, len(entries))
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			continue
+		}
+
+		name := entry.Name()
+
+		if name[0] == '.' {
+			continue
+		}
+
+		tags = append(tags, name)
+	}
+
+	return
+}
+
+// Remove is part of the Store interface.
+func (s *DirStore) Remove(tag string) error {
+	return os.RemoveAll(filepath.Join(s.path, tag))
+}