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authorJörg Frings-Fürst <debian@jff-webhosting.net>2014-07-23 09:06:59 +0200
committerJörg Frings-Fürst <debian@jff-webhosting.net>2014-07-23 09:06:59 +0200
commit4ea2cc3bd4a7d9b1c54a9d33e6a1cf82e7c8c21d (patch)
treed2e54377d14d604356c86862a326f64ae64dadd6 /src/core/DatabaseSourceCollection.vala
Imported Upstream version 0.18.1upstream/0.18.1
Diffstat (limited to 'src/core/DatabaseSourceCollection.vala')
-rw-r--r--src/core/DatabaseSourceCollection.vala86
1 files changed, 86 insertions, 0 deletions
diff --git a/src/core/DatabaseSourceCollection.vala b/src/core/DatabaseSourceCollection.vala
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+/* Copyright 2011-2014 Yorba Foundation
+ *
+ * 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);
+
+ public 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);
+ }
+}
+