Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 990 insertions, 0 deletions

diff --git a/toolkit/components/find/nsFind.cpp b/toolkit/components/find/nsFind.cpp
new file mode 100644
index 0000000000..8a5c291fdf
--- /dev/null
+++ b/toolkit/components/find/nsFind.cpp
@@ -0,0 +1,990 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// #define DEBUG_FIND 1
+
+#include "nsFind.h"
+#include "mozilla/Likely.h"
+#include "nsContentCID.h"
+#include "nsIContent.h"
+#include "nsINode.h"
+#include "nsIFrame.h"
+#include "nsITextControlFrame.h"
+#include "nsIFormControl.h"
+#include "nsTextFragment.h"
+#include "nsString.h"
+#include "nsAtom.h"
+#include "nsServiceManagerUtils.h"
+#include "nsUnicharUtils.h"
+#include "nsUnicodeProperties.h"
+#include "nsCRT.h"
+#include "nsRange.h"
+#include "nsReadableUtils.h"
+#include "nsContentUtils.h"
+#include "mozilla/DebugOnly.h"
+#include "mozilla/TextEditor.h"
+#include "mozilla/dom/ChildIterator.h"
+#include "mozilla/dom/TreeIterator.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/HTMLOptionElement.h"
+#include "mozilla/dom/HTMLSelectElement.h"
+#include "mozilla/dom/Text.h"
+#include "mozilla/intl/Segmenter.h"
+#include "mozilla/intl/UnicodeProperties.h"
+#include "mozilla/StaticPrefs_browser.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+using namespace mozilla::unicode;
+
+// Yikes!  Casting a char to unichar can fill with ones!
+#define CHAR_TO_UNICHAR(c) ((char16_t)(unsigned char)c)
+
+#define CH_SHY ((char16_t)0xAD)
+
+// nsFind::Find casts CH_SHY to char before calling StripChars
+// This works correctly if and only if CH_SHY <= 255
+static_assert(CH_SHY <= 255, "CH_SHY is not an ascii character");
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsFind)
+  NS_INTERFACE_MAP_ENTRY(nsIFind)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsFind)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsFind)
+
+NS_IMPL_CYCLE_COLLECTION(nsFind)
+
+#ifdef DEBUG_FIND
+#  define DEBUG_FIND_PRINTF(...) printf(__VA_ARGS__)
+#else
+#  define DEBUG_FIND_PRINTF(...) /* nothing */
+#endif
+
+static nsIContent& AnonymousSubtreeRootParentOrHost(const nsINode& aNode) {
+  MOZ_ASSERT(aNode.IsInNativeAnonymousSubtree());
+  return *aNode.GetClosestNativeAnonymousSubtreeRootParentOrHost();
+}
+
+static void DumpNode(const nsINode* aNode) {
+#ifdef DEBUG_FIND
+  if (!aNode) {
+    printf(">>>> Node: NULL\n");
+    return;
+  }
+  nsString nodeName = aNode->NodeName();
+  if (aNode->IsText()) {
+    nsAutoString newText;
+    aNode->AsText()->AppendTextTo(newText);
+    printf(">>>> Text node (node name %s): '%s'\n",
+           NS_LossyConvertUTF16toASCII(nodeName).get(),
+           NS_LossyConvertUTF16toASCII(newText).get());
+  } else {
+    printf(">>>> Node: %s\n", NS_LossyConvertUTF16toASCII(nodeName).get());
+  }
+#endif
+}
+
+static bool IsBlockNode(const nsIContent* aContent) {
+  if (aContent->IsElement() && aContent->AsElement()->IsDisplayContents()) {
+    return false;
+  }
+
+  // FIXME(emilio): This is dubious...
+  if (aContent->IsAnyOfHTMLElements(nsGkAtoms::img, nsGkAtoms::hr,
+                                    nsGkAtoms::th, nsGkAtoms::td)) {
+    return true;
+  }
+
+  nsIFrame* frame = aContent->GetPrimaryFrame();
+  if (!frame) {
+    return false;
+  }
+
+  const auto& disp = *frame->StyleDisplay();
+  // We also treat internal table frames as "blocks" for the purpose of
+  // locating boundaries for searches (see
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=1645990).
+  return disp.IsBlockOutsideStyle() || disp.IsInternalTableStyleExceptCell();
+}
+
+static bool IsDisplayedNode(const nsINode* aNode) {
+  if (!aNode->IsContent()) {
+    return false;
+  }
+
+  if (aNode->AsContent()->GetPrimaryFrame()) {
+    return true;
+  }
+
+  // If there's no frame, it's not displayed, unless it's display: contents.
