// // fastiv-io.c: image loaders // // Copyright (c) 2021, Přemysl Eric Janouch // // Permission to use, copy, modify, and/or distribute this software for any // purpose with or without fee is hereby granted. // // THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES // WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF // MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY // SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES // WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION // OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN // CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. // #include "config.h" #include #include #include #ifdef HAVE_LIBRAW #include #endif // HAVE_LIBRAW #ifdef HAVE_LIBRSVG #include #endif // HAVE_LIBRSVG #ifdef HAVE_GDKPIXBUF #include #include #endif // HAVE_GDKPIXBUF #define WUFFS_IMPLEMENTATION #define WUFFS_CONFIG__MODULES #define WUFFS_CONFIG__MODULE__ADLER32 #define WUFFS_CONFIG__MODULE__BASE #define WUFFS_CONFIG__MODULE__BMP #define WUFFS_CONFIG__MODULE__CRC32 #define WUFFS_CONFIG__MODULE__DEFLATE #define WUFFS_CONFIG__MODULE__GIF #define WUFFS_CONFIG__MODULE__LZW #define WUFFS_CONFIG__MODULE__PNG #define WUFFS_CONFIG__MODULE__ZLIB #include "wuffs-mirror-release-c/release/c/wuffs-v0.3.c" #include #include #include "xdg.h" #include "fastiv-io.h" // A subset of shared-mime-info that produces an appropriate list of // file extensions. Chiefly motivated by the suckiness of RAW images: // someone else will maintain the list of file extensions for us. const char *fastiv_io_supported_media_types[] = { "image/bmp", "image/gif", "image/png", "image/jpeg", #ifdef HAVE_LIBRAW "image/x-dcraw", #endif // HAVE_LIBRAW #ifdef HAVE_LIBRSVG "image/svg+xml", #endif // HAVE_LIBRSVG NULL }; // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - #define FASTIV_IO_ERROR fastiv_io_error_quark() G_DEFINE_QUARK(fastiv-io-error-quark, fastiv_io_error) enum FastivIoError { FASTIV_IO_ERROR_OPEN, }; static void set_error(GError **error, const char *message) { g_set_error_literal(error, FASTIV_IO_ERROR, FASTIV_IO_ERROR_OPEN, message); } // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - // https://github.com/google/wuffs/blob/main/example/gifplayer/gifplayer.c // is pure C, and a good reference. I can't use the auxiliary libraries, // since they depend on C++, which is undesirable. static cairo_surface_t * open_wuffs( wuffs_base__image_decoder *dec, wuffs_base__io_buffer src, GError **error) { wuffs_base__image_config cfg; wuffs_base__status status = wuffs_base__image_decoder__decode_image_config(dec, &cfg, &src); if (!wuffs_base__status__is_ok(&status)) { set_error(error, wuffs_base__status__message(&status)); return NULL; } if (!wuffs_base__image_config__is_valid(&cfg)) { set_error(error, "invalid Wuffs image configuration"); return NULL; } // We need to check because of the Cairo API. uint32_t width = wuffs_base__pixel_config__width(&cfg.pixcfg); uint32_t height = wuffs_base__pixel_config__height(&cfg.pixcfg); if (width > INT_MAX || height > INT_MAX) { set_error(error, "image dimensions overflow"); return NULL; } // CAIRO_FORMAT_ARGB32: "The 32-bit quantities are stored native-endian. // Pre-multiplied alpha is used." // CAIRO_FORMAT_RGB{24,30}: analogous, not going to use these so far. // // Wuffs: /doc/note/pixel-formats.md specifies it as "memory order", which, // for our purposes, means big endian. Currently useful formats, as per // support within wuffs_base__pixel_swizzler__prepare__*(): // - WUFFS_BASE__PIXEL_FORMAT__ARGB_PREMUL: big-endian // - WUFFS_BASE__PIXEL_FORMAT__BGRA_PREMUL: little-endian // - WUFFS_BASE__PIXEL_FORMAT__XRGB: big-endian // - WUFFS_BASE__PIXEL_FORMAT__BGRX: little-endian // // TODO(p): Make Wuffs support RGB30 as a