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 string search_for_file(const string &filename)
  41 {
  42         if (!filename.empty() && filename[0] == '/') {
  43                 // Absolute path.
  44                 return filename;
  45         }
  46
  47         // Look for the file in all theme_dirs until we find one;
  48         // that will be the permanent resolution of this file, whether
  49         // it is actually valid or not.
  50         // We store errors from all the attempts, and show them
  51         // once we know we can't find any of them.
  52         vector<string> errors;
  53         for (const string &dir : global_flags.theme_dirs) {
  54                 string pathname = dir + "/" + filename;
  55                 if (access(pathname.c_str(), O_RDONLY) == 0) {
  56                         return pathname;
  57                 } else {
  58                         char buf[512];
  59                         snprintf(buf, sizeof(buf), "%s: %s", pathname.c_str(), strerror(errno));
  60                         errors.push_back(buf);
  61                 }
  62         }
  63
  64         for (const string &error : errors) {
  65                 fprintf(stderr, "%s\n", error.c_str());
  66         }
  67         return "";
  68 }
  69
  70 string search_for_file_or_die(const string &filename)
  71 {
  72         string pathname = search_for_file(filename);
  73         if (pathname.empty()) {
  74                 fprintf(stderr, "Couldn't find %s in any directory in --theme-dirs, exiting.\n",
  75                         filename.c_str());
  76                 exit(1);
  77         }
  78         return pathname;
  79 }
  80
  81 ImageInput::ImageInput(const string &filename)
  82         : movit::FlatInput({movit::COLORSPACE_sRGB, movit::GAMMA_sRGB}, movit::FORMAT_RGBA_POSTMULTIPLIED_ALPHA,
  83                            GL_UNSIGNED_BYTE, 1280, 720),  // Resolution will be overwritten.
  84           filename(filename),
  85           pathname(search_for_file_or_die(filename)),
  86           current_image(load_image(filename, pathname))
  87 {
  88         if (current_image == nullptr) {  // Could happen even though search_for_file() returned.
  89                 fprintf(stderr, "Couldn't load image, exiting.\n");
  90                 exit(1);
  91         }
  92         set_width(current_image->width);
  93         set_height(current_image->height);
  94         set_pixel_data(current_image->pixels.get());
  95 }
  96
  97 void ImageInput::set_gl_state(GLuint glsl_program_num, const string& prefix, unsigned *sampler_num)
  98 {
  99         // See if the background thread has given us a new version of our image.
 100         // Note: The old version might still be lying around in other ImageInputs
 101         // (in fact, it's likely), but at least the total amount of memory used
 102         // is bounded. Currently we don't even share textures between them,
 103         // so there's a fair amount of OpenGL memory waste anyway (the cache
 104         // is mostly there to save startup time, not RAM).
 105         {
 106                 unique_lock<mutex> lock(all_images_lock);
 107                 if (all_images[pathname] != current_image) {
 108                         current_image = all_images[pathname];
 109                         set_pixel_data(current_image->pixels.get());
 110                 }
 111         }
 112         movit::FlatInput::set_gl_state(glsl_program_num, prefix, sampler_num);
 113 }
 114
 115 shared_ptr<const ImageInput::Image> ImageInput::load_image(const string &filename, const string &pathname)
 116 {
 117         unique_lock<mutex> lock(all_images_lock);  // Held also during loading.
 118         if (all_images.count(pathname)) {
 119                 return all_images[pathname];
 120         }
 121
 122         all_images[pathname] = load_image_raw(pathname);
 123         timespec first_modified = all_images[pathname]->last_modified;
 124         update_threads[pathname] =
 125                 thread(bind(update_thread_func, filename, pathname, first_modified));
 126
 127         return all_images[pathname];
 128 }
 129
 130 shared_ptr<const ImageInput::Image> ImageInput::load_image_raw(const string &pathname)
 131 {
 132         // Note: Call before open, not after; otherwise, there's a race.
 133         // (There is now, too, but it tips the correct way. We could use fstat()
 134         // if we had the file descriptor.)