+  return aNode->IsElement() && aNode->AsElement()->IsDisplayContents();
+}
+
+static bool IsRubyAnnotationNode(const nsINode* aNode) {
+  if (!aNode->IsContent()) {
+    return false;
+  }
+
+  nsIFrame* frame = aNode->AsContent()->GetPrimaryFrame();
+  if (!frame) {
+    return false;
+  }
+
+  StyleDisplay display = frame->StyleDisplay()->mDisplay;
+  return StyleDisplay::RubyText == display ||
+         StyleDisplay::RubyTextContainer == display;
+}
+
+static bool IsVisibleNode(const nsINode* aNode) {
+  if (!IsDisplayedNode(aNode)) {
+    return false;
+  }
+
+  nsIFrame* frame = aNode->AsContent()->GetPrimaryFrame();
+  if (!frame) {
+    // display: contents
+    return true;
+  }
+
+  if (frame->HidesContent(nsIFrame::IncludeContentVisibility::Hidden) ||
+      frame->IsHiddenByContentVisibilityOnAnyAncestor(
+          nsIFrame::IncludeContentVisibility::Hidden)) {
+    return false;
+  }
+
+  return frame->StyleVisibility()->IsVisible();
+}
+
+static bool ShouldFindAnonymousContent(const nsIContent& aContent) {
+  MOZ_ASSERT(aContent.IsInNativeAnonymousSubtree());
+
+  nsIContent& host = AnonymousSubtreeRootParentOrHost(aContent);
+  if (nsCOMPtr<nsIFormControl> formControl = do_QueryInterface(&host)) {
+    if (formControl->IsTextControl(/* aExcludePassword = */ true)) {
+      // Only editable NAC in textfields should be findable. That is, we want to
+      // find "bar" in `<input value="bar">`, but not in `<input
+      // placeholder="bar">`.
+      //
+      // TODO(emilio): Ideally we could lift this restriction, but we hide the
+      // placeholder text at paint-time instead of with CSS visibility, which
+      // means that we won't skip it even if invisible. We should probably fix
+      // that.
+      return aContent.IsEditable();
+    }
+
+    // We want to avoid finding in password inputs anyway, as it is confusing.
+    if (formControl->ControlType() == FormControlType::InputPassword) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+static bool SkipNode(const nsIContent* aContent) {
+  const nsIContent* content = aContent;
+  while (content) {
+    if (!IsDisplayedNode(content) || content->IsComment() ||
+        content->IsAnyOfHTMLElements(nsGkAtoms::select)) {
+      DEBUG_FIND_PRINTF("Skipping node: ");
+      DumpNode(content);
+      return true;
+    }
+
+    // Skip option nodes if their select is a combo box, or if they
+    // have no select (somehow).
+    if (const auto* option = HTMLOptionElement::FromNode(content)) {
+      auto* select = HTMLSelectElement::FromNodeOrNull(option->GetParent());
+      if (!select || select->IsCombobox()) {
+        DEBUG_FIND_PRINTF("Skipping node: ");
+        DumpNode(content);
+        return true;
+      }
+    }
+
+    if (StaticPrefs::browser_find_ignore_ruby_annotations() &&
+        IsRubyAnnotationNode(content)) {
+      DEBUG_FIND_PRINTF("Skipping node: ");
+      DumpNode(content);
+      return true;
+    }
+
+    if (content->IsInNativeAnonymousSubtree() &&
+        !ShouldFindAnonymousContent(*content)) {
+      DEBUG_FIND_PRINTF("Skipping node: ");
+      DumpNode(content);
+      return true;
+    }
+
+    // Only climb to the nearest block node
+    if (IsBlockNode(content)) {
+      return false;
+    }
+
+    content = content->GetFlattenedTreeParent();
+  }
+
+  return false;
+}
+
+static const nsIContent* GetBlockParent(const Text& aNode) {
+  for (const nsIContent* current = aNode.GetFlattenedTreeParent(); current;
+       current = current->GetFlattenedTreeParent()) {
+    if (IsBlockNode(current)) {
+      return current;
+    }
+  }
+  return nullptr;
+}
+
+static bool NonTextNodeForcesBreak(const nsINode& aNode) {
+  nsIFrame* frame =
+      aNode.IsContent() ? aNode.AsContent()->GetPrimaryFrame() : nullptr;
+  // TODO(emilio): Maybe we should treat <br> more like a space instead of a
+  // forced break? Unclear...
