IDBObserver: Lifetime Management: Adding Observer

content/browser/indexed_db/indexed_db_connection.cc

 // Copyright 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_connection.h"
 
 namespace content {
 
 IndexedDBConnection::IndexedDBConnection(
     scoped_refptr<IndexedDBDatabase> database,
     scoped_refptr<IndexedDBDatabaseCallbacks> callbacks)
     : database_(database), callbacks_(callbacks), weak_factory_(this) {}
 
 IndexedDBConnection::~IndexedDBConnection() {}
 
 void IndexedDBConnection::Close() {
   if (!callbacks_.get())
     return;
   base::WeakPtr<IndexedDBConnection> this_obj = weak_factory_.GetWeakPtr();
   database_->Close(this, false /* forced */);
   if (this_obj) {
     database_ = nullptr;
     callbacks_ = nullptr;
+    active_observers_.clear();
   }
 }
 
 void IndexedDBConnection::ForceClose() {
   if (!callbacks_.get())
     return;
 
   // IndexedDBDatabase::Close() can delete this instance.
   base::WeakPtr<IndexedDBConnection> this_obj = weak_factory_.GetWeakPtr();
   scoped_refptr<IndexedDBDatabaseCallbacks> callbacks(callbacks_);
   database_->Close(this, true /* forced */);
   if (this_obj) {
     database_ = nullptr;
     callbacks_ = nullptr;
+    active_observers_.clear();
   }
   callbacks->OnForcedClose();
 }
 
 void IndexedDBConnection::VersionChangeIgnored() {
   if (!database_.get())
     return;
   database_->VersionChangeIgnored();
 }
 
 bool IndexedDBConnection::IsConnected() {
   return database_.get() != NULL;
 }
 
+void IndexedDBConnection::ActivatePendingObservers(
+    std::vector<std::unique_ptr<IndexedDBObserver>>* pending_observers) {
+  for (uint32_t i = 0; i < pending_observers->size(); i++) {
+    active_observers_.emplace_back(std::move(pending_observers->at(i)));

[dmurph, 2016/06/23 21:53:04]

I believe we just want push_back here. emplace_back is the same, except it also
takes a list of construction arguments for the item we're inserting. We want to
avoid accidentally doing this, so let's just use push_back.

[palakj1, 2016/06/24 00:03:00]

Changed.

+  }
+}
+
+void IndexedDBConnection::RemoveObservers(
+    const std::vector<int32_t>& remove_observer_ids) {
+  // TODO(palakj): Change from vector to set or create tmp vector instead of
+  // erase.
+  std::vector<int32_t> pending_observer_ids;
+  for (uint32_t i = 0; i < remove_observer_ids.size(); i++) {
+    bool removed = false;
+    for (uint32_t j = 0; j < active_observers_.size(); j++) {
+      if (active_observers_[j]->id() == remove_observer_ids[i]) {
+        active_observers_.erase(active_observers_.begin() + j);

[dmurph, 2016/06/23 21:53:04]

In order for us to be able to erase while iterating, we should either use the
iterator interface (which lets us call remove or something), or iterate
backwards through the list. This currently won't work (we would skip elements).

[palakj1, 2016/06/24 00:03:00]

After each erase, we break. So the state of iterator doesn't really matter.

+        removed = true;
+        break;
+      }
+    }
+    // If observer not in active_observers_ , must be in pending_observer list
+    // of one of the transactions.
+    if (!removed)
+      pending_observer_ids.push_back(remove_observer_ids[i]);
+  }
+
+  if (!pending_observer_ids.empty())
+    database_->RemovePendingObservers(this, pending_observer_ids);
+}
+
 }  // namespace content