From c1c7b938f91d80d9453d93ab41ea3cc7117a8d45 Mon Sep 17 00:00:00 2001
From: Henri Sivonen <hsivonen@iki.fi>
Date: Wed, 4 Mar 2009 16:36:52 +0200
Subject: [PATCH] Be smarter about searching the array of elements seen in this
 append batch in HTML5 parsing

---
 .../src/nsHtml5TreeBuilderCppSupplement.h     | 12 ++++-
 .../src/nsHtml5TreeBuilderHSupplement.h       | 52 ++++++++-----------
 2 files changed, 33 insertions(+), 31 deletions(-)

diff --git a/content/html/parser/src/nsHtml5TreeBuilderCppSupplement.h b/content/html/parser/src/nsHtml5TreeBuilderCppSupplement.h
index e28da82400b..ca2a06eae15 100644
--- a/content/html/parser/src/nsHtml5TreeBuilderCppSupplement.h
+++ b/content/html/parser/src/nsHtml5TreeBuilderCppSupplement.h
@@ -256,6 +256,9 @@ nsHtml5TreeBuilder::end()
 #ifdef DEBUG_hsivonen
   printf("MAX INSERTION BATCH LEN: %d\n", sInsertionBatchMaxLength);
   printf("MAX NOTIFICATION BATCH LEN: %d\n", sAppendBatchMaxSize);
+  if (sAppendBatchExaminations != 0) {
+    printf("AVERAGE SLOTS EXAMINED: %d\n", sAppendBatchSlotsExamined / sAppendBatchExaminations);
+  }
 #endif
 }
 
@@ -445,15 +448,18 @@ nsHtml5TreeBuilder::Flush()
 {
   if (!mFlushing) {
     mFlushing = PR_TRUE;
+    PRUint32 opQueueLength = mOpQueue.Length();
+    mElementsSeenInThisAppendBatch.SetCapacity(opQueueLength * 2);
+    // XXX alloc failure
     const nsHtml5TreeOperation* start = mOpQueue.Elements();
-    const nsHtml5TreeOperation* end = start + mOpQueue.Length();
+    const nsHtml5TreeOperation* end = start + opQueueLength;
     for (nsHtml5TreeOperation* iter = (nsHtml5TreeOperation*)start; iter < end; ++iter) {
       iter->Perform(this);
     }
     FlushPendingAppendNotifications();
 #ifdef DEBUG_hsivonen
     if (mOpQueue.Length() > sInsertionBatchMaxLength) {
-      sInsertionBatchMaxLength = mOpQueue.Length();
+      sInsertionBatchMaxLength = opQueueLength;
     }
 #endif
     mOpQueue.Clear();
@@ -464,5 +470,7 @@ nsHtml5TreeBuilder::Flush()
 #ifdef DEBUG_hsivonen
 PRUint32 nsHtml5TreeBuilder::sInsertionBatchMaxLength = 0;
 PRUint32 nsHtml5TreeBuilder::sAppendBatchMaxSize = 0;
+PRUint32 nsHtml5TreeBuilder::sAppendBatchSlotsExamined = 0;
+PRUint32 nsHtml5TreeBuilder::sAppendBatchExaminations = 0;
 #endif
 
diff --git a/content/html/parser/src/nsHtml5TreeBuilderHSupplement.h b/content/html/parser/src/nsHtml5TreeBuilderHSupplement.h
index 832a31a04fd..9f5a1bfa679 100644
--- a/content/html/parser/src/nsHtml5TreeBuilderHSupplement.h
+++ b/content/html/parser/src/nsHtml5TreeBuilderHSupplement.h
@@ -39,6 +39,8 @@
 #ifdef DEBUG_hsivonen
     static PRUint32 sInsertionBatchMaxLength;
     static PRUint32 sAppendBatchMaxSize;
+    static PRUint32 sAppendBatchSlotsExamined;
+    static PRUint32 sAppendBatchExaminations;
 #endif
     nsHtml5Parser* mParser; // weak ref
     PRBool         mHasProcessedBase;
@@ -53,38 +55,30 @@
     void Flush();
     
     inline void PostPendingAppendNotification(nsIContent* aParent, nsIContent* aChild) {
-      nsIContent* parent = aParent; // this gets nulled when found
-      nsIContent* child = aChild->IsNodeOfType(nsINode::eELEMENT) ? aChild : nsnull; // this gets nulled when found
-      const nsIContentPtr* start = mElementsSeenInThisAppendBatch.Elements();
-      const nsIContentPtr* end = start + mElementsSeenInThisAppendBatch.Length();
-      // XXX backwards iterate
-      for (const nsIContentPtr* iter = start; iter < end; ++iter) {
-        if (*iter == parent) {
-          parent = nsnull;
-        }
-        if (*iter == child) {
-          child = nsnull;
-        }
-        if (!(parent || child)) {
+      PRBool newParent = PR_TRUE;
+      const nsIContentPtr* first = mElementsSeenInThisAppendBatch.Elements();
+      const nsIContentPtr* last = first + (mElementsSeenInThisAppendBatch.Length() - 1);
+      for (const nsIContentPtr* iter = last; iter >= first; --iter) {
+#ifdef DEBUG_hsivonen
+        sAppendBatchSlotsExamined++;
+#endif
+        if (*iter == aParent) {
+          newParent = PR_FALSE;
           break;
-        } 
-      }
-      if (child) {
-        mElementsSeenInThisAppendBatch.AppendElement(child);
-      }
-      if (parent) {
-        // parents that are in mPendingNotifications don't need to be added to
-        // mElementsSeenInThisAppendBatch
-        const nsHtml5PendingNotification* startNotifications = mPendingNotifications.Elements();
-        const nsHtml5PendingNotification* endNotifications = startNotifications + mPendingNotifications.Length();
-        // XXX backwards iterate
-        for (nsHtml5PendingNotification* iter = (nsHtml5PendingNotification*)startNotifications; iter < endNotifications; ++iter) {
-          if (iter->Contains(parent)) {
-            return;
-          }
         }
-        mPendingNotifications.AppendElement(parent);
       }
+      if (aChild->IsNodeOfType(nsINode::eELEMENT)) {
+        mElementsSeenInThisAppendBatch.AppendElement(aChild);
+      }
+      mElementsSeenInThisAppendBatch.AppendElement(aParent);
+      if (newParent) {
+        mPendingNotifications.AppendElement(aParent);
+      }
+
+#ifdef DEBUG_hsivonen
+      sAppendBatchExaminations++;
+#endif
+
     }
     
     inline void FlushPendingAppendNotifications() {