From b8d216a0575fbdc5a8eeeed07a1aeda8bd83ffea Mon Sep 17 00:00:00 2001
From: fiaxh <git@lightrise.org>
Date: Sat, 14 Nov 2020 17:00:09 +0100
Subject: Add a WeakMap implementation + tests

---
 libdino/src/util/weak_map.vala | 115 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 libdino/src/util/weak_map.vala

(limited to 'libdino/src/util/weak_map.vala')

diff --git a/libdino/src/util/weak_map.vala b/libdino/src/util/weak_map.vala
new file mode 100644
index 00000000..5a89be11
--- /dev/null
+++ b/libdino/src/util/weak_map.vala
@@ -0,0 +1,115 @@
+using Gee;
+
+public class WeakMap<K, V> : Gee.AbstractMap<K, V> {
+
+    private HashMap<K, weak V> hash_map;
+    private HashMap<K, WeakNotifyWrapper> notify_map;
+
+    public WeakMap(owned HashDataFunc<K>? key_hash_func = null, owned EqualDataFunc<K>? key_equal_func = null, owned EqualDataFunc<V>? value_equal_func = null) {
+        if (!typeof(V).is_object()) {
+            error("WeakMap only takes values that are Objects");
+        }
+
+        hash_map = new HashMap<K, weak V>(key_hash_func, key_equal_func, value_equal_func);
+        notify_map = new HashMap<K, WeakNotifyWrapper>(key_hash_func, key_equal_func, value_equal_func);
+    }
+
+    public override void clear() {
+        foreach (K key in notify_map.keys) {
+            Object o = (Object) hash_map[key];
+            o.weak_unref(notify_map[key].func);
+        }
+        hash_map.clear();
+        notify_map.clear();
+    }
+
+    public override V @get(K key) {
+        if (!hash_map.has_key(key)) return null;
+
+        var v = hash_map[key];
+
+        return (owned) v;
+    }
+
+    public override bool has(K key, V value) {
+        assert_not_reached();
+    }
+
+    public override bool has_key(K key) {
+        return hash_map.has_key(key);
+    }
+
+    public override Gee.MapIterator<K,V> map_iterator() {
+        assert_not_reached();
+    }
+
+    public override void @set(K key, V value) {
+        assert(value != null);
+
+        unset(key);
+
+        Object v_obj = (Object) value;
+        var notify_wrap = new WeakNotifyWrapper((obj) => {
+            hash_map.unset(key);
+            notify_map.unset(key);
+        });
+        notify_map[key] = notify_wrap;
+        v_obj.weak_ref(notify_wrap.func);
+
+        hash_map[key] = value;
+    }
+
+    public override bool unset(K key, out V value = null) {
+        if (!hash_map.has_key(key)) return false;
+
+        Object v_obj = (Object) hash_map[key];
+        v_obj.weak_unref(notify_map[key].func);
+        notify_map.unset(key);
+        return hash_map.unset(key);
+    }
+    public override Gee.Set<Gee.Map.Entry<K,V>> entries { owned get; }
+
+    [CCode (notify = false)]
+    public Gee.EqualDataFunc<K> key_equal_func {
+        get { return hash_map.key_equal_func; }
+    }
+
+    [CCode (notify = false)]
+    public Gee.HashDataFunc<K> key_hash_func {
+        get { return hash_map.key_hash_func; }
+    }
+
+    public override Gee.Set<K> keys {
+        owned get { return hash_map.keys; }
+    }
+
+    public override bool read_only { get { assert_not_reached(); } }
+
+    public override int size { get { return hash_map.size; } }
+
+    [CCode (notify = false)]
+    public Gee.EqualDataFunc<V> value_equal_func {
+        get { return hash_map.value_equal_func; }
+    }
+
+    public override Gee.Collection<V> values {
+        owned get {
+            assert_not_reached();
+        }
+    }
+
+    public override void dispose() {
+        foreach (K key in notify_map.keys) {
+            Object o = (Object) hash_map[key];
+            o.weak_unref(notify_map[key].func);
+        }
+    }
+}
+
+internal class WeakNotifyWrapper {
+    public WeakNotify func;
+
+    public WeakNotifyWrapper(owned WeakNotify func) {
+        this.func = (owned) func;
+    }
+}
\ No newline at end of file
-- 
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