Support bucket versioning (#9377)

- Implement a new xl.json 2.0.0 format to support,
  this moves the entire marshaling logic to POSIX
  layer, top layer always consumes a common FileInfo
  construct which simplifies the metadata reads.
- Implement list object versions
- Migrate to siphash from crchash for new deployments
  for object placements.

Fixes #2111

cmd/erasure-common_test.go

@@ -0,0 +1,98 @@
+/*
+ * MinIO Cloud Storage, (C) 2017 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 (
+	"bytes"
+	"context"
+	"os"
+	"testing"
+)
+
+// Tests for if parent directory is object
+func TestErasureParentDirIsObject(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	obj, fsDisks, err := prepareErasure16(ctx)
+	if err != nil {
+		t.Fatalf("Unable to initialize 'Erasure' object layer.")
+	}
+
+	// Remove all disks.
+	for _, disk := range fsDisks {
+		defer os.RemoveAll(disk)
+	}
+
+	bucketName := "testbucket"
+	objectName := "object"
+
+	if err = obj.MakeBucketWithLocation(GlobalContext, bucketName, BucketOptions{}); err != nil {
+		t.Fatal(err)
+	}
+	objectContent := "12345"
+	objInfo, err := obj.PutObject(GlobalContext, bucketName, objectName,
+		mustGetPutObjReader(t, bytes.NewReader([]byte(objectContent)), int64(len(objectContent)), "", ""), ObjectOptions{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if objInfo.Name != objectName {
+		t.Fatalf("Unexpected object name returned got %s, expected %s", objInfo.Name, objectName)
+	}
+
+	z := obj.(*erasureZones)
+	xl := z.zones[0].sets[0]
+	testCases := []struct {
+		parentIsObject bool
+		objectName     string
+	}{
+		// parentIsObject is true if object is available.
+		{
+			parentIsObject: true,
+			objectName:     objectName,
+		},
+		{
+			parentIsObject: false,
+			objectName:     "",
+		},
+		{
+			parentIsObject: false,
+			objectName:     ".",
+		},
+		// Should not cause infinite loop.
+		{
+			parentIsObject: false,
+			objectName:     SlashSeparator,
+		},
+		{
+			parentIsObject: false,
+			objectName:     "\\",
+		},
+		// Should not cause infinite loop with double forward slash.
+		{
+			parentIsObject: false,
+			objectName:     "//",
+		},
+	}
+
+	for i, testCase := range testCases {
+		gotValue := xl.parentDirIsObject(GlobalContext, bucketName, testCase.objectName)
+		if testCase.parentIsObject != gotValue {
+			t.Errorf("Test %d: Unexpected value returned got %t, expected %t", i+1, gotValue, testCase.parentIsObject)
+		}
+	}
+}