Relieve SyncerSession,SyncCycleState, SyncProcessState, SyncerSession, Syncer...

chrome/browser/sync/sessions/sync_session_context.h

+// Copyright (c) 2009 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.
+
+// SyncSessionContext encapsulates the contextual information and engine
+// components specific to a SyncSession. A context is accessible via
+// a SyncSession so that session SyncerCommands and parts of the engine have
+// a convenient way to access other parts. In this way it can be thought of as
+// the surrounding environment for the SyncSession. The components of this
+// environment are either valid or not valid for the entire context lifetime,
+// or they are valid for explicitly scoped periods of time by using Scoped
+// installation utilities found below. This means that the context assumes no
+// ownership whatsoever of any object that was not created by the context
+// itself.
+//
+// It can only be used from the SyncerThread.
+
+#ifndef CHROME_BROWSER_SYNC_SESSIONS_SYNC_SESSION_CONTEXT_H_
+#define CHROME_BROWSER_SYNC_SESSIONS_SYNC_SESSION_CONTEXT_H_
+
+#include <string>
+#include "chrome/browser/chrome_thread.h"
+#include "chrome/browser/sync/engine/model_safe_worker.h"
+#include "chrome/browser/sync/engine/syncer_types.h"
+#include "chrome/browser/sync/util/extensions_activity_monitor.h"
+
+namespace syncable {
+class DirectoryManager;
+}
+
+namespace browser_sync {
+
+class ConflictResolver;
+class ServerConnectionManager;
+
+namespace sessions {
+class ScopedSessionContextConflictResolver;
+class ScopedSessionContextSyncerEventChannel;
+
+class SyncSessionContext {
+ public:
+  SyncSessionContext(ServerConnectionManager* connection_manager,
+                     syncable::DirectoryManager* directory_manager,
+                     ModelSafeWorker* model_safe_worker)
+      : resolver_(NULL),
+        syncer_event_channel_(NULL),
+        connection_manager_(connection_manager),
+        directory_manager_(directory_manager),
+        model_safe_worker_(model_safe_worker),
+        extensions_activity_monitor_(new ExtensionsActivityMonitor()),
+        notifications_enabled_(false) {
+  }
+
+  ~SyncSessionContext() {
+    // In unittests, there may be no UI thread, so the above will fail.
+    if (!ChromeThread::DeleteSoon(ChromeThread::UI, FROM_HERE,
+                                  extensions_activity_monitor_)) {
+      delete extensions_activity_monitor_;
+    }
+  }
+
+  ConflictResolver* resolver() { return resolver_; }
+  ServerConnectionManager* connection_manager() {
+    return connection_manager_;
+  }
+  syncable::DirectoryManager* directory_manager() {
+    return directory_manager_;
+  }
+  SyncerEventChannel* syncer_event_channel() {
+    return syncer_event_channel_;
+  }
+  ModelSafeWorker* model_safe_worker() {
+    return model_safe_worker_.get();
+  }
+  ExtensionsActivityMonitor* extensions_monitor() {
+    return extensions_activity_monitor_;
+  }
+
+  // Talk notification status.
+  void set_notifications_enabled(bool enabled) {
+    notifications_enabled_ = enabled;
+  }
+  bool notifications_enabled() { return notifications_enabled_; }
+
+  // Account name, set once a directory has been opened.
+  void set_account_name(const std::string name) {
+    DCHECK(account_name_.empty());
+    account_name_ = name;
+  }
+  const std::string& account_name() { return account_name_; }
+
+ private:
+  // Rather than force clients to set and null-out various context members, we
+  // extend our encapsulation boundary to scoped helpers that take care of this
+  // once they are allocated. See definitions of these below.
+  friend class ScopedSessionContextConflictResolver;
+  friend class ScopedSessionContextSyncerEventChannel;
+
+  // These are installed by Syncer objects when needed and may be NULL.
+  ConflictResolver* resolver_;
+  SyncerEventChannel* syncer_event_channel_;
+
+  ServerConnectionManager* const connection_manager_;
+  syncable::DirectoryManager* const directory_manager_;
+
+  // A worker capable of processing work closures on a thread that is
+  // guaranteed to be safe for model modifications.
+  scoped_ptr<ModelSafeWorker> model_safe_worker_;
+
+  // We use this to stuff extensions activity into CommitMessages so the server
+  // can correlate commit traffic with extension-related bookmark mutations.
+  ExtensionsActivityMonitor* extensions_activity_monitor_;
+
+  // Kept up to date with talk events to determine whether notifications are
+  // enabled. True only if the notification channel is authorized and open.
+  bool notifications_enabled_;
+
+  // The name of the account being synced.
+  std::string account_name_;
+
+  DISALLOW_COPY_AND_ASSIGN(SyncSessionContext);
+};
+
+// Installs a ConflictResolver to a given session context for the lifetime of
+// the ScopedSessionContextConflictResolver.  There should never be more than
+// one ConflictResolver in the system, so it is an error to use this if the
+// context already has a resolver.
+class ScopedSessionContextConflictResolver {
+ public:
+  // Note: |context| and |resolver| should outlive |this|.
+  ScopedSessionContextConflictResolver(SyncSessionContext* context,
+                                       ConflictResolver* resolver)
+      : context_(context), resolver_(resolver) {
+    DCHECK(NULL == context->resolver_);
+    context->resolver_ = resolver;
+  }
+  ~ScopedSessionContextConflictResolver() {
+    context_->resolver_ = NULL;
+   }
+ private:
+  SyncSessionContext* context_;
+  ConflictResolver* resolver_;
+  DISALLOW_COPY_AND_ASSIGN(ScopedSessionContextConflictResolver);
+};
+
+// Installs a SyncerEventChannel to a given session context for the lifetime of
+// the ScopedSessionContextSyncerEventChannel.  There should never be more than
+// one SyncerEventChannel in the context, so it is an error to use this if the
+// context already has a channel.
+class ScopedSessionContextSyncerEventChannel {
+ public:
+  ScopedSessionContextSyncerEventChannel(SyncSessionContext* context,
+                                         SyncerEventChannel* channel)
+      : context_(context), channel_(channel) {
+    DCHECK(NULL == context->syncer_event_channel_);
+    context->syncer_event_channel_ = channel_;
+  }
+  ~ScopedSessionContextSyncerEventChannel() {
+    context_->syncer_event_channel_ = NULL;
+  }
+ private:
+  SyncSessionContext* context_;
+  SyncerEventChannel* channel_;
+  DISALLOW_COPY_AND_ASSIGN(ScopedSessionContextSyncerEventChannel);
+};
+
+}  // namespace sessions
+}  // namespace browser_sync
+
+#endif  // CHROME_BROWSER_SYNC_SESSIONS_SYNC_SESSION_CONTEXT_H_