Modified cancel and interrupt processing to avoid race with history.

chrome/browser/download/download_manager.cc

Index: chrome/browser/download/download_manager.cc
diff --git a/chrome/browser/download/download_manager.cc b/chrome/browser/download/download_manager.cc
index 26a58bede0001edf11ab5441d78ef1998ead02e4..3b03e4524901960091663439599d3991d0cc862c 100644
--- a/chrome/browser/download/download_manager.cc
+++ b/chrome/browser/download/download_manager.cc
@@ -106,8 +106,7 @@ void DownloadManager::Shutdown() {
       // from all queues.
       download->Delete(DownloadItem::DELETE_DUE_TO_BROWSER_SHUTDOWN);
     } else if (download->IsPartialDownload()) {
-      download->Cancel(false);
-      download_history_->UpdateEntry(download);
+      download->Cancel();
     }
   }
 
@@ -644,6 +643,15 @@ void DownloadManager::OnResponseCompleted(int32 download_id,
   }
 }
 
+void DownloadManager::CancelDownload(int32 download_id) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DownloadMap::iterator it = active_downloads_.find(download_id);
+  if (it == active_downloads_.end())
+    return;
+
+  it->second->Cancel();
+}
+
 void DownloadManager::OnAllDataSaved(int32 download_id,
                                      int64 size,
                                      const std::string& hash) {
@@ -718,8 +726,8 @@ void DownloadManager::AssertQueueStateConsistent(DownloadItem* download) {
 
   CHECK(ContainsKey(active_downloads_, download->id()) ==
         (download->state() == DownloadItem::IN_PROGRESS));
-  CHECK(ContainsKey(in_progress_, download->id()) ==
-        (download->state() == DownloadItem::IN_PROGRESS));
+  // Would check in_progress_, but removal from that queue happens
+  // before transition from IN_PROGRESS for legacy reasons, so skipping.
 }
 
 bool DownloadManager::IsDownloadReadyForCompletion(DownloadItem* download) {
@@ -816,33 +824,27 @@ void DownloadManager::OnDownloadRenamedToFinalName(int download_id,
   download_history_->UpdateDownloadPath(item, full_path);
 }
 
-void DownloadManager::DownloadCancelled(int32 download_id) {
+void DownloadManager::DownloadStopped(int32 download_id) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DownloadMap::iterator it = in_progress_.find(download_id);
-  if (it == in_progress_.end())
+  DownloadMap::iterator it = active_downloads_.find(download_id);
+  if (it == active_downloads_.end())
     return;
   DownloadItem* download = it->second;
 
   VLOG(20) << __FUNCTION__ << "()" << " download_id = " << download_id
            << " download = " << download->DebugString(true);
 
-  // Clean up will happen when the history system create callback runs if we
-  // don't have a valid db_handle yet.
-  if (download->db_handle() != DownloadHistory::kUninitializedHandle) {
-    in_progress_.erase(it);
-    active_downloads_.erase(download_id);
-    UpdateAppIcon();  // Reflect removal from in_progress_.
-    download_history_->UpdateEntry(download);
-  }
+  in_progress_.erase(download_id);
+  active_downloads_.erase(download_id);
+  UpdateAppIcon();  // Reflect removal from in_progress_.
 
-  DownloadCancelledInternal(download_id, download->request_handle());
-}
+  // The history service should always outlive the DownloadManager.
+  download_history_->UpdateEntry(download);
 
-void DownloadManager::DownloadCancelledInternal(
-    int download_id, DownloadRequestHandle request_handle) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  request_handle.CancelRequest();
+  download->request_handle().CancelRequest();
 
+  // TODO(ahendrickson) - Remove this when we add resuming of interrupted
+  // downloads, as we will keep the download item around in that case.
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
       NewRunnableMethod(
@@ -865,24 +867,7 @@ void DownloadManager::OnDownloadError(int32 download_id,
            << " at offset " << download->received_bytes()
            << " for download = " << download->DebugString(true);
 
-  download->Interrupted(size, os_error);
-
-  // TODO(ahendrickson) - Remove this when we add resuming of interrupted
-  // downloads, as we will keep the download item around in that case.
-  //
-  // Clean up will happen when the history system create callback runs if we
-  // don't have a valid db_handle yet.
-  if (download->db_handle() != DownloadHistory::kUninitializedHandle) {
-    in_progress_.erase(download_id);
-    active_downloads_.erase(download_id);
-    UpdateAppIcon();  // Reflect removal from in_progress_.
-    download_history_->UpdateEntry(download);
-  }
-
-  BrowserThread::PostTask(
-      BrowserThread::FILE, FROM_HERE,
-      NewRunnableMethod(
-          file_manager_, &DownloadFileManager::CancelDownload, download_id));
+  download->Interrupt(size, os_error);
 }
 
 void DownloadManager::UpdateAppIcon() {
@@ -890,17 +875,14 @@ void DownloadManager::UpdateAppIcon() {
     status_updater_->Update();
 }
 
-void DownloadManager::RemoveDownload(int64 download_handle) {
-  DownloadMap::iterator it = history_downloads_.find(download_handle);
-  if (it == history_downloads_.end())
-    return;
-
-  // Make history update.
-  DownloadItem* download = it->second;
-  download_history_->RemoveEntry(download);
+void DownloadManager::RemoveDownload(DownloadItem* download) {
+  // Silently ignores request if db handled indicates that the download

[Randy Smith (Not in Mondays), 2011/06/30 23:05:13]

"handled" -> "handle"

[Randy Smith (Not in Mondays), 2011/07/05 20:28:44]

Done.

