Merge pull request #4173 from AllenX2018/fix-bug-queryRow

Fix issue 3866

pkg/infrastructure/utils/kv.go

@@ -0,0 +1,87 @@
+// Copyright 2020 beego-dev
+//
+// 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 utils
+
+type KV interface {
+	GetKey() interface{}
+	GetValue() interface{}
+}
+
+// SimpleKV is common structure to store key-value pairs.
+// When you need something like Pair, you can use this
+type SimpleKV struct {
+	Key   interface{}
+	Value interface{}
+}
+
+var _ KV = new(SimpleKV)
+
+func (s *SimpleKV) GetKey() interface{} {
+	return s.Key
+}
+
+func (s *SimpleKV) GetValue() interface{} {
+	return s.Value
+}
+
+// KVs interface
+type KVs interface {
+	GetValueOr(key interface{}, defValue interface{}) interface{}
+	Contains(key interface{}) bool
+	IfContains(key interface{}, action func(value interface{})) KVs
+}
+
+// SimpleKVs will store SimpleKV collection as map
+type SimpleKVs struct {
+	kvs map[interface{}]interface{}
+}
+
+var _ KVs = new(SimpleKVs)
+
+// GetValueOr returns the value for a given key, if non-existant
+// it returns defValue
+func (kvs *SimpleKVs) GetValueOr(key interface{}, defValue interface{}) interface{} {
+	v, ok := kvs.kvs[key]
+	if ok {
+		return v
+	}
+	return defValue
+}
+
+// Contains checks if a key exists
+func (kvs *SimpleKVs) Contains(key interface{}) bool {
+	_, ok := kvs.kvs[key]
+	return ok
+}
+
+// IfContains invokes the action on a key if it exists
+func (kvs *SimpleKVs) IfContains(key interface{}, action func(value interface{})) KVs {
+	v, ok := kvs.kvs[key]
+	if ok {
+		action(v)
+	}
+	return kvs
+}
+
+// NewKVs creates the *KVs instance
+func NewKVs(kvs ...KV) KVs {
+	res := &SimpleKVs{
+		kvs: make(map[interface{}]interface{}, len(kvs)),
+	}
+	for _, kv := range kvs {
+		res.kvs[kv.GetKey()] = kv.GetValue()
+	}
+	return res
+}