JUCE/extras/Projucer/Source/LiveBuildEngine/jucer_CompileEngineDLL.h

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

   This file is part of the JUCE 6 technical preview.
   Copyright (c) 2017 - ROLI Ltd.

   You may use this code under the terms of the GPL v3
   (see www.gnu.org/licenses).

   For this technical preview, this file is not subject to commercial licensing.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

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

#pragma once

#include "jucer_LiveCodeBuilderDLL.h"

//==============================================================================
struct CompileEngineDLL  : private DeletedAtShutdown
{
    CompileEngineDLL()
    {
        tryLoadDll();
    }

    ~CompileEngineDLL()
    {
        shutdown();
        clearSingletonInstance();
    }

    bool tryLoadDll()
    {
        // never load the dynamic lib multiple times
        if (! isLoaded())
        {
            auto f = findDLLFile();

            if (f != File() && dll.open (f.getLinkedTarget().getFullPathName()))
            {
               #define INIT_LIVE_DLL_FN(name, returnType, params)    name = (name##_type) dll.getFunction (#name);
                LIVE_DLL_FUNCTIONS (INIT_LIVE_DLL_FN);
               #undef INIT_LIVE_DLL_FN

                return true;
            }

            return false;
        }

        return true;
    }

    void initialise (CrashCallbackFunction crashFn, QuitCallbackFunction quitFn, bool setupSignals)
    {
        if (isLoaded())
            projucer_initialise (crashFn, quitFn, setPropertyCallback, getPropertyCallback, setupSignals);
    }

    void shutdown()
    {
        if (isLoaded())
            projucer_shutdown();
    }

    bool isLoaded() const
    {
        #define CHECK_LIVE_DLL_FN(name, returnType, params)    if (name == nullptr) return false;
        LIVE_DLL_FUNCTIONS (CHECK_LIVE_DLL_FN);
        #undef CHECK_LIVE_DLL_FN

        return projucer_getVersion() == requiredVersion;
    }

    #define DECLARE_LIVE_DLL_FN(name, returnType, params) \
        typedef returnType (*name##_type) params; \
        name##_type name = nullptr;

    LIVE_DLL_FUNCTIONS (DECLARE_LIVE_DLL_FN)

    #undef DECLARE_LIVE_DLL_FN

    static String getDLLName()
    {
       #if JUCE_MAC
        return "JUCECompileEngine.dylib";
       #elif JUCE_LINUX
        return "JUCECompileEngine.so";
       #elif JUCE_WINDOWS
        return "JUCECompileEngine.dll";
       #else
        #error
        return "JUCECompileEngine.so";
       #endif
    }

    static File getVersionedUserAppSupportFolder()
    {
        auto userAppData = File::getSpecialLocation (File::userApplicationDataDirectory);

       #if JUCE_MAC
        userAppData = userAppData.getChildFile ("Application Support");
       #endif

        return userAppData.getChildFile ("Projucer").getChildFile (String ("CompileEngine-") + ProjectInfo::versionString);
    }

    JUCE_DECLARE_SINGLETON (CompileEngineDLL, false)

private:
    DynamicLibrary dll;

    enum { requiredVersion = 2 };

    static File findDLLFile()
    {
        auto dllFile = File();

        if (tryFindDLLFileInAppFolder (dllFile))
            return dllFile;

       #if JUCE_MAC
        if (tryFindDLLFileInAppBundle(dllFile))
            return dllFile;
       #endif

        if (tryFindDLLFileInAppConfigFolder (dllFile))
            return dllFile;

        return {};
    }

   #if JUCE_MAC
    static bool tryFindDLLFileInAppBundle (File& outFile)
    {
        File currentAppFile (File::getSpecialLocation (File::currentApplicationFile));
        return tryFindDLLFileInFolder (currentAppFile.getChildFile ("Contents"), outFile);
    }
   #endif

    static bool tryFindDLLFileInAppFolder (File& outFile)
    {
        auto currentAppFile = File::getSpecialLocation (File::currentApplicationFile);
        return tryFindDLLFileInFolder (currentAppFile.getParentDirectory(), outFile);
    }

    static bool tryFindDLLFileInAppConfigFolder (File& outFile)
    {
        auto userAppDataFolder = getVersionedUserAppSupportFolder();
        return tryFindDLLFileInFolder (userAppDataFolder, outFile);
    }

    static bool tryFindDLLFileInFolder(File folder, File& outFile)
    {
        auto file = folder.getChildFile (getDLLName());
        if (isDLLFile (file))
        {
            outFile = file;
            return true;
        }

        return false;
    }

    static bool isDLLFile (const File& f)
    {
        return f.getFileName().equalsIgnoreCase (getDLLName()) && f.exists();
    }

    static void setPropertyCallback (const char* key, const char* value)
    {
        auto keyStr = String (key);
        if (keyStr.isNotEmpty())
            getGlobalProperties().setValue (key, value);
        else
            jassertfalse;
    }

    static void getPropertyCallback (const char* key, char* value, size_t size)
    {
        jassert (getGlobalProperties().getValue (key).getNumBytesAsUTF8() < size);

        value[0] = 0;
        getGlobalProperties().getValue (key).copyToUTF8 (value, size);
    }

    static void crashCallback (const char*) {}
    static void quitCallback() {}
};