Integrate public as bindata optionally (#293)

* Dropped unused codekit config

* Integrated dynamic and static bindata for public

* Ignore public bindata

* Add a general generate make task

* Integrated flexible public assets into web command

* Updated vendoring, added all missiong govendor deps

* Made the linter happy with the bindata and dynamic code

* Moved public bindata definition to modules directory

* Ignoring the new bindata path now

* Updated to the new public modules import path

* Updated public bindata command and drop the new prefix

vendor/github.com/pingcap/tidb/evaluator/builtin_control.go

@@ -0,0 +1,76 @@
+// Copyright 2015 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 evaluator
+
+import (
+	"github.com/pingcap/tidb/context"
+	"github.com/pingcap/tidb/util/types"
+)
+
+// See https://dev.mysql.com/doc/refman/5.7/en/control-flow-functions.html#function_if
+func builtinIf(args []interface{}, _ context.Context) (interface{}, error) {
+	// if(expr1, expr2, expr3)
+	// if expr1 is true, return expr2, otherwise, return expr3
+	v1 := args[0]
+	v2 := args[1]
+	v3 := args[2]
+
+	if v1 == nil {
+		return v3, nil
+	}
+
+	b, err := types.ToBool(v1)
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO: check return type, must be numeric or string
+	if b == 1 {
+		return v2, nil
+	}
+
+	return v3, nil
+}
+
+// See https://dev.mysql.com/doc/refman/5.7/en/control-flow-functions.html#function_ifnull
+func builtinIfNull(args []interface{}, _ context.Context) (interface{}, error) {
+	// ifnull(expr1, expr2)
+	// if expr1 is not null, return expr1, otherwise, return expr2
+	v1 := args[0]
+	v2 := args[1]
+
+	if v1 != nil {
+		return v1, nil
+	}
+
+	return v2, nil
+}
+
+// See https://dev.mysql.com/doc/refman/5.7/en/control-flow-functions.html#function_nullif
+func builtinNullIf(args []interface{}, _ context.Context) (interface{}, error) {
+	// nullif(expr1, expr2)
+	// returns null if expr1 = expr2 is true, otherwise returns expr1
+	v1 := args[0]
+	v2 := args[1]
+
+	if v1 == nil || v2 == nil {
+		return v1, nil
+	}
+
+	if n, err := types.Compare(v1, v2); err != nil || n == 0 {
+		return nil, err
+	}
+
+	return v1, nil
+}