+  // isn't in the history.
+  download_history_->RemoveEntry(download->db_handle());
 
   // Remove from our tables and delete.
-  history_downloads_.erase(it);
+  if (download->db_handle() != DownloadHistory::kUninitializedHandle)
+    history_downloads_.erase(download->db_handle());
   int downloads_count = downloads_.erase(download);
   DCHECK_EQ(1, downloads_count);
 
@@ -1106,7 +1088,7 @@ void DownloadManager::FileSelectionCanceled(void* params) {
   VLOG(20) << __FUNCTION__ << "()"
            << " download = " << download->DebugString(true);
 
-  DownloadCancelledInternal(download_id, download->request_handle());
+  download->Cancel();
 }
 
 // TODO(phajdan.jr): This is apparently not being exercised in tests.
@@ -1169,13 +1151,9 @@ void DownloadManager::OnQueryDownloadEntriesComplete(
 void DownloadManager::OnCreateDownloadEntryComplete(int32 download_id,
                                                     int64 db_handle) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DownloadItem* download = GetActiveDownloadItem(download_id);
-  if (!download)
-    return;
 
   VLOG(20) << __FUNCTION__ << "()" << " db_handle = " << db_handle
-           << " download_id = " << download_id
-           << " download = " << download->DebugString(true);
+           << " download_id = " << download_id;
 
   // It's not immediately obvious, but HistoryBackend::CreateDownload() can
   // call this function with an invalid |db_handle|. For instance, this can
@@ -1185,6 +1163,32 @@ void DownloadManager::OnCreateDownloadEntryComplete(int32 download_id,
   if (db_handle == DownloadHistory::kUninitializedHandle)
     db_handle = download_history_->GetNextFakeDbHandle();
 
+  DownloadItem* download = GetActiveDownloadItem(download_id);
+  if (!download) {
+    // The download was cancelled while the history system was entering it.
+    // We resolve this race by turning around and deleting it in the
+    // history system (implicitly treating is as a failure in download

[Randy Smith (Not in Mondays), 2011/06/30 23:05:13]

"is" -> "it"

[Randy Smith (Not in Mondays), 2011/07/05 20:28:44]

Done.

+    // initiation, which is appropriate as the only places the cancel could
+    // have come from were in resolving issues (like the file name) which
+    // we need to have resolved for history system insertion.

[Randy Smith (Not in Mondays), 2011/06/30 23:05:13]

Not quite true--could have come from FileSelectionCancelled.  Update comment for
accuracy?

[Randy Smith (Not in Mondays), 2011/07/05 20:28:44]

FileSelectionCancelled is part of resolving the file name.

+
+    // Make sure we haven't already been shutdown (the callback raced
+    // with shutdown), as that would mean that the history service has
+    // also been shutdown.  In that case, the history will be fixed up
+    // when it's next read in.

[Randy Smith (Not in Mondays), 2011/06/30 23:05:13]

"on next browser startup".

[Randy Smith (Not in Mondays), 2011/07/05 20:28:44]

Done.

+    if (download_history_.get())
+      download_history_->RemoveEntry(db_handle);
+    return;
+  }
+
+  VLOG(20) << __FUNCTION__ << "()" << " db_handle = " << db_handle
+           << " download_id = " << download_id
+           << " download = " << download->DebugString(true);
+
+  // The download shouldn't have been returned from GetActiveDownloadItem()
+  // if it's not in progress.
+  DCHECK(download->IsInProgress());
+
   DCHECK(download->db_handle() == DownloadHistory::kUninitializedHandle);
   download->set_db_handle(db_handle);
 
@@ -1198,23 +1202,7 @@ void DownloadManager::OnCreateDownloadEntryComplete(int32 download_id,
   // Inform interested objects about the new download.
   NotifyModelChanged();
 
-  // If the download is still in progress, try to complete it.
-  //
-  // Otherwise, download has been cancelled or interrupted before we've
-  // received the DB handle.  We post one final message to the history
-  // service so that it can be properly in sync with the DownloadItem's
-  // completion status, and also inform any observers so that they get
-  // more than just the start notification.
-  if (download->IsInProgress()) {
-    MaybeCompleteDownload(download);
-  } else {
-    DCHECK(download->IsCancelled())
-        << " download = " << download->DebugString(true);
-    in_progress_.erase(download_id);
-    active_downloads_.erase(download_id);
-    download_history_->UpdateEntry(download);
-    download->UpdateObservers();
-  }
+  MaybeCompleteDownload(download);
 }
 
 void DownloadManager::ShowDownloadInBrowser(DownloadItem* download) {
@@ -1264,6 +1252,16 @@ DownloadItem* DownloadManager::GetDownloadItem(int download_id) {
   return NULL;
 }
 
+void DownloadManager::GetInProgressDownloads(
+    std::vector<DownloadItem*>* result) {
+  DCHECK(result);
+
+  for (DownloadMap::iterator it = active_downloads_.begin();
+       it != active_downloads_.end(); ++it) {
+    result->push_back(it->second);
+  }
+}
+
 DownloadItem* DownloadManager::GetActiveDownloadItem(int download_id) {
   DCHECK(ContainsKey(active_downloads_, download_id));
   DownloadItem* download = active_downloads_[download_id];