implement "clear log". make sure the log is there before viewing it, otherwise

the user gets a nasty "file not found" alert, like they would on the browser.
r/sr=bienvenu.  for bug #167891.

mailnews/base/search/public/nsIMsgFilterList.idl

@@ -120,8 +120,11 @@ interface nsIMsgFilterList : nsISupports {
     void writeBoolAttr(in nsMsgFilterFileAttribValue attrib, in boolean value, in nsIOFileStream stream);
     boolean matchOrChangeFilterTarget(in string oldUri, in string newUri, in boolean caseInsensitive);
  
+    // for filter logging
     attribute nsIOutputStream logStream;
     readonly attribute string logURL;
+    void clearLog();
+    void ensureLogFile();
 };
 
 

mailnews/base/search/resources/content/viewLog.js

@@ -1,5 +1,6 @@
 var gFilterList;
 var gLogFilters;
+var gLogView;
 
 function onLoad()
 {
@@ -8,15 +9,16 @@ function onLoad()
   gLogFilters = document.getElementById("logFilters");
   gLogFilters.checked = gFilterList.loggingEnabled;
 
-  var logView = document.getElementById("logView");
+  gLogView = document.getElementById("logView");
 
   // for security, disable JS
-  logView.docShell.allowJavascript = false;
+  gLogView.docShell.allowJavascript = false;
 
-  // won't work yet
-  // Security Error: Content at chrome://messenger/content/filterLog.xul 
-  // may not load or link to file:///C|/Documents%20and%20Settings/Administrator/Application%20Data/Mozilla/Profiles/sspitzer/js48p4bs.slt/ImapMail/nsmail-1/filterlog.html.
-  logView.setAttribute("src", gFilterList.logURL);
+  // if log doesn't exist, this will create an empty file on disk
+  // otherwise, the user will get an error that the file doesn't exist
+  gFilterList.ensureLogFile();
+
+  gLogView.setAttribute("src", gFilterList.logURL);
 }
 
 function toggleLogFilters()
@@ -26,10 +28,9 @@ function toggleLogFilters()
 
 function clearLog()
 {
-  // var logURL = gFilterList.logURL;
-  // gFilterList.logStream = null;
-  // get file for logURL;
-  // truncate file
-  // reload blank log file in viewer
+  gFilterList.clearLog();
+
+  // reload the newly truncated file
+  gLogView.setAttribute("src", gFilterList.logURL);
 }
 

mailnews/base/search/src/nsMsgFilterList.cpp

@@ -120,6 +120,50 @@ NS_IMETHODIMP nsMsgFilterList::SaveToFile(nsIOFileStream *stream)
 	return SaveTextFilters(stream);
 }
 
+NS_IMETHODIMP nsMsgFilterList::EnsureLogFile()
+{
+  nsCOMPtr <nsIFileSpec> file;
+  nsresult rv = GetLogFileSpec(getter_AddRefs(file));
+  NS_ENSURE_SUCCESS(rv,rv);
+
+  PRBool exists;
+  rv = file->Exists(&exists);
+  if (NS_SUCCEEDED(rv) && !exists) {
+    rv = file->Touch();
+    NS_ENSURE_SUCCESS(rv,rv);
+  }
+  return NS_OK;
+}
+
+nsresult nsMsgFilterList::TruncateLog()
+{
+  // this will flush and close the steam
+  nsresult rv = SetLogStream(nsnull);
+  NS_ENSURE_SUCCESS(rv,rv);
+
+  nsCOMPtr <nsIFileSpec> file;
+  rv = GetLogFileSpec(getter_AddRefs(file));
+  NS_ENSURE_SUCCESS(rv,rv);
+
+  rv = file->Truncate(0);
+  NS_ENSURE_SUCCESS(rv,rv);
+  return rv;
+}
+
+NS_IMETHODIMP nsMsgFilterList::ClearLog()
+{
+  PRBool loggingEnabled = m_loggingEnabled;
+  
+  // disable logging while clearing
+  m_loggingEnabled = PR_FALSE;
+
+  nsresult rv = TruncateLog();
+  NS_ASSERTION(NS_SUCCEEDED(rv), "failed to truncate filter log");
+
+  m_loggingEnabled = loggingEnabled;
+  return NS_OK;
+}
+
 nsresult 
 nsMsgFilterList::GetLogFileSpec(nsIFileSpec **aFileSpec)
 {
@@ -154,12 +198,10 @@ nsMsgFilterList::GetLogURL(char **aLogURL)
 NS_IMETHODIMP
 nsMsgFilterList::SetLogStream(nsIOutputStream *aLogStream)
 {
-  // if there is a log stream already, flush it to disk and close it
+  // if there is a log stream already, close it
   if (m_logStream) {
-    nsresult rv = m_logStream->Flush();
-    NS_ENSURE_SUCCESS(rv,rv);
-
-    rv = m_logStream->Close();
+    // will flush
+    nsresult rv = m_logStream->Close();
     NS_ENSURE_SUCCESS(rv,rv);
   }
 

mailnews/base/search/src/nsMsgFilterList.h

@@ -99,7 +99,9 @@ protected:
   nsCOMPtr<nsISupportsArray> m_filters;
   nsCString m_arbitraryHeaders;
   nsCOMPtr<nsIFileSpec> m_defaultFile;
+
 private:
+  nsresult TruncateLog();
   nsresult GetLogFileSpec(nsIFileSpec **aFileSpec);
   nsCOMPtr<nsIOutputStream> m_logStream;
 };