xl/fs: Object layer - keep common functions into single place. (#1423)

object-common.go

@@ -0,0 +1,126 @@
+/*
+ * Minio Cloud Storage, (C) 2016 Minio, Inc.
+ *
+ * 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.
+ */
+
+package main
+
+import (
+	"path"
+	"sort"
+)
+
+/// Common object layer functions.
+
+// makeBucket - create a bucket, is a common function for both object layers.
+func makeBucket(storage StorageAPI, bucket string) error {
+	// Verify if bucket is valid.
+	if !IsValidBucketName(bucket) {
+		return BucketNameInvalid{Bucket: bucket}
+	}
+	if err := storage.MakeVol(bucket); err != nil {
+		return toObjectErr(err, bucket)
+	}
+	// This happens for the first time, but keep this here since this
+	// is the only place where it can be made expensive optimizing all
+	// other calls.
+	// Create minio meta volume, if it doesn't exist yet.
+	if err := storage.MakeVol(minioMetaVolume); err != nil {
+		if err != errVolumeExists {
+			return toObjectErr(err, minioMetaVolume)
+		}
+	}
+	return nil
+}
+
+// getBucketInfo - fetch bucket info, is a common function for both object layers.
+func getBucketInfo(storage StorageAPI, bucket string) (BucketInfo, error) {
+	// Verify if bucket is valid.
+	if !IsValidBucketName(bucket) {
+		return BucketInfo{}, BucketNameInvalid{Bucket: bucket}
+	}
+	vi, err := storage.StatVol(bucket)
+	if err != nil {
+		return BucketInfo{}, toObjectErr(err, bucket)
+	}
+	return BucketInfo{
+		Name:    bucket,
+		Created: vi.Created,
+		Total:   vi.Total,
+		Free:    vi.Free,
+	}, nil
+}
+
+// listBuckets - list all buckets, is a common function for both object layers.
+func listBuckets(storage StorageAPI) ([]BucketInfo, error) {
+	var bucketInfos []BucketInfo
+	vols, err := storage.ListVols()
+	if err != nil {
+		return nil, toObjectErr(err)
+	}
+	for _, vol := range vols {
+		// StorageAPI can send volume names which are incompatible
+		// with buckets, handle it and skip them.
+		if !IsValidBucketName(vol.Name) {
+			continue
+		}
+		bucketInfos = append(bucketInfos, BucketInfo{
+			Name:    vol.Name,
+			Created: vol.Created,
+			Total:   vol.Total,
+			Free:    vol.Free,
+		})
+	}
+	sort.Sort(byBucketName(bucketInfos))
+	return bucketInfos, nil
+}
+
+// deleteBucket - deletes a bucket, is a common function for both the layers.
+func deleteBucket(storage StorageAPI, bucket string) error {
+	// Verify if bucket is valid.
+	if !IsValidBucketName(bucket) {
+		return BucketNameInvalid{Bucket: bucket}
+	}
+	if err := storage.DeleteVol(bucket); err != nil {
+		return toObjectErr(err)
+	}
+	return nil
+}
+
+// isUploadIDExists - verify if a given uploadID exists and is valid.
+func isUploadIDExists(storage StorageAPI, bucket, object, uploadID string) (bool, error) {
+	uploadIDPath := path.Join(bucket, object, uploadID)
+	st, err := storage.StatFile(minioMetaVolume, uploadIDPath)
+	if err != nil {
+		// Upload id does not exist.
+		if err == errFileNotFound {
+			return false, nil
+		}
+		return false, err
+	}
+	// Upload id exists and is a regular file.
+	return st.Mode.IsRegular(), nil
+}
+
+// checks whether bucket exists.
+func isBucketExist(storage StorageAPI, bucketName string) (bool, error) {
+	// Check whether bucket exists.
+	if _, e := storage.StatVol(bucketName); e != nil {
+		if e == errVolumeNotFound {
+			return false, nil
+		}
+		return false, e
+	}
+	return true, nil
+}