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/PluginOcclusionSupport.h" 33 34 #include "core/HTMLNames.h" 35 #include "core/dom/Element.h" 36 #include "core/frame/FrameView.h" 37 #include "core/frame/LocalFrame.h" 38 #include "core/html/HTMLElement.h" 39 #include "core/html/HTMLFrameOwnerElement.h" 40 #include "core/rendering/RenderBox.h" 41 #include "core/rendering/RenderObject.h" 42 #include "platform/Widget.h" 43 #include "wtf/HashSet.h" 44 45 // This file provides a utility function to support rendering certain elements above plugins. 46 47 namespace blink { 48 49 static void getObjectStack(const RenderObject* ro, Vector<const RenderObject*>* roStack) 50 { 51 roStack->clear(); 52 while (ro) { 53 roStack->append(ro); 54 ro = ro->parent(); 55 } 56 } 57 58 // Returns true if stack1 is at or above stack2 59 static bool iframeIsAbovePlugin(const Vector<const RenderObject*>& iframeZstack, const Vector<const RenderObject*>& pluginZstack) 60 { 61 for (size_t i = 0; i < iframeZstack.size() && i < pluginZstack.size(); i++) { 62 // The root is at the end of these stacks. We want to iterate 63 // root-downwards so we index backwards from the end. 64 const RenderObject* ro1 = iframeZstack[iframeZstack.size() - 1 - i]; 65 const RenderObject* ro2 = pluginZstack[pluginZstack.size() - 1 - i]; 66 67 if (ro1 != ro2) { 68 // When we find nodes in the stack that are not the same, then 69 // we've found the nodes just below the lowest comment ancestor. 70 // Determine which should be on top. 71 72 // See if z-index determines an order. 73 if (ro1->style() && ro2->style()) { 74 int z1 = ro1->style()->zIndex(); 75 int z2 = ro2->style()->zIndex(); 76 if (z1 > z2) 77 return true; 78 if (z1 < z2) 79 return false; 80 } 81 82 // If the plugin does not have an explicit z-index it stacks behind the iframe. 83 // This is for maintaining compatibility with IE. 84 if (ro2->style()->position() == StaticPosition) { 85 // The 0'th elements of these RenderObject arrays represent the plugin node and 86 // the iframe. 87 const RenderObject* pluginRenderObject = pluginZstack[0]; 88 const RenderObject* iframeRenderObject = iframeZstack[0]; 89 90 if (pluginRenderObject->style() && iframeRenderObject->style()) { 91 if (pluginRenderObject->style()->zIndex() > iframeRenderObject->style()->zIndex()) 92 return false; 93 } 94 return true; 95 } 96 97 // Inspect the document order. Later order means higher stacking. 98 const RenderObject* parent = ro1->parent(); 99 if (!parent) 100 return false; 101 ASSERT(parent == ro2->parent()); 102 103 for (const RenderObject* ro = parent->slowFirstChild(); ro; ro = ro->nextSibling()) { 104 if (ro == ro1) 105 return false; 106 if (ro == ro2) 107 return true; 108 } 109 ASSERT(false); // We should have seen ro1 and ro2 by now. 110 return false; 111 } 112 } 113 return true; 114 } 115 116 static bool intersectsRect(const RenderObject* renderer, const IntRect& rect) 117 { 118 return renderer->absoluteBoundingBoxRectIgnoringTransforms().intersects(rect) 119 && (!renderer->style() || renderer->style()->visibility() == VISIBLE); 120 } 121 122 static void addToOcclusions(const RenderBox* renderer, Vector<IntRect>& occlusions) 123 { 124 IntPoint point = roundedIntPoint(renderer->localToAbsolute()); 125 IntSize size(renderer->width(), renderer->height()); 126 occlusions.append(IntRect(point, size)); 127 } 128 129 static void addTreeToOcclusions(const RenderObject* renderer, const IntRect& frameRect, Vector<IntRect>& occlusions) 130 { 131 if (!renderer) 132 return; 133 if (renderer->isBox() && intersectsRect(renderer, frameRect)) 134 addToOcclusions(toRenderBox(renderer), occlusions); 135 for (RenderObject* child = renderer->slowFirstChild(); child; child = child->nextSibling()) 136 addTreeToOcclusions(child, frameRect, occlusions); 137 } 138 139 static const Element* topLayerAncestor(const Element* element) 140 { 141 while (element && !element->isInTopLayer()) 142 element = element->parentOrShadowHostElement(); 143 return element; 144 } 145 146 // Return a set of rectangles that should not be overdrawn by the 147 // plugin ("cutouts"). This helps implement the "iframe shim" 148 // technique of overlaying a windowed plugin with content from the 149 // page. In a nutshell, iframe elements should occlude plugins when 150 // they occur higher in the stacking order. 151 void getPluginOcclusions(Element* element, Widget* parentWidget, const IntRect& frameRect, Vector<IntRect>& occlusions) 152 { 153 RenderObject* pluginNode = element->renderer(); 154 ASSERT(pluginNode); 155 if (!pluginNode->style()) 156 return; 157 Vector<const RenderObject*> pluginZstack; 158 Vector<const RenderObject*> iframeZstack; 159 getObjectStack(pluginNode, &pluginZstack); 160 161 if (!parentWidget->isFrameView()) 162 return; 163 164 FrameView* parentFrameView = toFrameView(parentWidget); 165 166 // Occlusions by iframes. 167 const HashSet<RefPtr<Widget> >* children = parentFrameView->children(); 168 for (HashSet<RefPtr<Widget> >::const_iterator it = children->begin(); it != children->end(); ++it) { 169 // We only care about FrameView's because iframes show up as FrameViews. 170 if (!(*it)->isFrameView()) 171 continue; 172 173 const FrameView* frameView = toFrameView((*it).get()); 174 // Check to make sure we can get both the element and the RenderObject 175 // for this FrameView, if we can't just move on to the next object. 176 // FIXME: Plugin occlusion by remote frames is probably broken. 177 HTMLElement* element = frameView->frame().deprecatedLocalOwner(); 178 if (!element || !element->renderer()) 179 continue; 180 181 RenderObject* iframeRenderer = element->renderer(); 182 183 if (isHTMLIFrameElement(*element) && intersectsRect(iframeRenderer, frameRect)) { 184 getObjectStack(iframeRenderer, &iframeZstack); 185 if (iframeIsAbovePlugin(iframeZstack, pluginZstack)) 186 addToOcclusions(toRenderBox(iframeRenderer), occlusions); 187 } 188 } 189 190 // Occlusions by top layer elements. 191 // FIXME: There's no handling yet for the interaction between top layer and 192 // iframes. For example, a plugin in the top layer will be occluded by an 193 // iframe. And a plugin inside an iframe in the top layer won't be respected 194 // as being in the top layer. 195 const Element* ancestor = topLayerAncestor(element); 196 Document* document = parentFrameView->frame().document(); 197 const WillBeHeapVector<RefPtrWillBeMember<Element> >& elements = document->topLayerElements(); 198 size_t start = ancestor ? elements.find(ancestor) + 1 : 0; 199 for (size_t i = start; i < elements.size(); ++i) 200 addTreeToOcclusions(elements[i]->renderer(), frameRect, occlusions); 201 } 202 203 } // namespace blink 204