destination format, // so far we only have WUFFS_BASE__PIXEL_FORMAT__BGRA_NONPREMUL_4X16LE // and in general, 16-bit depth swizzlers are stubbed. wuffs_base__pixel_config__set(&cfg.pixcfg, #if G_BYTE_ORDER == G_LITTLE_ENDIAN WUFFS_BASE__PIXEL_FORMAT__BGRA_PREMUL, #else WUFFS_BASE__PIXEL_FORMAT__ARGB_PREMUL, #endif WUFFS_BASE__PIXEL_SUBSAMPLING__NONE, width, height); wuffs_base__slice_u8 workbuf = {0}; uint64_t workbuf_len_max_incl = wuffs_base__image_decoder__workbuf_len(dec).max_incl; if (workbuf_len_max_incl) { workbuf = wuffs_base__malloc_slice_u8(malloc, workbuf_len_max_incl); if (!workbuf.ptr) { set_error(error, "failed to allocate a work buffer"); return NULL; } } cairo_surface_t *surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, width, height); cairo_status_t surface_status = cairo_surface_status(surface); if (surface_status != CAIRO_STATUS_SUCCESS) { set_error(error, cairo_status_to_string(surface_status)); cairo_surface_destroy(surface); free(workbuf.ptr); return NULL; } // CAIRO_STRIDE_ALIGNMENT is 4 bytes, so there will be no padding with // ARGB/BGR/XRGB/BGRX. This function does not support a stride different // from the width, maybe Wuffs internals do not either. wuffs_base__pixel_buffer pb = {0}; status = wuffs_base__pixel_buffer__set_from_slice(&pb, &cfg.pixcfg, wuffs_base__make_slice_u8(cairo_image_surface_get_data(surface), cairo_image_surface_get_stride(surface) * cairo_image_surface_get_height(surface))); if (!wuffs_base__status__is_ok(&status)) { set_error(error, wuffs_base__status__message(&status)); cairo_surface_destroy(surface); free(workbuf.ptr); return NULL; } #if 0 // We're not using this right now. wuffs_base__frame_config fc = {0}; status = wuffs_png__decoder__decode_frame_config(&dec, &fc, &src); if (!wuffs_base__status__is_ok(&status)) { set_error(error, wuffs_base__status__message(&status)); cairo_surface_destroy(surface); free(workbuf.ptr); return NULL; } #endif // Starting to modify pixel data directly. Probably an unnecessary call. cairo_surface_flush(surface); status = wuffs_base__image_decoder__decode_frame( dec, &pb, &src, WUFFS_BASE__PIXEL_BLEND__SRC, workbuf, NULL); if (!wuffs_base__status__is_ok(&status)) { set_error(error, wuffs_base__status__message(&status)); cairo_surface_destroy(surface); free(workbuf.ptr); return NULL; } // Pixel data has been written, need to let Cairo know. cairo_surface_mark_dirty(surface); free(workbuf.ptr); return surface; } static cairo_surface_t * open_wuffs_using(wuffs_base__image_decoder *(*allocate)(), const gchar *data, gsize len, GError **error) { wuffs_base__image_decoder *dec = allocate(); if (!dec) { set_error(error, "memory allocation failed or internal error"); return NULL; } cairo_surface_t *surface = open_wuffs( dec, wuffs_base__ptr_u8__reader((uint8_t *) data, len, TRUE), error); free(dec); return surface; } static void trivial_cmyk_to_bgra(unsigned char *p, int len) { // Inspired by gdk-pixbuf's io-jpeg.c: // // Assume that all YCCK/CMYK JPEG files use inverted CMYK, as Photoshop // does, see https://bugzilla.gnome.org/show_bug.cgi?id=618096 while (len--) { int c = p[0], m = p[1], y = p[2], k = p[3]; p[0] = k * y / 255; p[1] = k * m / 255; p[2] = k * c / 255; p[3] = 255; p += 4; } } static cairo_surface_t * open_libjpeg_turbo(const gchar *data, gsize len, GError **error) { tjhandle dec = tjInitDecompress(); if (!dec) { set_error(error, tjGetErrorStr2(dec)); return NULL; } int width = 0, height = 0, subsampling = TJSAMP_444, colorspace = TJCS_RGB; if (tjDecompressHeader3(dec, (const unsigned char *) data, len, &width, &height, &subsampling, &colorspace)) { set_error(error, tjGetErrorStr2(dec)); tjDestroy(dec); return NULL; } int pixel_format = (colorspace == TJCS_CMYK || colorspace == TJCS_YCCK) ? TJPF_CMYK : (G_BYTE_ORDER == G_LITTLE_ENDIAN ? TJPF_BGRA : TJPF_ARGB); cairo_surface_t *surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, width, height); cairo_status_t surface_status = cairo_surface_status(surface); if (surface_status != CAIRO_STATUS_SUCCESS) { set_error(error, cairo_status_to_string(surface_status)); cairo_surface_destroy(surface); tjDestroy(dec); return NULL; } // Starting to modify pixel data directly. Probably an unnecessary call. cairo_surface_flush(surface); int stride = cairo_image_surface_get_stride(surface); if (tjDecompress2(dec, (const unsigned char *) data, len, cairo_image_surface_get_data(surface), width, stride, height, pixel_format, TJFLAG_ACCURATEDCT)) { set_error(error, tjGetErrorStr2(dec)); cairo_surface_destroy(surface); tjDestroy(dec); return NULL; } // TODO(p): Support big-endian machines, too, those need ARGB ordering. if (pixel_format == TJPF_CMYK) { // CAIRO_STRIDE_ALIGNMENT is 4 bytes, so there will be no padding with // ARGB/BGR/XRGB/BGRX. trivial_cmyk_to_bgra( cairo_image_surface_get_data(surface), width * height); } // Pixel data has been written, need to let Cairo know. cairo_surface_mark_dirty(surface); tjDestroy(dec); return surface; } #ifdef HAVE_LIBRAW // --------------------------------------------------------- static cairo_surface_t * open_libraw(const gchar *data, gsize len, GError **error) { // https://github.com/LibRaw/LibRaw/issues/418 libraw_data_t *iprc = libraw_init( LIBRAW_OPIONS_NO_MEMERR_CALLBACK | LIBRAW_OPIONS_NO_DATAERR_CALLBACK); if (!iprc) { set_error(error, "failed to obtain a LibRaw handle"); return NULL; } #if 0 // TODO(p): Consider setting this--the image is still likely to be // rendered suboptimally, so why not make it faster. iprc->params.half_size = 1; #endif // TODO(p): Check if we need to set anything for autorotation (sizes.flip). iprc->params.use_camera_wb = 1; iprc->params.output_color = 1; // sRGB, TODO(p): Is this used? iprc->params.output_bps = 8; // This should be the default value. int err = 0; if ((err = libraw_open_buffer(iprc, (void *) data, len))) { set_error(error, libraw_strerror(err)); libraw_close(iprc); return NULL; } // TODO(p): Do we need to check iprc->idata.raw_count? Maybe for TIFFs? if ((err = libraw_unpack(iprc))) { set_error(error, libraw_strerror(err)); libraw_close(iprc); return NULL; } #if 0 // TODO(p): I'm not sure when this is necessary or useful yet. if ((err = libraw_adjust_sizes_info_only(iprc))) { set_error(error, libraw_strerror(err)); libraw_close(iprc); return NULL; } #endif // TODO(p): Documentation says I should look at the code and do it myself. if ((err = libraw_dcraw_process(iprc))) { set_error(error, libraw_strerror(err)); libraw_close(iprc); return NULL; } // FIXME: This is shittily written to iterate over the range of // idata.colors, and will be naturally slow. libraw_processed_image_t *image = libraw_dcraw_make_mem_image(iprc, &err); if (!image) { set_error(error, libraw_strerror(err)); libraw_close(iprc); return NULL; } // This should have been transformed, and kept, respectively. if (image->colors != 3 || image->bits != 8) { set_error(error, "unexpected number of colours, or bit depth"); libraw_dcraw_clear_mem(image); libraw_close(iprc); return NULL; } int width = image->width, height = image->height; cairo_surface_t *surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, width, height); cairo_status_t surface_status = cairo_surface_status(surface); if (surface_status != CAIRO_STATUS_SUCCESS) { set_error(error, cairo_status_to_string(surface_status)); cairo_surface_destroy(surface); libraw_dcraw_clear_mem(image); libraw_close(iprc); return NULL; } // Starting to modify pixel data directly. Probably an unnecessary call. cairo_surface_flush(surface); uint32_t *pixels = (uint32_t *) cairo_image_surface_get_data(surface); unsigned char *p = image->data; for (ushort y = 0; y < image->height; y++) { for (ushort x = 0; x < image->width; x++) { *pixels++ = 0xff000000 | (uint32_t) p[0] << 16 | (uint32_t) p[1] << 8 | (uint32_t) p[2]; p += 3; } } // Pixel data has been written, need to let Cairo know. cairo_surface_mark_dirty(surface); libraw_dcraw_clear_mem(image); libraw_close(iprc); return surface; } #endif // HAVE_LIBRAW --------------------------------------------------------- #ifdef HAVE_LIBRSVG // -------------------------------------------------------- #ifdef FASTIV_RSVG_DEBUG #include #include #endif // FIXME: librsvg rasterizes filters, so this method isn't fully appropriate. static cairo_surface_t * open_librsvg(const gchar *data, gsize len, const gchar *path, GError **error) { GFile *base_file = g_file_new_for_path(path); GInputStream *is = g_memory_input_stream_new_from_data(data, len, NULL); RsvgHandle *handle = rsvg_handle_new_from_stream_sync(is, base_file, RSVG_HANDLE_FLAG_KEEP_IMAGE_DATA, NULL, error); g_object_unref(base_file); g_object_unref(is); if (!handle) return NULL; // TODO(p): Acquire this from somewhere else. rsvg_handle_set_dpi(handle, 96); double w = 0, h = 0; if (!rsvg_handle_get_intrinsic_size_in_pixels(handle, &w, &h)) { RsvgRectangle viewbox = {}; gboolean has_viewport = FALSE; rsvg_handle_get_intrinsic_dimensions(handle, NULL, NULL, NULL, NULL, &has_viewport, &viewbox); if (!has_viewport) { set_error(error, "cannot compute pixel dimensions"); g_object_unref(handle); return NULL; } w = viewbox.width; h = viewbox.height; } cairo_rectangle_t extents = { .x = 0, .y = 0, .width = ceil(w), .height = ceil(h)}; cairo_surface_t *surface = cairo_recording_surface_create(CAIRO_CONTENT_COLOR_ALPHA, &extents); #ifdef FASTIV_RSVG_DEBUG cairo_device_t *script = cairo_script_create("cairo.script"); cairo_surface_t *tee = cairo_script_surface_create_for_target(script, surface); cairo_t *cr = cairo_create(tee); cairo_device_destroy(script); cairo_surface_destroy(tee); #else cairo_t *cr = cairo_create(surface); #endif RsvgRectangle viewport = {.x = 0, .y = 0, .width = w, .height = h}; if (!rsvg_handle_render_document(handle, cr, &viewport, error)) { cairo_surface_destroy(surface); cairo_destroy(cr); g_object_unref(handle); return NULL; } cairo_destroy(cr); g_object_unref(handle); #ifdef FASTIV_RSVG_DEBUG cairo_surface_t *svg = cairo_svg_surface_create("cairo.svg", w, h); cr = cairo_create(svg); cairo_set_source_surface(cr, surface, 0, 0); cairo_paint(cr); cairo_destroy(cr); cairo_surface_destroy(svg); cairo_surface_t *png = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, w * 10, h * 10); cr = cairo_create(png); cairo_scale(cr, 10, 10); cairo_set_source_surface(cr, surface, 0, 0); cairo_paint(cr); cairo_destroy(cr); cairo_surface_write_to_png(png, "cairo.png"); cairo_surface_destroy(png); #endif return surface; } #endif // HAVE_LIBRSVG -------------------------------------------------------- #ifdef HAVE_GDKPIXBUF // ------------------------------------------------------ static cairo_surface_t * open_gdkpixbuf(const gchar *data, gsize len, GError **error) { GInputStream *is = g_memory_input_stream_new_from_data(data, len, NULL); GdkPixbuf *pixbuf = gdk_pixbuf_new_from_stream(is, NULL, error); g_object_unref(is); if (!pixbuf) return NULL; cairo_surface_t *surface = gdk_cairo_surface_create_from_pixbuf(pixbuf, 1, NULL); g_object_unref(pixbuf); return surface; } #endif // HAVE_GDKPIXBUF ------------------------------------------------------ cairo_surface_t * fastiv_io_open(const gchar *path, GError **error) { // TODO(p): Don't always load everything into memory, test type first, // so that we can reject non-pictures early. Wuffs only needs the first // 16 bytes to make a guess