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         // See if we match ^[a-z]:/, which is probably a URL of some sort
  48         // (FFmpeg understands various forms of these).
  49         for (size_t i = 0; i < filename.size() - 1; ++i) {
  50                 if (filename[i] == ':' && filename[i + 1] == '/') {
  51                         return filename;
  52                 }
  53                 if (!isalpha(filename[i])) {
  54                         break;
  55                 }
  56         }
  57
  58         // Look for the file in all theme_dirs until we find one;
  59         // that will be the permanent resolution of this file, whether
  60         // it is actually valid or not.
  61         // We store errors from all the attempts, and show them
  62         // once we know we can't find any of them.
  63         vector<string> errors;
  64         for (const string &dir : global_flags.theme_dirs) {
  65                 string pathname = dir + "/" + filename;
  66                 if (access(pathname.c_str(), O_RDONLY) == 0) {
  67                         return pathname;
  68                 } else {
  69                         char buf[512];
  70                         snprintf(buf, sizeof(buf), "%s: %s", pathname.c_str(), strerror(errno));
  71                         errors.push_back(buf);
  72                 }
  73         }
  74
  75         for (const string &error : errors) {
  76                 fprintf(stderr, "%s\n", error.c_str());
  77         }
  78         return "";
  79 }
  80
  81 string search_for_file_or_die(const string &filename)
  82 {
  83         string pathname = search_for_file(filename);
  84         if (pathname.empty()) {
  85                 fprintf(stderr, "Couldn't find %s in any directory in --theme-dirs, exiting.\n",
  86                         filename.c_str());
  87                 exit(1);
  88         }
  89         return pathname;
  90 }
  91
  92 ImageInput::ImageInput(const string &filename)
  93         : movit::FlatInput({movit::COLORSPACE_sRGB, movit::GAMMA_sRGB}, movit::FORMAT_RGBA_POSTMULTIPLIED_ALPHA,
  94                            GL_UNSIGNED_BYTE, 1280, 720),  // Resolution will be overwritten.
  95           filename(filename),
  96           pathname(search_for_file_or_die(filename)),
  97           current_image(load_image(filename, pathname))
  98 {
  99         if (current_image == nullptr) {  // Could happen even though search_for_file() returned.
 100                 fprintf(stderr, "Couldn't load image, exiting.\n");
 101                 exit(1);
 102         }
 103         set_width(current_image->width);
 104         set_height(current_image->height);
 105         set_pixel_data(current_image->pixels.get());
 106 }
 107
 108 void ImageInput::set_gl_state(GLuint glsl_program_num, const string& prefix, unsigned *sampler_num)
 109 {
 110         // See if the background thread has given us a new version of our image.
 111         // Note: The old version might still be lying around in other ImageInputs
 112         // (in fact, it's likely), but at least the total amount of memory used
 113         // is bounded. Currently we don't even share textures between them,
 114         // so there's a fair amount of OpenGL memory waste anyway (the cache
 115         // is mostly there to save startup time, not RAM).
 116         {
 117                 unique_lock<mutex> lock(all_images_lock);
 118                 if (all_images[pathname] != current_image) {
 119                         current_image = all_images[pathname];
 120                         set_pixel_data(current_image->pixels.get());
 121                 }
 122         }
 123         movit::FlatInput::set_gl_state(glsl_program_num, prefix, sampler_num);
 124 }
 125
 126 shared_ptr<const ImageInput::Image> ImageInput::load_image(const string &filename, const string &pathname)
 127 {
 128         unique_lock<mutex> lock(all_images_lock);  // Held also during loading.
 129         if (all_images.count(pathname)) {
 130                 return all_images[pathname];
 131         }
 132
 133         all_images[pathname] = load_image_raw(pathname);
 134         timespec first_modified = all_images[pathname]->last_modified;
 135         update_threads[pathname] =
 136                 thread(bind(update_thread_func, filename, pathname, first_modified));
 137
 138         return all_images[pathname];
 139 }
 140
 141 shared_ptr<const ImageInput::Image> ImageInput::load_image_raw(const string &pathname)
 142 {
 143         // Note: Call before open, not after; otherwise, there's a race.
