[IndexedDB] Propogating Changes to Observer : Browser

content/browser/indexed_db/indexed_db_transaction.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/indexed_db/indexed_db_transaction.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/browser/indexed_db/indexed_db_backing_store.h"
 #include "content/browser/indexed_db/indexed_db_cursor.h"
 #include "content/browser/indexed_db/indexed_db_database.h"
 #include "content/browser/indexed_db/indexed_db_database_callbacks.h"
-#include "content/browser/indexed_db/indexed_db_observer.h"
+#include "content/browser/indexed_db/indexed_db_observation.h"
+#include "content/browser/indexed_db/indexed_db_observer_changes.h"
 #include "content/browser/indexed_db/indexed_db_tracing.h"
 #include "content/browser/indexed_db/indexed_db_transaction_coordinator.h"
 #include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBDatabaseException.h"
 #include "third_party/leveldatabase/env_chromium.h"
 
 namespace content {
 
 namespace {
 
 const int64_t kInactivityTimeoutPeriodSeconds = 60;
@@ skipping 309 matching lines @@
   // released, and order is critical.
   CloseOpenCursors();
   transaction_->Reset();
 
   // Transactions must also be marked as completed before the
   // front-end is notified, as the transaction completion unblocks
   // operations like closing connections.
   database_->transaction_coordinator().DidFinishTransaction(this);
 
   if (committed) {
-    // TODO (palakj) : Send Observations to observers
-    if (!pending_observers_.empty() && connection_)
-      connection_->ActivatePendingObservers(std::move(pending_observers_));
     abort_task_stack_.clear();
+
+    // SendObservations must be called before OnComplete to ensure consistency
+    // of callbacks at renderer.
+    if (!connection_changes_map_.empty()) {
+      database_->SendObservations(std::move(connection_changes_map_));
+      connection_changes_map_.clear();

[cmumford, 2016/07/19 16:00:16]

connection_changes_map_ was moved above and is already clear.

[Marijn Kruisselbrink, 2016/07/19 17:16:28]

The c++ standard gives no such guarantees. std::unique_ptr is the only std type
that gives any guarantees about the state it is in after you move from it. I
agree that most sane implementations will end up with a cleared map after moving
from it, but this is explicitly not guaranteed, so shouldn't be relied on.

(also just the fact that std::move is called does not necessarily mean that a
move happened. If for some reason SendObservations is later changed to accept
the map as std::map<>&& you would still need to call it with std::move around
the map, but there would be no guarantee that the implementation of it will
actually move from the argument).

+    }
     {
       IDB_TRACE1(
           "IndexedDBTransaction::CommitPhaseTwo.TransactionCompleteCallbacks",
           "txn.id", id());
       callbacks_->OnComplete(id_);
     }
+    if (!pending_observers_.empty() && connection_) {
+      connection_->ActivatePendingObservers(std::move(pending_observers_));
+      pending_observers_.clear();

[cmumford, 2016/07/19 16:00:16]

Also, no need to clear pending_observers_.

[Marijn Kruisselbrink, 2016/07/19 17:16:28]

Same here, no guarantees what moving from does to an stl container.

+    }
+
     database_->TransactionFinished(this, true);
   } else {
     while (!abort_task_stack_.empty())
       abort_task_stack_.pop().Run(NULL);
 
     IndexedDBDatabaseError error;
     if (leveldb_env::IndicatesDiskFull(s)) {
       error = IndexedDBDatabaseError(
           blink::WebIDBDatabaseExceptionQuotaError,
           "Encountered disk full while committing transaction.");
@@ skipping 79 matching lines @@
       base::ASCIIToUTF16("Transaction timed out due to inactivity.")));
 }
 
 void IndexedDBTransaction::CloseOpenCursors() {
   IDB_TRACE1("IndexedDBTransaction::CloseOpenCursors", "txn.id", id());
   for (auto* cursor : open_cursors_)
     cursor->Close();
   open_cursors_.clear();
 }
 
-void IndexedDBTransaction::AddPendingObserver(int32_t observer_id) {
-  pending_observers_.push_back(
-      base::WrapUnique(new IndexedDBObserver(observer_id)));
+void IndexedDBTransaction::AddPendingObserver(
+    int32_t observer_id,
+    IndexedDBObserver::Options options) {

[cmumford, 2016/07/19 16:00:16]

const IndexedDBObserver::Options& options

[palakj1, 2016/07/19 18:04:14]

done

+  pending_observers_.push_back(base::WrapUnique(
+      new IndexedDBObserver(observer_id, object_store_ids_, options)));
 }
 
 void IndexedDBTransaction::RemovePendingObservers(
     const std::vector<int32_t>& pending_observer_ids) {
   const auto& it = std::remove_if(
       pending_observers_.begin(), pending_observers_.end(),
       [&pending_observer_ids](const std::unique_ptr<IndexedDBObserver>& o) {
         return ContainsValue(pending_observer_ids, o->id());
       });
   if (it != pending_observers_.end())
     pending_observers_.erase(it, pending_observers_.end());
 }
 
+void IndexedDBTransaction::AddObservation(
+    int32_t connection_id,
+    std::unique_ptr<IndexedDBObservation> observation) {
+  auto it = connection_changes_map_.find(connection_id);
+  if (it == connection_changes_map_.end()) {
+    it = connection_changes_map_
+             .insert(std::make_pair(
+                 connection_id,
+                 base::WrapUnique(new IndexedDBObserverChanges())))
+             .first;
+  }
+  it->second->AddObservation(std::move(observation));
+}
+
+void IndexedDBTransaction::RecordObserverForLastObservation(
+    int32_t connection_id,
+    int32_t observer_id) {
+  auto it = connection_changes_map_.find(connection_id);
+  DCHECK(it != connection_changes_map_.end());
+  it->second->RecordObserverForLastObservation(observer_id);
+}
+
 }  // namespace content