right now. // // LibRaw poses an issue--there is no good registry for identification // of supported files. Many of them are compliant TIFF files. // The only good filtering method for RAWs are currently file extensions // extracted from shared-mime-info. // // SVG is also problematic, an unbounded search for its root element. // But problematic files can be assumed to be crafted. // // gdk-pixbuf exposes its detection data through gdk_pixbuf_get_formats(). // This may also be unbounded, as per format_check(). gchar *data = NULL; gsize len = 0; if (!g_file_get_contents(path, &data, &len, error)) return NULL; cairo_surface_t *surface = fastiv_io_open_from_data(data, len, path, error); free(data); return surface; } cairo_surface_t * fastiv_io_open_from_data(const char *data, size_t len, const gchar *path, GError **error) { wuffs_base__slice_u8 prefix = wuffs_base__make_slice_u8((uint8_t *) data, len); cairo_surface_t *surface = NULL; switch (wuffs_base__magic_number_guess_fourcc(prefix)) { case WUFFS_BASE__FOURCC__BMP: // Note that BMP can redirect into another format, // which is so far unsupported here. surface = open_wuffs_using( wuffs_bmp__decoder__alloc_as__wuffs_base__image_decoder, data, len, error); break; case WUFFS_BASE__FOURCC__GIF: surface = open_wuffs_using( wuffs_gif__decoder__alloc_as__wuffs_base__image_decoder, data, len, error); break; case WUFFS_BASE__FOURCC__PNG: surface = open_wuffs_using( wuffs_png__decoder__alloc_as__wuffs_base__image_decoder, data, len, error); break; case WUFFS_BASE__FOURCC__JPEG: surface = open_libjpeg_turbo(data, len, error); break; default: #ifdef HAVE_LIBRAW // --------------------------------------------------------- if ((surface = open_libraw(data, len, error))) break; // TODO(p): We should try to pass actual processing errors through, // notably only continue with LIBRAW_FILE_UNSUPPORTED. if (error) { g_debug("%s", (*error)->message); g_clear_error(error); } #endif // HAVE_LIBRAW --------------------------------------------------------- #ifdef HAVE_LIBRSVG // -------------------------------------------------------- if ((surface = open_librsvg(data, len, path, error))) break; // XXX: It doesn't look like librsvg can return sensible errors. if (error) { g_debug("%s", (*error)->message); g_clear_error(error); } #endif // HAVE_LIBRSVG -------------------------------------------------------- #ifdef HAVE_GDKPIXBUF // ------------------------------------------------------ // This is only used as a last resort, the rest above is special-cased. if ((surface = open_gdkpixbuf(data, len, error)) || (error && (*error)->code != GDK_PIXBUF_ERROR_UNKNOWN_TYPE)) break; if (error) { g_debug("%s", (*error)->message); g_clear_error(error); } #endif // HAVE_GDKPIXBUF ------------------------------------------------------ set_error(error, "unsupported file type"); } return surface; } // --- Thumbnails -------------------------------------------------------------- static int // tri-state check_spng_thumbnail_texts(struct spng_text *texts, uint32_t texts_len, const gchar *target, time_t mtime) { // May contain Thumb::Image::Width Thumb::Image::Height, // but those aren't interesting currently (would be for fast previews). bool need_uri = true, need_mtime = true; for (uint32_t i = 0; i < texts_len; i++) { struct spng_text *text = texts + i; if (!strcmp(text->keyword, "Thumb::URI")) { need_uri = false; if (strcmp(target, text->text)) return false; } if (!strcmp(text->keyword, "Thumb::MTime")) { need_mtime = false; if (atol(text->text) != mtime) return false; } } return need_uri || need_mtime ? -1 : true; } static int // tri-state check_spng_thumbnail(spng_ctx *ctx, const gchar *target, time_t mtime, int *err) { uint32_t texts_len = 0; if ((*err = spng_get_text(ctx, NULL, &texts_len))) return false; int result = false; struct spng_text *texts = g_malloc0_n(texts_len, sizeof *texts); if (!