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