+  return frame && frame->IsBrFrame();
+}
+
+static bool ForceBreakBetweenText(const Text& aPrevious, const Text& aNext) {
+  return GetBlockParent(aPrevious) != GetBlockParent(aNext);
+}
+
+struct nsFind::State final {
+  State(bool aFindBackward, nsIContent& aRoot, const nsRange& aStartPoint)
+      : mFindBackward(aFindBackward),
+        mInitialized(false),
+        mFoundBreak(false),
+        mIterOffset(-1),
+        mIterator(aRoot),
+        mStartPoint(aStartPoint) {}
+
+  void PositionAt(Text& aNode) { mIterator.Seek(aNode); }
+
+  bool ForcedBreak() const { return mFoundBreak; }
+
+  Text* GetCurrentNode() const {
+    if (MOZ_UNLIKELY(!mInitialized)) {
+      return nullptr;
+    }
+    nsINode* node = mIterator.GetCurrent();
+    MOZ_ASSERT(!node || node->IsText());
+    return node ? node->GetAsText() : nullptr;
+  }
+
+  Text* GetNextNode(bool aAlreadyMatching) {
+    if (MOZ_UNLIKELY(!mInitialized)) {
+      MOZ_ASSERT(!aAlreadyMatching);
+      Initialize();
+    } else {
+      Advance(Initializing::No, aAlreadyMatching);
+      mIterOffset = -1;  // mIterOffset only really applies to the first node.
+    }
+    return GetCurrentNode();
+  }
+
+ private:
+  enum class Initializing { No, Yes };
+
+  // Advance to the next visible text-node.
+  void Advance(Initializing, bool aAlreadyMatching);
+  // Sets up the first node position and offset.
+  void Initialize();
+
+  // Returns whether the node should be used (true) or skipped over (false)
+  static bool AnalyzeNode(const nsINode& aNode, const Text* aPrev,
+                          bool aAlreadyMatching, bool* aForcedBreak) {
+    if (!aNode.IsText()) {
+      *aForcedBreak = *aForcedBreak || NonTextNodeForcesBreak(aNode);
+      return false;
+    }
+    if (SkipNode(aNode.AsText())) {
+      return false;
+    }
+    *aForcedBreak = *aForcedBreak ||
+                    (aPrev && ForceBreakBetweenText(*aPrev, *aNode.AsText()));
+    if (*aForcedBreak) {
+      // If we've already found a break, we can stop searching and just use this
+      // node, regardless of the subtree we're on. There's no point to continue
+      // a match across different blocks, regardless of which subtree you're
+      // looking into.
+      return true;
+    }
+
+    // TODO(emilio): We can't represent ranges that span native anonymous /
+    // shadow tree boundaries, but if we did the following check could / should
+    // be removed.
+    if (aAlreadyMatching && aPrev &&
+        !nsContentUtils::IsInSameAnonymousTree(&aNode, aPrev)) {
+      // As an optimization, if we were finding inside an native-anonymous
+      // subtree (like a pseudo-element), we know those trees are "atomic" and
+      // can't have any other subtrees in between, so we can just break the
+      // match here.
+      if (aPrev->IsInNativeAnonymousSubtree()) {
+        *aForcedBreak = true;
+        return true;
+      }
+      // Otherwise we can skip the node and keep looking past this subtree.
+      return false;
+    }
+
+    return true;
+  }
+
+  const bool mFindBackward;
+
+  // Whether we've called GetNextNode() at least once.
+  bool mInitialized;
+
+ public:
+  // Whether we've found a forced break from the last node to the current one.
+  bool mFoundBreak;
+  // An offset into the text of the first node we're starting to search at.
+  int mIterOffset;
+  TreeIterator<StyleChildrenIterator> mIterator;
+
+  // These are only needed for the first GetNextNode() call.
+  const nsRange& mStartPoint;
+};
+
+void nsFind::State::Advance(Initializing aInitializing, bool aAlreadyMatching) {
+  MOZ_ASSERT(mInitialized);
+
+  // The Advance() call during Initialize() calls us in a partial state, where
+  // mIterator may not be pointing to a text node yet. aInitializing prevents
+  // tripping the invariants of GetCurrentNode().
+  const Text* prev =
+      aInitializing == Initializing::Yes ? nullptr : GetCurrentNode();
+  mFoundBreak = false;
+
+  while (true) {
+    nsIContent* current =
+        mFindBackward ? mIterator.GetPrev() : mIterator.GetNext();
+    if (!current) {
+      return;
+    }
+    if (AnalyzeNode(*current, prev, aAlreadyMatching, &mFoundBreak)) {
+      break;
+    }
+  }
+}
+
+void nsFind::State::Initialize() {
+  MOZ_ASSERT(!mInitialized);
+  mInitialized = true;
+  mIterOffset = mFindBackward ? -1 : 0;
+
+  nsINode* container = mFindBackward ? mStartPoint.GetStartContainer()
+                                     : mStartPoint.GetEndContainer();
+
+  // Set up ourselves at the first node we want to start searching at.
