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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 delegate int64 GetSourceDatabaseKey(DataSource source);
// A DatabaseSourceCollection is a SourceCollection that understands database keys (IDs) and the
// nature that a row in a database can only be instantiated once in the system, and so it tracks
// their existence in a map so they can be fetched by their key.
//
// TODO: This would be better implemented as an observer class, possibly with an interface to
// force subclasses to provide a fetch_by_key() method.
public abstract class DatabaseSourceCollection : SourceCollection {
private unowned GetSourceDatabaseKey source_key_func;
private Gee.HashMap<int64?, DataSource> map = new Gee.HashMap<int64?, DataSource>(int64_hash,
int64_equal);
protected DatabaseSourceCollection(string name, GetSourceDatabaseKey source_key_func) {
base (name);
this.source_key_func = source_key_func;
}
public override void notify_items_added(Gee.Iterable<DataObject> added) {
foreach (DataObject object in added) {
DataSource source = (DataSource) object;
int64 key = source_key_func(source);
assert(!map.has_key(key));
map.set(key, source);
}
base.notify_items_added(added);
}
public override void notify_items_removed(Gee.Iterable<DataObject> removed) {
foreach (DataObject object in removed) {
int64 key = source_key_func((DataSource) object);
bool is_removed = map.unset(key);
assert(is_removed);
}
base.notify_items_removed(removed);
}
protected DataSource fetch_by_key(int64 key) {
return map.get(key);
}
}
public class DatabaseSourceHoldingTank : SourceHoldingTank {
private unowned GetSourceDatabaseKey get_key;
private Gee.HashMap<int64?, DataSource> map = new Gee.HashMap<int64?, DataSource>(int64_hash,
int64_equal);
public DatabaseSourceHoldingTank(SourceCollection sources,
SourceHoldingTank.CheckToKeep check_to_keep, GetSourceDatabaseKey get_key) {
base (sources, check_to_keep);
this.get_key = get_key;
}
public DataSource? get_by_id(int64 id) {
return map.get(id);
}
protected override void notify_contents_altered(Gee.Collection<DataSource>? added,
Gee.Collection<DataSource>? removed) {
if (added != null) {
foreach (DataSource source in added)
map.set(get_key(source), source);
}
if (removed != null) {
foreach (DataSource source in removed)
map.unset(get_key(source));
}
base.notify_contents_altered(added, removed);
}
}
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