98 lines
2.8 KiB
Go
98 lines
2.8 KiB
Go
// Copyright 2015 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package expression
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import (
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"github.com/pingcap/tidb/pkg/types"
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"github.com/pingcap/tidb/pkg/util/chunk"
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"github.com/pingcap/tidb/pkg/util/collate"
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"github.com/pingcap/tidb/pkg/util/intest"
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"github.com/pingcap/tipb/go-tipb"
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)
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var (
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_ functionClass = &likeFunctionClass{}
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)
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var (
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_ builtinFunc = &builtinLikeSig{}
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)
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type likeFunctionClass struct {
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baseFunctionClass
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}
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func (c *likeFunctionClass) getFunction(ctx BuildContext, args []Expression) (builtinFunc, error) {
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if err := c.verifyArgs(args); err != nil {
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return nil, err
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}
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argTp := []types.EvalType{types.ETString, types.ETString, types.ETInt}
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bf, err := newBaseBuiltinFuncWithTp(ctx, c.funcName, args, types.ETInt, argTp...)
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if err != nil {
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return nil, err
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}
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bf.tp.SetFlen(1)
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sig := &builtinLikeSig{baseBuiltinFunc: bf}
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sig.setPbCode(tipb.ScalarFuncSig_LikeSig)
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return sig, nil
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}
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type builtinLikeSig struct {
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baseBuiltinFunc
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// pattern is not serialized with builtinLikeSig, treat them as a cache to accelerate
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// the evaluation of builtinLikeSig.
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patternCache builtinFuncCache[collate.WildcardPattern]
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}
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func (b *builtinLikeSig) Clone() builtinFunc {
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newSig := &builtinLikeSig{}
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newSig.cloneFrom(&b.baseBuiltinFunc)
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return newSig
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}
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// evalInt evals a builtinLikeSig.
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// See https://dev.mysql.com/doc/refman/5.7/en/string-comparison-functions.html#operator_like
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func (b *builtinLikeSig) evalInt(ctx EvalContext, row chunk.Row) (int64, bool, error) {
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valStr, isNull, err := b.args[0].EvalString(ctx, row)
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if isNull || err != nil {
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return 0, isNull, err
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}
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patternStr, isNull, err := b.args[1].EvalString(ctx, row)
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if isNull || err != nil {
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return 0, isNull, err
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}
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escape, isNull, err := b.args[2].EvalInt(ctx, row)
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if isNull || err != nil {
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return 0, isNull, err
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}
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var pattern collate.WildcardPattern
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if b.args[1].ConstLevel() >= ConstOnlyInContext && b.args[2].ConstLevel() >= ConstOnlyInContext {
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pattern, err = b.patternCache.getOrInitCache(ctx, func() (collate.WildcardPattern, error) {
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ret := b.collator().Pattern()
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ret.Compile(patternStr, byte(escape))
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return ret, nil
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})
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intest.AssertNoError(err)
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if err != nil {
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return 0, true, err
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}
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} else {
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pattern = b.collator().Pattern()
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pattern.Compile(patternStr, byte(escape))
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}
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return boolToInt64(pattern.DoMatch(valStr)), false, nil
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}
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