OpenShot Library | libopenshot-audio  0.2.0
juce_ValueTreeSynchroniser.h
1 
2 /** @weakgroup juce_data_structures-values
3  * @{
4  */
5 /*
6  ==============================================================================
7 
8  This file is part of the JUCE library.
9  Copyright (c) 2017 - ROLI Ltd.
10 
11  JUCE is an open source library subject to commercial or open-source
12  licensing.
13 
14  By using JUCE, you agree to the terms of both the JUCE 5 End-User License
15  Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
16  27th April 2017).
17 
18  End User License Agreement: www.juce.com/juce-5-licence
19  Privacy Policy: www.juce.com/juce-5-privacy-policy
20 
21  Or: You may also use this code under the terms of the GPL v3 (see
22  www.gnu.org/licenses).
23 
24  JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
25  EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
26  DISCLAIMED.
27 
28  ==============================================================================
29 */
30 
31 namespace juce
32 {
33 
34 //==============================================================================
35 /**
36  This class can be used to watch for all changes to the state of a ValueTree,
37  and to convert them to a transmittable binary encoding.
38 
39  The purpose of this class is to allow two or more ValueTrees to be remotely
40  synchronised by transmitting encoded changes over some kind of transport
41  mechanism.
42 
43  To use it, you'll need to implement a subclass of ValueTreeSynchroniser
44  and implement the stateChanged() method to transmit the encoded change (maybe
45  via a network or other means) to a remote destination, where it can be
46  applied to a target tree.
47 
48  @tags{DataStructures}
49 */
51 {
52 public:
53  /** Creates a ValueTreeSynchroniser that watches the given tree.
54 
55  After creating an instance of this class and somehow attaching it to
56  a target tree, you probably want to call sendFullSyncCallback() to
57  get them into a common starting state.
58  */
59  ValueTreeSynchroniser (const ValueTree& tree);
60 
61  /** Destructor. */
62  ~ValueTreeSynchroniser() override;
63 
64  /** This callback happens when the ValueTree changes and the given state-change message
65  needs to be applied to any other trees that need to stay in sync with it.
66  The data is an opaque blob of binary that you should transmit to wherever your
67  target tree lives, and use applyChange() to apply this to the target tree.
68  */
69  virtual void stateChanged (const void* encodedChange, size_t encodedChangeSize) = 0;
70 
71  /** Forces the sending of a full state message, which may be large, as it
72  encodes the entire ValueTree.
73 
74  This will internally invoke stateChanged() with the encoded version of the state.
75  */
76  void sendFullSyncCallback();
77 
78  /** Applies an encoded change to the given destination tree.
79 
80  When you implement a receiver for changes that were sent by the stateChanged()
81  message, this is the function that you'll need to call to apply them to the
82  target tree that you want to be synced.
83  */
84  static bool applyChange (ValueTree& target,
85  const void* encodedChangeData, size_t encodedChangeDataSize,
86  UndoManager* undoManager);
87 
88  /** Returns the root ValueTree that is being observed. */
89  const ValueTree& getRoot() noexcept { return valueTree; }
90 
91 private:
92  ValueTree valueTree;
93 
94  void valueTreePropertyChanged (ValueTree&, const Identifier&) override;
95  void valueTreeChildAdded (ValueTree&, ValueTree&) override;
96  void valueTreeChildRemoved (ValueTree&, ValueTree&, int) override;
97  void valueTreeChildOrderChanged (ValueTree&, int, int) override;
98  void valueTreeParentChanged (ValueTree&) override;
99 
100  JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ValueTreeSynchroniser)
101 };
102 
103 } // namespace juce
104 
105 /** @}*/
juce::ValueTree
A powerful tree structure that can be used to hold free-form data, and which can handle its own undo ...
Definition: juce_ValueTree.h:76
juce::UndoManager
Manages a list of undo/redo commands.
Definition: juce_UndoManager.h:56
JUCE_API
#define JUCE_API
This macro is added to all JUCE public class declarations.
Definition: juce_StandardHeader.h:143
juce::Identifier
Represents a string identifier, designed for accessing properties by name.
Definition: juce_Identifier.h:42
juce::ValueTreeSynchroniser
This class can be used to watch for all changes to the state of a ValueTree, and to convert them to a...
Definition: juce_ValueTreeSynchroniser.h:50
juce::ValueTreeSynchroniser::getRoot
const ValueTree & getRoot() noexcept
Returns the root ValueTree that is being observed.
Definition: juce_ValueTreeSynchroniser.h:89
juce::ValueTree::Listener
Listener class for events that happen to a ValueTree.
Definition: juce_ValueTree.h:478