+  nsIContent* beginning = mFindBackward ? mStartPoint.GetChildAtStartOffset()
+                                        : mStartPoint.GetChildAtEndOffset();
+  if (beginning) {
+    mIterator.Seek(*beginning);
+    // If the start point is pointing to a node, when looking backwards we'd
+    // start looking at the children of that node, and we don't really want
+    // that. When looking forwards, we look at the next sibling afterwards.
+    if (mFindBackward) {
+      mIterator.GetPrevSkippingChildren();
+    }
+  } else if (container && container->IsContent()) {
+    // Text-only range, or pointing to past the end of the node, for example.
+    mIterator.Seek(*container->AsContent());
+  }
+
+  nsINode* current = mIterator.GetCurrent();
+  if (!current) {
+    return;
+  }
+
+  const bool kAlreadyMatching = false;
+  if (!AnalyzeNode(*current, nullptr, kAlreadyMatching, &mFoundBreak)) {
+    Advance(Initializing::Yes, kAlreadyMatching);
+    current = mIterator.GetCurrent();
+    if (!current) {
+      return;
+    }
+  }
+
+  if (current != container) {
+    return;
+  }
+
+  mIterOffset =
+      mFindBackward ? mStartPoint.StartOffset() : mStartPoint.EndOffset();
+}
+
+class MOZ_STACK_CLASS nsFind::StateRestorer final {
+ public:
+  explicit StateRestorer(State& aState)
+      : mState(aState),
+        mIterOffset(aState.mIterOffset),
+        mFoundBreak(aState.mFoundBreak),
+        mCurrNode(aState.GetCurrentNode()) {}
+
+  ~StateRestorer() {
+    mState.mFoundBreak = mFoundBreak;
+    mState.mIterOffset = mIterOffset;
+    if (mCurrNode) {
+      mState.PositionAt(*mCurrNode);
+    }
+  }
+
+ private:
+  State& mState;
+
+  int32_t mIterOffset;
+  bool mFoundBreak;
+  Text* mCurrNode;
+};
+
+NS_IMETHODIMP
+nsFind::GetFindBackwards(bool* aFindBackward) {
+  if (!aFindBackward) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  *aFindBackward = mFindBackward;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFind::SetFindBackwards(bool aFindBackward) {
+  mFindBackward = aFindBackward;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFind::GetCaseSensitive(bool* aCaseSensitive) {
+  if (!aCaseSensitive) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  *aCaseSensitive = mCaseSensitive;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFind::SetCaseSensitive(bool aCaseSensitive) {
+  mCaseSensitive = aCaseSensitive;
+  return NS_OK;
+}
+
+/* attribute boolean entireWord; */
+NS_IMETHODIMP
+nsFind::GetEntireWord(bool* aEntireWord) {
+  if (!aEntireWord) return NS_ERROR_NULL_POINTER;
+
+  *aEntireWord = mEntireWord;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFind::SetEntireWord(bool aEntireWord) {
+  mEntireWord = aEntireWord;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFind::GetMatchDiacritics(bool* aMatchDiacritics) {
+  if (!aMatchDiacritics) {
+    return NS_ERROR_NULL_POINTER;
+  }
+
+  *aMatchDiacritics = mMatchDiacritics;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFind::SetMatchDiacritics(bool aMatchDiacritics) {
+  mMatchDiacritics = aMatchDiacritics;
+  return NS_OK;
+}
+
+// Here begins the find code. A ten-thousand-foot view of how it works: Find
+// needs to be able to compare across inline (but not block) nodes, e.g. find
+// for "abc" should match a<b>b</b>c. So after we've searched a node, we're not
+// done with it; in the case of a partial match we may need to reset the
+// iterator to go back to a previously visited node, so we always save the
+// "match anchor" node and offset.
+//
+// Text nodes store their text in an nsTextFragment, which is effectively a
+// union of a one-byte string or a two-byte string. Single and double strings
+// are intermixed in the dom. We don't have string classes which can deal with
+// intermixed strings, so all the handling is done explicitly here.
