Bug #43661 --> pass in the file name for the attachment

r=bienvenu

mailnews/base/src/nsMessenger.cpp

@@ -584,7 +584,7 @@ nsMessenger::OpenAttachment(const char * aContentType, const char * aUrl, const
   rv = GetMessageServiceFromURI(aMessageUri, &messageService);
   if (messageService)
   {
-    rv = messageService->OpenAttachment(aContentType, aUrl, aMessageUri, mDocShell, mMsgWindow, nsnull);
+    rv = messageService->OpenAttachment(aContentType, aDisplayName, aUrl, aMessageUri, mDocShell, mMsgWindow, nsnull);
   }
   if (messageService)
      ReleaseMessageServiceFromURI(aMessageUri, messageService);

mailnews/base/util/nsMsgMailNewsUrl.cpp

@@ -475,7 +475,13 @@ NS_IMETHODIMP nsMsgMailNewsUrl::SetDirectory(const char *aDirectory)
 
 NS_IMETHODIMP nsMsgMailNewsUrl::GetFileName(char * *aFileName)
 {
-	return m_baseURL->GetFileName(aFileName);
+  if (!mAttachmentFileName.IsEmpty())
+  {
+    *aFileName = mAttachmentFileName.ToNewCString();
+    return NS_OK;
+  }
+  else
+	  return m_baseURL->GetFileName(aFileName);
 }
 
 NS_IMETHODIMP nsMsgMailNewsUrl::GetFileBaseName(char * *aFileBaseName)
@@ -490,7 +496,17 @@ NS_IMETHODIMP nsMsgMailNewsUrl::SetFileBaseName(const char * aFileBaseName)
 
 NS_IMETHODIMP nsMsgMailNewsUrl::GetFileExtension(char * *aFileExtension)
 {
-	return m_baseURL->GetFileExtension(aFileExtension);
+  if (!mAttachmentFileName.IsEmpty())
+  {
+    nsCAutoString extension;
+    PRInt32 pos = mAttachmentFileName.RFindCharInSet(".");
+    if (pos > 0)
+      mAttachmentFileName.Mid(extension, pos + 1 /* skip the '.' */, -1);
+    *aFileExtension = extension.ToNewCString();
+    return NS_OK;
+  }
+  else
+	  return m_baseURL->GetFileExtension(aFileExtension);
 }
 
 NS_IMETHODIMP nsMsgMailNewsUrl::SetFileExtension(const char * aFileExtension)
@@ -500,7 +516,8 @@ NS_IMETHODIMP nsMsgMailNewsUrl::SetFileExtension(const char * aFileExtension)
 
 NS_IMETHODIMP nsMsgMailNewsUrl::SetFileName(const char * aFileName)
 {
-	return m_baseURL->SetFileName(aFileName);
+  mAttachmentFileName = aFileName;
+  return NS_OK;
 }
 
 NS_IMETHODIMP nsMsgMailNewsUrl::GetParam(char * *aParam)
@@ -542,4 +559,3 @@ NS_IMETHODIMP nsMsgMailNewsUrl::SetFilePath(const char *i_DirFile)
 {
 	return m_baseURL->SetFilePath(i_DirFile);
 }
-

mailnews/base/util/nsMsgMailNewsUrl.h

@@ -34,6 +34,7 @@
 #include "nsIURL.h"
 #include "nsILoadGroup.h"
 #include "nsIMsgSearchSession.h"
+
 ///////////////////////////////////////////////////////////////////////////////////
 // Okay, I found that all of the mail and news url interfaces needed to support
 // several common interfaces (in addition to those provided through nsIURI). 
@@ -68,9 +69,16 @@ protected:
 	PRBool	m_updatingFolder;
   PRBool  m_addContentToCache;
 
+  // the following field is really a bit of a hack to make 
+  // open attachments work. The external applications code sometimes trys to figure out the right
+  // handler to use by looking at the file extension of the url we are trying to load. Unfortunately,
+  // the attachment file name really isn't part of the url string....so we'll store it here...and if 
+  // the url we are running is an attachment url, we'll set it here. Then when the helper apps code
+  // asks us for it, we'll return the right value.
+  nsCString mAttachmentFileName;
+
 	// manager of all of current url listeners....
 	nsCOMPtr<nsIUrlListenerManager> m_urlListeners;
 };
 
-
 #endif /* nsMsgMailNewsUrl_h___ */