Bug 264412. Optimize GetRenderedText. r=mats

With these changes we're slightly faster than Chrome on the non-reflowing part of
Olli's testcase.

--HG--
extra : commitid : 75liwqsBeJY
extra : rebase_source : 34ee5d1fdfbb3b9d2ef8945f78ded935debb9106

dom/base/nsRange.cpp

@@ -3396,36 +3396,38 @@ nsRange::GetInnerTextNoFlush(DOMString& aValue, ErrorResult& aError,
       nsIContent* child = currentNode->GetFirstChild();
       if (child) {
         currentNode = child;
-      } else {
-        currentState = AFTER_NODE;
+        continue;
       }
-    } else {
-      if (isVisibleAndNotReplaced) {
-        if (currentNode->IsHTMLElement(nsGkAtoms::br)) {
+      currentState = AFTER_NODE;
+    }
+    if (currentNode == endNode && currentState == endState) {
+      break;
+    }
+    if (isVisibleAndNotReplaced) {
+      if (currentNode->IsHTMLElement(nsGkAtoms::br)) {
+        result.Append('\n');
+      }
+      switch (f->StyleDisplay()->mDisplay) {
+      case NS_STYLE_DISPLAY_TABLE_CELL:
+        if (!IsLastCellOfRow(f)) {
+          result.Append('\t');
+        }
+        break;
+      case NS_STYLE_DISPLAY_TABLE_ROW:
+        if (!IsLastRowOfRowGroup(f) ||
+            !IsLastNonemptyRowGroupOfTable(f->GetParent())) {
           result.Append('\n');
         }
-        switch (f->StyleDisplay()->mDisplay) {
-        case NS_STYLE_DISPLAY_TABLE_CELL:
-          if (!IsLastCellOfRow(f)) {
-            result.Append('\t');
-          }
-          break;
-        case NS_STYLE_DISPLAY_TABLE_ROW:
-          if (!IsLastRowOfRowGroup(f) ||
-              !IsLastNonemptyRowGroupOfTable(f->GetParent())) {
-            result.Append('\n');
-          }
-          break;
-        }
-        result.AddRequiredLineBreakCount(GetRequiredInnerTextLineBreakCount(f));
-      }
-      nsIContent* next = currentNode->GetNextSibling();
-      if (next) {
-        currentNode = next;
-        currentState = AT_NODE;
-      } else {
-        currentNode = currentNode->GetParent();
+        break;
       }
+      result.AddRequiredLineBreakCount(GetRequiredInnerTextLineBreakCount(f));
+    }
+    nsIContent* next = currentNode->GetNextSibling();
+    if (next) {
+      currentNode = next;
+      currentState = AT_NODE;
+    } else {
+      currentNode = currentNode->GetParent();
     }
   }
 

layout/generic/nsTextFrame.cpp

@@ -8948,31 +8948,37 @@ nsTextFrame::RecomputeOverflow(nsIFrame* aBlockFrame)
   return result;
 }
 
-static char16_t TransformChar(nsTextFrame* aFrame, const nsStyleText* aStyle,
-                              gfxTextRun* aTextRun, uint32_t aSkippedOffset,
-                              char16_t aChar)
+static void TransformChars(nsTextFrame* aFrame, const nsStyleText* aStyle,
+                           gfxTextRun* aTextRun, uint32_t aSkippedOffset,
+                           const nsTextFragment* aFrag, int32_t aFragOffset,
+                           int32_t aFragLen, nsAString& aOut)
 {
-  if (aChar == '\n') {
-    return aStyle->NewlineIsSignificant(aFrame) ? aChar : ' ';
-  }
-  if (aChar == '\t') {
-    return aStyle->TabIsSignificant() ? aChar : ' ';
+  aOut.SetLength(aOut.Length() + aFragLen);
+  char16_t* out = aOut.EndWriting() - aFragLen;
+  for (int32_t i = 0; i < aFragLen; ++i) {
+    char16_t ch = aFrag->CharAt(aFragOffset + i);
+    if ((ch == '\n' && !aStyle->NewlineIsSignificant(aFrame)) ||
+        (ch == '\t' && !aStyle->TabIsSignificant())) {
+      ch = ' ';
+    }
+    out[i] = ch;
   }
+
   switch (aStyle->mTextTransform) {
   case NS_STYLE_TEXT_TRANSFORM_LOWERCASE:
-    aChar = ToLowerCase(aChar);
+    ToLowerCase(out, out, aFragLen);
     break;
   case NS_STYLE_TEXT_TRANSFORM_UPPERCASE:
-    aChar = ToUpperCase(aChar);
+    ToUpperCase(out, out, aFragLen);
     break;
   case NS_STYLE_TEXT_TRANSFORM_CAPITALIZE:
-    if (aTextRun->CanBreakLineBefore(aSkippedOffset)) {
-      aChar = ToTitleCase(aChar);
+    for (int32_t i = 0; i < aFragLen; ++i) {
+      if (aTextRun->CanBreakLineBefore(aSkippedOffset + i)) {
+        out[i] = ToTitleCase(out[i]);
+      }
     }
     break;
   }
-
-  return aChar;
 }
 
 static bool
@@ -9093,18 +9099,24 @@ nsTextFrame::GetRenderedText(uint32_t aStartOffset,
     const nsStyleText* textStyle = textFrame->StyleText();
     iter.SetOriginalOffset(trimmedOffsets.mStart);
     while (iter.GetOriginalOffset() < trimmedOffsets.GetEnd()) {
-      char16_t ch = textFrag->CharAt(iter.GetOriginalOffset());
-      if (iter.IsOriginalCharSkipped()) {
-        if (ch == CH_SHY) {
-          // We should preserve soft hyphens. They can't be transformed.
-          result.mString.Append(ch);
+      int32_t runLength;
+      bool isSkipped = iter.IsOriginalCharSkipped(&runLength);
+      runLength = std::min(runLength,
+                           trimmedOffsets.GetEnd() - iter.GetOriginalOffset());
+      if (isSkipped) {
+        for (int32_t i = 0; i < runLength; ++i) {
+          char16_t ch = textFrag->CharAt(iter.GetOriginalOffset() + i);
+          if (ch == CH_SHY) {
+            // We should preserve soft hyphens. They can't be transformed.
+            result.mString.Append(ch);
+          }
         }
       } else {
-        result.mString.Append(
-              TransformChar(textFrame, textStyle, textFrame->mTextRun,
-                            iter.GetSkippedOffset(), ch));
+        TransformChars(textFrame, textStyle, textFrame->mTextRun,
+                       iter.GetSkippedOffset(), textFrag,
+                       iter.GetOriginalOffset(), runLength, result.mString);
       }
-      iter.AdvanceOriginal(1);
+      iter.AdvanceOriginal(runLength);
     }
 
     if (trimmedSignificantNewline && GetContentEnd() <= endOffset) {