+
+char32_t nsFind::DecodeChar(const char16_t* t2b, int32_t* index) const {
+  char32_t c = t2b[*index];
+  if (mFindBackward) {
+    if (*index >= 1 && NS_IS_SURROGATE_PAIR(t2b[*index - 1], t2b[*index])) {
+      c = SURROGATE_TO_UCS4(t2b[*index - 1], t2b[*index]);
+      (*index)--;
+    }
+  } else {
+    if (NS_IS_SURROGATE_PAIR(t2b[*index], t2b[*index + 1])) {
+      c = SURROGATE_TO_UCS4(t2b[*index], t2b[*index + 1]);
+      (*index)++;
+    }
+  }
+  return c;
+}
+
+bool nsFind::BreakInBetween(char32_t x, char32_t y) const {
+  nsAutoStringN<4> text;
+  AppendUCS4ToUTF16(x, text);
+  const uint32_t x16Len = text.Length();
+  AppendUCS4ToUTF16(y, text);
+
+  intl::WordBreakIteratorUtf16 iter(text);
+  return *iter.Seek(x16Len - 1) == x16Len;
+}
+
+char32_t nsFind::PeekNextChar(State& aState, bool aAlreadyMatching) const {
+  // We need to restore the necessary state before this function returns.
+  StateRestorer restorer(aState);
+
+  while (true) {
+    const Text* text = aState.GetNextNode(aAlreadyMatching);
+    if (!text || aState.ForcedBreak()) {
+      return L'\0';
+    }
+
+    const nsTextFragment& frag = text->TextFragment();
+    uint32_t len = frag.GetLength();
+    if (!len) {
+      continue;
+    }
+
+    const char16_t* t2b = nullptr;
+    const char* t1b = nullptr;
+
+    if (frag.Is2b()) {
+      t2b = frag.Get2b();
+    } else {
+      t1b = frag.Get1b();
+    }
+
+    int32_t index = mFindBackward ? len - 1 : 0;
+    return t1b ? CHAR_TO_UNICHAR(t1b[index]) : DecodeChar(t2b, &index);
+  }
+}
+
+#define NBSP_CHARCODE (CHAR_TO_UNICHAR(160))
+#define IsSpace(c) (nsCRT::IsAsciiSpace(c) || (c) == NBSP_CHARCODE)
+#define OVERFLOW_PINDEX (mFindBackward ? pindex < 0 : pindex > patLen)
+#define DONE_WITH_PINDEX (mFindBackward ? pindex <= 0 : pindex >= patLen)
+
+// Take nodes out of the tree with NextNode, until null (NextNode will return 0
+// at the end of our range).
+NS_IMETHODIMP
+nsFind::Find(const nsAString& aPatText, nsRange* aSearchRange,
+             nsRange* aStartPoint, nsRange* aEndPoint, nsRange** aRangeRet) {
+  DEBUG_FIND_PRINTF("============== nsFind::Find('%s'%s, %p, %p, %p)\n",
+                    NS_LossyConvertUTF16toASCII(aPatText).get(),
+                    mFindBackward ? " (backward)" : " (forward)",
+                    (void*)aSearchRange, (void*)aStartPoint, (void*)aEndPoint);
+
+  NS_ENSURE_ARG(aSearchRange);
+  NS_ENSURE_ARG(aStartPoint);
+  NS_ENSURE_ARG(aEndPoint);
+  NS_ENSURE_ARG_POINTER(aRangeRet);
+
+  Document* document =
+      aStartPoint->GetRoot() ? aStartPoint->GetRoot()->OwnerDoc() : nullptr;
+  NS_ENSURE_ARG(document);
+
+  Element* root = document->GetRootElement();
+  NS_ENSURE_ARG(root);
+
+  *aRangeRet = 0;
+
+  nsAutoString patAutoStr(aPatText);
+  if (!mCaseSensitive) {
+    ToFoldedCase(patAutoStr);
+  }
+  if (!mMatchDiacritics) {
+    ToNaked(patAutoStr);
+  }
+
+  // Ignore soft hyphens in the pattern
+  static const char16_t kShy[] = {CH_SHY, 0};
+  patAutoStr.StripChars(kShy);
+
+  const char16_t* patStr = patAutoStr.get();
+  int32_t patLen = patAutoStr.Length() - 1;
+
+  // If this function is called with an empty string, we should early exit.
