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

pkg/bucket/versioning/error.go

@@ -0,0 +1,44 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 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 versioning
+
+import (
+	"fmt"
+)
+
+// Error is the generic type for any error happening during tag
+// parsing.
+type Error struct {
+	err error
+}
+
+// Errorf - formats according to a format specifier and returns
+// the string as a value that satisfies error of type tagging.Error
+func Errorf(format string, a ...interface{}) error {
+	return Error{err: fmt.Errorf(format, a...)}
+}
+
+// Unwrap the internal error.
+func (e Error) Unwrap() error { return e.err }
+
+// Error 'error' compatible method.
+func (e Error) Error() string {
+	if e.err == nil {
+		return "versioning: cause <nil>"
+	}
+	return e.err.Error()
+}

pkg/bucket/versioning/versioning.go

@@ -0,0 +1,79 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 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 versioning
+
+import (
+	"encoding/xml"
+	"io"
+)
+
+// State - enabled/disabled/suspended states
+// for multifactor and status of versioning.
+type State string
+
+// Various supported states
+const (
+	Enabled State = "Enabled"
+	// Disabled  State = "Disabled" only used by MFA Delete not supported yet.
+	Suspended State = "Suspended"
+)
+
+// Versioning - Configuration for bucket versioning.
+type Versioning struct {
+	XMLNS   string   `xml:"xmlns,attr,omitempty"`
+	XMLName xml.Name `xml:"VersioningConfiguration"`
+	// MFADelete State    `xml:"MFADelete,omitempty"` // not supported yet.
+	Status State `xml:"Status,omitempty"`
+}
+
+// Validate - validates the versioning configuration
+func (v Versioning) Validate() error {
+	// Not supported yet
+	// switch v.MFADelete {
+	// case Enabled, Disabled:
+	// default:
+	// 	return Errorf("unsupported MFADelete state %s", v.MFADelete)
+	// }
+	switch v.Status {
+	case Enabled, Suspended:
+	default:
+		return Errorf("unsupported Versioning status %s", v.Status)
+	}
+	return nil
+}
+
+// Enabled - returns true if versioning is enabled
+func (v Versioning) Enabled() bool {
+	return v.Status == Enabled
+}
+
+// Suspended - returns true if versioning is suspended
+func (v Versioning) Suspended() bool {
+	return v.Status == Suspended
+}
+
+// ParseConfig - parses data in given reader to VersioningConfiguration.
+func ParseConfig(reader io.Reader) (*Versioning, error) {
+	var v Versioning
+	if err := xml.NewDecoder(reader).Decode(&v); err != nil {
+		return nil, err
+	}
+	if err := v.Validate(); err != nil {
+		return nil, err
+	}
+	return &v, nil
+}