server: Move all the top level files into cmd folder. (#2490)

This change brings a change which was done for the 'mc'
package to allow for clean repo and have a cleaner
github drop in experience.

cmd/object-common.go

@@ -0,0 +1,187 @@
+/*
+ * 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 cmd
+
+import (
+	"path/filepath"
+	"strings"
+	"sync"
+)
+
+const (
+	// Block size used for all internal operations version 1.
+	blockSizeV1 = 10 * 1024 * 1024 // 10MiB.
+
+	// Staging buffer read size for all internal operations version 1.
+	readSizeV1 = 128 * 1024 // 128KiB.
+
+	// Buckets meta prefix.
+	bucketMetaPrefix = "buckets"
+)
+
+// isErrIgnored should we ignore this error?, takes a list of errors which can be ignored.
+func isErrIgnored(err error, ignoredErrs []error) bool {
+	for _, ignoredErr := range ignoredErrs {
+		if ignoredErr == err {
+			return true
+		}
+	}
+	return false
+}
+
+// House keeping code needed for FS.
+func fsHouseKeeping(storageDisk StorageAPI) error {
+	// Cleanup all temp entries upon start.
+	err := cleanupDir(storageDisk, minioMetaBucket, tmpMetaPrefix)
+	if err != nil {
+		return toObjectErr(err, minioMetaBucket, tmpMetaPrefix)
+	}
+	return nil
+}
+
+// Depending on the disk type network or local, initialize storage API.
+func newStorageAPI(disk string) (storage StorageAPI, err error) {
+	if !strings.ContainsRune(disk, ':') || filepath.VolumeName(disk) != "" {
+		// Initialize filesystem storage API.
+		return newPosix(disk)
+	}
+	// Initialize rpc client storage API.
+	return newRPCClient(disk)
+}
+
+// Initializes meta volume on all input storage disks.
+func initMetaVolume(storageDisks []StorageAPI) error {
+	// 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.
+	var wg = &sync.WaitGroup{}
+
+	// Initialize errs to collect errors inside go-routine.
+	var errs = make([]error, len(storageDisks))
+
+	// Initialize all disks in parallel.
+	for index, disk := range storageDisks {
+		if disk == nil {
+			// Ignore create meta volume on disks which are not found.
+			continue
+		}
+		wg.Add(1)
+		go func(index int, disk StorageAPI) {
+			// Indicate this wait group is done.
+			defer wg.Done()
+
+			// Attempt to create `.minio`.
+			err := disk.MakeVol(minioMetaBucket)
+			if err != nil {
+				switch err {
+				// Ignored errors.
+				case errVolumeExists, errDiskNotFound, errFaultyDisk:
+				default:
+					errs[index] = err
+				}
+			}
+		}(index, disk)
+	}
+
+	// Wait for all cleanup to finish.
+	wg.Wait()
+
+	// Return upon first error.
+	for _, err := range errs {
+		if err == nil {
+			continue
+		}
+		return toObjectErr(err, minioMetaBucket)
+	}
+
+	// Return success here.
+	return nil
+}
+
+// House keeping code needed for XL.
+func xlHouseKeeping(storageDisks []StorageAPI) error {
+	// 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 metavolume.
+	var wg = &sync.WaitGroup{}
+
+	// Initialize errs to collect errors inside go-routine.
+	var errs = make([]error, len(storageDisks))
+
+	// Initialize all disks in parallel.
+	for index, disk := range storageDisks {
+		if disk == nil {
+			continue
+		}
+		wg.Add(1)
+		go func(index int, disk StorageAPI) {
+			// Indicate this wait group is done.
+			defer wg.Done()
+
+			// Cleanup all temp entries upon start.
+			err := cleanupDir(disk, minioMetaBucket, tmpMetaPrefix)
+			if err != nil {
+				errs[index] = err
+			}
+		}(index, disk)
+	}
+
+	// Wait for all cleanup to finish.
+	wg.Wait()
+
+	// Return upon first error.
+	for _, err := range errs {
+		if err == nil {
+			continue
+		}
+		return toObjectErr(err, minioMetaBucket, tmpMetaPrefix)
+	}
+
+	// Return success here.
+	return nil
+}
+
+// Cleanup a directory recursively.
+func cleanupDir(storage StorageAPI, volume, dirPath string) error {
+	var delFunc func(string) error
+	// Function to delete entries recursively.
+	delFunc = func(entryPath string) error {
+		if !strings.HasSuffix(entryPath, slashSeparator) {
+			// Delete the file entry.
+			return storage.DeleteFile(volume, entryPath)
+		}
+
+		// If it's a directory, list and call delFunc() for each entry.
+		entries, err := storage.ListDir(volume, entryPath)
+		// If entryPath prefix never existed, safe to ignore.
+		if err == errFileNotFound {
+			return nil
+		} else if err != nil { // For any other errors fail.
+			return err
+		} // else on success..
+
+		// Recurse and delete all other entries.
+		for _, entry := range entries {
+			if err = delFunc(pathJoin(entryPath, entry)); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+	err := delFunc(retainSlash(pathJoin(dirPath)))
+	return err
+}