[BackgroundSync] Initial land of the BackgroundSyncManager

content/browser/background_sync/background_sync_manager.cc

+// Copyright 2015 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/background_sync/background_sync_manager.h"
+
+#include "base/barrier_closure.h"
+#include "base/bind.h"
+#include "content/browser/background_sync/background_sync.pb.h"
+#include "content/browser/service_worker/service_worker_context_wrapper.h"
+#include "content/browser/service_worker/service_worker_storage.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace {
+const char kBackgroundSyncUserDataKey[] = "BackgroundSyncUserData";
+}
+
+namespace content {
+
+BackgroundSyncManager::BackgroundSyncRegistrations::
+    BackgroundSyncRegistrations()
+    : id_counter(kInitialCounterId) {
+}
+BackgroundSyncManager::BackgroundSyncRegistrations::BackgroundSyncRegistrations(
+    BackgroundSyncRegistration::RegistrationId id_counter)
+    : id_counter(id_counter) {
+}
+BackgroundSyncManager::BackgroundSyncRegistrations::
+    ~BackgroundSyncRegistrations() {
+}
+
+// static
+scoped_ptr<BackgroundSyncManager> BackgroundSyncManager::Create(
+    const scoped_refptr<ServiceWorkerContextWrapper>& service_worker_context) {
+  BackgroundSyncManager* sync_manager =
+      new BackgroundSyncManager(service_worker_context);
+  sync_manager->Init();
+  return make_scoped_ptr(sync_manager);
+}
+
+BackgroundSyncManager::~BackgroundSyncManager() {
+}
+
+void BackgroundSyncManager::Register(
+    const GURL& origin,
+    int64 sw_registration_id,
+    const BackgroundSyncRegistration& sync_registration,
+    const StatusAndRegistrationCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK(sync_registration.id ==

[davidben, 2015/03/25 16:01:09]

Nit: DCHECK -> DCHECK_EQ

[jkarlin, 2015/03/25 19:24:18]

Done.

+         BackgroundSyncRegistration::kInvalidRegistrationId);
+
+  StatusAndRegistrationCallback pending_callback =
+      base::Bind(&BackgroundSyncManager::PendingStatusAndRegistrationCallback,
+                 weak_ptr_factory_.GetWeakPtr(), callback);
+
+  op_scheduler_.ScheduleOperation(base::Bind(
+      &BackgroundSyncManager::RegisterImpl, weak_ptr_factory_.GetWeakPtr(),
+      origin, sw_registration_id, sync_registration, pending_callback));
+}
+
+void BackgroundSyncManager::Unregister(
+    const GURL& origin,
+    int64 sw_registration_id,
+    const std::string& sync_registration_name,
+    BackgroundSyncRegistration::RegistrationId sync_registration_id,
+    const StatusCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  StatusCallback pending_callback =
+      base::Bind(&BackgroundSyncManager::PendingStatusCallback,
+                 weak_ptr_factory_.GetWeakPtr(), callback);
+
+  op_scheduler_.ScheduleOperation(base::Bind(
+      &BackgroundSyncManager::UnregisterImpl, weak_ptr_factory_.GetWeakPtr(),
+      origin, sw_registration_id, sync_registration_name, sync_registration_id,
+      pending_callback));
+}
+
+void BackgroundSyncManager::GetRegistration(
+    const GURL& origin,
+    int64 sw_registration_id,
+    const std::string sync_registration_name,
+    const StatusAndRegistrationCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  StatusAndRegistrationCallback pending_callback =
+      base::Bind(&BackgroundSyncManager::PendingStatusAndRegistrationCallback,
+                 weak_ptr_factory_.GetWeakPtr(), callback);
+
+  op_scheduler_.ScheduleOperation(
+      base::Bind(&BackgroundSyncManager::GetRegistrationImpl,
+                 weak_ptr_factory_.GetWeakPtr(), origin, sw_registration_id,
+                 sync_registration_name, pending_callback));
+}
+
+BackgroundSyncManager::BackgroundSyncManager(
+    const scoped_refptr<ServiceWorkerContextWrapper>& service_worker_context)
+    : service_worker_context_(service_worker_context), weak_ptr_factory_(this) {
+}
+
+void BackgroundSyncManager::Init() {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  DCHECK(!op_scheduler_.ScheduledOperations());
+
+  op_scheduler_.ScheduleOperation(base::Bind(&BackgroundSyncManager::InitImpl,
+                                             weak_ptr_factory_.GetWeakPtr()));
+}
+
+void BackgroundSyncManager::InitImpl() {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  GetDataFromBackend(
+      kBackgroundSyncUserDataKey,
+      base::Bind(&BackgroundSyncManager::InitDidGetDataFromBackend,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
+void BackgroundSyncManager::InitDidGetDataFromBackend(
+    const std::vector<std::pair<int64, std::string>>& user_data,
+    ServiceWorkerStatusCode status) {
+  for (const std::pair<int64, std::string>& data : user_data) {
+    BackgroundSyncRegistrationsProto registrations_proto;
+    if (registrations_proto.ParseFromString(data.second)) {
+      sw_to_registrations_map_[data.first] = BackgroundSyncRegistrations(
+          registrations_proto.registration_id_counter());
+      BackgroundSyncRegistrations* registrations =
+          &sw_to_registrations_map_[data.first];
+
+      for (int i = 0, max = registrations_proto.registration_size(); i < max;
+           ++i) {
+        const BackgroundSyncRegistrationProto& registration_proto =
+            registrations_proto.registration(i);
+        BackgroundSyncRegistration registration(registration_proto.id(),
+                                                registration_proto.name());

