video_frame_pool.cpp

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#include "config_msvc.h"
 
#include "video_frame_pool.h"
 
#include <cassert>
#include <cstdlib>             // for free, malloc
#include <condition_variable>
#include <exception>           // for exception
#include <functional>
#include <iostream>
#include <memory>
#include <mutex>
#include <queue>
#include <stdexcept>
#include <utility>
 
#include "video_codec.h"
#include "video_frame.h"
 
struct video_frame_pool::impl {
      public:
        explicit impl(
            unsigned int                      max_used_frames = 0,
            video_frame_pool_allocator const &alloc = default_data_allocator());
        ~impl();
        void                         reconfigure(struct video_desc new_desc,
                                                 size_t            new_size = SIZE_MAX);
        std::shared_ptr<video_frame> get_frame();
        struct video_frame          *get_disposable_frame();
        struct video_frame          *get_pod_frame();
        video_frame_pool_allocator const &get_allocator();
 
      private:
        void remove_free_frames();
        void deallocate_frame(struct video_frame *frame);
 
        std::unique_ptr<video_frame_pool_allocator> m_allocator = std::unique_ptr<video_frame_pool_allocator>(new default_data_allocator);
        std::queue<struct video_frame *>            m_free_frames;
        std::mutex                                  m_lock;
        std::condition_variable                     m_frame_returned;
        int                                         m_generation = 0;
        struct video_desc                           m_desc{};
        size_t                                      m_max_data_len = 0;
        unsigned int                                m_unreturned_frames = 0;
        unsigned int                                m_max_used_frames;
};
 
//                      _
//     .  _|  _  _     (_  _  _   _   _     _   _   _  |
//  \/ | (_| (- (_) __ |  |  (_| ||| (- __ |_) (_) (_) |
//                                         |
video_frame_pool &video_frame_pool::operator=(video_frame_pool &&) = default;
video_frame_pool::video_frame_pool(unsigned int max_used_frames,
                                   video_frame_pool_allocator const &alloc)
    : m_impl(std::make_unique<video_frame_pool::impl>(max_used_frames, alloc))
{
}
video_frame_pool::~video_frame_pool() = default;
void
video_frame_pool::reconfigure(struct video_desc new_desc, size_t new_size)
{
        m_impl->reconfigure(new_desc, new_size);
}
std::shared_ptr<video_frame>
video_frame_pool::get_frame()
{
        return m_impl->get_frame();
}
struct video_frame *
video_frame_pool::get_disposable_frame()
{
        return m_impl->get_disposable_frame();
}
struct video_frame *
video_frame_pool::get_pod_frame()
{
        return m_impl->get_pod_frame();
}
video_frame_pool_allocator const &
video_frame_pool::get_allocator()
{
        return m_impl->get_allocator();
}
 
//          _
//   _|  _ (_  _      | |_     _|  _  |_  _      _  | |  _   _  _  |_  _   _
//  (_| (- |  (_| |_| | |_ __ (_| (_| |_ (_| __ (_| | | (_) (_ (_| |_ (_) |
//
void *default_data_allocator::allocate(size_t size) {
        return malloc(size);
}
void default_data_allocator::deallocate(void *ptr) {
        free(ptr);
}
struct video_frame_pool_allocator *default_data_allocator::clone() const {
        return new default_data_allocator(*this);
}
 
//                      _
//     .  _|  _  _     (_  _  _   _   _     _   _   _  | . . .  _   _  |
//  \/ | (_| (- (_) __ |  |  (_| ||| (- __ |_) (_) (_) | . . | ||| |_) |
//                                         |                       |
video_frame_pool::impl::impl(unsigned int max_used_frames,
                                   video_frame_pool_allocator const &alloc)
    : m_allocator(alloc.clone()), m_max_used_frames(max_used_frames)
{
}
 
video_frame_pool::impl::~impl() {
        std::unique_lock<std::mutex> lk(m_lock);
        remove_free_frames();
        // wait also for all frames we gave out to return us
        m_frame_returned.wait(lk, [this] {return m_unreturned_frames == 0;});
}
 
void video_frame_pool::impl::reconfigure(struct video_desc new_desc, size_t new_size) {
        std::unique_lock<std::mutex> lk(m_lock);
        m_desc = new_desc;
        m_max_data_len = new_size != SIZE_MAX ? new_size : new_desc.height * vc_get_linesize(new_desc.width, new_desc.color_spec);
        remove_free_frames();
        m_generation++;
}
 
