40 lines
1.4 KiB
Go
40 lines
1.4 KiB
Go
// Copyright 2024 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 exprctx
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import (
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"github.com/pingcap/errors"
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"github.com/pingcap/tidb/pkg/types"
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)
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// ErrParamIndexExceedParamCounts describes the error that the index exceed the count of all params
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var ErrParamIndexExceedParamCounts = errors.New("Param index exceed param counts")
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// ParamValues is a readonly interface to return param
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type ParamValues interface {
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// GetParamValue returns the value of the parameter by index.
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GetParamValue(idx int) (types.Datum, error)
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}
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// EmptyParamValues is the `ParamValues` which contains nothing
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var EmptyParamValues ParamValues = &emptyParamValues{}
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type emptyParamValues struct{}
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// GetParamValue always returns the `ErrParamIndexExceedParamCounts` for any index
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func (e *emptyParamValues) GetParamValue(_ int) (types.Datum, error) {
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return types.Datum{}, ErrParamIndexExceedParamCounts
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}
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