1/*
2 * Copyright (C) 2011 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
8 *     * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *     * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 *     * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include "config.h"
32#include "core/plugins/IFrameShimSupport.h"
33
34#include "HTMLNames.h"
35#include "core/dom/Element.h"
36#include "core/html/HTMLElement.h"
37#include "core/html/HTMLFrameOwnerElement.h"
38#include "core/page/Frame.h"
39#include "core/page/FrameView.h"
40#include "core/platform/Widget.h"
41#include "core/rendering/RenderBox.h"
42#include "core/rendering/RenderObject.h"
43#include "wtf/HashSet.h"
44
45// This file provides plugin-related utility functions for iframe shims and is shared by platforms that inherit
46// from PluginView (e.g. Qt) and those that do not (e.g. Chromium).
47
48namespace WebCore {
49
50static void getObjectStack(const RenderObject* ro, Vector<const RenderObject*>* roStack)
51{
52    roStack->clear();
53    while (ro) {
54        roStack->append(ro);
55        ro = ro->parent();
56    }
57}
58
59// Returns true if stack1 is at or above stack2
60static bool iframeIsAbovePlugin(const Vector<const RenderObject*>& iframeZstack, const Vector<const RenderObject*>& pluginZstack)
61{
62    for (size_t i = 0; i < iframeZstack.size() && i < pluginZstack.size(); i++) {
63        // The root is at the end of these stacks.  We want to iterate
64        // root-downwards so we index backwards from the end.
65        const RenderObject* ro1 = iframeZstack[iframeZstack.size() - 1 - i];
66        const RenderObject* ro2 = pluginZstack[pluginZstack.size() - 1 - i];
67
68        if (ro1 != ro2) {
69            // When we find nodes in the stack that are not the same, then
70            // we've found the nodes just below the lowest comment ancestor.
71            // Determine which should be on top.
72
73            // See if z-index determines an order.
74            if (ro1->style() && ro2->style()) {
75                int z1 = ro1->style()->zIndex();
76                int z2 = ro2->style()->zIndex();
77                if (z1 > z2)
78                    return true;
79                if (z1 < z2)
80                    return false;
81            }
82
83            // If the plugin does not have an explicit z-index it stacks behind the iframe.
84            // This is for maintaining compatibility with IE.
85            if (ro2->style()->position() == StaticPosition) {
86                // The 0'th elements of these RenderObject arrays represent the plugin node and
87                // the iframe.
88                const RenderObject* pluginRenderObject = pluginZstack[0];
89                const RenderObject* iframeRenderObject = iframeZstack[0];
90
91                if (pluginRenderObject->style() && iframeRenderObject->style()) {
92                    if (pluginRenderObject->style()->zIndex() > iframeRenderObject->style()->zIndex())
93                        return false;
94                }
95                return true;
96            }
97
98            // Inspect the document order.  Later order means higher stacking.
99            const RenderObject* parent = ro1->parent();
100            if (!parent)
101                return false;
102            ASSERT(parent == ro2->parent());
103
104            for (const RenderObject* ro = parent->firstChild(); ro; ro = ro->nextSibling()) {
105                if (ro == ro1)
106                    return false;
107                if (ro == ro2)
108                    return true;
109            }
110            ASSERT(false); // We should have seen ro1 and ro2 by now.
111            return false;
112        }
113    }
114    return true;
115}
116
117// Return a set of rectangles that should not be overdrawn by the
118// plugin ("cutouts").  This helps implement the "iframe shim"
119// technique of overlaying a windowed plugin with content from the
120// page.  In a nutshell, iframe elements should occlude plugins when
121// they occur higher in the stacking order.
122void getPluginOcclusions(Element* element, Widget* parentWidget, const IntRect& frameRect, Vector<IntRect>& occlusions)
123{
124    RenderObject* pluginNode = element->renderer();
125    ASSERT(pluginNode);
126    if (!pluginNode->style())
127        return;
128    Vector<const RenderObject*> pluginZstack;
129    Vector<const RenderObject*> iframeZstack;
130    getObjectStack(pluginNode, &pluginZstack);
131
132    if (!parentWidget->isFrameView())
133        return;
134
135    FrameView* parentFrameView = toFrameView(parentWidget);
136
137    const HashSet<RefPtr<Widget> >* children = parentFrameView->children();
138    for (HashSet<RefPtr<Widget> >::const_iterator it = children->begin(); it != children->end(); ++it) {
139        // We only care about FrameView's because iframes show up as FrameViews.
140        if (!(*it)->isFrameView())
141            continue;
142
143        const FrameView* frameView = toFrameView((*it).get());
144        // Check to make sure we can get both the element and the RenderObject
145        // for this FrameView, if we can't just move on to the next object.
146        if (!frameView->frame() || !frameView->frame()->ownerElement()
147            || !frameView->frame()->ownerElement()->renderer())
148            continue;
149
150        HTMLElement* element = frameView->frame()->ownerElement();
151        RenderObject* iframeRenderer = element->renderer();
152
153        if (element->hasTagName(HTMLNames::iframeTag)
154            && iframeRenderer->absoluteBoundingBoxRectIgnoringTransforms().intersects(frameRect)
155            && (!iframeRenderer->style() || iframeRenderer->style()->visibility() == VISIBLE)) {
156            getObjectStack(iframeRenderer, &iframeZstack);
157            if (iframeIsAbovePlugin(iframeZstack, pluginZstack)) {
158                IntPoint point = roundedIntPoint(iframeRenderer->localToAbsolute());
159                RenderBox* rbox = toRenderBox(iframeRenderer);
160                IntSize size(rbox->width(), rbox->height());
161                occlusions.append(IntRect(point, size));
162            }
163        }
164    }
165}
166
167} // namespace WebCore
168