Bug 1942080, part 4 - Text Fragments: Use NodeIndexCache to further speed up nsContentUtils::ComparePoints(). r=farre,dom-core

`nsContentUtils::ComparePoints()` already has a cache which
keeps the last 100 indices in a stack-allocated array.

This patch makes use of this cache in the hot path.

Differential Revision: https://phabricator.services.mozilla.com/D235557

dom/base/TextDirectiveCreator.cpp

@@ -873,6 +873,7 @@ Result<nsTArray<RefPtr<nsRange>>, ErrorResult>
 TextDirectiveCreator::FindAllMatchingRanges(const nsString& aSearchQuery) {
   MOZ_ASSERT(!aSearchQuery.IsEmpty());
   ErrorResult rv;
+  nsContentUtils::NodeIndexCache nodeIndexCache;
   RangeBoundary documentStart{&mDocument, 0u};
   RefPtr<nsRange> searchRange =
       nsRange::Create(documentStart, mInputRange->EndRef(), rv);
@@ -888,14 +889,14 @@ TextDirectiveCreator::FindAllMatchingRanges(const nsString& aSearchQuery) {
       return matchingRanges;
     }
     RefPtr<nsRange> searchResult = TextDirectiveUtil::FindStringInRange(
-        searchStart, searchEnd, aSearchQuery, true, true);
+        searchStart, searchEnd, aSearchQuery, true, true, &nodeIndexCache);
     if (!searchResult) {
       // This would mean we reached a weird edge case in which the search query
       // is not in the search range.
       break;
     }
     if (TextDirectiveUtil::NormalizedRangeBoundariesAreEqual(
-            searchResult->EndRef(), searchEnd)) {
+            searchResult->EndRef(), searchEnd, &nodeIndexCache)) {
       // It is safe to assume that this algorithm reached the end of all
       // potential ranges if the search result is equal to the search query.
       // Therefore, this range is not added to the results.

dom/base/TextDirectiveFinder.cpp

@@ -97,6 +97,7 @@ RefPtr<nsRange> TextDirectiveFinder::FindRangeForTextDirective(
   if (rv.Failed()) {
     return nullptr;
   }
+  nsContentUtils::NodeIndexCache nodeIndexCache;
   // 2. While searchRange is not collapsed:
   while (!searchRange->Collapsed()) {
     // 2.1. Let potentialMatch be null.
@@ -108,7 +109,7 @@ RefPtr<nsRange> TextDirectiveFinder::FindRangeForTextDirective(
       // searchRange, wordStartBounded true and wordEndBounded false.
       RefPtr<nsRange> prefixMatch = TextDirectiveUtil::FindStringInRange(
           searchRange->StartRef(), searchRange->EndRef(), aTextDirective.prefix,
-          true, false);
+          true, false, &nodeIndexCache);
       // 2.2.2. If prefixMatch is null, return null.
       if (!prefixMatch) {
         TEXT_FRAGMENT_LOG(
@@ -213,7 +214,7 @@ RefPtr<nsRange> TextDirectiveFinder::FindRangeForTextDirective(
       // wordStartBounded true, and wordEndBounded mustEndAtWordBoundary.
       potentialMatch = TextDirectiveUtil::FindStringInRange(
           searchRange->StartRef(), searchRange->EndRef(), aTextDirective.start,
-          true, mustEndAtWordBoundary);
+          true, mustEndAtWordBoundary, &nodeIndexCache);
       // 2.3.3. If potentialMatch is null, return null.
       if (!potentialMatch) {
         TEXT_FRAGMENT_LOG(
@@ -258,7 +259,7 @@ RefPtr<nsRange> TextDirectiveFinder::FindRangeForTextDirective(
         // mustEndAtWordBoundary.
         RefPtr<nsRange> endMatch = TextDirectiveUtil::FindStringInRange(
             rangeEndSearchRange->StartRef(), rangeEndSearchRange->EndRef(),
-            aTextDirective.end, true, mustEndAtWordBoundary);
+            aTextDirective.end, true, mustEndAtWordBoundary, &nodeIndexCache);
         // 2.5.1.3. If endMatch is null then return null.
         if (!endMatch) {
           TEXT_FRAGMENT_LOG(

dom/base/TextDirectiveUtil.cpp

@@ -425,8 +425,8 @@ TextDirectiveUtil::FindBlockBoundaryInRange(const nsRange& aRange,
 }
 
 /* static */ bool TextDirectiveUtil::NormalizedRangeBoundariesAreEqual(
-    const RangeBoundary& aRangeBoundary1,
+    const RangeBoundary& aRangeBoundary1, const RangeBoundary& aRangeBoundary2,
-    const RangeBoundary& aRangeBoundary2) {
+    nsContentUtils::NodeIndexCache* aCache /* = nullptr */) {
   MOZ_ASSERT(aRangeBoundary1.IsSetAndValid() &&
              aRangeBoundary2.IsSetAndValid());
   if (aRangeBoundary1 == aRangeBoundary2) {
@@ -468,7 +468,8 @@ TextDirectiveUtil::FindBlockBoundaryInRange(const nsRange& aRange,
 
   mozilla::UnsafePreContentIterator iter;
   // ContentIterator classes require boundaries to be in correct order.
-  auto comp = nsContentUtils::ComparePoints(aRangeBoundary1, aRangeBoundary2);
+  auto comp =
+      nsContentUtils::ComparePoints(aRangeBoundary1, aRangeBoundary2, aCache);
   if (!comp) {
     return false;
   }

dom/base/TextDirectiveUtil.h

@@ -193,7 +193,8 @@ class TextDirectiveUtil final {
    */
   static bool NormalizedRangeBoundariesAreEqual(
       const RangeBoundary& aRangeBoundary1,
-      const RangeBoundary& aRangeBoundary2);
+      const RangeBoundary& aRangeBoundary2,
+      nsContentUtils::NodeIndexCache* aCache = nullptr);
 
   /**
    * @brief Extends the range boundaries to word boundaries across nodes.