[davidben, 2015/03/25 16:01:09]

Optional: since this data comes from disk, is it worth checking consistency
between registration_proto.id() and registration_id_counter() here? Not sure
what you'd do in that case though... drop it on the floor?

I guess there's also other invariants like "no repeated SW ids" and "no repeated
registration names" and such. How much it's worth bothering with, I dunno.

[jkarlin, 2015/03/25 19:24:18]

Done.

+        if (registration_proto.has_min_period())
+          registration.min_period = registration_proto.min_period();
+        registrations->name_to_registration_map[registration_proto.name()] =
+            registration;
+      }
+    }
+  }
+
+  // TODO(jkarlin): Call the scheduling algorithm here.
+
+  op_scheduler_.CompleteOperationAndRunNext();
+}
+
+void BackgroundSyncManager::RegisterImpl(
+    const GURL& origin,
+    int64 sw_registration_id,
+    const BackgroundSyncRegistration& sync_registration,
+    const StatusAndRegistrationCallback& callback) {
+  BackgroundSyncRegistration existing_registration;
+  if (HasRegistration(sw_registration_id, sync_registration.name,
+                      &existing_registration)) {
+    if (existing_registration.Equals(sync_registration)) {

[davidben, 2015/03/25 16:01:10]

This check gives an interesting interaction with Unregister. Say you call
Unregister(old_registration) and race it with Register(new_registration) under
the same name.

Normally, because Unregister checks an id, you know it will win.

But because of this Equals check, if the old and the new happen to have the same
contents, it depends on which hits the op_scheduler_ first.

(One hopes that no one would do that, and if a SW does weird things like this to
its background registration state with two independent pieces of code fighting
over a name, it's going to be confused regardless. But it is a little odd of
behavior for this component.)

[jkarlin, 2015/03/25 19:24:18]

Interesting. The race potential is there, sync functions can be called from the
document or the SW. However, that's getting into pretty wonky territory and I'm
inclined to leave this as is as it saves writing back to storage each time the
page is loaded (I assume people will register for sync each time they load the
page). 

[davidben, 2015/03/25 19:42:03]

Sounds good.

+      base::MessageLoop::current()->PostTask(
+          FROM_HERE,
+          base::Bind(callback, ERROR_TYPE_OK, existing_registration));
+      return;
+    }
+  }
+
+  BackgroundSyncRegistration new_registration = sync_registration;
+  BackgroundSyncRegistrations* registrations =
+      &sw_to_registrations_map_[sw_registration_id];
+  new_registration.id = registrations->id_counter++;
+
+  AddRegistrationToMap(sw_registration_id, new_registration);
+
+  StoreRegistrations(
+      origin, sw_registration_id,
+      base::Bind(&BackgroundSyncManager::RegisterDidStore,
+                 weak_ptr_factory_.GetWeakPtr(), sw_registration_id,
+                 new_registration, existing_registration, callback));
+}
+
+bool BackgroundSyncManager::HasRegistration(
+    int64 sw_registration_id,
+    const std::string& sync_registration_name,
+    BackgroundSyncRegistration* existing_registration) {
+  SWIdToRegistrationsMap::iterator it =
+      sw_to_registrations_map_.find(sw_registration_id);
+  if (it == sw_to_registrations_map_.end())
+    return false;
+
+  const BackgroundSyncRegistrations& registrations = it->second;
+  const BackgroundSyncRegistrations::NameToRegistrationMap::const_iterator

[davidben, 2015/03/25 16:01:09]

Nit/optional: This type name is probably a prime candidate to use 'auto' with.
:-)

[jkarlin, 2015/03/25 19:24:18]

Done.

