1 files changed, 342 insertions, 0 deletions
diff --git a/Source/WebInspectorUI/UserInterface/Views/View.js b/Source/WebInspectorUI/UserInterface/Views/View.js
new file mode 100644
index 000000000..ace04b96b
--- /dev/null
+++ b/Source/WebInspectorUI/UserInterface/Views/View.js
@@ -0,0 +1,342 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+WebInspector.View = class View extends WebInspector.Object
+{
+    constructor(element)
+    {
+        super();
+
+        this._element = element || document.createElement("div");
+        this._element.__view = this;
+        this._parentView = null;
+        this._subviews = [];
+        this._dirty = false;
+        this._dirtyDescendantsCount = 0;
+        this._needsLayoutWhenAttachedToRoot = false;
+        this._isAttachedToRoot = false;
+        this._layoutReason = null;
+        this._didInitialLayout = false;
+    }
+
+    // Static
+
+    static rootView()
+    {
+        if (!WebInspector.View._rootView)
+            WebInspector.View._rootView = new WebInspector.View(document.body);
+
+        return WebInspector.View._rootView;
+    }
+
+    // Public
+
+    get element()
+    {
+        return this._element;
+    }
+
+    get layoutPending()
+    {
+        return this._dirty;
+    }
+
+    get parentView()
+    {
+        return this._parentView;
+    }
+
+    get subviews()
+    {
+        return this._subviews;
+    }
+
+    isDescendantOf(view)
+    {
+        let parentView = this._parentView;
+        while (parentView) {
+            if (parentView === view)
+                return true;
+            parentView = parentView.parentView;
+        }
+
+        return false;
+    }
+
+    addSubview(view)
+    {
+        this.insertSubviewBefore(view, null);
+    }
+
+    insertSubviewBefore(view, referenceView)
+    {
+        console.assert(view instanceof WebInspector.View);
+        console.assert(!referenceView || referenceView instanceof WebInspector.View);
+        console.assert(view !== WebInspector.View._rootView, "Root view cannot be a subview.");
+
+        if (this._subviews.includes(view)) {
+            console.assert(false, "Cannot add view that is already a subview.", view);
+            return;
+        }
+
+        const beforeIndex = referenceView ? this._subviews.indexOf(referenceView) : this._subviews.length;
+        if (beforeIndex === -1) {
+            console.assert(false, "Cannot insert view. Invalid reference view.", referenceView);
+            return;
+        }
+
+        this._subviews.insertAtIndex(view, beforeIndex);
+
+        if (!view.element.parentNode)
+            this._element.insertBefore(view.element, referenceView ? referenceView.element : null);
+
+        view.didMoveToParent(this);
+    }
+
+    removeSubview(view)
+    {
+        console.assert(view instanceof WebInspector.View);
+        console.assert(view.element.parentNode === this._element, "Subview DOM element must be a child of the parent view element.");
+
+        if (!this._subviews.includes(view)) {
+            console.assert(false, "Cannot remove view which isn't a subview.", view);
+            return;
+        }
+
+        this._subviews.remove(view, true);
+        this._element.removeChild(view.element);
+
+        view.didMoveToParent(null);
+    }
+
+    replaceSubview(oldView, newView)
+    {
+        console.assert(oldView !== newView, "Cannot replace subview with itself.");
+
+        this.insertSubviewBefore(newView, oldView);
+        this.removeSubview(oldView);
+    }
+
+    updateLayout(layoutReason)
+    {
+        this.cancelLayout();
+
+        this._setLayoutReason(layoutReason);
+        this._layoutSubtree();
+    }
+
+    updateLayoutIfNeeded()
+    {
+        if (!this._dirty && this._didInitialLayout)
+            return;
+
+        this.updateLayout();
+    }
+
+    needsLayout(layoutReason)
+    {
+        this._setLayoutReason(layoutReason);
+
+        if (this._dirty)
+            return;
+
+        WebInspector.View._scheduleLayoutForView(this);
+    }
+
+    cancelLayout()
+    {
+        WebInspector.View._cancelScheduledLayoutForView(this);
+    }
+
+    // Protected
+
+    get layoutReason() { return this._layoutReason; }
+
+    didMoveToWindow(isAttachedToRoot)
+    {
+        this._isAttachedToRoot = isAttachedToRoot;
+
+        if (this._isAttachedToRoot && this._needsLayoutWhenAttachedToRoot) {
+            WebInspector.View._scheduleLayoutForView(this);
+            this._needsLayoutWhenAttachedToRoot = false;
+        }
+
+        for (let view of this._subviews)
+            view.didMoveToWindow(isAttachedToRoot);
+    }
+
+    didMoveToParent(parentView)
+    {
+        this._parentView = parentView;
+
+        let isAttachedToRoot = this.isDescendantOf(WebInspector.View._rootView);
+        this.didMoveToWindow(isAttachedToRoot);
+
+        if (!this._parentView)
+            return;
+
+        let pendingLayoutsCount = this._dirtyDescendantsCount;
+        if (this._dirty)
+            pendingLayoutsCount++;
+
+        let view = this._parentView;
+        while (view) {
+            view._dirtyDescendantsCount += pendingLayoutsCount;
+            view = view.parentView;
+        }
+    }
+
+    initialLayout()
+    {
+        // Implemented by subclasses.
