100 lines
2.8 KiB
Go
100 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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// See the License for the specific language governing permissions and
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// limitations under the License.
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package context
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import (
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"fmt"
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"time"
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"github.com/pingcap/tidb/kv"
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"github.com/pingcap/tidb/sessionctx/variable"
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)
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// Context is an interface for transaction and executive args environment.
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type Context interface {
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// NewTxn creates a new transaction for further execution.
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// If old transaction is valid, it is committed first.
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// It's used in BEGIN statement and DDL statements to commit old transaction.
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NewTxn() error
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// Txn returns the current transaction which is created before executing a statement.
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Txn() kv.Transaction
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// GetClient gets a kv.Client.
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GetClient() kv.Client
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// SetValue saves a value associated with this context for key.
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SetValue(key fmt.Stringer, value interface{})
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// Value returns the value associated with this context for key.
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Value(key fmt.Stringer) interface{}
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// ClearValue clears the value associated with this context for key.
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ClearValue(key fmt.Stringer)
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GetSessionVars() *variable.SessionVars
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// ActivePendingTxn receives the pending transaction from the transaction channel.
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// It should be called right before we builds an executor.
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ActivePendingTxn() error
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// InitTxnWithStartTS initializes a transaction with startTS.
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// It should be called right before we builds an executor.
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InitTxnWithStartTS(startTS uint64) error
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// Done returns a channel for cancelation, the same as standard context.Context.
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// See https://godoc.org/context for more examples of how to use it.
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Done() <-chan struct{}
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}
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// CtxForCancel implements the standard Go context.Context interface.
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type CtxForCancel struct {
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Context
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}
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// Value implements the standard Go context.Context interface.
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func (ctx CtxForCancel) Value(interface{}) interface{} {
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return nil
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}
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// Deadline implements the standard Go context.Context interface.
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func (ctx CtxForCancel) Deadline() (deadline time.Time, ok bool) {
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return
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}
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// Err implements the standard Go context.Context interface.
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func (ctx CtxForCancel) Err() error {
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return nil
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}
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type basicCtxType int
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func (t basicCtxType) String() string {
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switch t {
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case QueryString:
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return "query_string"
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case Initing:
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return "initing"
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}
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return "unknown"
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}
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// Context keys.
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const (
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// QueryString is the key for original query string.
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QueryString basicCtxType = 1
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// Initing is the key for indicating if the server is running bootstrap or upgrad job.
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Initing basicCtxType = 2
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)
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