Bug 429968. Handle situations where first-letter text detects first-letter style should not be applied, by creating a zero-length 'first letter'. r+sr=dbaron

--HG--
extra : rebase_source : 650611aec3adb1498dc5d8d6d38212ddf09e32fc

layout/generic/nsFirstLetterFrame.cpp

@@ -224,23 +224,26 @@ nsFirstLetterFrame::Reflow(nsPresContext*          aPresContext,
     ll.BeginLineReflow(bp.left, bp.top, availSize.width, NS_UNCONSTRAINEDSIZE,
                        PR_FALSE, PR_TRUE);
     rs.mLineLayout = ≪
+    ll.SetInFirstLetter(PR_TRUE);
     ll.SetFirstLetterStyleOK(PR_TRUE);
 
     kid->WillReflow(aPresContext);
     kid->Reflow(aPresContext, aMetrics, rs, aReflowStatus);
 
     ll.EndLineReflow();
+    ll.SetInFirstLetter(PR_FALSE);
   }
   else {
     // Pretend we are a span and reflow the child frame
     nsLineLayout* ll = aReflowState.mLineLayout;
     PRBool        pushedFrame;
 
-    NS_ASSERTION(ll->GetFirstLetterStyleOK() || GetPrevContinuation(),
-                 "First-continuation first-letter should have first-letter style enabled in nsLineLayout!");
+    ll->SetInFirstLetter(
+      mStyleContext->GetPseudoType() == nsCSSPseudoElements::firstLetter);
     ll->BeginSpan(this, &aReflowState, bp.left, availSize.width);
     ll->ReflowFrame(kid, aReflowStatus, &aMetrics, pushedFrame);
     ll->EndSpan(this);
+    ll->SetInFirstLetter(PR_FALSE);
   }
 
   // Place and size the child and update the output metrics

layout/generic/nsLineLayout.h

@@ -163,7 +163,8 @@ protected:
 #define LL_NEEDBACKUP                  0x00000400
 #define LL_INFIRSTLINE                 0x00000800
 #define LL_GOTLINEBOX                  0x00001000
-#define LL_LASTFLAG                    LL_GOTLINEBOX
+#define LL_INFIRSTLETTER               0x00002000
+#define LL_LASTFLAG                    LL_INFIRSTLETTER
 
   PRUint16 mFlags;
 
@@ -245,6 +246,14 @@ public:
     SetFlag(LL_FIRSTLETTERSTYLEOK, aSetting);
   }
 
+  PRBool GetInFirstLetter() const {
+    return GetFlag(LL_INFIRSTLETTER);
+  }
+
+  void SetInFirstLetter(PRBool aSetting) {
+    SetFlag(LL_INFIRSTLETTER, aSetting);
+  }
+
   PRBool GetInFirstLine() const {
     return GetFlag(LL_INFIRSTLINE);
   }

layout/generic/nsTextFrameThebes.cpp

@@ -5757,10 +5757,10 @@ nsTextFrame::Reflow(nsPresContext*           aPresContext,
   PRBool completedFirstLetter = PR_FALSE;
   // Layout dependent styles are a problem because we need to reconstruct
   // the gfxTextRun based on our layout.
-  if (lineLayout.GetFirstLetterStyleOK() || lineLayout.GetInFirstLine()) {
+  if (lineLayout.GetInFirstLetter() || lineLayout.GetInFirstLine()) {
     SetLength(maxContentLength);
 
-    if (lineLayout.GetFirstLetterStyleOK()) {
+    if (lineLayout.GetInFirstLetter()) {
       // floating first-letter boundaries are significant in textrun
       // construction, so clear the textrun out every time we hit a first-letter
       // and have changed our length (which controls the first-letter boundary)
@@ -5771,17 +5771,27 @@ nsTextFrame::Reflow(nsPresContext*           aPresContext,
 