+  if (patLen < 0) {
+    return NS_OK;
+  }
+
+  const int32_t patternStart = mFindBackward ? patLen : 0;
+
+  // current offset into the pattern -- reset to beginning/end:
+  int32_t pindex = patternStart;
+
+  // Current offset into the fragment
+  int32_t findex = 0;
+
+  // Direction to move pindex and ptr*
+  int incr = mFindBackward ? -1 : 1;
+
+  const nsTextFragment* frag = nullptr;
+  int32_t fragLen = 0;
+
+  // Pointers into the current fragment:
+  const char16_t* t2b = nullptr;
+  const char* t1b = nullptr;
+
+  // Keep track of when we're in whitespace:
+  // (only matters when we're matching)
+  bool inWhitespace = false;
+
+  // Place to save the range start point in case we find a match:
+  Text* matchAnchorNode = nullptr;
+  int32_t matchAnchorOffset = 0;
+  char32_t matchAnchorChar = 0;
+
+  // Get the end point, so we know when to end searches:
+  nsINode* endNode = aEndPoint->GetEndContainer();
+  uint32_t endOffset = aEndPoint->EndOffset();
+
+  char32_t c = 0;
+  char32_t patc = 0;
+  char32_t prevCharInMatch = 0;
+
+  State state(mFindBackward, *root, *aStartPoint);
+  Text* current = nullptr;
+
+  auto EndPartialMatch = [&]() -> bool {
+    // If we didn't match, go back to the beginning of patStr, and set findex
+    // back to the next char after we started the current match.
+    //
+    // There's no need to do this if we're still at the beginning of the pattern
+    // (this can happen e.g. with whitespace, and prevents exponential
+    // complexity when scanning a pattern that starts with whitespace).
+    const bool restart = !!matchAnchorNode && pindex != patternStart;
+    if (restart) {  // we're ending a partial match
+      findex = matchAnchorOffset;
+      state.mIterOffset = matchAnchorOffset;
+      c = matchAnchorChar;
+      // +incr will be added to findex when we continue
+
+      // Are we going back to a previous node?
+      if (matchAnchorNode != state.GetCurrentNode()) {
+        frag = nullptr;
+        state.PositionAt(*matchAnchorNode);
+        DEBUG_FIND_PRINTF("Repositioned anchor node\n");
+      }
+      DEBUG_FIND_PRINTF(
+          "Ending a partial match; findex -> %d, mIterOffset -> %d\n", findex,
+          state.mIterOffset);
+    }
+    matchAnchorNode = nullptr;
+    matchAnchorOffset = 0;
+    matchAnchorChar = 0;
+    inWhitespace = false;
+    prevCharInMatch = 0;
+    pindex = patternStart;
+    DEBUG_FIND_PRINTF("Setting findex back to %d, pindex to %d\n", findex,
+                      pindex);
+    return restart;
+  };
+
+  while (true) {
+    DEBUG_FIND_PRINTF("Loop (pindex = %d)...\n", pindex);
+
+    // If this is our first time on a new node, reset the pointers:
+    if (!frag) {
+      current = state.GetNextNode(!!matchAnchorNode);
+      if (!current) {
+        DEBUG_FIND_PRINTF("Reached the end, matching: %d\n", !!matchAnchorNode);
+        if (EndPartialMatch()) {
+          continue;
+        }
+        return NS_OK;
+      }
+
+      // We have a new text content. See if we need to force a break due to
+      // <br>, different blocks or what not.
+      if (state.ForcedBreak()) {
+        DEBUG_FIND_PRINTF("Forced break!\n");
+        if (EndPartialMatch()) {
+          continue;
+        }
+        // This ensures word breaking thinks it has a new word, which is
+        // effectively what we want.
+        c = 0;
+      }
+
+      frag = &current->TextFragment();
+      fragLen = frag->GetLength();
+
+      // Set our starting point in this node. If we're going back to the anchor
+      // node, which means that we just ended a partial match, use the saved
+      // offset:
+      //
+      // FIXME(emilio): How could current ever be the anchor node, if we had not
+      // seen current so far?
