Bug 293084: perf improvement in nsMsgSearchNews::DuplicateHit; p=Bruno 'Aqualon' Escherl <aqualon@aquachan.de>, r=me, sr=bienvenu

mailnews/base/search/src/nsMsgSearchNews.cpp

@@ -349,64 +349,71 @@ void nsMsgSearchNews::PreExitFunction (URL_Struct * /*url*/, int status, MWConte
   }
 }
 #endif // 0
+
 PRBool nsMsgSearchNews::DuplicateHit(PRUint32 artNum)
-// ASSUMES m_hits is sorted!!
 {
-  PRUint32 index;
-  for (index = 0; index < m_hits.GetSize(); index++)
+  // Assert that m_hits is sorted!
+  PRUint32 size = m_hits.GetSize();
+  for (PRUint32 index = 0; index < size; ++index)
     if (artNum == m_hits.ElementAt(index))
       return PR_TRUE;
   return PR_FALSE;
 }
 
 
-void nsMsgSearchNews::CollateHits ()
+void nsMsgSearchNews::CollateHits()
 {
   // Since the XPAT commands are processed one at a time, the result set for the
-  // entire query is the intersection of results for each XPAT command if an AND Search
-  // otherwise we want the union of all the search hits (minus the duplicates of course)
+  // entire query is the intersection of results for each XPAT command if an AND search,
+  // otherwise we want the union of all the search hits (minus the duplicates of course).
 
-  if (m_candidateHits.GetSize() == 0)
+  PRUint32 size = m_candidateHits.GetSize();
+  if (!size)
     return;
 
   // Sort the article numbers first, so it's easy to tell how many hits
   // on a given article we got
   m_candidateHits.QuickSort(CompareArticleNumbers);
-  int size = m_candidateHits.GetSize();
-  int index = 0;
-  PRUint32 candidate = m_candidateHits.ElementAt(index);
+
+  PRUint32 candidate = m_candidateHits.ElementAt(0);
 
   if (m_ORSearch)
   {
-    for (index = 0; index < size; index++)
+    // first candidate, so just add it
+    m_hits.Add(candidate);
+    for (PRUint32 index = 1; index < size; ++index)
     {
       candidate = m_candidateHits.ElementAt(index);
       if (!DuplicateHit(candidate)) // if not a dup, add it to the hit list
-        m_hits.Add (candidate);
+        m_hits.Add(candidate);
     }
     return;
   }
 
-
-  // otherwise we have a traditional and search which must be collated
+  // otherwise we have a traditional AND search which must be collated
 
   // In order to get promoted into the hits list, a candidate article number
   // must appear in the results of each XPAT command. So if we fire 3 XPAT
   // commands (one per search term), the article number must appear 3 times.
-  // If it appears less than 3 times, it matched some search terms, but not all
+  // If it appears less than 3 times, it matched some search terms, but not all.
 
   PRUint32 termCount;
   m_searchTerms->Count(&termCount);
   PRUint32 candidateCount = 0;
-  while (index < size)
+  for (PRUint32 index = 0; index < size; ++index)   
   {
-    if (candidate == m_candidateHits.ElementAt(index))
-      candidateCount++;
+    PRUint32 possibleCandidate = m_candidateHits.ElementAt(index);
+    if (candidate == possibleCandidate)
+    {
+      ++candidateCount;
+    }
     else
+    {
       candidateCount = 1;
+      candidate = possibleCandidate;
+    }
     if (candidateCount == termCount)
-      m_hits.Add (m_candidateHits.ElementAt(index));
-    candidate = m_candidateHits.ElementAt(index++);
+      m_hits.Add(candidate);
   }
 }
 
@@ -424,7 +431,8 @@ void nsMsgSearchNews::ReportHits ()
 
   if (db)
   {
-    for (PRUint32 i = 0; i < m_hits.GetSize(); i++)
+    PRUint32 size = m_hits.GetSize();
+    for (PRUint32 i = 0; i < size; ++i)
     {
       nsCOMPtr <nsIMsgDBHdr> header;