/*
 * vfs_async.cc
 * Copyright 2010-2014 Ariadne Conill and John Lindgren
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions, and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions, and the following disclaimer in the documentation
 *    provided with the distribution.
 *
 * This software is provided "as is" and without any warranty, express or
 * implied. In no event shall the authors be liable for any damages arising from
 * the use of this software.
 */

#include "vfs_async.h"
#include "list.h"
#include "mainloop.h"
#include "threads.h"
#include "vfs.h"

struct QueuedData : public ListNode
{
    const String filename;
    const VFSConsumer cons_f;

    std::thread thread;
    Index<char> buf;

    QueuedData(const char * filename, VFSConsumer cons_f)
        : filename(filename), cons_f(cons_f)
    {
    }
};

static QueuedFunc queued_func;
static List<QueuedData> queue;
static aud::mutex mutex;

static void send_data()
{
    auto mh = mutex.take();

    QueuedData * data;
    while ((data = queue.head()))
    {
        queue.remove(data);

        mh.unlock();

        data->thread.join();
        data->cons_f(data->filename, data->buf);
        delete data;

        mh.lock();
    }
}

static void read_worker(QueuedData * data)
{
    VFSFile file(data->filename, "r");
    if (file)
        data->buf = file.read_all();

    auto mh = mutex.take();

    if (!queue.head())
        queued_func.queue(send_data);

    queue.append(data);
}

EXPORT void vfs_async_file_get_contents(const char * filename,
                                        VFSConsumer cons_f)
{
    auto data = new QueuedData(filename, cons_f);
    data->thread = std::thread(read_worker, data);
}
