Bug 918185. When Range.getBoundingClientRect/getClientRects needs a textframe for a node, create one if the textframe was optimized away. r=bz

content/base/src/nsGenericDOMDataNode.h

@@ -50,7 +50,11 @@ enum {
   // This bit is only meaningful if the NS_CACHED_TEXT_IS_ONLY_WHITESPACE
   // bit is set, and if so it indicates whether we're only whitespace or
   // not.
-  NS_TEXT_IS_ONLY_WHITESPACE =            DATA_NODE_FLAG_BIT(3)
+  NS_TEXT_IS_ONLY_WHITESPACE =            DATA_NODE_FLAG_BIT(3),
+
+  // This bit is set to indicate that we must create frames for this text node
+  // even if it's only whitespace next to a block boundary.
+  NS_CREATE_FRAME_FOR_IGNORABLE_WHITESPACE = DATA_NODE_FLAG_BIT(4)
 };
 
 // Make sure we have enough space for those bits

content/base/src/nsRange.cpp

@@ -32,6 +32,7 @@
 #include "mozilla/dom/RangeBinding.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/Likely.h"
+#include "nsCSSFrameConstructor.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
@@ -2747,12 +2748,25 @@ static void ExtractRectFromOffset(nsIFrame* aFrame,
   }
 }
 
+static nsTextFrame*
+GetTextFrameForContent(nsIContent* aContent)
+{
+  nsIPresShell* presShell = aContent->OwnerDoc()->GetShell();
+  if (presShell) {
+    nsIFrame* frame = presShell->FrameConstructor()->EnsureFrameForTextNode(
+        static_cast<nsGenericDOMDataNode*>(aContent));
+    if (frame && frame->GetType() == nsGkAtoms::textFrame) {
+      return static_cast<nsTextFrame*>(frame);
+    }
+  }
+  return nullptr;
+}
+
 static nsresult GetPartialTextRect(nsLayoutUtils::RectCallback* aCallback,
                                    nsIContent* aContent, int32_t aStartOffset, int32_t aEndOffset)
 {
-  nsIFrame* frame = aContent->GetPrimaryFrame();
-  if (frame && frame->GetType() == nsGkAtoms::textFrame) {
-    nsTextFrame* textFrame = static_cast<nsTextFrame*>(frame);
+  nsTextFrame* textFrame = GetTextFrameForContent(aContent);
+  if (textFrame) {
     nsIFrame* relativeTo = nsLayoutUtils::GetContainingBlockForClientRect(textFrame);
     for (nsTextFrame* f = textFrame; f; f = static_cast<nsTextFrame*>(f->GetNextContinuation())) {
       int32_t fstart = f->GetContentOffset(), fend = f->GetContentEnd();
@@ -2808,9 +2822,8 @@ static void CollectClientRects(nsLayoutUtils::RectCallback* aCollector,
     // the range is collapsed, only continue if the cursor is in a text node
     nsCOMPtr<nsIContent> content = do_QueryInterface(aStartParent);
     if (content && content->IsNodeOfType(nsINode::eTEXT)) {
-      nsIFrame* frame = content->GetPrimaryFrame();
-      if (frame && frame->GetType() == nsGkAtoms::textFrame) {
-        nsTextFrame* textFrame = static_cast<nsTextFrame*>(frame);
+      nsTextFrame* textFrame = GetTextFrameForContent(content);
+      if (textFrame) {
         int32_t outOffset;
         nsIFrame* outFrame;
         textFrame->GetChildFrameContainingOffset(aStartOffset, false, 

