git.sesse.net Git - nageru/blob - image_input.cpp

   1 #include "image_input.h"
   2
   3 #include <movit/image_format.h>
   4
   5 extern "C" {
   6 #include <libavcodec/avcodec.h>
   7 #include <libavformat/avformat.h>
   8 #include <libavutil/imgutils.h>
   9 #include <libavutil/pixfmt.h>
  10 #include <libswscale/swscale.h>
  11 }
  12
  13 #include <sys/types.h>
  14 #include <sys/stat.h>
  15 #include <unistd.h>
  16 #include <fcntl.h>
  17
  18 #include <mutex>
  19 #include <thread>
  20
  21 #include "ffmpeg_raii.h"
  22 #include "flags.h"
  23
  24 using namespace std;
  25
  26 namespace {
  27
  28 string search_for_file(const string &filename)
  29 {
  30         // Look for the file in all theme_dirs until we find one;
  31         // that will be the permanent resolution of this file, whether
  32         // it is actually valid or not.
  33         // We store errors from all the attempts, and show them
  34         // once we know we can't find any of them.
  35         vector<string> errors;
  36         for (const string &dir : global_flags.theme_dirs) {
  37                 string pathname = dir + "/" + filename;
  38                 if (access(pathname.c_str(), O_RDONLY) == 0) {
  39                         return pathname;
  40                 } else {
  41                         char buf[512];
  42                         snprintf(buf, sizeof(buf), "%s: %s", pathname.c_str(), strerror(errno));
  43                         errors.push_back(buf);
  44                 }
  45         }
  46
  47         for (const string &error : errors) {
  48                 fprintf(stderr, "%s\n", error.c_str());
  49         }
  50         fprintf(stderr, "Couldn't find %s in any directory in --theme-dirs, exiting.\n",
  51                 filename.c_str());
  52         exit(1);
  53 }
  54
  55 }  // namespace
  56
  57 ImageInput::ImageInput(const string &filename)
  58         : movit::FlatInput({movit::COLORSPACE_sRGB, movit::GAMMA_sRGB}, movit::FORMAT_RGBA_POSTMULTIPLIED_ALPHA,
  59                            GL_UNSIGNED_BYTE, 1280, 720),  // FIXME
  60           pathname(search_for_file(filename)),
  61           current_image(load_image(pathname))
  62 {
  63         if (current_image == nullptr) {  // Could happen even though search_for_file() returned.
  64                 fprintf(stderr, "Couldn't load image, exiting.\n");
  65                 exit(1);
  66         }
  67         set_pixel_data(current_image->pixels.get());
  68 }
  69
  70 void ImageInput::set_gl_state(GLuint glsl_program_num, const string& prefix, unsigned *sampler_num)
  71 {
  72         // See if the background thread has given us a new version of our image.
  73         // Note: The old version might still be lying around in other ImageInputs
  74         // (in fact, it's likely), but at least the total amount of memory used
  75         // is bounded. Currently we don't even share textures between them,
  76         // so there's a fair amount of OpenGL memory waste anyway (the cache
  77         // is mostly there to save startup time, not RAM).
  78         {
  79                 unique_lock<mutex> lock(all_images_lock);
  80                 if (all_images[pathname] != current_image) {
  81                         current_image = all_images[pathname];
  82                         set_pixel_data(current_image->pixels.get());
  83                 }
  84         }
  85         movit::FlatInput::set_gl_state(glsl_program_num, prefix, sampler_num);
  86 }
  87
  88 shared_ptr<const ImageInput::Image> ImageInput::load_image(const string &pathname)
  89 {
  90         unique_lock<mutex> lock(all_images_lock);  // Held also during loading.