       if (mTextRun) {
         PRInt32 firstLetterLength = length;
-        completedFirstLetter =
-          FindFirstLetterRange(frag, mTextRun, offset, iter, &firstLetterLength);
-        if (newLineOffset >= 0) {
-          // Don't allow a preformatted newline to be part of a first-letter.
-          firstLetterLength = PR_MIN(firstLetterLength, length - 1);
-          if (length == 1) {
-            // There is no text to be consumed by the first-letter before the
-            // preformatted newline. Note that the first letter is therefore
-            // complete (FindFirstLetterRange will have returned false).
-            completedFirstLetter = PR_TRUE;
+        if (lineLayout.GetFirstLetterStyleOK()) {
+          completedFirstLetter =
+            FindFirstLetterRange(frag, mTextRun, offset, iter, &firstLetterLength);
+          if (newLineOffset >= 0) {
+            // Don't allow a preformatted newline to be part of a first-letter.
+            firstLetterLength = PR_MIN(firstLetterLength, length - 1);
+            if (length == 1) {
+              // There is no text to be consumed by the first-letter before the
+              // preformatted newline. Note that the first letter is therefore
+              // complete (FindFirstLetterRange will have returned false).
+              completedFirstLetter = PR_TRUE;
+            }
           }
+        } else {
+          // We're in a first-letter frame's first in flow, so if there
+          // was a first-letter, we'd be it. However, for one reason
+          // or another (e.g., preformatted line break before this text),
+          // we're not actually supposed to have first-letter style. So
+          // just make a zero-length first-letter.
+          firstLetterLength = 0;
+          completedFirstLetter = PR_TRUE;
         }
         length = firstLetterLength;
         if (length) {
@@ -6049,9 +6059,6 @@ nsTextFrame::Reflow(nsPresContext*           aPresContext,
                                              eNormalBreak);
     }
   }
-  if (completedFirstLetter) {
-    lineLayout.SetFirstLetterStyleOK(PR_FALSE);
-  }
 
   // Compute reflow status
   aStatus = contentLength == maxContentLength

layout/reftests/first-letter/429968-1-ref.html

@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html>
+<head>
+<style>
+body { white-space:pre; color:black; }
+</style>
+</head>
+<body>
+AB</body>
+</html>

layout/reftests/first-letter/429968-1a.html

@@ -0,0 +1,11 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<style>
+body { white-space:pre; color:black; }
+#inner::first-letter { color:red; text-decoration:underline; font-size:200%; }
+</style>
+</head>
+<body><div id="inner"><span>
+</span>AB</div></body>
+</html>

layout/reftests/first-letter/429968-1b.html

@@ -0,0 +1,15 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<style>
+body { white-space:pre; color:blue; }
+#inner::first-letter { color:red; text-decoration:underline; font-size:200%; }
+</style>
+</head>
+<body><div id="inner"><span>
+</span>AB</div></body>
+<script>
+document.body.offsetTop;
+document.body.style.color = "black";
+</script>
+</html>

layout/reftests/first-letter/429968-2-ref.html

@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html>
+<head>
+<style>
+body { color:black; }
+span { color:lime; }
+</style>
+</head>
+<body><span>A</span>B</body>
+</html>

layout/reftests/first-letter/429968-2a.html

@@ -0,0 +1,15 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<style>
+body { white-space:pre; color:black; }
+#inner::first-letter { color:lime; }
+</style>
+</head>
+<body><div id="inner"><span id="s">
+</span>AB</div></body>
+<script>
+document.body.offsetTop;
+document.getElementById("s").textContent = "";
+</script>
+</html>

layout/reftests/first-letter/429968-2b.html

@@ -0,0 +1,15 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<style>
+body { white-space:pre; color:black; }
+#inner::first-letter { color:lime; }
+</style>
+</head>
+<body><div id="inner"><span id="s">
+</span>AB</div></body>
+<script>
+document.body.offsetTop;
+document.getElementById("s").firstChild.data = "";
+</script>
+</html>

layout/reftests/first-letter/429968-2c.html

@@ -0,0 +1,15 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+<style>
+body { white-space:pre; color:black; }
+#inner::first-letter { color:lime; }
+</style>
+</head>
+<body><div id="inner"><span id="s">
+</span>AB</div></body>
+<script>
+document.body.offsetTop;
+document.getElementById("s").style.whiteSpace = "normal";
+</script>
+</html>

layout/reftests/first-letter/reftest.list

@@ -43,5 +43,10 @@ random-if(MOZ_WIDGET_TOOLKIT=="gtk2") == 329069-1.html 329069-1-ref.html # failu
 == 399941-7.html 399941-7-ref.html
 == 399941-8.html 399941-8-ref.html
 == 399941-9.html 399941-9-ref.html
+== 429968-1a.html 429968-1-ref.html
+== 429968-1b.html 429968-1-ref.html
+== 429968-2a.html 429968-2-ref.html
+== 429968-2b.html 429968-2-ref.html
+== 429968-2c.html 429968-2-ref.html
 == 441418-1.html 441418-1-ref.html
 == 469227-1.html 469227-1-ref.html