зеркало из https://github.com/mozilla/gecko-dev.git
114 строки
3.8 KiB
C++
114 строки
3.8 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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*
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* The contents of this file are subject to the Netscape Public License
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* Version 1.0 (the "NPL"); you may not use this file except in
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* compliance with the NPL. You may obtain a copy of the NPL at
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* http://www.mozilla.org/NPL/
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*
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* Software distributed under the NPL is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
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* for the specific language governing rights and limitations under the
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* NPL.
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*
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* The Initial Developer of this code under the NPL is Netscape
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* Communications Corporation. Portions created by Netscape are
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* Copyright (C) 1998 Netscape Communications Corporation. All Rights
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* Reserved.
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*/
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#ifndef nsITransaction_h__
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#define nsITransaction_h__
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#include "nsISupports.h"
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#include "nsIOutputStream.h"
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#include "nsString.h"
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/*
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Transaction interface to outside world
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*/
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#define NS_ITRANSACTION_IID \
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{ /* 58E330C1-7B48-11d2-98B9-00805F297D89 */ \
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0x58e330c1, 0x7b48, 0x11d2, \
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{ 0x98, 0xb9, 0x0, 0x80, 0x5f, 0x29, 0x7d, 0x89 } }
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/**
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* A transaction specific interface.
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* <P>
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* It's implemented by an object that executes some behavior that must be
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* tracked by the transaction manager.
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*/
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class nsITransaction : public nsISupports{
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public:
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static const nsIID& IID() { static nsIID iid = NS_ITRANSACTION_IID; return iid; }
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/**
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* Executes the transaction.
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*/
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virtual nsresult Do(void) = 0;
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/**
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* Restores the state to what it was before the transaction was executed.
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*/
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virtual nsresult Undo(void) = 0;
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/**
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* Executes the transaction again. Can only be called on a transaction that
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* was previously undone.
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* <P>
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* In most cases, the Redo() method will actually call the Do() method to
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* execute the transaction again.
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*/
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virtual nsresult Redo(void) = 0;
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/**
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* Retrieves the transaction's transient state. This method is called by
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* the transaction manager after the transaction's Do() method is executed.
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* If the transient state is false, a reference to the transaction is
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* held by the transaction manager so that the transactions' Undo() and
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* Redo() methods can be called. If the transient state is true, the
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* transaction manager returns immediately after the transaction's Do()
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* method is executed, no references to the transaction are maintained.
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* Transient transactions cannot be undone or redone by the transaction
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* manager.
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* @param aIsTransient will contain the transaction's transient state.
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*/
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virtual nsresult GetIsTransient(PRBool *aIsTransient) = 0;
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/**
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* Attempts to merge a transaction into "this" transaction. Both transactions
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* must be in their undo state, Do() methods already executed. The transaction
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* manager calls this method to coalesce a new transaction with the
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* transaction on the top of the undo stack.
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* @param aDidMerge will contain merge result. True if transactions were
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* merged successfully. False if merge is not possible or failed. If true,
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* the transaction manager will Release() the new transacton instead of
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* pushing it on the undo stack.
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* @param aTransaction the previously executed transaction to merge.
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*/
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virtual nsresult Merge(PRBool *aDidMerge, nsITransaction *aTransaction) = 0;
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/**
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* Write a stream representation of the current state of the transaction.
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* @param aOutputStream the stream to write to.
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*/
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virtual nsresult Write(nsIOutputStream *aOutputStream) = 0;
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/**
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* Returns the string to display for the undo menu item.
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* @param aString will point to string to display.
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*/
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virtual nsresult GetUndoString(nsString **aString) = 0;
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/**
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* Returns the string to display for the redo menu item.
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* @param aString will point to string to display.
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*/
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virtual nsresult GetRedoString(nsString **aString) = 0;
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};
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#endif // nsITransaction_h__
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