Add table namespace classifier (#761)

server/core/tablecodec.go

@@ -0,0 +1,59 @@
+// Copyright 2016 PingCAP, 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,
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package core
+
+import (
+	"bytes"
+	"encoding/binary"
+	"github.com/juju/errors"
+)
+
+var tablePrefix = []byte{'t'}
+
+const signMask uint64 = 0x8000000000000000
+
+// Key represents high-level Key type.
+type Key []byte
+
+// HasPrefix tests whether the Key begins with prefix.
+func (k Key) HasPrefix(prefix Key) bool {
+	return bytes.HasPrefix(k, prefix)
+}
+
+// DecodeTableID decodes the table ID of the key, if the key is not table key, returns 0.
+func DecodeTableID(key Key) int64 {
+	if !key.HasPrefix(tablePrefix) {
+		return 0
+	}
+	key = key[len(tablePrefix):]
+	_, tableID, _ := DecodeInt(key)
+	return tableID
+}
+
+// DecodeInt decodes value encoded by EncodeInt before.
+// It returns the leftover un-decoded slice, decoded value if no error.
+func DecodeInt(b []byte) ([]byte, int64, error) {
+	if len(b) < 8 {
+		return nil, 0, errors.New("insufficient bytes to decode value")
+	}
+
+	u := binary.BigEndian.Uint64(b[:8])
+	v := decodeCmpUintToInt(u)
+	b = b[8:]
+	return b, v, nil
+}
+
+func decodeCmpUintToInt(u uint64) int64 {
+	return int64(u ^ signMask)
+}

server/tableNamespaceClassifier.go

@@ -0,0 +1,46 @@
+package server
+
+import (
+	"github.com/pingcap/pd/server/core"
+	"github.com/pingcap/pd/server/namespace"
+)
+
+type tableNamespaceClassifier struct {
+	nsInfo *namespacesInfo
+}
+
+func newTableNamespaceClassifier(nsInfo *namespacesInfo) tableNamespaceClassifier {
+	return tableNamespaceClassifier{
+		nsInfo,
+	}
+}
+
+func (classifier tableNamespaceClassifier) GetAllNamespaces() []string {
+	nsList := make([]string, len(classifier.nsInfo.namespaces))
+	for name := range classifier.nsInfo.namespaces {
+		nsList = append(nsList, name)
+	}
+	return nsList
+}
+
+func (classifier tableNamespaceClassifier) GetStoreNamespace(storeInfo *core.StoreInfo) string {
+	for name, ns := range classifier.nsInfo.namespaces {
+		if storeInfo.Id == ns.ID {
+			return name
+		}
+	}
+	return namespace.DefaultNamespace
+}
+
+func (classifier tableNamespaceClassifier) GetRegionNamespace(regionInfo *core.RegionInfo) string {
+	for name, ns := range classifier.nsInfo.namespaces {
+		startTable := core.DecodeTableID(regionInfo.StartKey)
+		endTable := core.DecodeTableID(regionInfo.EndKey)
+		for _, tableID := range ns.TableIDs {
+			if tableID == startTable && tableID == endTable {
+				return name
+			}
+		}
+	}
+	return namespace.DefaultNamespace
+}