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

   1 #include "image_input.h"
   2
   3 #include <errno.h>
   4 #include <movit/image_format.h>
   5 #include <stdint.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <string.h>
   9
  10 extern "C" {
  11 #include <libavcodec/avcodec.h>
  12 #include <libavformat/avformat.h>
  13 #include <libavutil/avutil.h>
  14 #include <libavutil/error.h>
  15 #include <libavutil/frame.h>
  16 #include <libavutil/imgutils.h>
  17 #include <libavutil/mem.h>
  18 #include <libavutil/pixfmt.h>
  19 #include <libswscale/swscale.h>
  20 }
  21
  22 #include <fcntl.h>
  23 #include <sys/stat.h>
  24 #include <unistd.h>
  25 #include <cstddef>
  26 #include <functional>
  27 #include <mutex>
  28 #include <thread>
  29 #include <utility>
  30 #include <vector>
  31
  32 #include "ffmpeg_raii.h"
  33 #include "flags.h"
  34 #include "flat_input.h"
  35
  36 struct SwsContext;
  37
  38 using namespace std;
  39
  40 namespace {
  41
  42 string search_for_file(const string &filename)
  43 {
  44         // Look for the file in all theme_dirs until we find one;
  45         // that will be the permanent resolution of this file, whether
  46         // it is actually valid or not.
  47         // We store errors from all the attempts, and show them
  48         // once we know we can't find any of them.
  49         vector<string> errors;
  50         for (const string &dir : global_flags.theme_dirs) {
  51                 string pathname = dir + "/" + filename;
  52                 if (access(pathname.c_str(), O_RDONLY) == 0) {
  53                         return pathname;
  54                 } else {
  55                         char buf[512];
  56                         snprintf(buf, sizeof(buf), "%s: %s", pathname.c_str(), strerror(errno));
  57                         errors.push_back(buf);
  58                 }
  59         }
  60
  61         for (const string &error : errors) {
  62                 fprintf(stderr, "%s\n", error.c_str());
  63         }
  64         fprintf(stderr, "Couldn't find %s in any directory in --theme-dirs, exiting.\n",
  65                 filename.c_str());
  66         exit(1);
  67 }
  68
  69 }  // namespace
  70
  71 ImageInput::ImageInput(const string &filename)
  72         : movit::FlatInput({movit::COLORSPACE_sRGB, movit::GAMMA_sRGB}, movit::FORMAT_RGBA_POSTMULTIPLIED_ALPHA,
  73                            GL_UNSIGNED_BYTE, 1280, 720),  // Resolution will be overwritten.
  74           filename(filename),
  75           pathname(search_for_file(filename)),
  76           current_image(load_image(filename, pathname))
  77 {
  78         if (current_image == nullptr) {  // Could happen even though search_for_file() returned.
  79                 fprintf(stderr, "Couldn't load image, exiting.\n");
  80                 exit(1);
  81         }
  82         set_width(current_image->width);
  83         set_height(current_image->height);
  84         set_pixel_data(current_image->pixels.get());
  85 }
  86
  87 void ImageInput::set_gl_state(GLuint glsl_program_num, const string& prefix, unsigned *sampler_num)
  88 {
  89         // See if the background thread has given us a new version of our image.
  90         // Note: The old version might still be lying around in other ImageInputs
  91         // (in fact, it's likely), but at least the total amount of memory used
  92         // is bounded. Currently we don't even share textures between them,
  93         // so there's a fair amount of OpenGL memory waste anyway (the cache
  94         // is mostly there to save startup time, not RAM).
  95         {
  96                 unique_lock<mutex> lock(all_images_lock);
  97                 if (all_images[pathname] != current_image) {
  98                         current_image = all_images[pathname];
  99                         set_pixel_data(current_image->pixels.get());
 100                 }
 101         }
 102         movit::FlatInput::set_gl_state(glsl_program_num, prefix, sampler_num);
 103 }
 104
 105 shared_ptr<const ImageInput::Image> ImageInput::load_image(const string &filename, const string &pathname)
 106 {
 107         unique_lock<mutex> lock(all_images_lock);  // Held also during loading.
