refactor(fsrepo) extract component.Component

repo/fsrepo/serialize/serialize.go

@@ -0,0 +1,79 @@
+package fsrepo
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/facebookgo/atomicfile"
+	"github.com/jbenet/go-ipfs/repo/config"
+	"github.com/jbenet/go-ipfs/util"
+	"github.com/jbenet/go-ipfs/util/debugerror"
+)
+
+var log = util.Logger("fsrepo")
+
+// ReadConfigFile reads the config from `filename` into `cfg`.
+func ReadConfigFile(filename string, cfg interface{}) error {
+	f, err := os.Open(filename)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	if err := json.NewDecoder(f).Decode(cfg); err != nil {
+		return fmt.Errorf("Failure to decode config: %s", err)
+	}
+	return nil
+}
+
+// WriteConfigFile writes the config from `cfg` into `filename`.
+func WriteConfigFile(filename string, cfg interface{}) error {
+	err := os.MkdirAll(filepath.Dir(filename), 0775)
+	if err != nil {
+		return err
+	}
+
+	f, err := atomicfile.New(filename, 0775)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	return encode(f, cfg)
+}
+
+// encode configuration with JSON
+func encode(w io.Writer, value interface{}) error {
+	// need to prettyprint, hence MarshalIndent, instead of Encoder
+	buf, err := config.Marshal(value)
+	if err != nil {
+		return err
+	}
+	_, err = w.Write(buf)
+	return err
+}
+
+// Load reads given file and returns the read config, or error.
+func Load(filename string) (*config.Config, error) {
+	// if nothing is there, fail. User must run 'ipfs init'
+	if !util.FileExists(filename) {
+		return nil, debugerror.New("ipfs not initialized, please run 'ipfs init'")
+	}
+
+	var cfg config.Config
+	err := ReadConfigFile(filename, &cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	// tilde expansion on datastore path
+	// TODO why is this here??
+	cfg.Datastore.Path, err = util.TildeExpansion(cfg.Datastore.Path)
+	if err != nil {
+		return nil, err
+	}
+
+	return &cfg, err
+}