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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.
*/
//
// PhotoFileAdapter
//
// PhotoFileAdapter (and its immediate children, PhotoFileReader and PhotoFileWriter) are drivers
// hiding details of reading and writing image files and their metadata. They should keep
// minimal state beyond the filename, if any stat at all. In particular, they should avoid caching
// values, especially the readers, as writers may be created at any time and invalidate that
// information, unless the readers monitor the file for these changes.
//
// PhotoFileAdapters should be entirely thread-safe. They are not, however, responsible for
// atomicity on the filesystem.
//
public abstract class PhotoFileAdapter {
private string filepath;
private PhotoFileFormat file_format;
private File file = null;
public PhotoFileAdapter(string filepath, PhotoFileFormat file_format) {
this.filepath = filepath;
this.file_format = file_format;
}
public bool file_exists() {
return FileUtils.test(filepath, FileTest.IS_REGULAR);
}
public string get_filepath() {
return filepath;
}
public File get_file() {
File result;
lock (file) {
if (file == null)
file = File.new_for_path(filepath);
result = file;
}
return result;
}
public PhotoFileFormat get_file_format() {
return file_format;
}
}
//
// PhotoFileReader
//
public abstract class PhotoFileReader : PhotoFileAdapter {
protected PhotoFileReader(string filepath, PhotoFileFormat file_format) {
base (filepath, file_format);
}
public PhotoFileWriter create_writer() throws PhotoFormatError {
return get_file_format().create_writer(get_filepath());
}
public PhotoFileMetadataWriter create_metadata_writer() throws PhotoFormatError {
return get_file_format().create_metadata_writer(get_filepath());
}
public abstract PhotoMetadata read_metadata() throws Error;
public abstract Gdk.Pixbuf unscaled_read() throws Error;
public virtual Gdk.Pixbuf scaled_read(Dimensions full, Dimensions scaled) throws Error {
return resize_pixbuf(unscaled_read(), scaled, Gdk.InterpType.BILINEAR);
}
}
//
// PhotoFileWriter
//
public abstract class PhotoFileWriter : PhotoFileAdapter {
protected PhotoFileWriter(string filepath, PhotoFileFormat file_format) {
base (filepath, file_format);
}
public PhotoFileReader create_reader() {
return get_file_format().create_reader(get_filepath());
}
public abstract void write(Gdk.Pixbuf pixbuf, Jpeg.Quality quality) throws Error;
}
//
// PhotoFileMetadataWriter
//
public abstract class PhotoFileMetadataWriter : PhotoFileAdapter {
protected PhotoFileMetadataWriter(string filepath, PhotoFileFormat file_format) {
base (filepath, file_format);
}
public PhotoFileReader create_reader() {
return get_file_format().create_reader(get_filepath());
}
public abstract void write_metadata(PhotoMetadata metadata) throws Error;
}
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