layout/base/nsCSSFrameConstructor.cpp

@@ -5433,12 +5433,16 @@ nsCSSFrameConstructor::ConstructFramesFromItem(nsFrameConstructorState& aState,
     // due to dynamic changes.
     // We don't do it for SVG text, since we might need to position and
     // measure the white space glyphs due to x/y/dx/dy attributes.
+    // We check that NS_CREATE_FRAME_FOR_IGNORABLE_WHITESPACE is not set on
+    // the node. This lets us disable this optimization for specific nodes
+    // (e.g. nodes whose geometry is being queried via DOM APIs).
     if (AtLineBoundary(aIter) &&
         !styleContext->StyleText()->WhiteSpaceOrNewlineIsSignificant() &&
         aIter.List()->ParentHasNoXBLChildren() &&
         !(aState.mAdditionalStateBits & NS_FRAME_GENERATED_CONTENT) &&
         (item.mFCData->mBits & FCDATA_IS_LINE_PARTICIPANT) &&
         !(item.mFCData->mBits & FCDATA_IS_SVG_TEXT) &&
+        !item.mContent->HasFlag(NS_CREATE_FRAME_FOR_IGNORABLE_WHITESPACE) &&
         item.IsWhitespace(aState))
       return;
 
@@ -7613,6 +7617,22 @@ InvalidateCanvasIfNeeded(nsIPresShell* presShell, nsIContent* node)
   rootFrame->InvalidateFrameSubtree();
 }
 
+nsIFrame*
+nsCSSFrameConstructor::EnsureFrameForTextNode(nsGenericDOMDataNode* aContent)
+{
+  if (aContent->HasFlag(NS_CREATE_FRAME_IF_NON_WHITESPACE) &&
+      !aContent->HasFlag(NS_CREATE_FRAME_FOR_IGNORABLE_WHITESPACE)) {
+    // Text frame may have been suppressed. Disable suppression and signal
+    // that a flush should be performed.
+    aContent->SetFlags(NS_CREATE_FRAME_FOR_IGNORABLE_WHITESPACE);
+    nsAutoScriptBlocker blocker;
+    BeginUpdate();
+    RecreateFramesForContent(aContent, false);
+    EndUpdate();
+  }
+  return aContent->GetPrimaryFrame();
+}
+
 nsresult
 nsCSSFrameConstructor::CharacterDataChanged(nsIContent* aContent,
                                             CharacterDataChangeInfo* aInfo)

layout/base/nsCSSFrameConstructor.h

@@ -31,6 +31,7 @@ struct nsGenConInitializer;
 class nsICSSAnonBoxPseudo;
 class nsPageContentFrame;
 struct PendingBinding;
+class nsGenericDOMDataNode;
 
 class nsFrameConstructorState;
 class nsFrameConstructorSaveState;
@@ -198,6 +199,13 @@ public:
   nsresult CharacterDataChanged(nsIContent* aContent,
                                 CharacterDataChangeInfo* aInfo);
 
+  // If aContent is a text node that has been optimized away due to being
+  // whitespace next to a block boundary (or for some other reason), stop
+  // doing that and create a frame for it if it should have one. This recreates
+  // frames so be careful (although this should not change actual layout).
+  // Returns the frame for aContent if there is one.
+  nsIFrame* EnsureFrameForTextNode(nsGenericDOMDataNode* aContent);
+
   // generate the child frames and process bindings
   nsresult GenerateChildFrames(nsIFrame* aFrame);
 

layout/base/tests/Makefile.in

@@ -143,6 +143,7 @@ MOCHITEST_FILES =	\
 		  bug851445_helper.html \
 		test_emulateMedium.html \
 		enableTestPlugin.js \
+		test_getClientRects_emptytext.html \
 		$(NULL)
 
 ifeq (,$(filter gonk,$(MOZ_WIDGET_TOOLKIT)))

layout/base/tests/test_getClientRects_emptytext.html

@@ -0,0 +1,26 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="/tests/SimpleTest/EventUtils.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none">
+</div>
+<div id="testDiv"> </div>
+<script>
+var textNode = testDiv.firstChild;
+var range = new Range();
+range.selectNodeContents(textNode);
+is(range.getClientRects().length, 1, "Text node should have a rectangle");
+var rect = range.getClientRects()[0];
+ok(rect.left > 0, "Rectangle x should be greater than zero");
+ok(rect.top > 0, "Rectangle y should be greater than zero");
+is(rect.width, 0, "Rectangle should be zero width");
+is(rect.height, 0, "Rectangle should be zero height");
+</script>
+</body>
+</html>