Add an overloaded version of findPlainText() accepting two Positions.

Source/core/editing/TextIterator.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2005 Alexey Proskuryakov.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 1459 matching lines @@
 PassRefPtr<Range> SimplifiedBackwardsTextIterator::range() const
 {
     if (m_positionNode)
         return Range::create(m_positionNode->document(), m_positionNode, m_positionStartOffset, m_positionNode, m_positionEndOffset);
 
     return Range::create(m_startNode->document(), m_startNode, m_startOffset, m_startNode, m_startOffset);
 }
 
 // --------
 
-CharacterIterator::CharacterIterator(const Range* r, TextIteratorBehaviorFlags behavior)
+CharacterIterator::CharacterIterator(const Range* range, TextIteratorBehaviorFlags behavior)
     : m_offset(0)
     , m_runOffset(0)
     , m_atBreak(true)
-    , m_textIterator(r, behavior)
+    , m_textIterator(range, behavior)
+{
+    initialize();
+}
+
+CharacterIterator::CharacterIterator(const Position& start, const Position& end, TextIteratorBehaviorFlags behavior)
+    : m_offset(0)
+    , m_runOffset(0)
+    , m_atBreak(true)
+    , m_textIterator(start, end, behavior)
+{
+    initialize();
+}
+
+void CharacterIterator::initialize()
 {
     while (!atEnd() && !m_textIterator.length())
         m_textIterator.advance();
 }
 
 PassRefPtr<Range> CharacterIterator::range() const
 {
     RefPtr<Range> r = m_textIterator.range();
     if (!m_textIterator.atEnd()) {
         if (m_textIterator.length() <= 1) {
@@ skipping 557 matching lines @@
     return builder.toString();
 }
 
 static PassRefPtr<Range> collapsedToBoundary(const Range* range, bool forward)
 {
     RefPtr<Range> result = range->cloneRange(ASSERT_NO_EXCEPTION);
     result->collapse(!forward, ASSERT_NO_EXCEPTION);
     return result.release();
 }
 
-static size_t findPlainText(CharacterIterator& it, const String& target, FindOptions options, size_t& matchStart)
+static size_t findPlainTextInternal(CharacterIterator& it, const String& target, FindOptions options, size_t& matchStart)
 {
     matchStart = 0;
     size_t matchLength = 0;
 
     SearchBuffer buffer(target, options);
 
     if (buffer.needsMoreContext()) {
         RefPtr<Range> startRange = it.range();
         RefPtr<Range> beforeStartRange = startRange->ownerDocument().createRange();
         beforeStartRange->setEnd(startRange->startContainer(), startRange->startOffset(), IGNORE_EXCEPTION);
@@ skipping 25 matching lines @@
         }
         if (it.atBreak() && !buffer.atBreak()) {
             buffer.reachedBreak();
             goto tryAgain;
         }
     }
 
     return matchLength;
 }
 
+static const TextIteratorBehaviorFlags iteratorFlagsForFindPlainText = TextIteratorEntersTextControls | TextIteratorEntersAuthorShadowRoots;
+
 PassRefPtr<Range> findPlainText(const Range* range, const String& target, FindOptions options)
 {
     // CharacterIterator requires renderers to be up-to-date
     range->ownerDocument().updateLayout();
 
     // First, find the text.
     size_t matchStart;
     size_t matchLength;
     {
-        CharacterIterator findIterator(range, TextIteratorEntersTextControls | TextIteratorEntersAuthorShadowRoots);
-        matchLength = findPlainText(findIterator, target, options, matchStart);
+        CharacterIterator findIterator(range, iteratorFlagsForFindPlainText);
+        matchLength = findPlainTextInternal(findIterator, target, options, matchStart);
         if (!matchLength)
             return collapsedToBoundary(range, !(options & Backwards));
     }
 
     // Then, find the document position of the start and the end of the text.
-    CharacterIterator computeRangeIterator(range, TextIteratorEntersTextControls | TextIteratorEntersAuthorShadowRoots);
+    CharacterIterator computeRangeIterator(range, iteratorFlagsForFindPlainText);
     return characterSubrange(computeRangeIterator, matchStart, matchLength);
 }
 
+PassRefPtr<Range> findPlainText(const Position& start, const Position& end, const String& target, FindOptions options)
+{
+    // CharacterIterator requires renderers to be up-to-date.
+    if (!start.inDocument())
+        return nullptr;
+    ASSERT(start.document() == end.document());
+    start.document()->updateLayout();
+
+    // FIXME: Reduce the code duplication with above (but how?).
+    size_t matchStart;
+    size_t matchLength;
+    {
+        CharacterIterator findIterator(start, end, iteratorFlagsForFindPlainText);
+        matchLength = findPlainTextInternal(findIterator, target, options, matchStart);
+        if (!matchLength) {
+            const Position& collapseTo = options & Backwards ? start : end;
+            return Range::create(*start.document(), collapseTo, collapseTo);
+        }
+    }
+
+    CharacterIterator computeRangeIterator(start, end, iteratorFlagsForFindPlainText);
+    return characterSubrange(computeRangeIterator, matchStart, matchLength);
+}
+
 }