  91         if (all_images.count(pathname)) {
  92                 return all_images[pathname];
  93         }
  94
  95         all_images[pathname] = load_image_raw(pathname);
  96         timespec first_modified = all_images[pathname]->last_modified;
  97         update_threads[pathname] =
  98                 thread(bind(update_thread_func, pathname, first_modified));
  99
 100         return all_images[pathname];
 101 }
 102
 103 shared_ptr<const ImageInput::Image> ImageInput::load_image_raw(const string &pathname)
 104 {
 105         // Note: Call before open, not after; otherwise, there's a race.
 106         // (There is now, too, but it tips the correct way. We could use fstat()
 107         // if we had the file descriptor.)
 108         struct stat buf;
 109         if (stat(pathname.c_str(), &buf) != 0) {
 110                 fprintf(stderr, "%s: Error stat-ing file\n", pathname.c_str());
 111                 return nullptr;
 112         }
 113         timespec last_modified = buf.st_mtim;
 114
 115         auto format_ctx = avformat_open_input_unique(pathname.c_str(), nullptr, nullptr);
 116         if (format_ctx == nullptr) {
 117                 fprintf(stderr, "%s: Error opening file\n", pathname.c_str());
 118                 return nullptr;
 119         }
 120
 121         if (avformat_find_stream_info(format_ctx.get(), nullptr) < 0) {
 122                 fprintf(stderr, "%s: Error finding stream info\n", pathname.c_str());
 123                 return nullptr;
 124         }
 125
 126         int stream_index = -1;
 127         for (unsigned i = 0; i < format_ctx->nb_streams; ++i) {
 128                 if (format_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
 129                         stream_index = i;
 130                         break;
 131                 }
 132         }
 133         if (stream_index == -1) {
 134                 fprintf(stderr, "%s: No video stream found\n", pathname.c_str());
 135                 return nullptr;
 136         }
 137
 138         const AVCodecParameters *codecpar = format_ctx->streams[stream_index]->codecpar;
 139         AVCodecContextWithDeleter codec_ctx = avcodec_alloc_context3_unique(nullptr);
 140         if (avcodec_parameters_to_context(codec_ctx.get(), codecpar) < 0) {
 141                 fprintf(stderr, "%s: Cannot fill codec parameters\n", pathname.c_str());
 142                 return nullptr;
 143         }
 144         AVCodec *codec = avcodec_find_decoder(codecpar->codec_id);
 145         if (codec == nullptr) {
 146                 fprintf(stderr, "%s: Cannot find decoder\n", pathname.c_str());
 147                 return nullptr;
 148         }
 149         if (avcodec_open2(codec_ctx.get(), codec, nullptr) < 0) {
 150                 fprintf(stderr, "%s: Cannot open decoder\n", pathname.c_str());
 151                 return nullptr;
 152         }
 153         unique_ptr<AVCodecContext, decltype(avcodec_close)*> codec_ctx_cleanup(
 154                 codec_ctx.get(), avcodec_close);
 155
 156         // Read packets until we have a frame or there are none left.
 157         int frame_finished = 0;
 158         AVFrameWithDeleter frame = av_frame_alloc_unique();
 159         bool eof = false;
 160         do {
 161                 AVPacket pkt;
 162                 unique_ptr<AVPacket, decltype(av_packet_unref)*> pkt_cleanup(
 163                         &pkt, av_packet_unref);
 164                 av_init_packet(&pkt);
 165                 pkt.data = nullptr;
 166                 pkt.size = 0;
 167                 if (av_read_frame(format_ctx.get(), &pkt) == 0) {
 168                         if (pkt.stream_index != stream_index) {
 169                                 continue;
 170                         }
 171                         if (avcodec_send_packet(codec_ctx.get(), &pkt) < 0) {
 172                                 fprintf(stderr, "%s: Cannot send packet to codec.\n", pathname.c_str());
 173                                 return nullptr;
 174                         }
 175                 } else {
 176                         eof = true;  // Or error, but ignore that for the time being.