 108         if (all_images.count(pathname)) {
 109                 return all_images[pathname];
 110         }
 111
 112         all_images[pathname] = load_image_raw(pathname);
 113         timespec first_modified = all_images[pathname]->last_modified;
 114         update_threads[pathname] =
 115                 thread(bind(update_thread_func, filename, pathname, first_modified));
 116
 117         return all_images[pathname];
 118 }
 119
 120 shared_ptr<const ImageInput::Image> ImageInput::load_image_raw(const string &pathname)
 121 {
 122         // Note: Call before open, not after; otherwise, there's a race.
 123         // (There is now, too, but it tips the correct way. We could use fstat()
 124         // if we had the file descriptor.)
 125         struct stat buf;
 126         if (stat(pathname.c_str(), &buf) != 0) {
 127                 fprintf(stderr, "%s: Error stat-ing file\n", pathname.c_str());
 128                 return nullptr;
 129         }
 130         timespec last_modified = buf.st_mtim;
 131
 132         auto format_ctx = avformat_open_input_unique(pathname.c_str(), nullptr, nullptr);
 133         if (format_ctx == nullptr) {
 134                 fprintf(stderr, "%s: Error opening file\n", pathname.c_str());
 135                 return nullptr;
 136         }
 137
 138         if (avformat_find_stream_info(format_ctx.get(), nullptr) < 0) {
 139                 fprintf(stderr, "%s: Error finding stream info\n", pathname.c_str());
 140                 return nullptr;
 141         }
 142
 143         int stream_index = -1;
 144         for (unsigned i = 0; i < format_ctx->nb_streams; ++i) {
 145                 if (format_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
 146                         stream_index = i;
 147                         break;
 148                 }
 149         }
 150         if (stream_index == -1) {
 151                 fprintf(stderr, "%s: No video stream found\n", pathname.c_str());
 152                 return nullptr;
 153         }
 154
 155         const AVCodecParameters *codecpar = format_ctx->streams[stream_index]->codecpar;
 156         AVCodecContextWithDeleter codec_ctx = avcodec_alloc_context3_unique(nullptr);
 157         if (avcodec_parameters_to_context(codec_ctx.get(), codecpar) < 0) {
 158                 fprintf(stderr, "%s: Cannot fill codec parameters\n", pathname.c_str());
 159                 return nullptr;
 160         }
 161         AVCodec *codec = avcodec_find_decoder(codecpar->codec_id);
 162         if (codec == nullptr) {
 163                 fprintf(stderr, "%s: Cannot find decoder\n", pathname.c_str());
 164                 return nullptr;
 165         }
 166         if (avcodec_open2(codec_ctx.get(), codec, nullptr) < 0) {
 167                 fprintf(stderr, "%s: Cannot open decoder\n", pathname.c_str());
 168                 return nullptr;
 169         }
 170         unique_ptr<AVCodecContext, decltype(avcodec_close)*> codec_ctx_cleanup(
 171                 codec_ctx.get(), avcodec_close);
 172
 173         // Read packets until we have a frame or there are none left.
 174         int frame_finished = 0;
 175         AVFrameWithDeleter frame = av_frame_alloc_unique();
 176         bool eof = false;
 177         do {
 178                 AVPacket pkt;
 179                 unique_ptr<AVPacket, decltype(av_packet_unref)*> pkt_cleanup(
 180                         &pkt, av_packet_unref);
 181                 av_init_packet(&pkt);
 182                 pkt.data = nullptr;
 183                 pkt.size = 0;
 184                 if (av_read_frame(format_ctx.get(), &pkt) == 0) {
 185                         if (pkt.stream_index != stream_index) {
 186                                 continue;
 187                         }
 188                         if (avcodec_send_packet(codec_ctx.get(), &pkt) < 0) {
 189                                 fprintf(stderr, "%s: Cannot send packet to codec.\n", pathname.c_str());
 190                                 return nullptr;
 191                         }
 192                 } else {
 193                         eof = true;  // Or error, but ignore that for the time being.
