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/optimizer/logic.go

@@ -0,0 +1,65 @@
+// 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 optimizer
+
+import (
+	"github.com/pingcap/tidb/ast"
+	"github.com/pingcap/tidb/context"
+	"github.com/pingcap/tidb/evaluator"
+)
+
+// logicOptimize does logic optimization works on AST.
+func logicOptimize(ctx context.Context, node ast.Node) error {
+	return preEvaluate(ctx, node)
+}
+
+// preEvaluate evaluates preEvaluable expression and rewrites constant expression to value expression.
+func preEvaluate(ctx context.Context, node ast.Node) error {
+	pe := preEvaluator{ctx: ctx}
+	node.Accept(&pe)
+	return pe.err
+}
+
+type preEvaluator struct {
+	ctx context.Context
+	err error
+}
+
+func (r *preEvaluator) Enter(in ast.Node) (ast.Node, bool) {
+	return in, false
+}
+
+func (r *preEvaluator) Leave(in ast.Node) (ast.Node, bool) {
+	if expr, ok := in.(ast.ExprNode); ok {
+		if _, ok = expr.(*ast.ValueExpr); ok {
+			return in, true
+		} else if ast.IsPreEvaluable(expr) {
+			val, err := evaluator.Eval(r.ctx, expr)
+			if err != nil {
+				r.err = err
+				return in, false
+			}
+			if ast.IsConstant(expr) {
+				// The expression is constant, rewrite the expression to value expression.
+				valExpr := &ast.ValueExpr{}
+				valExpr.SetText(expr.Text())
+				valExpr.SetType(expr.GetType())
+				valExpr.SetValue(val)
+				return valExpr, true
+			}
+			expr.SetValue(val)
+		}
+	}
+	return in, true
+}