xl/fs: Split object layer into interface. (#1415)

posix-utils.go

@@ -0,0 +1,100 @@
+/*
+ * 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 (
+	"regexp"
+	"runtime"
+	"strings"
+	"unicode/utf8"
+)
+
+// validVolname regexp.
+var validVolname = regexp.MustCompile(`^.{3,63}$`)
+
+// isValidVolname verifies a volname name in accordance with object
+// layer requirements.
+func isValidVolname(volname string) bool {
+	if !validVolname.MatchString(volname) {
+		return false
+	}
+	switch runtime.GOOS {
+	case "windows":
+		// Volname shouldn't have reserved characters on windows in it.
+		return !strings.ContainsAny(volname, "/\\:*?\"<>|")
+	default:
+		// Volname shouldn't have '/' in it.
+		return !strings.ContainsAny(volname, "/")
+	}
+}
+
+// Keeping this as lower bound value supporting Linux, Darwin and Windows operating systems.
+const pathMax = 4096
+
+// isValidPath verifies if a path name is in accordance with FS limitations.
+func isValidPath(path string) bool {
+	// TODO: Make this FSType or Operating system specific.
+	if len(path) > pathMax || len(path) == 0 {
+		return false
+	}
+	if !utf8.ValidString(path) {
+		return false
+	}
+	return true
+}
+
+// isValidPrefix verifies where the prefix is a valid path.
+func isValidPrefix(prefix string) bool {
+	// Prefix can be empty.
+	if prefix == "" || prefix == "/" {
+		return true
+	}
+	// Verify if prefix is a valid path.
+	return isValidPath(prefix)
+}
+
+// List of reserved words for files, includes old and new ones.
+var reservedKeywords = []string{
+	"$multiparts",
+	"$tmpobject",
+	"$tmpfile",
+	// Add new reserved words if any used in future.
+}
+
+// hasReservedPrefix - returns true if name has a reserved keyword suffixed.
+func hasReservedSuffix(name string) (isReserved bool) {
+	for _, reservedKey := range reservedKeywords {
+		if strings.HasSuffix(name, reservedKey) {
+			isReserved = true
+			break
+		}
+		isReserved = false
+	}
+	return isReserved
+}
+
+// hasReservedPrefix - has reserved prefix.
+func hasReservedPrefix(name string) (isReserved bool) {
+	for _, reservedKey := range reservedKeywords {
+		if strings.HasPrefix(name, reservedKey) {
+			isReserved = true
+			break
+		}
+		isReserved = false
+	}
+	return isReserved
+}