JUCE/modules/juce_gui_basics/commands/juce_ApplicationCommandTarget.cpp

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

   This file is part of the JUCE library.
   Copyright (c) 2013 - Raw Material Software Ltd.

   Permission is granted to use this software under the terms of either:
   a) the GPL v2 (or any later version)
   b) the Affero GPL v3

   Details of these licenses can be found at: www.gnu.org/licenses

   JUCE is distributed in the hope that it will be useful, but WITHOUT ANY
   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
   A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

   ------------------------------------------------------------------------------

   To release a closed-source product which uses JUCE, commercial licenses are
   available: visit www.juce.com for more information.

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

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

    void messageCallback()
    {
        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;
        }
        else
        {
            const bool success = perform (info);

            jassert (success);  // 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.
            return success;
        }
    }

    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)
{
}