+
+        // Called once when the view is shown for the first time.
+        // Views with complex DOM subtrees should create UI elements in
+        // initialLayout rather than at construction time.
+    }
+
+    layout()
+    {
+        // Implemented by subclasses.
+
+        // Not responsible for recursing to child views.
+        // Should not be called directly; use updateLayout() instead.
+    }
+
+    sizeDidChange()
+    {
+        // Implemented by subclasses.
+
+        // Called after initialLayout, and before layout.
+    }
+
+    // Private
+
+    _layoutSubtree()
+    {
+        this._dirty = false;
+        this._dirtyDescendantsCount = 0;
+
+        if (!this._didInitialLayout) {
+            this.initialLayout();
+            this._didInitialLayout = true;
+        }
+
+        if (this._layoutReason === WebInspector.View.LayoutReason.Resize)
+            this.sizeDidChange();
+
+        this.layout();
+
+        for (let view of this._subviews) {
+            view._setLayoutReason(this._layoutReason);
+            view._layoutSubtree();
+        }
+
+        this._layoutReason = null;
+    }
+
+    _setLayoutReason(layoutReason)
+    {
+        if (this._layoutReason === WebInspector.View.LayoutReason.Resize)
+            return;
+
+        this._layoutReason = layoutReason || WebInspector.View.LayoutReason.Dirty;
+    }
+
+    // Layout controller logic
+
+    static _scheduleLayoutForView(view)
+    {
+        view._dirty = true;
+
+        let parentView = view.parentView;
+        while (parentView) {
+            parentView._dirtyDescendantsCount++;
+            parentView = parentView.parentView;
+        }
+
+        if (!view._isAttachedToRoot) {
+            // Don't schedule layout of the view unless it is a descendant of the root view.
+            // When it moves to a rooted view tree, schedule an initial layout.
+            view._needsLayoutWhenAttachedToRoot = true;
+            return;
+        }
+
+        if (WebInspector.View._scheduledLayoutUpdateIdentifier)
+            return;
+
+        WebInspector.View._scheduledLayoutUpdateIdentifier = requestAnimationFrame(WebInspector.View._visitViewTreeForLayout);
+    }
+
+    static _cancelScheduledLayoutForView(view)
+    {
+        let cancelledLayoutsCount = view._dirtyDescendantsCount;
+        if (view.layoutPending)
+            cancelledLayoutsCount++;
+
+        let parentView = view.parentView;
+        while (parentView) {
+            parentView._dirtyDescendantsCount = Math.max(0, parentView._dirtyDescendantsCount - cancelledLayoutsCount);
+            parentView = parentView.parentView;
+        }
+
+        if (!WebInspector.View._scheduledLayoutUpdateIdentifier)
+            return;
+
+        let rootView = WebInspector.View._rootView;
+        if (!rootView || rootView._dirtyDescendantsCount)
+            return;
+
+        // No views need layout, so cancel the pending requestAnimationFrame.
+        cancelAnimationFrame(WebInspector.View._scheduledLayoutUpdateIdentifier);
+        WebInspector.View._scheduledLayoutUpdateIdentifier = undefined;
+    }
+
+    static _visitViewTreeForLayout()
+    {
+        console.assert(WebInspector.View._rootView, "Cannot layout view tree without a root.");
+
+        WebInspector.View._scheduledLayoutUpdateIdentifier = undefined;
+
+        let views = [WebInspector.View._rootView];
+        while (views.length) {
+            let view = views.shift();
+            if (view.layoutPending)
+                view._layoutSubtree();
+            else if (view._dirtyDescendantsCount) {
+                views = views.concat(view.subviews);
+                view._dirtyDescendantsCount = 0;
+            }
+        }
+    }
+};
+
+WebInspector.View.LayoutReason = {
+    Dirty: Symbol("layout-reason-dirty"),
+    Resize: Symbol("layout-reason-resize")
+};
+
+WebInspector.View._rootView = null;
+WebInspector.View._scheduledLayoutUpdateIdentifier = undefined;