std::shared_ptr<video_frame> video_frame_pool::impl::get_frame() {
        struct video_frame *ret = NULL;
        std::unique_lock<std::mutex> lk(m_lock);
        assert(m_generation != 0);
        if (!m_free_frames.empty()) {
                ret = m_free_frames.front();
                m_free_frames.pop();
        } else if (m_max_used_frames > 0 && m_max_used_frames == m_unreturned_frames) {
                m_frame_returned.wait(lk, [this] {return m_unreturned_frames < m_max_used_frames;});
                assert(!m_free_frames.empty());
                ret = m_free_frames.front();
                m_free_frames.pop();
        } else {
                try {
                        ret = vf_alloc_desc(m_desc);
                        for (unsigned int i = 0; i < m_desc.tile_count; ++i) {
                                ret->tiles[i].data =
                                    (char *) m_allocator->allocate(
                                        m_max_data_len + MAX_PADDING);
                                if (ret->tiles[i].data == NULL) {
                                        throw std::runtime_error("Cannot allocate data");
                                }
                                ret->tiles[i].data_len = m_max_data_len;
                        }
                } catch (std::exception &e) {
                        std::cerr << e.what() << std::endl;
                        deallocate_frame(ret);
                        throw e;
                }
        }
        m_unreturned_frames += 1;
        return std::shared_ptr<video_frame>(ret, std::bind([this](struct video_frame *frame, int generation) {
                                std::unique_lock<std::mutex> lk(m_lock);
 
                                assert(m_unreturned_frames > 0);
                                m_unreturned_frames -= 1;
                                m_frame_returned.notify_one();
 
                                if (this->m_generation != generation) {
                                this->deallocate_frame(frame);
                                } else {
                                m_free_frames.push(frame);
                                }
                                }, std::placeholders::_1, m_generation));
}
 
struct video_frame *video_frame_pool::impl::get_disposable_frame() {
        auto && frame = get_frame();
        struct video_frame *out = frame.get();
        out->callbacks.dispose_udata =
            new std::shared_ptr<video_frame>(std::move(frame));
        static auto dispose = [](video_frame *f) { delete static_cast<std::shared_ptr<video_frame> *>(f->callbacks.dispose_udata); };
        out->callbacks.dispose = dispose;
        return out;
}
 
struct video_frame *video_frame_pool::impl::get_pod_frame() {
        auto && frame = get_frame();
        struct video_frame *out = vf_alloc_desc(video_desc_from_frame(frame.get()));
        for (unsigned int i = 0; i < frame->tile_count; ++i) {
                out->tiles[i].data = frame->tiles[i].data;
        }
        out->callbacks.dispose_udata =
            new std::shared_ptr<video_frame>(std::move(frame));
        static auto deleter = [](video_frame *f) { delete static_cast<std::shared_ptr<video_frame> *>(f->callbacks.dispose_udata); };
        out->callbacks.data_deleter = deleter;
        return out;
}
 
video_frame_pool_allocator const & video_frame_pool::impl::get_allocator() {
        return *m_allocator;
}
 
void video_frame_pool::impl::remove_free_frames() {
        while (!m_free_frames.empty()) {
                struct video_frame *frame = m_free_frames.front();
                m_free_frames.pop();
                deallocate_frame(frame);
        }
}
 
void video_frame_pool::impl::deallocate_frame(struct video_frame *frame) {
        if (frame == NULL)
                return;
        for (unsigned int i = 0; i < frame->tile_count; ++i) {
                m_allocator->deallocate(frame->tiles[i].data);
        }
        vf_free(frame);
}
 
//  __         __
// /      /\  |__) |
// \__   /--\ |    |
//
void *video_frame_pool_init(struct video_desc desc, int len) {
        auto *out = new video_frame_pool(len, default_data_allocator());
        out->reconfigure(desc);
        return (void *) out;
}
 
struct video_frame *video_frame_pool_get_disposable_frame(void *state) {
        auto *s = static_cast<video_frame_pool* >(state);
        return s->get_disposable_frame();
}
 
void video_frame_pool_destroy(void *state) {
        auto *s = static_cast<video_frame_pool* >(state);
        delete s;
}