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230 lines
10 KiB
230 lines
10 KiB
/*
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==============================================================================
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This file is part of the JUCE library.
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Copyright (c) 2013 - Raw Material Software Ltd.
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Permission is granted to use this software under the terms of either:
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a) the GPL v2 (or any later version)
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b) the Affero GPL v3
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Details of these licenses can be found at: www.gnu.org/licenses
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JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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------------------------------------------------------------------------------
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To release a closed-source product which uses JUCE, commercial licenses are
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available: visit www.juce.com for more information.
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==============================================================================
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*/
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#ifndef JUCE_UNDOMANAGER_H_INCLUDED
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#define JUCE_UNDOMANAGER_H_INCLUDED
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//==============================================================================
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/**
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Manages a list of undo/redo commands.
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An UndoManager object keeps a list of past actions and can use these actions
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to move backwards and forwards through an undo history.
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To use it, create subclasses of UndoableAction which perform all the
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actions you need, then when you need to actually perform an action, create one
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and pass it to the UndoManager's perform() method.
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The manager also uses the concept of 'transactions' to group the actions
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together - all actions performed between calls to beginNewTransaction() are
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grouped together and are all undone/redone as a group.
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The UndoManager is a ChangeBroadcaster, so listeners can register to be told
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when actions are performed or undone.
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@see UndoableAction
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*/
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class JUCE_API UndoManager : public ChangeBroadcaster
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{
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public:
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//==============================================================================
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/** Creates an UndoManager.
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@param maxNumberOfUnitsToKeep each UndoableAction object returns a value
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to indicate how much storage it takes up
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(UndoableAction::getSizeInUnits()), so this
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lets you specify the maximum total number of
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units that the undomanager is allowed to
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keep in memory before letting the older actions
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drop off the end of the list.
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@param minimumTransactionsToKeep this specifies the minimum number of transactions
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that will be kept, even if this involves exceeding
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the amount of space specified in maxNumberOfUnitsToKeep
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*/
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UndoManager (int maxNumberOfUnitsToKeep = 30000,
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int minimumTransactionsToKeep = 30);
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/** Destructor. */
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~UndoManager();
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//==============================================================================
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/** Deletes all stored actions in the list. */
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void clearUndoHistory();
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/** Returns the current amount of space to use for storing UndoableAction objects.
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@see setMaxNumberOfStoredUnits
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*/
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int getNumberOfUnitsTakenUpByStoredCommands() const;
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/** Sets the amount of space that can be used for storing UndoableAction objects.
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@param maxNumberOfUnitsToKeep each UndoableAction object returns a value
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to indicate how much storage it takes up
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(UndoableAction::getSizeInUnits()), so this
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lets you specify the maximum total number of
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units that the undomanager is allowed to
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keep in memory before letting the older actions
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drop off the end of the list.
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@param minimumTransactionsToKeep this specifies the minimum number of transactions
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that will be kept, even if this involves exceeding
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the amount of space specified in maxNumberOfUnitsToKeep
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@see getNumberOfUnitsTakenUpByStoredCommands
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*/
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void setMaxNumberOfStoredUnits (int maxNumberOfUnitsToKeep,
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int minimumTransactionsToKeep);
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//==============================================================================
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/** Performs an action and adds it to the undo history list.
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@param action the action to perform - this will be deleted by the UndoManager
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when no longer needed
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@param actionName if this string is non-empty, the current transaction will be
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given this name; if it's empty, the current transaction name will
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be left unchanged. See setCurrentTransactionName()
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@returns true if the command succeeds - see UndoableAction::perform
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@see beginNewTransaction
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*/
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bool perform (UndoableAction* action,
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const String& actionName = String());
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/** Starts a new group of actions that together will be treated as a single transaction.
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All actions that are passed to the perform() method between calls to this
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method are grouped together and undone/redone together by a single call to
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undo() or redo().
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@param actionName a description of the transaction that is about to be
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performed
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*/
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void beginNewTransaction (const String& actionName = String());
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/** Changes the name stored for the current transaction.
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Each transaction is given a name when the beginNewTransaction() method is
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called, but this can be used to change that name without starting a new
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transaction.
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*/
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void setCurrentTransactionName (const String& newName);
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//==============================================================================
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/** Returns true if there's at least one action in the list to undo.
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@see getUndoDescription, undo, canRedo
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*/
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bool canUndo() const;
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/** Returns the description of the transaction that would be next to get undone.
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The description returned is the one that was passed into beginNewTransaction
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before the set of actions was performed.
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@see undo
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*/
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String getUndoDescription() const;
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/** Tries to roll-back the last transaction.
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@returns true if the transaction can be undone, and false if it fails, or
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if there aren't any transactions to undo
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*/
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bool undo();
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/** Tries to roll-back any actions that were added to the current transaction.
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This will perform an undo() only if there are some actions in the undo list
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that were added after the last call to beginNewTransaction().
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This is useful because it lets you call beginNewTransaction(), then
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perform an operation which may or may not actually perform some actions, and
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then call this method to get rid of any actions that might have been done
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without it rolling back the previous transaction if nothing was actually
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done.
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@returns true if any actions were undone.
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*/
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bool undoCurrentTransactionOnly();
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/** Returns a list of the UndoableAction objects that have been performed during the
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transaction that is currently open.
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Effectively, this is the list of actions that would be undone if undoCurrentTransactionOnly()
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were to be called now.
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The first item in the list is the earliest action performed.
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*/
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void getActionsInCurrentTransaction (Array <const UndoableAction*>& actionsFound) const;
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/** Returns the number of UndoableAction objects that have been performed during the
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transaction that is currently open.
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@see getActionsInCurrentTransaction
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*/
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int getNumActionsInCurrentTransaction() const;
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/** Returns the time to which the state would be restored if undo() was to be called.
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If an undo isn't currently possible, it'll return Time().
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*/
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Time getTimeOfUndoTransaction() const;
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/** Returns the time to which the state would be restored if redo() was to be called.
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If a redo isn't currently possible, it'll return Time::getCurrentTime().
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*/
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Time getTimeOfRedoTransaction() const;
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//==============================================================================
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/** Returns true if there's at least one action in the list to redo.
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@see getRedoDescription, redo, canUndo
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*/
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bool canRedo() const;
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/** Returns the description of the transaction that would be next to get redone.
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The description returned is the one that was passed into beginNewTransaction
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before the set of actions was performed.
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@see redo
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*/
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String getRedoDescription() const;
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/** Tries to redo the last transaction that was undone.
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@returns true if the transaction can be redone, and false if it fails, or
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if there aren't any transactions to redo
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*/
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bool redo();
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private:
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//==============================================================================
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struct ActionSet;
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friend struct ContainerDeletePolicy<ActionSet>;
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OwnedArray<ActionSet> transactions;
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String currentTransactionName;
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int totalUnitsStored, maxNumUnitsToKeep, minimumTransactionsToKeep, nextIndex;
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bool newTransaction, reentrancyCheck;
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ActionSet* getCurrentSet() const noexcept;
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ActionSet* getNextSet() const noexcept;
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void clearFutureTransactions();
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JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (UndoManager)
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};
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#endif // JUCE_UNDOMANAGER_H_INCLUDED
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