moved to root

inspector/Base/IterableWeakSet.js

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+/*
+ * Copyright (C) 2022 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+ * THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+class IterableWeakSet
+{
+    constructor(items = [])
+    {
+        this._wrappers = new Set;
+        this._wrapperForItem = new WeakMap;
+
+        for (let item of items)
+            this.add(item);
+    }
+
+    // Public
+
+    get size()
+    {
+        let size = 0;
+        for (let wrapper of this._wrappers) {
+            if (wrapper.deref())
+                ++size;
+        }
+        return size;
+    }
+
+    has(item)
+    {
+        let result = this._wrapperForItem.has(item);
+        console.assert(Array.from(this._wrappers).some((wrapper) => wrapper.deref() === item) === result, this, item);
+        return result;
+    }
+
+    add(item)
+    {
+        console.assert(typeof item === "object", item);
+        console.assert(item !== null, item);
+
+        if (this.has(item))
+            return;
+
+        let wrapper = new WeakRef(item);
+        this._wrappers.add(wrapper);
+        this._wrapperForItem.set(item, wrapper);
+        this._finalizationRegistry.register(item, {weakThis: new WeakRef(this), wrapper}, wrapper);
+    }
+
+    delete(item)
+    {
+        return !!this.take(item);
+    }
+
+    take(item)
+    {
+        let wrapper = this._wrapperForItem.get(item);
+        if (!wrapper)
+            return undefined;
+
+        let itemDeleted = this._wrapperForItem.delete(item);
+        console.assert(itemDeleted, this, item);
+
+        let wrapperDeleted = this._wrappers.delete(wrapper);
+        console.assert(wrapperDeleted, this, item);
+
+        this._finalizationRegistry.unregister(wrapper);
+
+        console.assert(wrapper.deref() === item, this, item);
+        return item;
+    }
+
+    clear()
+    {
+        for (let wrapper of this._wrappers) {
+            this._wrapperForItem.delete(wrapper);
+            this._finalizationRegistry.unregister(wrapper);
+        }
+
+        this._wrappers.clear();
+    }
+
+    keys()
+    {
+        return this.values();
+    }
+
+    *values()
+    {
+        for (let wrapper of this._wrappers) {
+            let item = wrapper.deref();
+            console.assert(!item === !this._wrapperForItem.has(item), this, item);
+            if (item)
+                yield item;
+        }
+    }
+
+    [Symbol.iterator]()
+    {
+        return this.values();
+    }
+
+    copy()
+    {
+        return new IterableWeakSet(this.toJSON());
+    }
+
+    toJSON()
+    {
+        return Array.from(this);
+    }
+
+    // Private
+
+    get _finalizationRegistry()
+    {
+        return IterableWeakSet._finalizationRegistry ??= new FinalizationRegistry(function(heldValue) {
+            heldValue.weakThis.deref()?._wrappers.delete(heldValue.wrapper);
+        });
+    }
+}