fs/xl: Combine input checks into re-usable functions. (#3383)

Repeated code around both object layers are moved
and combined into simple re-usable functions.

cmd/object-api-utils.go

@@ -0,0 +1,183 @@
+/*
+ * Minio Cloud Storage, (C) 2015, 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 (
+	"encoding/hex"
+	"fmt"
+	"io"
+	"path"
+	"regexp"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/skyrings/skyring-common/tools/uuid"
+)
+
+const (
+	// Minio meta bucket.
+	minioMetaBucket = ".minio.sys"
+	// Multipart meta prefix.
+	mpartMetaPrefix = "multipart"
+	// Minio Multipart meta prefix.
+	minioMetaMultipartBucket = minioMetaBucket + "/" + mpartMetaPrefix
+	// Minio Tmp meta prefix.
+	minioMetaTmpBucket = minioMetaBucket + "/tmp"
+)
+
+// validBucket regexp.
+var validBucket = regexp.MustCompile(`^[a-z0-9][a-z0-9\.\-]{1,61}[a-z0-9]$`)
+var isIPAddress = regexp.MustCompile(`^(\d+\.){3}\d+$`)
+
+// IsValidBucketName verifies a bucket name in accordance with Amazon's
+// requirements. It must be 3-63 characters long, can contain dashes
+// and periods, but must begin and end with a lowercase letter or a number.
+// See: http://docs.aws.amazon.com/AmazonS3/latest/dev/BucketRestrictions.html
+func IsValidBucketName(bucket string) bool {
+	// Special case when bucket is equal to 'metaBucket'.
+	if bucket == minioMetaBucket {
+		return true
+	}
+	if len(bucket) < 3 || len(bucket) > 63 {
+		return false
+	}
+	if bucket[0] == '.' || bucket[len(bucket)-1] == '.' {
+		return false
+	}
+	return (validBucket.MatchString(bucket) &&
+		!isIPAddress.MatchString(bucket) &&
+		!strings.Contains(bucket, ".."))
+}
+
+// IsValidObjectName verifies an object name in accordance with Amazon's
+// requirements. It cannot exceed 1024 characters and must be a valid UTF8
+// string.
+//
+// See:
+// http://docs.aws.amazon.com/AmazonS3/latest/dev/UsingMetadata.html
+//
+// You should avoid the following characters in a key name because of
+// significant special handling for consistency across all
+// applications.
+//
+// Rejects strings with following characters.
+//
+// - Backslash ("\")
+//
+// additionally minio does not support object names with trailing "/".
+func IsValidObjectName(object string) bool {
+	if len(object) == 0 {
+		return false
+	}
+	if strings.HasSuffix(object, slashSeparator) {
+		return false
+	}
+	if strings.HasPrefix(object, slashSeparator) {
+		return false
+	}
+	return IsValidObjectPrefix(object)
+}
+
+// IsValidObjectPrefix verifies whether the prefix is a valid object name.
+// Its valid to have a empty prefix.
+func IsValidObjectPrefix(object string) bool {
+	if len(object) > 1024 {
+		return false
+	}
+	if !utf8.ValidString(object) {
+		return false
+	}
+	// Reject unsupported characters in object name.
+	if strings.ContainsAny(object, "\\") {
+		return false
+	}
+	return true
+}
+
+// Slash separator.
+const slashSeparator = "/"
+
+// retainSlash - retains slash from a path.
+func retainSlash(s string) string {
+	return strings.TrimSuffix(s, slashSeparator) + slashSeparator
+}
+
+// pathJoin - like path.Join() but retains trailing "/" of the last element
+func pathJoin(elem ...string) string {
+	trailingSlash := ""
+	if len(elem) > 0 {
+		if strings.HasSuffix(elem[len(elem)-1], slashSeparator) {
+			trailingSlash = "/"
+		}
+	}
+	return path.Join(elem...) + trailingSlash
+}
+
+// mustGetUUID - get a random UUID.
+func mustGetUUID() string {
+	uuid, err := uuid.New()
+	if err != nil {
+		panic(fmt.Sprintf("Random UUID generation failed. Error: %s", err))
+	}
+
+	return uuid.String()
+}
+
+// Create an s3 compatible MD5sum for complete multipart transaction.
+func getCompleteMultipartMD5(parts []completePart) (string, error) {
+	var finalMD5Bytes []byte
+	for _, part := range parts {
+		md5Bytes, err := hex.DecodeString(part.ETag)
+		if err != nil {
+			return "", traceError(err)
+		}
+		finalMD5Bytes = append(finalMD5Bytes, md5Bytes...)
+	}
+	s3MD5 := fmt.Sprintf("%s-%d", getMD5Hash(finalMD5Bytes), len(parts))
+	return s3MD5, nil
+}
+
+// byBucketName is a collection satisfying sort.Interface.
+type byBucketName []BucketInfo
+
+func (d byBucketName) Len() int           { return len(d) }
+func (d byBucketName) Swap(i, j int)      { d[i], d[j] = d[j], d[i] }
+func (d byBucketName) Less(i, j int) bool { return d[i].Name < d[j].Name }
+
+// rangeReader returns a Reader that reads from r
+// but returns error after Max bytes read as errDataTooLarge.
+// but returns error if reader exits before reading Min bytes
+// errDataTooSmall.
+type rangeReader struct {
+	Reader io.Reader // underlying reader
+	Min    int64     // min bytes remaining
+	Max    int64     // max bytes remaining
+}
+
+func (l *rangeReader) Read(p []byte) (n int, err error) {
+	n, err = l.Reader.Read(p)
+	l.Max -= int64(n)
+	l.Min -= int64(n)
+	if l.Max < 0 {
+		// If more data is available than what is expected we return error.
+		return 0, errDataTooLarge
+	}
+	if err == io.EOF && l.Min > 0 {
+		return 0, errDataTooSmall
+	}
+	return
+}