/
builtin_info.go
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/
builtin_info.go
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// 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 expression
import (
"github.com/chrislusf/gleam/sql/context"
"github.com/chrislusf/gleam/sql/mysql"
"github.com/chrislusf/gleam/sql/util/types"
"github.com/juju/errors"
)
var (
_ functionClass = &databaseFunctionClass{}
_ functionClass = &foundRowsFunctionClass{}
_ functionClass = ¤tUserFunctionClass{}
_ functionClass = &userFunctionClass{}
_ functionClass = &versionFunctionClass{}
)
var (
_ builtinFunc = &builtinDatabaseSig{}
_ builtinFunc = &builtinFoundRowsSig{}
_ builtinFunc = &builtinCurrentUserSig{}
_ builtinFunc = &builtinUserSig{}
_ builtinFunc = &builtinVersionSig{}
)
type databaseFunctionClass struct {
baseFunctionClass
}
func (c *databaseFunctionClass) getFunction(args []Expression, ctx context.Context) (builtinFunc, error) {
if err := errors.Trace(c.verifyArgs(args)); err != nil {
return nil, errors.Trace(err)
}
bt := &builtinDatabaseSig{newBaseBuiltinFunc(args, ctx)}
bt.deterministic = false
return bt, nil
}
type builtinDatabaseSig struct {
baseBuiltinFunc
}
func (b *builtinDatabaseSig) eval(row []types.Datum) (types.Datum, error) {
args, err := b.evalArgs(row)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
return builtinDatabase(args, b.ctx)
}
// See https://dev.mysql.com/doc/refman/5.7/en/information-functions.html
func builtinDatabase(args []types.Datum, ctx context.Context) (d types.Datum, err error) {
currentDB := ctx.GetSessionVars().CurrentDB
if currentDB == "" {
return d, nil
}
d.SetString(currentDB)
return d, nil
}
type foundRowsFunctionClass struct {
baseFunctionClass
}
func (c *foundRowsFunctionClass) getFunction(args []Expression, ctx context.Context) (builtinFunc, error) {
if err := errors.Trace(c.verifyArgs(args)); err != nil {
return nil, errors.Trace(err)
}
bt := &builtinFoundRowsSig{newBaseBuiltinFunc(args, ctx)}
bt.deterministic = false
return bt, nil
}
type builtinFoundRowsSig struct {
baseBuiltinFunc
}
func (b *builtinFoundRowsSig) eval(row []types.Datum) (types.Datum, error) {
args, err := b.evalArgs(row)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
return builtinFoundRows(args, b.ctx)
}
func builtinFoundRows(arg []types.Datum, ctx context.Context) (d types.Datum, err error) {
data := ctx.GetSessionVars()
if data == nil {
return d, errors.Errorf("Missing session variable when evalue builtin")
}
d.SetUint64(data.StmtCtx.FoundRows())
return d, nil
}
type currentUserFunctionClass struct {
baseFunctionClass
}
func (c *currentUserFunctionClass) getFunction(args []Expression, ctx context.Context) (builtinFunc, error) {
if err := errors.Trace(c.verifyArgs(args)); err != nil {
return nil, errors.Trace(err)
}
bt := &builtinCurrentUserSig{newBaseBuiltinFunc(args, ctx)}
bt.deterministic = false
return bt, nil
}
type builtinCurrentUserSig struct {
baseBuiltinFunc
}
func (b *builtinCurrentUserSig) eval(row []types.Datum) (types.Datum, error) {
args, err := b.evalArgs(row)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
return builtinCurrentUser(args, b.ctx)
}
// See https://dev.mysql.com/doc/refman/5.7/en/information-functions.html#function_current-user
// TODO: The value of CURRENT_USER() can differ from the value of USER(). We will finish this after we support grant tables.
func builtinCurrentUser(args []types.Datum, ctx context.Context) (d types.Datum, err error) {
data := ctx.GetSessionVars()
if data == nil {
return d, errors.Errorf("Missing session variable when evalue builtin")
}
d.SetString(data.User)
return d, nil
}
type userFunctionClass struct {
baseFunctionClass
}
func (c *userFunctionClass) getFunction(args []Expression, ctx context.Context) (builtinFunc, error) {
if err := errors.Trace(c.verifyArgs(args)); err != nil {
return nil, errors.Trace(err)
}
bt := &builtinUserSig{newBaseBuiltinFunc(args, ctx)}
bt.deterministic = false
return bt, nil
}
type builtinUserSig struct {
baseBuiltinFunc
}
func (b *builtinUserSig) eval(row []types.Datum) (types.Datum, error) {
args, err := b.evalArgs(row)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
return builtinUser(args, b.ctx)
}
func builtinUser(args []types.Datum, ctx context.Context) (d types.Datum, err error) {
data := ctx.GetSessionVars()
if data == nil {
return d, errors.Errorf("Missing session variable when evalue builtin")
}
d.SetString(data.User)
return d, nil
}
type versionFunctionClass struct {
baseFunctionClass
}
func (c *versionFunctionClass) getFunction(args []Expression, ctx context.Context) (builtinFunc, error) {
if err := errors.Trace(c.verifyArgs(args)); err != nil {
return nil, errors.Trace(err)
}
bt := &builtinVersionSig{newBaseBuiltinFunc(args, ctx)}
bt.deterministic = false
return bt, nil
}
type builtinVersionSig struct {
baseBuiltinFunc
}
func (b *builtinVersionSig) eval(row []types.Datum) (types.Datum, error) {
args, err := b.evalArgs(row)
if err != nil {
return types.Datum{}, errors.Trace(err)
}
return builtinVersion(args, b.ctx)
}
func builtinVersion(args []types.Datum, ctx context.Context) (d types.Datum, err error) {
d.SetString(mysql.ServerVersion)
return d, nil
}