+      if (current == matchAnchorNode) {
+        findex = matchAnchorOffset + (mFindBackward ? 1 : 0);
+      } else if (state.mIterOffset >= 0) {
+        findex = state.mIterOffset - (mFindBackward ? 1 : 0);
+      } else {
+        findex = mFindBackward ? (fragLen - 1) : 0;
+      }
+
+      // Offset can only apply to the first node:
+      state.mIterOffset = -1;
+
+      DEBUG_FIND_PRINTF("Starting from offset %d of %d\n", findex, fragLen);
+
+      // If this is outside the bounds of the string, then skip this node:
+      if (findex < 0 || findex > fragLen - 1) {
+        DEBUG_FIND_PRINTF(
+            "At the end of a text node -- skipping to the next\n");
+        frag = nullptr;
+        continue;
+      }
+
+      if (frag->Is2b()) {
+        t2b = frag->Get2b();
+        t1b = nullptr;
+#ifdef DEBUG_FIND
+        nsAutoString str2(t2b, fragLen);
+        DEBUG_FIND_PRINTF("2 byte, '%s'\n",
+                          NS_LossyConvertUTF16toASCII(str2).get());
+#endif
+      } else {
+        t1b = frag->Get1b();
+        t2b = nullptr;
+#ifdef DEBUG_FIND
+        nsAutoCString str1(t1b, fragLen);
+        DEBUG_FIND_PRINTF("1 byte, '%s'\n", str1.get());
+#endif
+      }
+    } else {
+      // Still on the old node. Advance the pointers, then see if we need to
+      // pull a new node.
+      findex += incr;
+      DEBUG_FIND_PRINTF("Same node -- (%d, %d)\n", pindex, findex);
+      if (mFindBackward ? (findex < 0) : (findex >= fragLen)) {
+        DEBUG_FIND_PRINTF(
+            "Will need to pull a new node: mAO = %d, frag len=%d\n",
+            matchAnchorOffset, fragLen);
+        // Done with this node.  Pull a new one.
+        frag = nullptr;
+        continue;
+      }
+    }
+
+    // Have we gone past the endpoint yet? If we have, and we're not in the
+    // middle of a match, return.
+    if (state.GetCurrentNode() == endNode &&
+        ((mFindBackward && findex < static_cast<int32_t>(endOffset)) ||
+         (!mFindBackward && findex > static_cast<int32_t>(endOffset)))) {
+      DEBUG_FIND_PRINTF("Reached the end and not in the middle of a match\n");
+      return NS_OK;
+    }
+
+    // Save the previous character for word boundary detection
+    char32_t prevChar = c;
+    // The two characters we'll be comparing are c and patc. If not matching
+    // diacritics, don't leave c set to a combining diacritical mark. (patc is
+    // already guaranteed to not be a combining diacritical mark.)
+    c = (t2b ? DecodeChar(t2b, &findex) : CHAR_TO_UNICHAR(t1b[findex]));
+    if (!mMatchDiacritics && IsCombiningDiacritic(c) &&
+        !intl::UnicodeProperties::IsMathOrMusicSymbol(prevChar)) {
+      continue;
+    }
+    patc = DecodeChar(patStr, &pindex);
+
+    DEBUG_FIND_PRINTF(
+        "Comparing '%c'=%#x to '%c'=%#x (%d of %d), findex=%d%s\n", (char)c,
+        (int)c, (char)patc, (int)patc, pindex, patLen, findex,
+        inWhitespace ? " (inWhitespace)" : "");
+
+    // Do we need to go back to non-whitespace mode? If inWhitespace, then this
+    // space in the pat str has already matched at least one space in the
+    // document.
+    if (inWhitespace && !IsSpace(c)) {
+      inWhitespace = false;
+      pindex += incr;
+#ifdef DEBUG
+      // This shouldn't happen -- if we were still matching, and we were at the
+      // end of the pat string, then we should have caught it in the last
+      // iteration and returned success.
+      if (OVERFLOW_PINDEX) {
+        NS_ASSERTION(false, "Missed a whitespace match");
+      }
+#endif
+      patc = DecodeChar(patStr, &pindex);
+    }
+    if (!inWhitespace && IsSpace(patc)) {
+      inWhitespace = true;
+    } else if (!inWhitespace) {
+      if (!mCaseSensitive) {
+        c = ToFoldedCase(c);
+      }
+      if (!mMatchDiacritics) {
+        c = ToNaked(c);
+      }
+    }
+
+    if (c == CH_SHY) {
+      // ignore soft hyphens in the document
+      continue;
+    }
+
+    if (pindex != patternStart && c != patc && !inWhitespace) {
+      // A non-matching '\n' between CJ characters is ignored
+      if (c == '\n' && t2b && IS_CJ_CHAR(prevCharInMatch)) {
+        int32_t nindex = findex + incr;
+        if (mFindBackward ? (nindex >= 0) : (nindex < fragLen)) {
+          if (IS_CJ_CHAR(t2b[nindex])) {
+            continue;
+          }
+        }
+      }
+
+      // We also ignore ZWSP and other default-ignorable characters.
+      if (IsDefaultIgnorable(c)) {
+        continue;
+      }
+    }
+
+    // Figure whether the previous char is a word-breaking one,
+    // if we care about word boundaries.
