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/* Copyright 2016 Software Freedom Conservancy Inc.
*
* This software is licensed under the GNU Lesser General Public License
* (version 2.1 or later). See the COPYING file in this distribution.
*/
public abstract class GdkReader : PhotoFileReader {
protected GdkReader(string filepath, PhotoFileFormat file_format) {
base (filepath, file_format);
}
public override PhotoMetadata read_metadata() throws Error {
PhotoMetadata metadata = new PhotoMetadata();
metadata.read_from_file(get_file());
return metadata;
}
public override Gdk.Pixbuf unscaled_read() throws Error {
return new Gdk.Pixbuf.from_file(get_filepath());
}
public override Gdk.Pixbuf scaled_read(Dimensions full, Dimensions scaled) throws Error {
return new Gdk.Pixbuf.from_file_at_scale(get_filepath(), scaled.width, scaled.height, false);
}
}
public abstract class GdkSniffer : PhotoFileSniffer {
private DetectedPhotoInformation detected = null;
private bool size_ready = false;
private bool area_prepared = false;
protected GdkSniffer(File file, PhotoFileSniffer.Options options) {
base (file, options);
}
public override DetectedPhotoInformation? sniff(out bool is_corrupted) throws Error {
detected = new DetectedPhotoInformation();
Gdk.PixbufLoader pixbuf_loader = new Gdk.PixbufLoader();
pixbuf_loader.size_prepared.connect(on_size_prepared);
pixbuf_loader.area_prepared.connect(on_area_prepared);
// valac chokes on the ternary operator here
Checksum? md5_checksum = null;
if (calc_md5)
md5_checksum = new Checksum(ChecksumType.MD5);
detected.metadata = new PhotoMetadata();
try {
detected.metadata.read_from_file(file);
} catch (Error err) {
// no metadata detected
detected.metadata = null;
}
if (calc_md5 && detected.metadata != null) {
detected.exif_md5 = detected.metadata.exif_hash();
detected.thumbnail_md5 = detected.metadata.thumbnail_hash();
}
// if no MD5, don't read as much, as the needed info will probably be gleaned
// in the first 8K to 16K
uint8[] buffer = calc_md5 ? new uint8[64 * 1024] : new uint8[8 * 1024];
size_t count = 0;
// loop through until all conditions we're searching for are met
FileInputStream fins = file.read(null);
for (;;) {
size_t bytes_read = fins.read(buffer, null);
if (bytes_read <= 0)
break;
count += bytes_read;
if (calc_md5)
md5_checksum.update(buffer, bytes_read);
// keep parsing the image until the size is discovered
if (!size_ready || !area_prepared)
pixbuf_loader.write(buffer[0:bytes_read]);
// if not searching for anything else, exit
if (!calc_md5 && size_ready && area_prepared)
break;
}
// PixbufLoader throws an error if you close it with an incomplete image, so trap this
try {
pixbuf_loader.close();
} catch (Error err) {
}
if (fins != null)
fins.close(null);
if (calc_md5)
detected.md5 = md5_checksum.get_string();
// if size and area are not ready, treat as corrupted file (entire file was read)
is_corrupted = !size_ready || !area_prepared;
return detected;
}
private void on_size_prepared(Gdk.PixbufLoader loader, int width, int height) {
detected.image_dim = Dimensions(width, height);
size_ready = true;
}
private void on_area_prepared(Gdk.PixbufLoader pixbuf_loader) {
Gdk.Pixbuf? pixbuf = pixbuf_loader.get_pixbuf();
if (pixbuf == null)
return;
detected.colorspace = pixbuf.get_colorspace();
detected.channels = pixbuf.get_n_channels();
detected.bits_per_channel = pixbuf.get_bits_per_sample();
unowned Gdk.PixbufFormat format = pixbuf_loader.get_format();
detected.format_name = format.get_name();
detected.file_format = PhotoFileFormat.from_pixbuf_name(detected.format_name);
area_prepared = true;
}
}
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