 144         // (There is now, too, but it tips the correct way. We could use fstat()
 145         // if we had the file descriptor.)
 146         struct stat buf;
 147         if (stat(pathname.c_str(), &buf) != 0) {
 148                 fprintf(stderr, "%s: Error stat-ing file\n", pathname.c_str());
 149                 return nullptr;
 150         }
 151         timespec last_modified = buf.st_mtim;
 152
 153         auto format_ctx = avformat_open_input_unique(pathname.c_str(), nullptr, nullptr);
 154         if (format_ctx == nullptr) {
 155                 fprintf(stderr, "%s: Error opening file\n", pathname.c_str());
 156                 return nullptr;
 157         }
 158
 159         if (avformat_find_stream_info(format_ctx.get(), nullptr) < 0) {
 160                 fprintf(stderr, "%s: Error finding stream info\n", pathname.c_str());
 161                 return nullptr;
 162         }
 163
 164         int stream_index = -1;
 165         for (unsigned i = 0; i < format_ctx->nb_streams; ++i) {
 166                 if (format_ctx->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
 167                         stream_index = i;
 168                         break;
 169                 }
 170         }
 171         if (stream_index == -1) {
 172                 fprintf(stderr, "%s: No video stream found\n", pathname.c_str());
 173                 return nullptr;
 174         }
 175
 176         const AVCodecParameters *codecpar = format_ctx->streams[stream_index]->codecpar;
 177         AVCodecContextWithDeleter codec_ctx = avcodec_alloc_context3_unique(nullptr);
 178         if (avcodec_parameters_to_context(codec_ctx.get(), codecpar) < 0) {
 179                 fprintf(stderr, "%s: Cannot fill codec parameters\n", pathname.c_str());
 180                 return nullptr;
 181         }
 182         AVCodec *codec = avcodec_find_decoder(codecpar->codec_id);
 183         if (codec == nullptr) {
 184                 fprintf(stderr, "%s: Cannot find decoder\n", pathname.c_str());
 185                 return nullptr;
 186         }
 187         if (avcodec_open2(codec_ctx.get(), codec, nullptr) < 0) {
 188                 fprintf(stderr, "%s: Cannot open decoder\n", pathname.c_str());
 189                 return nullptr;
 190         }
 191         unique_ptr<AVCodecContext, decltype(avcodec_close)*> codec_ctx_cleanup(
 192                 codec_ctx.get(), avcodec_close);
 193
 194         // Read packets until we have a frame or there are none left.
 195         int frame_finished = 0;
 196         AVFrameWithDeleter frame = av_frame_alloc_unique();
 197         bool eof = false;
 198         do {
 199                 AVPacket pkt;
 200                 unique_ptr<AVPacket, decltype(av_packet_unref)*> pkt_cleanup(
 201                         &pkt, av_packet_unref);
 202                 av_init_packet(&pkt);
 203                 pkt.data = nullptr;
 204                 pkt.size = 0;
 205                 if (av_read_frame(format_ctx.get(), &pkt) == 0) {
 206                         if (pkt.stream_index != stream_index) {
 207                                 continue;
 208                         }
 209                         if (avcodec_send_packet(codec_ctx.get(), &pkt) < 0) {
 210                                 fprintf(stderr, "%s: Cannot send packet to codec.\n", pathname.c_str());
 211                                 return nullptr;
 212                         }
 213                 } else {
 214                         eof = true;  // Or error, but ignore that for the time being.
