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_math.go

@@ -0,0 +1,83 @@
+// Copyright 2013 The ql Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSES/QL-LICENSE file.
+
+// 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 (
+	"math"
+	"math/rand"
+
+	"github.com/juju/errors"
+	"github.com/pingcap/tidb/context"
+	"github.com/pingcap/tidb/util/types"
+)
+
+// see https://dev.mysql.com/doc/refman/5.7/en/mathematical-functions.html
+
+func builtinAbs(args []types.Datum, _ context.Context) (d types.Datum, err error) {
+	d = args[0]
+	switch d.Kind() {
+	case types.KindNull:
+		return d, nil
+	case types.KindUint64:
+		return d, nil
+	case types.KindInt64:
+		iv := d.GetInt64()
+		if iv >= 0 {
+			d.SetInt64(iv)
+			return d, nil
+		}
+		d.SetInt64(-iv)
+		return d, nil
+	default:
+		// we will try to convert other types to float
+		// TODO: if time has no precision, it will be a integer
+		f, err := d.ToFloat64()
+		d.SetFloat64(math.Abs(f))
+		return d, errors.Trace(err)
+	}
+}
+
+func builtinRand(args []types.Datum, _ context.Context) (d types.Datum, err error) {
+	if len(args) == 1 && args[0].Kind() != types.KindNull {
+		seed, err := args[0].ToInt64()
+		if err != nil {
+			d.SetNull()
+			return d, errors.Trace(err)
+		}
+
+		rand.Seed(seed)
+	}
+	d.SetFloat64(rand.Float64())
+	return d, nil
+}
+
+func builtinPow(args []types.Datum, _ context.Context) (d types.Datum, err error) {
+	x, err := args[0].ToFloat64()
+	if err != nil {
+		d.SetNull()
+		return d, errors.Trace(err)
+	}
+
+	y, err := args[1].ToFloat64()
+	if err != nil {
+		d.SetNull()
+		return d, errors.Trace(err)
+	}
+	d.SetFloat64(math.Pow(x, y))
+	return d, nil
+}