139576 r=bienvenu sr=mscott Fixing a performance regression in downloading pop3 mail on MAC and other platforms (not win32 & linux). This was because seek is expensive, atleast on mac. Made it so that we

seek whenever absolutely necessary.

mailnews/db/msgdb/src/nsMailDatabase.cpp

@@ -70,6 +70,7 @@ nsMailDatabase::~nsMailDatabase()
 
 NS_IMETHODIMP nsMailDatabase::SetFolderStream(nsIOFileStream *aFileStream)
 {
+  NS_ASSERTION(!m_folderStream || !aFileStream, "m_folderStream is not null and we are assigning a non null stream to it");
   m_folderStream = aFileStream; //m_folderStream is set externally, so m_ownFolderStream is false
   m_ownFolderStream = PR_FALSE;
   return NS_OK;
@@ -331,6 +332,7 @@ void nsMailDatabase::UpdateFolderFlag(nsIMsgDBHdr *mailHdr, PRBool bSet,
 							  MsgFlags flag, nsIOFileStream **ppFileStream)
 {
   static char buf[50];
+  PRInt32 folderStreamPos; //saves the folderStream pos in case we are sharing the stream with other code
   nsIOFileStream *fileStream = (m_folderStream) ? m_folderStream : *ppFileStream;
   //#ifdef GET_FILE_STUFF_TOGETHER
 #ifdef XP_MAC
@@ -356,6 +358,11 @@ void nsMailDatabase::UpdateFolderFlag(nsIMsgDBHdr *mailHdr, PRBool bSet,
     {
       fileStream = new nsIOFileStream(nsFileSpec(*m_folderSpec));
     }
+    else if (!m_ownFolderStream)
+    {
+      m_folderStream->flush();
+      folderStreamPos = m_folderStream->tell();
+    }
     if (fileStream) 
     {
       PRUint32 msgOffset;
@@ -454,6 +461,8 @@ void nsMailDatabase::UpdateFolderFlag(nsIMsgDBHdr *mailHdr, PRBool bSet,
   //#endif // GET_FILE_STUFF_TOGETHER
   if (!m_folderStream)
     *ppFileStream = fileStream; // This tells the caller that we opened the file, and please to close it.
+  else if (!m_ownFolderStream)
+    m_folderStream->seek(PR_SEEK_SET, folderStreamPos);
 }
 
 NS_IMETHODIMP nsMailDatabase::GetSummaryValid(PRBool *aResult)

mailnews/local/src/nsPop3Sink.cpp

@@ -447,11 +447,9 @@ nsresult nsPop3Sink::WriteLineToMailbox(char *buffer)
     // See bug 62480
         if (!m_outFileStream)
             return NS_ERROR_OUT_OF_MEMORY;
+        
+        NS_ASSERTION(m_outFileStream->eof(), "we are not writing to end-of-file");
 
-        /*This file stream is also used by db so file pos could have changed
-        set it to the end of the file before writing anything */
-
-        m_outFileStream->seek(PR_SEEK_END, 0);
         PRInt32 bytes = m_outFileStream->write(buffer,bufferLen);
         if (bytes != bufferLen) return NS_ERROR_FAILURE;
 	}
@@ -475,13 +473,8 @@ nsPop3Sink::IncorporateComplete(nsIMsgWindow *msgWindow)
     if (NS_FAILED(rv)) return rv;
     NS_ASSERTION(m_newMailParser, "could not get m_newMailParser");
     if (m_newMailParser)
-    {
       m_newMailParser->PublishMsgHeader(msgWindow); 
 
-      //PublishMsgHeader might have changed the postion of file stream pointer, reset it back.
-      m_outFileStream->seek(PR_SEEK_END, 0);
-    }    
-
 #ifdef DEBUG
 	printf("Incorporate message complete.\n");
 #endif