+      reg_iter =
+          registrations.name_to_registration_map.find(sync_registration_name);
+  if (reg_iter == registrations.name_to_registration_map.end())
+    return false;
+
+  if (existing_registration)
+    *existing_registration = reg_iter->second;
+
+  return true;
+}
+
+void BackgroundSyncManager::StoreRegistrations(
+    const GURL& origin,
+    int64 sw_registration_id,
+    const ServiceWorkerStorage::StatusCallback& callback) {
+  // Serialize the data.
+  const BackgroundSyncRegistrations& registrations =
+      sw_to_registrations_map_[sw_registration_id];
+  BackgroundSyncRegistrationsProto registrations_proto;
+  registrations_proto.set_registration_id_counter(registrations.id_counter);
+
+  for (const auto& name_and_registration :
+       registrations.name_to_registration_map) {
+    const BackgroundSyncRegistration& registration =
+        name_and_registration.second;
+    BackgroundSyncRegistrationProto* registration_proto =
+        registrations_proto.add_registration();
+    registration_proto->set_id(registration.id);
+    registration_proto->set_name(registration.name);
+    if (registration.min_period != 0)
+      registration_proto->set_min_period(registration.min_period);
+  }
+  std::string serialized;
+  bool success = registrations_proto.SerializeToString(&serialized);
+  DCHECK(success);
+
+  StoreDataInBackend(sw_registration_id, origin, kBackgroundSyncUserDataKey,
+                     serialized, callback);
+}
+
+void BackgroundSyncManager::RegisterDidStore(
+    int64 sw_registration_id,
+    const BackgroundSyncRegistration& sync_registration,

[davidben, 2015/03/25 16:01:09]

Nit: new_registration, to match the rename in the caller?

[jkarlin, 2015/03/25 19:24:18]

Done.

+    const BackgroundSyncRegistration& previous_registration,
+    const StatusAndRegistrationCallback& callback,
+    ServiceWorkerStatusCode status) {
+  if (status != SERVICE_WORKER_OK) {
+    // Restore the previous state.
+    if (previous_registration.id !=
+        BackgroundSyncRegistration::kInvalidRegistrationId) {
+      AddRegistrationToMap(sw_registration_id, previous_registration);
+    } else {
+      RemoveRegistrationFromMap(sw_registration_id, sync_registration.name,
+                                nullptr);
+    }
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(callback, ERROR_TYPE_STORAGE, BackgroundSyncRegistration()));
+    return;
+  }
+
+  // TODO(jkarlin): Run the registration algorithm.
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE, base::Bind(callback, ERROR_TYPE_OK, sync_registration));
+}
+
+void BackgroundSyncManager::RemoveRegistrationFromMap(
+    int64 sw_registration_id,
+    const std::string& sync_registration_name,
+    BackgroundSyncRegistration* old_registration) {

[davidben, 2015/03/25 16:01:09]

This never writes the old entry to old_registration.

[jkarlin, 2015/03/25 19:24:18]

!!!!

Done.

+  DCHECK(HasRegistration(sw_registration_id, sync_registration_name, nullptr));
+
+  BackgroundSyncRegistrations* registrations =
+      &sw_to_registrations_map_[sw_registration_id];
+  registrations->name_to_registration_map.erase(sync_registration_name);
+}
+
+void BackgroundSyncManager::AddRegistrationToMap(
+    int64 sw_registration_id,
+    const BackgroundSyncRegistration& sync_registration) {
+  DCHECK(sw_registration_id !=

[davidben, 2015/03/25 16:01:09]

Nit: DCHECK_NE

[jkarlin, 2015/03/25 19:24:18]

Done.