 215                 }
 216
 217                 int err = avcodec_receive_frame(codec_ctx.get(), frame.get());
 218                 if (err == 0) {
 219                         frame_finished = true;
 220                         break;
 221                 } else if (err != AVERROR(EAGAIN)) {
 222                         fprintf(stderr, "%s: Cannot receive frame from codec.\n", pathname.c_str());
 223                         return nullptr;
 224                 }
 225         } while (!eof);
 226
 227         if (!frame_finished) {
 228                 fprintf(stderr, "%s: Decoder did not output frame.\n", pathname.c_str());
 229                 return nullptr;
 230         }
 231
 232         uint8_t *pic_data[4] = {nullptr};
 233         unique_ptr<uint8_t *, decltype(av_freep)*> pic_data_cleanup(
 234                 &pic_data[0], av_freep);
 235         int linesizes[4];
 236         if (av_image_alloc(pic_data, linesizes, frame->width, frame->height, AV_PIX_FMT_RGBA, 1) < 0) {
 237                 fprintf(stderr, "%s: Could not allocate picture data\n", pathname.c_str());
 238                 return nullptr;
 239         }
 240         unique_ptr<SwsContext, decltype(sws_freeContext)*> sws_ctx(
 241                 sws_getContext(frame->width, frame->height,
 242                         (AVPixelFormat)frame->format, frame->width, frame->height,
 243                         AV_PIX_FMT_RGBA, SWS_BICUBIC, nullptr, nullptr, nullptr),
 244                 sws_freeContext);
 245         if (sws_ctx == nullptr) {
 246                 fprintf(stderr, "%s: Could not create scaler context\n", pathname.c_str());
 247                 return nullptr;
 248         }
 249         sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
 250
 251         size_t len = frame->width * frame->height * 4;
 252         unique_ptr<uint8_t[]> image_data(new uint8_t[len]);
 253         av_image_copy_to_buffer(image_data.get(), len, pic_data, linesizes, AV_PIX_FMT_RGBA, frame->width, frame->height, 1);
 254
 255         shared_ptr<Image> image(new Image{unsigned(frame->width), unsigned(frame->height), move(image_data), last_modified});
 256         return image;
 257 }
 258
 259 // Fire up a thread to update the image every second.
 260 // We could do inotify, but this is good enough for now.
 261 void ImageInput::update_thread_func(const std::string &filename, const std::string &pathname, const timespec &first_modified)
 262 {
 263         char thread_name[16];
 264         snprintf(thread_name, sizeof(thread_name), "Update_%s", filename.c_str());
 265         pthread_setname_np(pthread_self(), thread_name);
 266
 267         timespec last_modified = first_modified;
 268         struct stat buf;
 269         for ( ;; ) {
 270                 {
 271                         unique_lock<mutex> lock(threads_should_quit_mu);
 272                         threads_should_quit_modified.wait_for(lock, chrono::seconds(1), []() { return threads_should_quit; });
 273                 }
 274
 275                 if (threads_should_quit) {
 276                         return;
 277                 }
 278
 279                 if (stat(pathname.c_str(), &buf) != 0) {
 280                         fprintf(stderr, "%s: Couldn't check for new version, leaving the old in place.\n", pathname.c_str());
 281                         continue;
 282                 }
 283                 if (buf.st_mtim.tv_sec == last_modified.tv_sec &&
 284                     buf.st_mtim.tv_nsec == last_modified.tv_nsec) {
 285                         // Not changed.
 286                         continue;
 287                 }
 288                 shared_ptr<const Image> image = load_image_raw(pathname);
 289                 if (image == nullptr) {
 290                         fprintf(stderr, "Couldn't load image, leaving the old in place.\n");
 291                         continue;
 292                 }
 293                 fprintf(stderr, "Loaded new version of %s from disk.\n", pathname.c_str());
 294                 unique_lock<mutex> lock(all_images_lock);
 295                 all_images[pathname] = image;
 296                 last_modified = image->last_modified;
 297         }
 298 }
 299
 300 void ImageInput::shutdown_updaters()
 301 {
 302         {
 303                 unique_lock<mutex> lock(threads_should_quit_mu);
 304                 threads_should_quit = true;
 305                 threads_should_quit_modified.notify_all();
 306         }
 307         for (auto &it : update_threads) {
 308                 it.second.join();
 309         }
 310 }
 311
 312 mutex ImageInput::all_images_lock;
 313 map<string, shared_ptr<const ImageInput::Image>> ImageInput::all_images;
 314 map<string, thread> ImageInput::update_threads;
 315 mutex ImageInput::threads_should_quit_mu;
 316 bool ImageInput::threads_should_quit = false;
 317 condition_variable ImageInput::threads_should_quit_modified;