juce_ValueTreeSynchroniser.cpp

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 /*
  ==============================================================================
 
   This file is part of the JUCE library.
   Copyright (c) 2022 - Raw Material Software Limited
 
   JUCE is an open source library subject to commercial or open-source
   licensing.
 
   By using JUCE, you agree to the terms of both the JUCE 7 End-User License
   Agreement and JUCE Privacy Policy.
 
   End User License Agreement: www.juce.com/juce-7-licence
   Privacy Policy: www.juce.com/juce-privacy-policy
 
   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).
 
   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.
 
  ==============================================================================
*/
 
namespace juce
{
 
namespace ValueTreeSynchroniserHelpers
{
    enum ChangeType
    {
        propertyChanged  = 1,
        fullSync         = 2,
        childAdded       = 3,
        childRemoved     = 4,
        childMoved       = 5,
        propertyRemoved  = 6
    };
 
    static void getValueTreePath (ValueTree v, const ValueTree& topLevelTree, Array<int>& path)
    {
        while (v != topLevelTree)
        {
            ValueTree parent (v.getParent());
 
            if (! parent.isValid())
                break;
 
            path.add (parent.indexOf (v));
            v = parent;
        }
    }
 
    static void writeHeader (MemoryOutputStream& stream, ChangeType type)
    {
        stream.writeByte ((char) type);
    }
 
    static void writeHeader (ValueTreeSynchroniser& target, MemoryOutputStream& stream,
                             ChangeType type, ValueTree v)
    {
        writeHeader (stream, type);
 
        Array<int> path;
        getValueTreePath (v, target.getRoot(), path);
 
        stream.writeCompressedInt (path.size());
 
        for (int i = path.size(); --i >= 0;)
            stream.writeCompressedInt (path.getUnchecked (i));
    }
 
    static ValueTree readSubTreeLocation (MemoryInputStream& input, ValueTree v)
    {
        const int numLevels = input.readCompressedInt();
 
        if (! isPositiveAndBelow (numLevels, 65536)) // sanity-check
            return {};
 
        for (int i = numLevels; --i >= 0;)
        {
            const int index = input.readCompressedInt();
 
            if (! isPositiveAndBelow (index, v.getNumChildren()))
                return {};
 
            v = v.getChild (index);
        }
 
        return v;
    }
}
 
ValueTreeSynchroniser::ValueTreeSynchroniser (const ValueTree& tree)  : valueTree (tree)
{
    valueTree.addListener (this);
}
 
ValueTreeSynchroniser::~ValueTreeSynchroniser()
{
    valueTree.removeListener (this);
}
 
void ValueTreeSynchroniser::sendFullSyncCallback()
{
    MemoryOutputStream m;
    writeHeader (m, ValueTreeSynchroniserHelpers::fullSync);
    valueTree.writeToStream (m);
    stateChanged (m.getData(), m.getDataSize());
}
 
void ValueTreeSynchroniser::valueTreePropertyChanged (ValueTree& vt, const Identifier& property)
{
    MemoryOutputStream m;
 
    if (auto* value = vt.getPropertyPointer (property))
    {
        ValueTreeSynchroniserHelpers::writeHeader (*this, m, ValueTreeSynchroniserHelpers::propertyChanged, vt);
        m.writeString (property.toString());
        value->writeToStream (m);
    }
    else
    {
        ValueTreeSynchroniserHelpers::writeHeader (*this, m, ValueTreeSynchroniserHelpers::propertyRemoved, vt);
        m.writeString (property.toString());
    }
 
    stateChanged (m.getData(), m.getDataSize());
}
 
void ValueTreeSynchroniser::valueTreeChildAdded (ValueTree& parentTree, ValueTree& childTree)
{
    const int index = parentTree.indexOf (childTree);
    jassert (index >= 0);
 
    MemoryOutputStream m;
    ValueTreeSynchroniserHelpers::writeHeader (*this, m, ValueTreeSynchroniserHelpers::childAdded, parentTree);
    m.writeCompressedInt (index);
    childTree.writeToStream (m);
    stateChanged (m.getData(), m.getDataSize());
}
 
void ValueTreeSynchroniser::valueTreeChildRemoved (ValueTree& parentTree, ValueTree&, int oldIndex)
{
    MemoryOutputStream m;
    ValueTreeSynchroniserHelpers::writeHeader (*this, m, ValueTreeSynchroniserHelpers::childRemoved, parentTree);
    m.writeCompressedInt (oldIndex);
    stateChanged (m.getData(), m.getDataSize());
}
 
void ValueTreeSynchroniser::valueTreeChildOrderChanged (ValueTree& parent, int oldIndex, int newIndex)
{
    MemoryOutputStream m;
    ValueTreeSynchroniserHelpers::writeHeader (*this, m, ValueTreeSynchroniserHelpers::childMoved, parent);
    m.writeCompressedInt (oldIndex);
    m.writeCompressedInt (newIndex);
    stateChanged (m.getData(), m.getDataSize());
}
 
bool ValueTreeSynchroniser::applyChange (ValueTree& root, const void* data, size_t dataSize, UndoManager* undoManager)
{
    MemoryInputStream input (data, dataSize, false);
 
    const ValueTreeSynchroniserHelpers::ChangeType type = (ValueTreeSynchroniserHelpers::ChangeType) input.readByte();
 
    if (type == ValueTreeSynchroniserHelpers::fullSync)
    {
        root = ValueTree::readFromStream (input);
        return true;
    }
 
    ValueTree v (ValueTreeSynchroniserHelpers::readSubTreeLocation (input, root));
 
    if (! v.isValid())
        return false;
 
    switch (type)
    {
        case ValueTreeSynchroniserHelpers::propertyChanged:
        {
            Identifier property (input.readString());
            v.setProperty (property, var::readFromStream (input), undoManager);
            return true;
        }
 
        case ValueTreeSynchroniserHelpers::propertyRemoved:
        {
            Identifier property (input.readString());
            v.removeProperty (property, undoManager);
            return true;
        }
 
        case ValueTreeSynchroniserHelpers::childAdded:
        {
            const int index = input.readCompressedInt();
            v.addChild (ValueTree::readFromStream (input), index, undoManager);
            return true;
        }
 
        case ValueTreeSynchroniserHelpers::childRemoved:
        {
            const int index = input.readCompressedInt();
 
            if (isPositiveAndBelow (index, v.getNumChildren()))
            {
                v.removeChild (index, undoManager);
                return true;
            }
 
            jassertfalse; // Either received some corrupt data, or the trees have drifted out of sync
            break;
        }
 
        case ValueTreeSynchroniserHelpers::childMoved:
        {
            const int oldIndex = input.readCompressedInt();
            const int newIndex = input.readCompressedInt();
 
            if (isPositiveAndBelow (oldIndex, v.getNumChildren())
                 && isPositiveAndBelow (newIndex, v.getNumChildren()))
            {
                v.moveChild (oldIndex, newIndex, undoManager);
                return true;
            }
 
            jassertfalse; // Either received some corrupt data, or the trees have drifted out of sync
            break;
        }
 
        case ValueTreeSynchroniserHelpers::fullSync:
            break;
 
        default:
            jassertfalse; // Seem to have received some corrupt data?
            break;
    }
 
    return false;
}
 
} // namespace juce