 194                 }
 195
 196                 int err = avcodec_receive_frame(codec_ctx.get(), frame.get());
 197                 if (err == 0) {
 198                         frame_finished = true;
 199                         break;
 200                 } else if (err != AVERROR(EAGAIN)) {
 201                         fprintf(stderr, "%s: Cannot receive frame from codec.\n", pathname.c_str());
 202                         return nullptr;
 203                 }
 204         } while (!eof);
 205
 206         if (!frame_finished) {
 207                 fprintf(stderr, "%s: Decoder did not output frame.\n", pathname.c_str());
 208                 return nullptr;
 209         }
 210
 211         uint8_t *pic_data[4] = {nullptr};
 212         unique_ptr<uint8_t *, decltype(av_freep)*> pic_data_cleanup(
 213                 &pic_data[0], av_freep);
 214         int linesizes[4];
 215         if (av_image_alloc(pic_data, linesizes, frame->width, frame->height, AV_PIX_FMT_RGBA, 1) < 0) {
 216                 fprintf(stderr, "%s: Could not allocate picture data\n", pathname.c_str());
 217                 return nullptr;
 218         }
 219         unique_ptr<SwsContext, decltype(sws_freeContext)*> sws_ctx(
 220                 sws_getContext(frame->width, frame->height,
 221                         (AVPixelFormat)frame->format, frame->width, frame->height,
 222                         AV_PIX_FMT_RGBA, SWS_BICUBIC, nullptr, nullptr, nullptr),
 223                 sws_freeContext);
 224         if (sws_ctx == nullptr) {
 225                 fprintf(stderr, "%s: Could not create scaler context\n", pathname.c_str());
 226                 return nullptr;
 227         }
 228         sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
 229
 230         size_t len = frame->width * frame->height * 4;
 231         unique_ptr<uint8_t[]> image_data(new uint8_t[len]);
 232         av_image_copy_to_buffer(image_data.get(), len, pic_data, linesizes, AV_PIX_FMT_RGBA, frame->width, frame->height, 1);
 233
 234         shared_ptr<Image> image(new Image{unsigned(frame->width), unsigned(frame->height), move(image_data), last_modified});
 235         return image;
 236 }
 237
 238 // Fire up a thread to update the image every second.
 239 // We could do inotify, but this is good enough for now.
 240 void ImageInput::update_thread_func(const std::string &filename, const std::string &pathname, const timespec &first_modified)
 241 {
 242         char thread_name[16];
 243         snprintf(thread_name, sizeof(thread_name), "Update_%s", filename.c_str());
 244         pthread_setname_np(pthread_self(), thread_name);
 245
 246         timespec last_modified = first_modified;
 247         struct stat buf;
 248         for ( ;; ) {
 249                 {
 250                         unique_lock<mutex> lock(threads_should_quit_mu);
 251                         threads_should_quit_modified.wait_for(lock, chrono::seconds(1), []() { return threads_should_quit; });
 252                 }
 253
 254                 if (threads_should_quit) {
 255                         return;
 256                 }
 257
 258                 if (stat(pathname.c_str(), &buf) != 0) {
 259                         fprintf(stderr, "%s: Couldn't check for new version, leaving the old in place.\n", pathname.c_str());
 260                         continue;
 261                 }
 262                 if (buf.st_mtim.tv_sec == last_modified.tv_sec &&
 263                     buf.st_mtim.tv_nsec == last_modified.tv_nsec) {
 264                         // Not changed.
 265                         continue;
 266                 }
 267                 shared_ptr<const Image> image = load_image_raw(pathname);
 268                 if (image == nullptr) {
 269                         fprintf(stderr, "Couldn't load image, leaving the old in place.\n");
 270                         continue;
 271                 }
 272                 fprintf(stderr, "Loaded new version of %s from disk.\n", pathname.c_str());
 273                 unique_lock<mutex> lock(all_images_lock);
 274                 all_images[pathname] = image;
 275                 last_modified = image->last_modified;
 276         }
 277 }
 278
 279 void ImageInput::shutdown_updaters()
 280 {
 281         {
 282                 unique_lock<mutex> lock(threads_should_quit_mu);
 283                 threads_should_quit = true;
 284                 threads_should_quit_modified.notify_all();
 285         }
 286         for (auto &it : update_threads) {
 287                 it.second.join();
 288         }
 289 }
 290
 291 mutex ImageInput::all_images_lock;
 292 map<string, shared_ptr<const ImageInput::Image>> ImageInput::all_images;
 293 map<string, thread> ImageInput::update_threads;
 294 mutex ImageInput::threads_should_quit_mu;
 295 bool ImageInput::threads_should_quit = false;
 296 condition_variable ImageInput::threads_should_quit_modified;