73 lines
2.4 KiB
Go
73 lines
2.4 KiB
Go
// Copyright 2022 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 extension
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import (
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"context"
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"github.com/pingcap/errors"
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"github.com/pingcap/tidb/pkg/parser/auth"
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"github.com/pingcap/tidb/pkg/sessionctx/variable"
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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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)
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// FunctionContext is an interface to provide context to the custom function
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type FunctionContext interface {
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context.Context
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User() *auth.UserIdentity
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ActiveRoles() []*auth.RoleIdentity
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CurrentDB() string
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ConnectionInfo() *variable.ConnectionInfo
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EvalArgs(row chunk.Row) ([]types.Datum, error)
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}
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// FunctionDef is the definition for the custom function
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type FunctionDef struct {
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// Name is the function's name
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Name string
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// EvalTp is the type of the return value
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EvalTp types.EvalType
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// ArgTps is the argument types
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ArgTps []types.EvalType
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// OptionalArgsLen is the length of the optional args
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OptionalArgsLen int
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// EvalStringFunc is the eval function when `EvalTp` is `types.ETString`
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EvalStringFunc func(ctx FunctionContext, row chunk.Row) (string, bool, error)
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// EvalIntFunc is the eval function when `EvalTp` is `types.ETInt`
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EvalIntFunc func(ctx FunctionContext, row chunk.Row) (int64, bool, error)
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// RequireDynamicPrivileges is a function to return a list of dynamic privileges to check.
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RequireDynamicPrivileges func(sem bool) []string
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}
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// Validate validates the function definition
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func (def *FunctionDef) Validate() error {
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if def.Name == "" {
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return errors.New("extension function name should not be empty")
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}
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for def.OptionalArgsLen < 0 || def.OptionalArgsLen > len(def.ArgTps) {
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return errors.Errorf("invalid OptionalArgsLen: %d", def.OptionalArgsLen)
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}
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return nil
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}
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// RegisterExtensionFunc is to avoid dependency cycle
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var RegisterExtensionFunc func(*FunctionDef) error
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// RemoveExtensionFunc is to avoid dependency cycle
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var RemoveExtensionFunc func(string)
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