+         BackgroundSyncRegistration::kInvalidRegistrationId);
+
+  BackgroundSyncRegistrations* registrations =
+      &sw_to_registrations_map_[sw_registration_id];
+  registrations->name_to_registration_map[sync_registration.name] =
+      sync_registration;
+}
+
+void BackgroundSyncManager::StoreDataInBackend(
+    int64 sw_registration_id,
+    const GURL& origin,
+    const std::string& key,
+    const std::string& data,
+    const ServiceWorkerStorage::StatusCallback& callback) {
+  service_worker_context_->context()->storage()->StoreUserData(
+      sw_registration_id, origin, key, data, callback);
+}
+
+void BackgroundSyncManager::GetDataFromBackend(
+    const std::string& key,
+    const ServiceWorkerStorage::GetUserDataForAllRegistrationsCallback&
+        callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  service_worker_context_->context()->storage()->GetUserDataForAllRegistrations(
+      key, callback);
+}
+
+void BackgroundSyncManager::UnregisterImpl(
+    const GURL& origin,
+    int64 sw_registration_id,
+    const std::string& sync_registration_name,
+    BackgroundSyncRegistration::RegistrationId sync_registration_id,
+    const StatusCallback& callback) {
+  BackgroundSyncRegistration existing_registration;
+  if (!HasRegistration(sw_registration_id, sync_registration_name,
+                       &existing_registration) ||
+      existing_registration.id != sync_registration_id) {
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE, base::Bind(callback, ERROR_TYPE_NOT_FOUND));
+    return;
+  }
+
+  BackgroundSyncRegistration old_sync_registration;
+  RemoveRegistrationFromMap(sw_registration_id, sync_registration_name,
+                            &old_sync_registration);
+
+  StoreRegistrations(
+      origin, sw_registration_id,
+      base::Bind(&BackgroundSyncManager::UnregisterDidStore,
+                 weak_ptr_factory_.GetWeakPtr(), sw_registration_id,
+                 old_sync_registration, callback));
+}
+
+void BackgroundSyncManager::UnregisterDidStore(
+    int64 sw_registration_id,
+    const BackgroundSyncRegistration& old_sync_registration,
+    const StatusCallback& callback,
+    ServiceWorkerStatusCode status) {
+  if (status != SERVICE_WORKER_OK) {
+    // Restore the previous state.
+    AddRegistrationToMap(sw_registration_id, old_sync_registration);
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE, base::Bind(callback, ERROR_TYPE_STORAGE));
+    return;
+  }
+
+  // TODO(jkarlin): Run the registration algorithm.
+  base::MessageLoop::current()->PostTask(FROM_HERE,
+                                         base::Bind(callback, ERROR_TYPE_OK));
+}
+
+void BackgroundSyncManager::GetRegistrationImpl(
+    const GURL& origin,
+    int64 sw_registration_id,
+    const std::string sync_registration_name,
+    const StatusAndRegistrationCallback& callback) {

[davidben, 2015/03/25 16:01:09]

I think this function can just call HasRegistration now.

EDIT: Possibly disregard this if you end up removing the RegisterImpl
special-case and this no longer needs an output parameter. Though maybe it'd be
cleaner anyway? I dunno.

[jkarlin, 2015/03/25 19:24:18]

Done.

+  SWIdToRegistrationsMap::const_iterator it =
+      sw_to_registrations_map_.find(sw_registration_id);
+
+  if (it == sw_to_registrations_map_.end()) {
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE, base::Bind(callback, ERROR_TYPE_NOT_FOUND,
+                              BackgroundSyncRegistration()));
+    return;
+  }
+
+  const BackgroundSyncRegistrations& registrations = it->second;
+  const BackgroundSyncRegistrations::NameToRegistrationMap::const_iterator

[davidben, 2015/03/25 16:01:10]

Optional/nit: ditto about maybe using auto here.

[jkarlin, 2015/03/25 19:24:18]

no longer needed

+      reg_iter =
+          registrations.name_to_registration_map.find(sync_registration_name);
+  if (reg_iter == registrations.name_to_registration_map.end()) {
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE, base::Bind(callback, ERROR_TYPE_NOT_FOUND,
+                              BackgroundSyncRegistration()));
+    return;
+  }
+
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE, base::Bind(callback, ERROR_TYPE_OK, reg_iter->second));
+}
+
+void BackgroundSyncManager::PendingStatusAndRegistrationCallback(
+    const StatusAndRegistrationCallback& callback,
+    ErrorType error,
+    const BackgroundSyncRegistration& sync_registration) {
+  // The callback might delete this object, so hang onto a weak ptr to find out.
+  base::WeakPtr<BackgroundSyncManager> manager = weak_ptr_factory_.GetWeakPtr();
+  callback.Run(error, sync_registration);
+  if (manager)
+    op_scheduler_.CompleteOperationAndRunNext();
+}
+
+void BackgroundSyncManager::PendingStatusCallback(
+    const StatusCallback& callback,
+    ErrorType error) {
+  // The callback might delete this object, so hang onto a weak ptr to find out.
+  base::WeakPtr<BackgroundSyncManager> manager = weak_ptr_factory_.GetWeakPtr();
+  callback.Run(error);
+  if (manager)
+    op_scheduler_.CompleteOperationAndRunNext();
+}
+
+}  // namespace content