https://phabricator.services.mozilla.com/D270713

ntlm_account_sync_workaround.diff

diff --git a/mailnews/protocols/ews/src/EwsIncomingServer.cpp b/mailnews/protocols/ews/src/EwsIncomingServer.cpp
--- a/mailnews/protocols/ews/src/EwsIncomingServer.cpp
+++ b/mailnews/protocols/ews/src/EwsIncomingServer.cpp
@@ -104,6 +104,38 @@ NS_IMETHODIMP EwsBiffUrlListener::OnStop
 
 }  // namespace
 
+/**
+ * A timer used to delay requests when syncing multiple folders at once. See the
+ * comment in `EwsIncomingServer::SyncFolders` for more information.
+ */
+class EwsNTLMSyncTimer : public nsITimerCallback, public nsINamed {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITIMERCALLBACK
+  NS_DECL_NSINAMED
+
+  explicit EwsNTLMSyncTimer(std::function<void()> done)
+      : mDone(std::move(done)) {};
+
+ protected:
+  virtual ~EwsNTLMSyncTimer() = default;
+
+ private:
+  std::function<void()> mDone;
+};
+
+NS_IMPL_ISUPPORTS(EwsNTLMSyncTimer, nsITimerCallback, nsINamed)
+
+NS_IMETHODIMP EwsNTLMSyncTimer::GetName(nsACString& name) {
+  name.Assign("EwsNTLMSyncTimer");
+  return NS_OK;
+}
+
+NS_IMETHODIMP EwsNTLMSyncTimer::Notify(nsITimer* timer) {
+  mDone();
+  return NS_OK;
+}
+
 NS_IMPL_ADDREF_INHERITED(EwsIncomingServer, nsMsgIncomingServer)
 NS_IMPL_RELEASE_INHERITED(EwsIncomingServer, nsMsgIncomingServer)
 NS_IMPL_QUERY_HEAD(EwsIncomingServer)
@@ -498,20 +530,65 @@ nsresult EwsIncomingServer::SyncFolderLi
 nsresult EwsIncomingServer::SyncFolders(
     const nsTArray<RefPtr<nsIMsgFolder>>& folders, nsIMsgWindow* aMsgWindow,
     nsIUrlListener* urlListener) {
+  nsMsgAuthMethodValue authMethod;
+  MOZ_TRY(GetAuthMethod(&authMethod));
+
   // TODO: For now, we sync every folder at once, but obviously that's not an
   // amazing solution. In the future, we should probably try to maintain some
   // kind of queue so we can properly batch and sync folders. In the meantime,
   // though, the EWS client should handle any kind of rate limiting well enough,
   // so this improvement can come later.
+  uint32_t delay = 0;
+  nsCOMPtr<nsIMsgWindow> window = aMsgWindow;
+  nsCOMPtr<nsIUrlListener> listener = urlListener;
   for (const auto& folder : folders) {
-    nsresult rv = folder->GetNewMessages(aMsgWindow, urlListener);
-    if (NS_FAILED(rv)) {
-      // If we encounter an error, just log it rather than fail the whole sync.
-      nsCString name;
-      folder->GetName(name);
-      NS_ERROR(nsPrintfCString("failed to get new messages for folder %s: %s",
-                               name.get(), mozilla::GetStaticErrorName(rv))
-                   .get());
+    nsCString name;
+    folder->GetName(name);
+
+    auto syncFn = [folder, window, listener, name]() {
+      nsresult rv = folder->GetNewMessages(window, listener);
+      if (NS_FAILED(rv)) {
+        // If we encounter an error, just log it rather than fail the whole
+        // sync.
+        NS_ERROR(nsPrintfCString("failed to get new messages for folder %s: %s",
+                                 name.get(), mozilla::GetStaticErrorName(rv))
+                     .get());
+      }
+    };
+
+    // FIXME: NTLM works in a fairly different way than other supported
+    // authentication methods: request are authenticated by a cookie created
+    // from a challenge-based flow spanning multiple requests. This means that
+    // if an authentication error happens while we're trying to update a bunch
+    // of folders at once, properly handling it with the current EWS client
+    // architecture gets really difficult.
+    //
+    // So, as a temporary solution, we delay each request from each other in an
+    // attempt to ensure authentication errors are resolved before the next
+    // request. The plan is to improve the current EWS client architecture to
+    // address this situation, at which point this workaround will be removed,
+    // before we update the frontend to offer NTLM to EWS users.
+    if (authMethod == nsMsgAuthMethod::NTLM) {
+      delay += 500;
+
+      nsCOMPtr<nsITimer> timer = do_CreateInstance("@mozilla.org/timer;1");
+      nsresult rv = timer->InitWithCallback(new EwsNTLMSyncTimer(syncFn), delay,
+                                            nsITimer::TYPE_ONE_SHOT);
+
+      if (NS_FAILED(rv)) {
+        // If we encounter an error, just log it rather than fail the whole
+        // sync.
+        NS_ERROR(
+            nsPrintfCString("failed to schedule new messages for folder %s: %s",
+                            name.get(), mozilla::GetStaticErrorName(rv))
+                .get());
+      }
+
+      // Add the timer to the member array to prevent it from being
+      // automatically dropped.
+      mNTLMSyncTimers.AppendElement(timer);
+    } else {
+      syncFn();
     }
   }
 
diff --git a/mailnews/protocols/ews/src/EwsIncomingServer.h b/mailnews/protocols/ews/src/EwsIncomingServer.h
--- a/mailnews/protocols/ews/src/EwsIncomingServer.h
+++ b/mailnews/protocols/ews/src/EwsIncomingServer.h
@@ -7,6 +7,7 @@
 
 #include "IEwsIncomingServer.h"
 #include "msgIOAuth2Module.h"
+#include "nsITimer.h"
 #include "nsMsgIncomingServer.h"
 
 #define EWS_INCOMING_SERVER_IID \
@@ -94,6 +95,12 @@ class EwsIncomingServer : public nsMsgIn
   nsresult UpdateTrashFolder();
 
   nsCOMPtr<msgIOAuth2Module> mOAuth2Module;
+
+  // An array of timers used when syncing the account, if the account uses NTLM
+  // (see the comment in `EwsIncomingServer::SyncFolders` for why we're using
+  // timers). We need to store them here to prevent them from being dropped
+  // after `EwsIncomingServer::SyncFolders` returns.
+  nsTArray<nsCOMPtr<nsITimer>> mNTLMSyncTimers;
 };
 
 #endif  // COMM_MAILNEWS_PROTOCOLS_EWS_SRC_EWSINCOMINGSERVER_H_