 177                 }
 178
 179                 int err = avcodec_receive_frame(codec_ctx.get(), frame.get());
 180                 if (err == 0) {
 181                         frame_finished = true;
 182                         break;
 183                 } else if (err != AVERROR(EAGAIN)) {
 184                         fprintf(stderr, "%s: Cannot receive frame from codec.\n", pathname.c_str());
 185                         return nullptr;
 186                 }
 187         } while (!eof);
 188
 189         if (!frame_finished) {
 190                 fprintf(stderr, "%s: Decoder did not output frame.\n", pathname.c_str());
 191                 return nullptr;
 192         }
 193
 194         // TODO: Scale down if needed!
 195         uint8_t *pic_data[4] = {nullptr};
 196         unique_ptr<uint8_t *, decltype(av_freep)*> pic_data_cleanup(
 197                 &pic_data[0], av_freep);
 198         int linesizes[4];
 199         if (av_image_alloc(pic_data, linesizes, frame->width, frame->height, AV_PIX_FMT_RGBA, 1) < 0) {
 200                 fprintf(stderr, "%s: Could not allocate picture data\n", pathname.c_str());
 201                 return nullptr;
 202         }
 203         unique_ptr<SwsContext, decltype(sws_freeContext)*> sws_ctx(
 204                 sws_getContext(frame->width, frame->height,
 205                         (AVPixelFormat)frame->format, frame->width, frame->height,
 206                         AV_PIX_FMT_RGBA, SWS_BICUBIC, nullptr, nullptr, nullptr),
 207                 sws_freeContext);
 208         if (sws_ctx == nullptr) {
 209                 fprintf(stderr, "%s: Could not create scaler context\n", pathname.c_str());
 210                 return nullptr;
 211         }
 212         sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
 213
 214         size_t len = frame->width * frame->height * 4;
 215         unique_ptr<uint8_t[]> image_data(new uint8_t[len]);
 216         av_image_copy_to_buffer(image_data.get(), len, pic_data, linesizes, AV_PIX_FMT_RGBA, frame->width, frame->height, 1);
 217
 218         shared_ptr<Image> image(new Image{move(image_data), last_modified});
 219         return image;
 220 }
 221
 222 // Fire up a thread to update the image every second.
 223 // We could do inotify, but this is good enough for now.
 224 void ImageInput::update_thread_func(const std::string &pathname, const timespec &first_modified)
 225 {
 226         timespec last_modified = first_modified;
 227         struct stat buf;
 228         for ( ;; ) {
 229                 sleep(1);
 230
 231                 if (threads_should_quit) {
 232                         return;
 233                 }
 234
 235                 if (stat(pathname.c_str(), &buf) != 0) {
 236                         fprintf(stderr, "%s: Couldn't check for new version, leaving the old in place.\n", pathname.c_str());
 237                         continue;
 238                 }
 239                 if (buf.st_mtim.tv_sec == last_modified.tv_sec &&
 240                     buf.st_mtim.tv_nsec == last_modified.tv_nsec) {
 241                         // Not changed.
 242                         continue;
 243                 }
 244                 shared_ptr<const Image> image = load_image_raw(pathname);
 245                 if (image == nullptr) {
 246                         fprintf(stderr, "Couldn't load image, leaving the old in place.\n");
 247                         continue;
 248                 }
 249                 fprintf(stderr, "Loaded new version of %s from disk.\n", pathname.c_str());
 250                 unique_lock<mutex> lock(all_images_lock);
 251                 all_images[pathname] = image;
 252                 last_modified = image->last_modified;
 253         }
 254 }
 255
 256 void ImageInput::shutdown_updaters()
 257 {
 258         // TODO: Kick these out of the sleep before one second?
 259         threads_should_quit = true;
 260
 261         for (auto &it : update_threads) {
 262                 it.second.join();
 263         }
 264 }
 265
 266 mutex ImageInput::all_images_lock;
 267 map<string, shared_ptr<const ImageInput::Image>> ImageInput::all_images;
 268 map<string, thread> ImageInput::update_threads;
 269 volatile bool ImageInput::threads_should_quit = false;