 135         struct stat buf;
 136         if (stat(pathname.c_str(), &buf) != 0) {
 137                 fprintf(stderr, "%s: Error stat-ing file\n", pathname.c_str());
 138                 return nullptr;
 139         }
 140         timespec last_modified = buf.st_mtim;
 141
 142         auto format_ctx = avformat_open_input_unique(pathname.c_str(), nullptr, nullptr);
 143         if (format_ctx == nullptr) {
 144                 fprintf(stderr, "%s: Error opening file\n", pathname.c_str());
 145                 return nullptr;
 146         }
 147
 148         if (avformat_find_stream_info(format_ctx.get(), nullptr) < 0) {
 149                 fprintf(stderr, "%s: Error finding stream info\n", pathname.c_str());
 150                 return nullptr;
 151         }
 152
 153         int stream_index = -1;
 154         for (unsigned i = 0; i < format_ctx->nb_streams; ++i) {
 155                 if (format_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
 156                         stream_index = i;
 157                         break;
 158                 }
 159         }
 160         if (stream_index == -1) {
 161                 fprintf(stderr, "%s: No video stream found\n", pathname.c_str());
 162                 return nullptr;
 163         }
 164
 165         const AVCodecParameters *codecpar = format_ctx->streams[stream_index]->codecpar;
 166         AVCodecContextWithDeleter codec_ctx = avcodec_alloc_context3_unique(nullptr);
 167         if (avcodec_parameters_to_context(codec_ctx.get(), codecpar) < 0) {
 168                 fprintf(stderr, "%s: Cannot fill codec parameters\n", pathname.c_str());
 169                 return nullptr;
 170         }
 171         AVCodec *codec = avcodec_find_decoder(codecpar->codec_id);
 172         if (codec == nullptr) {
 173                 fprintf(stderr, "%s: Cannot find decoder\n", pathname.c_str());
 174                 return nullptr;
 175         }
 176         if (avcodec_open2(codec_ctx.get(), codec, nullptr) < 0) {
 177                 fprintf(stderr, "%s: Cannot open decoder\n", pathname.c_str());
 178                 return nullptr;
 179         }
 180         unique_ptr<AVCodecContext, decltype(avcodec_close)*> codec_ctx_cleanup(
 181                 codec_ctx.get(), avcodec_close);
 182
 183         // Read packets until we have a frame or there are none left.
 184         int frame_finished = 0;
 185         AVFrameWithDeleter frame = av_frame_alloc_unique();
 186         bool eof = false;
 187         do {
 188                 AVPacket pkt;
 189                 unique_ptr<AVPacket, decltype(av_packet_unref)*> pkt_cleanup(
 190                         &pkt, av_packet_unref);
 191                 av_init_packet(&pkt);
 192                 pkt.data = nullptr;
 193                 pkt.size = 0;
 194                 if (av_read_frame(format_ctx.get(), &pkt) == 0) {
 195                         if (pkt.stream_index != stream_index) {
 196                                 continue;
 197                         }
 198                         if (avcodec_send_packet(codec_ctx.get(), &pkt) < 0) {
 199                                 fprintf(stderr, "%s: Cannot send packet to codec.\n", pathname.c_str());
 200                                 return nullptr;
 201                         }
 202                 } else {
 203                         eof = true;  // Or error, but ignore that for the time being.
