JUCE/modules/juce_gui_basics/commands/juce_ApplicationCommandTarget.cpp

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   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 5 End-User License
   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
   27th April 2017).

   End User License Agreement: www.juce.com/juce-5-licence
   Privacy Policy: www.juce.com/juce-5-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.

  ==============================================================================
*/

class ApplicationCommandTarget::CommandMessage  : public MessageManager::MessageBase
{
public:
    CommandMessage (ApplicationCommandTarget* const target, const InvocationInfo& inf)
        : owner (target), info (inf)
    {
    }

    void messageCallback() override
    {
        if (ApplicationCommandTarget* const target = owner)
            target->tryToInvoke (info, false);
    }

private:
    WeakReference<ApplicationCommandTarget> owner;
    const InvocationInfo info;

    JUCE_DECLARE_NON_COPYABLE (CommandMessage)
};

//==============================================================================
ApplicationCommandTarget::ApplicationCommandTarget()
{
}

ApplicationCommandTarget::~ApplicationCommandTarget()
{
    masterReference.clear();
}

//==============================================================================
bool ApplicationCommandTarget::tryToInvoke (const InvocationInfo& info, const bool async)
{
    if (isCommandActive (info.commandID))
    {
        if (async)
        {
            (new CommandMessage (this, info))->post();
            return true;
        }

        if (perform (info))
            return true;

        // Hmm.. your target claimed that it could perform this command, but failed to do so.
        // If it can't do it at the moment for some reason, it should clear the 'isActive' flag
        // when it returns the command's info.
        jassertfalse;
    }

    return false;
}

ApplicationCommandTarget* ApplicationCommandTarget::findFirstTargetParentComponent()
{
    if (Component* const c = dynamic_cast<Component*> (this))
        return c->findParentComponentOfClass<ApplicationCommandTarget>();

    return nullptr;
}

ApplicationCommandTarget* ApplicationCommandTarget::getTargetForCommand (const CommandID commandID)
{
    ApplicationCommandTarget* target = this;
    int depth = 0;

    while (target != nullptr)
    {
        Array<CommandID> commandIDs;
        target->getAllCommands (commandIDs);

        if (commandIDs.contains (commandID))
            return target;

        target = target->getNextCommandTarget();

        ++depth;
        jassert (depth < 100); // could be a recursive command chain??
        jassert (target != this); // definitely a recursive command chain!

        if (depth > 100 || target == this)
            break;
    }

    if (target == nullptr)
    {
        target = JUCEApplication::getInstance();

        if (target != nullptr)
        {
            Array<CommandID> commandIDs;
            target->getAllCommands (commandIDs);

            if (commandIDs.contains (commandID))
                return target;
        }
    }

    return nullptr;
}

bool ApplicationCommandTarget::isCommandActive (const CommandID commandID)
{
    ApplicationCommandInfo info (commandID);
    info.flags = ApplicationCommandInfo::isDisabled;

    getCommandInfo (commandID, info);

    return (info.flags & ApplicationCommandInfo::isDisabled) == 0;
}

//==============================================================================
bool ApplicationCommandTarget::invoke (const InvocationInfo& info, const bool async)
{
    ApplicationCommandTarget* target = this;
    int depth = 0;

    while (target != nullptr)
    {
        if (target->tryToInvoke (info, async))
            return true;

        target = target->getNextCommandTarget();

        ++depth;
        jassert (depth < 100); // could be a recursive command chain??
        jassert (target != this); // definitely a recursive command chain!

        if (depth > 100 || target == this)
            break;
    }

    if (target == nullptr)
    {
        target = JUCEApplication::getInstance();

        if (target != nullptr)
            return target->tryToInvoke (info, async);
    }

    return false;
}

bool ApplicationCommandTarget::invokeDirectly (const CommandID commandID, const bool asynchronously)
{
    ApplicationCommandTarget::InvocationInfo info (commandID);
    info.invocationMethod = ApplicationCommandTarget::InvocationInfo::direct;

    return invoke (info, asynchronously);
}

//==============================================================================
ApplicationCommandTarget::InvocationInfo::InvocationInfo (const CommandID command)
    : commandID (command),
      commandFlags (0),
      invocationMethod (direct),
      originatingComponent (nullptr),
      isKeyDown (false),
      millisecsSinceKeyPressed (0)
{
}