cleanup: Remove definitions and move them to its relative places accordingly

- Move fs-definitions.go and break them into fs-datatypes.go, fs-bucket-acl.go
  and fs-utils.go
- Move api-definitions.go to api-response.go, where they should be.
- Move web-definitions to its related handlers.

pkg/fs/fs-bucket-acl.go

@@ -0,0 +1,96 @@
+/*
+ * 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 fs
+
+// IsPrivateBucket - is private bucket
+func (fs Filesystem) IsPrivateBucket(bucket string) bool {
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
+	bucketMetadata, ok := fs.buckets.Metadata[bucket]
+	if !ok {
+		return true
+	}
+	return bucketMetadata.ACL.IsPrivate()
+}
+
+// IsPublicBucket - is public bucket
+func (fs Filesystem) IsPublicBucket(bucket string) bool {
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
+	bucketMetadata, ok := fs.buckets.Metadata[bucket]
+	if !ok {
+		return true
+	}
+	return bucketMetadata.ACL.IsPublicReadWrite()
+}
+
+// IsReadOnlyBucket - is read only bucket
+func (fs Filesystem) IsReadOnlyBucket(bucket string) bool {
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
+	bucketMetadata, ok := fs.buckets.Metadata[bucket]
+	if !ok {
+		return true
+	}
+	return bucketMetadata.ACL.IsPublicRead()
+}
+
+// BucketACL - bucket level access control
+type BucketACL string
+
+// different types of ACL's currently supported for buckets
+const (
+	BucketPrivate         = BucketACL("private")
+	BucketPublicRead      = BucketACL("public-read")
+	BucketPublicReadWrite = BucketACL("public-read-write")
+)
+
+func (b BucketACL) String() string {
+	return string(b)
+}
+
+// IsPrivate - is acl Private
+func (b BucketACL) IsPrivate() bool {
+	return b == BucketACL("private")
+}
+
+// IsPublicRead - is acl PublicRead
+func (b BucketACL) IsPublicRead() bool {
+	return b == BucketACL("public-read")
+}
+
+// IsPublicReadWrite - is acl PublicReadWrite
+func (b BucketACL) IsPublicReadWrite() bool {
+	return b == BucketACL("public-read-write")
+}
+
+// IsValidBucketACL - is provided acl string supported
+func IsValidBucketACL(acl string) bool {
+	switch acl {
+	case "private":
+		fallthrough
+	case "public-read":
+		fallthrough
+	case "public-read-write":
+		return true
+	case "":
+		// by default its "private"
+		return true
+	default:
+		return false
+	}
+}