(*err = spng_get_text(ctx, texts, &texts_len))) result = check_spng_thumbnail_texts(texts, texts_len, target, mtime); g_free(texts); return result; } static cairo_surface_t * read_spng_thumbnail( const gchar *path, const gchar *uri, time_t mtime, GError **error) { FILE *fp; if (!(fp = fopen(path, "rb"))) { set_error(error, g_strerror(errno)); return NULL; } cairo_surface_t *result = NULL; errno = 0; spng_ctx *ctx = spng_ctx_new(0); if (!ctx) { set_error(error, g_strerror(errno)); goto fail_init; } int err; size_t size = 0; if ((err = spng_set_png_file(ctx, fp)) || (err = spng_set_image_limits(ctx, INT16_MAX, INT16_MAX)) || (err = spng_decoded_image_size(ctx, SPNG_FMT_RGBA8, &size))) { set_error(error, spng_strerror(err)); goto fail; } if (check_spng_thumbnail(ctx, uri, mtime, &err) == false) { set_error(error, err ? spng_strerror(err) : "mismatch"); goto fail; } uint32_t *data = g_malloc0(size); if ((err = spng_decode_image(ctx, data, size, SPNG_FMT_RGBA8, SPNG_DECODE_TRNS | SPNG_DECODE_GAMMA))) { set_error(error, spng_strerror(err)); goto fail_data; } // The specification does not say where the required metadata should be, // it could very well be broken up into two parts. if (check_spng_thumbnail(ctx, uri, mtime, &err) != true) { set_error( error, err ? spng_strerror(err) : "mismatch or not a thumbnail"); goto fail_data; } struct spng_ihdr ihdr = {}; spng_get_ihdr(ctx, &ihdr); cairo_surface_t *surface = cairo_image_surface_create( CAIRO_FORMAT_ARGB32, ihdr.width, ihdr.height); cairo_status_t surface_status = cairo_surface_status(surface); if (surface_status != CAIRO_STATUS_SUCCESS) { set_error(error, cairo_status_to_string(surface_status)); cairo_surface_destroy(surface); goto fail_data; } g_assert((size_t) cairo_image_surface_get_stride(surface) * cairo_image_surface_get_height(surface) == size); // pixman can be mildly abused to do this operation, but it won't be faster. uint32_t *output = (uint32_t *) cairo_image_surface_get_data(surface); cairo_surface_flush(surface); struct spng_trns trns = {}; if (ihdr.color_type == SPNG_COLOR_TYPE_GRAYSCALE_ALPHA || ihdr.color_type == SPNG_COLOR_TYPE_TRUECOLOR_ALPHA || !spng_get_trns(ctx, &trns)) { for (size_t i = size / sizeof *output; i--; ) { uint8_t *unit = (uint8_t *) &data[i], a = unit[3], b = unit[2] * a / 255, g = unit[1] * a / 255, r = unit[0] * a / 255; output[i] = a << 24 | r << 16 | g << 8 | b; } } else { for (size_t i = size / sizeof *output; i--; ) { uint8_t *unit = (uint8_t *) &data[i], a = unit[3], b = unit[2], g = unit[1], r = unit[0]; output[i] = a << 24 | r << 16 | g << 8 | b; } } cairo_surface_mark_dirty((result = surface)); fail_data: free(data); fail: spng_ctx_free(ctx); fail_init: fclose(fp); return result; } cairo_surface_t * fastiv_io_lookup_thumbnail(const gchar *target) { GStatBuf st; if (g_stat(target, &st)) return NULL; // TODO(p): Consider making the `target` an absolute path, if it isn't. // Or maybe let it fail, and document the requirement. gchar *uri = g_filename_to_uri(target, NULL, NULL); if (!uri) return NULL; gchar *sum = g_compute_checksum_for_string(G_CHECKSUM_MD5, uri, -1); gchar *cache_dir = get_xdg_home_dir("XDG_CACHE_HOME", ".cache"); cairo_surface_t *result = NULL; const gchar *sizes[] = {"large", "x-large", "xx-large", "normal"}; GError *error = NULL; for (gsize i = 0; !result && i < G_N_ELEMENTS(sizes); i++) { gchar *path = g_strdup_printf( "%s/thumbnails/%s/%s.png", cache_dir, sizes[i], sum); result = read_spng_thumbnail(path, uri, st.st_mtim.tv_sec, &error); if (error) { g_debug("%s: %s", path, error->message); g_clear_error(&error); } g_free(path); } g_free(cache_dir); g_free(sum); g_free(uri); return result; }