Files
tidb/extension/function.go

49 lines
1.9 KiB
Go

// Copyright 2022 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,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package extension
import (
"github.com/pingcap/tidb/types"
"github.com/pingcap/tidb/util/chunk"
)
// FunctionContext is a interface to provide context to the custom function
type FunctionContext interface {
EvalArgs(row chunk.Row) ([]types.Datum, error)
}
// FunctionDef is the definition for the custom function
type FunctionDef struct {
Name string
EvalTp types.EvalType
ArgTps []types.EvalType
// EvalStringFunc is the eval function when `EvalTp` is `types.ETString`
EvalStringFunc func(ctx FunctionContext, row chunk.Row) (string, bool, error)
// EvalIntFunc is the eval function when `EvalTp` is `types.ETInt`
EvalIntFunc func(ctx FunctionContext, row chunk.Row) (int64, bool, error)
// RequireDynamicPrivileges is the dynamic privileges needed to invoke the function
// If `RequireDynamicPrivileges` is empty, it means every one can invoke this function
RequireDynamicPrivileges []string
// SemRequireDynamicPrivileges is the dynamic privileges needed to invoke the function in sem mode
// If `SemRequireDynamicPrivileges` is empty, `DynamicPrivileges` will be used in sem mode
SemRequireDynamicPrivileges []string
}
// RegisterExtensionFunc is to avoid dependency cycle
var RegisterExtensionFunc func(*FunctionDef) error
// RemoveExtensionFunc is to avoid dependency cycle
var RemoveExtensionFunc func(string)