+    bool wordBreakPrev = true;
+    if (mEntireWord && prevChar) {
+      if (prevChar == NBSP_CHARCODE) {
+        prevChar = CHAR_TO_UNICHAR(' ');
+      }
+      wordBreakPrev = BreakInBetween(prevChar, c);
+    }
+
+    // Compare. Match if we're in whitespace and c is whitespace, or if the
+    // characters match and at least one of the following is true:
+    // a) we're not matching the entire word
+    // b) a match has already been stored
+    // c) the previous character is a different "class" than the current
+    // character.
+    if ((c == patc && (!mEntireWord || matchAnchorNode || wordBreakPrev)) ||
+        (inWhitespace && IsSpace(c))) {
+      prevCharInMatch = c;
+      if (inWhitespace) {
+        DEBUG_FIND_PRINTF("YES (whitespace)(%d of %d)\n", pindex, patLen);
+      } else {
+        DEBUG_FIND_PRINTF("YES! '%c' == '%c' (%d of %d)\n", c, patc, pindex,
+                          patLen);
+      }
+
+      // Save the range anchors if we haven't already:
+      if (!matchAnchorNode) {
+        matchAnchorNode = state.GetCurrentNode();
+        matchAnchorOffset = findex;
+        if (!IS_IN_BMP(c)) {
+          matchAnchorOffset -= incr;
+        }
+        matchAnchorChar = c;
+      }
+
+      // Are we done?
+      if (DONE_WITH_PINDEX) {
+        // Matched the whole string!
+        DEBUG_FIND_PRINTF("Found a match!\n");
+
+        // Make the range:
+        // Check for word break (if necessary)
+        if (mEntireWord || inWhitespace) {
+          int32_t nextfindex = findex + incr;
+
+          char32_t nextChar;
+          // If still in array boundaries, get nextChar.
+          if (mFindBackward ? (nextfindex >= 0) : (nextfindex < fragLen)) {
+            if (t2b) {
+              nextChar = DecodeChar(t2b, &nextfindex);
+            } else {
+              nextChar = CHAR_TO_UNICHAR(t1b[nextfindex]);
+            }
+          } else {
+            // Get next character from the next node.
+            nextChar = PeekNextChar(state, !!matchAnchorNode);
+          }
+
+          if (nextChar == NBSP_CHARCODE) {
+            nextChar = CHAR_TO_UNICHAR(' ');
+          }
+
+          // If a word break isn't there when it needs to be, reset search.
+          if (mEntireWord && nextChar && !BreakInBetween(c, nextChar)) {
+            matchAnchorNode = nullptr;
+            continue;
+          }
+
+          if (inWhitespace && IsSpace(nextChar)) {
+            // If the next character is also an space, keep going, this space
+            // will collapse.
+            continue;
+          }
+        }
+
+        int32_t matchStartOffset;
+        int32_t matchEndOffset;
+        // convert char index to range point:
+        int32_t mao = matchAnchorOffset + (mFindBackward ? 1 : 0);
+        Text* startParent;
+        Text* endParent;
+        if (mFindBackward) {
+          startParent = current;
+          endParent = matchAnchorNode;
+          matchStartOffset = findex;
+          matchEndOffset = mao;
+        } else {
+          startParent = matchAnchorNode;
+          endParent = current;
+          matchStartOffset = mao;
+          matchEndOffset = findex + 1;
+        }
+
+        RefPtr<nsRange> range = nsRange::Create(current);
+        if (startParent && endParent && IsVisibleNode(startParent) &&
+            IsVisibleNode(endParent)) {
+          IgnoredErrorResult rv;
+          range->SetStart(*startParent, matchStartOffset, rv);
+          if (!rv.Failed()) {
+            range->SetEnd(*endParent, matchEndOffset, rv);
+          }
+          if (!rv.Failed()) {
+            range.forget(aRangeRet);
+            return NS_OK;
+          }
+        }
+
+        // This match is no good, continue on in document
+        matchAnchorNode = nullptr;
+      }
+
+      if (matchAnchorNode) {
+        // Not done, but still matching. Advance and loop around for the next
+        // characters. But don't advance from a space to a non-space:
+        if (!inWhitespace || DONE_WITH_PINDEX ||
+            IsSpace(patStr[pindex + incr])) {
+          pindex += incr;
+          inWhitespace = false;
+          DEBUG_FIND_PRINTF("Advancing pindex to %d\n", pindex);
+        }
+
+        continue;
+      }
+    }
+
+    DEBUG_FIND_PRINTF("NOT: %c == %c\n", c, patc);
+    EndPartialMatch();
+  }
+}