 204                 }
 205
 206                 int err = avcodec_receive_frame(codec_ctx.get(), frame.get());
 207                 if (err == 0) {
 208                         frame_finished = true;
 209                         break;
 210                 } else if (err != AVERROR(EAGAIN)) {
 211                         fprintf(stderr, "%s: Cannot receive frame from codec.\n", pathname.c_str());
 212                         return nullptr;
 213                 }
 214         } while (!eof);
 215
 216         if (!frame_finished) {
 217                 fprintf(stderr, "%s: Decoder did not output frame.\n", pathname.c_str());
 218                 return nullptr;
 219         }
 220
 221         uint8_t *pic_data[4] = {nullptr};
 222         unique_ptr<uint8_t *, decltype(av_freep)*> pic_data_cleanup(
 223                 &pic_data[0], av_freep);
 224         int linesizes[4];
 225         if (av_image_alloc(pic_data, linesizes, frame->width, frame->height, AV_PIX_FMT_RGBA, 1) < 0) {
 226                 fprintf(stderr, "%s: Could not allocate picture data\n", pathname.c_str());
 227                 return nullptr;
 228         }
 229         unique_ptr<SwsContext, decltype(sws_freeContext)*> sws_ctx(
 230                 sws_getContext(frame->width, frame->height,
 231                         (AVPixelFormat)frame->format, frame->width, frame->height,
 232                         AV_PIX_FMT_RGBA, SWS_BICUBIC, nullptr, nullptr, nullptr),
 233                 sws_freeContext);
 234         if (sws_ctx == nullptr) {
 235                 fprintf(stderr, "%s: Could not create scaler context\n", pathname.c_str());
 236                 return nullptr;
 237         }
 238         sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
 239
 240         size_t len = frame->width * frame->height * 4;
 241         unique_ptr<uint8_t[]> image_data(new uint8_t[len]);
 242         av_image_copy_to_buffer(image_data.get(), len, pic_data, linesizes, AV_PIX_FMT_RGBA, frame->width, frame->height, 1);
 243
 244         shared_ptr<Image> image(new Image{unsigned(frame->width), unsigned(frame->height), move(image_data), last_modified});
 245         return image;
 246 }
 247
 248 // Fire up a thread to update the image every second.
 249 // We could do inotify, but this is good enough for now.
 250 void ImageInput::update_thread_func(const std::string &filename, const std::string &pathname, const timespec &first_modified)
 251 {
 252         char thread_name[16];
 253         snprintf(thread_name, sizeof(thread_name), "Update_%s", filename.c_str());
 254         pthread_setname_np(pthread_self(), thread_name);
 255
 256         timespec last_modified = first_modified;
 257         struct stat buf;
 258         for ( ;; ) {
 259                 {
 260                         unique_lock<mutex> lock(threads_should_quit_mu);
 261                         threads_should_quit_modified.wait_for(lock, chrono::seconds(1), []() { return threads_should_quit; });
 262                 }
 263
 264                 if (threads_should_quit) {
 265                         return;
 266                 }
 267
 268                 if (stat(pathname.c_str(), &buf) != 0) {
 269                         fprintf(stderr, "%s: Couldn't check for new version, leaving the old in place.\n", pathname.c_str());
 270                         continue;
 271                 }
 272                 if (buf.st_mtim.tv_sec == last_modified.tv_sec &&
 273                     buf.st_mtim.tv_nsec == last_modified.tv_nsec) {
 274                         // Not changed.
 275                         continue;
 276                 }
 277                 shared_ptr<const Image> image = load_image_raw(pathname);
 278                 if (image == nullptr) {
 279                         fprintf(stderr, "Couldn't load image, leaving the old in place.\n");
 280                         continue;
 281                 }
 282                 fprintf(stderr, "Loaded new version of %s from disk.\n", pathname.c_str());
 283                 unique_lock<mutex> lock(all_images_lock);
 284                 all_images[pathname] = image;
 285                 last_modified = image->last_modified;
 286         }
 287 }
 288
 289 void ImageInput::shutdown_updaters()
 290 {
 291         {
 292                 unique_lock<mutex> lock(threads_should_quit_mu);
 293                 threads_should_quit = true;
 294                 threads_should_quit_modified.notify_all();
 295         }
 296         for (auto &it : update_threads) {
 297                 it.second.join();
 298         }
 299 }
 300
 301 mutex ImageInput::all_images_lock;
 302 map<string, shared_ptr<const ImageInput::Image>> ImageInput::all_images;
 303 map<string, thread> ImageInput::update_threads;
 304 mutex ImageInput::threads_should_quit_mu;
 305 bool ImageInput::threads_should_quit = false;
 306 condition_variable ImageInput::threads_should_quit_modified;