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