bug #169583 (r=jst, sr=darin) URILoader should allow nsIContentHandler::DoContent() to fail...

mailnews/imap/src/nsImapService.cpp

@@ -3990,6 +3990,9 @@ nsImapService::HandleContent(const char * aContentType, const char * aCommand, n
       rv = messengerWindowService->OpenMessengerWindowWithUri("mail:3pane", uriStr.get(), nsMsgKey_None);
       NS_ENSURE_SUCCESS(rv, rv);
     }
+  } else {
+    // The content-type was not x-application-imapfolder
+    return NS_ERROR_WONT_HANDLE_CONTENT;
   }
 
   return rv;

mailnews/news/src/nsNntpService.cpp

@@ -1647,6 +1647,9 @@ nsNntpService::HandleContent(const char * aContentType, const char * aCommand, n
         NS_ENSURE_SUCCESS(rv, rv);
       }
     }
+  } else {
+    // The content-type was not x-application-newsgroup.
+    return NS_ERROR_WONT_HANDLE_CONTENT;
   }
 
   return rv;

uriloader/base/nsIContentHandler.idl

@@ -49,3 +49,9 @@ interface nsIContentHandler : nsISupports
                      in nsIRequest aRequest);
 };
 
+
+%{C++
+
+#define NS_ERROR_WONT_HANDLE_CONTENT   NS_ERROR_GENERATE_FAILURE(NS_ERROR_MODULE_URILOADER, 1)
+
+%}

uriloader/base/nsURILoader.cpp

@@ -57,7 +57,6 @@
 #include "nsIMultiPartChannel.h"
 #include "netCore.h"
 #include "nsCRT.h"
-
 #include "nsIDocShell.h"
 #include "nsIDocShellTreeItem.h"
 #include "nsIDocShellTreeOwner.h"
@@ -864,8 +863,19 @@ NS_IMETHODIMP nsURILoader::DispatchContent(const char * aContentType,
   aContentHandler = do_CreateInstance(handlerContractID.get(), &rv);
   if (NS_SUCCEEDED(rv)) // we did indeed have a content handler for this type!! yippee...
   {
-      rv = aContentHandler->HandleContent(aContentType, "view", aSrcWindowContext, request);
+    rv = aContentHandler->HandleContent(aContentType, "view", aSrcWindowContext, request);
+    if (rv != NS_ERROR_WONT_HANDLE_CONTENT) {
       *aAbortProcess = PR_TRUE;
+
+      // The content handler has unexpectedly failed.  Cancel the request
+      // just in case the handler didn't...
+      if (NS_FAILED(rv)) {
+        request->Cancel(rv);
+      }
+    }
+    // If WONT_HANDLE_CONTENT is returned -- do not abort.  Just return the
+    // failure and keep looking for another consumer (ie. the unknown
+    // content handler)...
   }
   
   return rv;

xpcom/base/nsError.h

@@ -88,6 +88,7 @@
 #define NS_ERROR_MODULE_SECURITY   21
 #define NS_ERROR_MODULE_DOM_XPATH  22
 #define NS_ERROR_MODULE_DOM_RANGE  23
+#define NS_ERROR_MODULE_URILOADER  24
 
 /* NS_ERROR_MODULE_GENERAL should be used by modules that do not
  * care if return code values overlap. Callers of methods that

xpinstall/src/nsInstallTrigger.cpp

@@ -161,6 +161,9 @@ nsInstallTrigger::HandleContent(const char * aContentType,
                 }
             }
         }
+    } else {
+        // The content-type was not application/x-xpinstall
+        return NS_ERROR_WONT_HANDLE_CONTENT;
     }
 
     return NS_ERROR_FAILURE;