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// Copyright (c) 2010 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.
// A class representing an attempt to synchronize the local syncable data
// store with a sync server. A SyncSession instance is passed as a stateful
// bundle to and from various SyncerCommands with the goal of converging the
// client view of data with that of the server. The commands twiddle with
// session status in response to events and hiccups along the way, set and
// query session progress with regards to conflict resolution and applying
// server updates, and access the SyncSessionContext for the current session
// via SyncSession instances.
#ifndef CHROME_BROWSER_SYNC_SESSIONS_SYNC_SESSION_H_
#define CHROME_BROWSER_SYNC_SESSIONS_SYNC_SESSION_H_
#pragma once
#include <map>
#include <string>
#include <utility>
#include <vector>
#include "base/basictypes.h"
#include "base/scoped_ptr.h"
#include "base/time.h"
#include "chrome/browser/sync/engine/model_safe_worker.h"
#include "chrome/browser/sync/sessions/ordered_commit_set.h"
#include "chrome/browser/sync/sessions/session_state.h"
#include "chrome/browser/sync/sessions/status_controller.h"
#include "chrome/browser/sync/sessions/sync_session_context.h"
#include "chrome/browser/sync/syncable/model_type.h"
#include "chrome/browser/sync/util/extensions_activity_monitor.h"
namespace syncable {
class WriteTransaction;
}
namespace browser_sync {
class ModelSafeWorker;
namespace sessions {
class SyncSession {
public:
// The Delegate services events that occur during the session requiring an
// explicit (and session-global) action, as opposed to events that are simply
// recorded in per-session state.
class Delegate {
public:
// The client was throttled and should cease-and-desist syncing activity
// until the specified time.
virtual void OnSilencedUntil(const base::TimeTicks& silenced_until) = 0;
// Silenced intervals can be out of phase with individual sessions, so the
// delegate is the only thing that can give an authoritative answer for
// "is syncing silenced right now". This shouldn't be necessary very often
// as the delegate ensures no session is started if syncing is silenced.
// ** Note ** This will return true if silencing commenced during this
// session and the interval has not yet elapsed, but the contract here is
// solely based on absolute time values. So, this cannot be used to infer
// that any given session _instance_ is silenced. An example of reasonable
// use is for UI reporting.
virtual bool IsSyncingCurrentlySilenced() = 0;
// The client has been instructed to change its short poll interval.
virtual void OnReceivedShortPollIntervalUpdate(
const base::TimeDelta& new_interval) = 0;
// The client has been instructed to change its long poll interval.
virtual void OnReceivedLongPollIntervalUpdate(
const base::TimeDelta& new_interval) = 0;
// The client needs to cease and desist syncing at once. This occurs when
// the Syncer detects that the backend store has fundamentally changed or
// is a different instance altogether (e.g. swapping from a test instance
// to production, or a global stop syncing operation has wiped the store).
virtual void OnShouldStopSyncingPermanently() = 0;
protected:
virtual ~Delegate() {}
};
SyncSession(SyncSessionContext* context,
Delegate* delegate,
const SyncSourceInfo& source,
const ModelSafeRoutingInfo& routing_info,
const std::vector<ModelSafeWorker*>& workers);
~SyncSession();
// Builds a thread-safe and read-only copy of the current session state.
SyncSessionSnapshot TakeSnapshot() const;
// Returns true if this session contains data that should go through the sync
// engine again.
bool HasMoreToSync() const;
// Collects all state pertaining to how and why |s| originated and unions it
// with corresponding state in |this|, leaving |s| unchanged. Allows |this|
// to take on the responsibilities |s| had (e.g. certain data types) in the
// next SyncShare operation using |this|, rather than needed two separate
// sessions.
void Coalesce(const SyncSession& session);
// Should be called any time |this| is being re-used in a new call to
// SyncShare (e.g., HasMoreToSync returned true).
void ResetTransientState();
SyncSessionContext* context() const { return context_; }
Delegate* delegate() const { return delegate_; }
syncable::WriteTransaction* write_transaction() { return write_transaction_; }
StatusController* status_controller() { return status_controller_.get(); }
const ExtensionsActivityMonitor::Records& extensions_activity() const {
return extensions_activity_;
}
ExtensionsActivityMonitor::Records* mutable_extensions_activity() {
return &extensions_activity_;
}
// Volatile reader for the source member of the sync session object. The
// value is set to the SYNC_CYCLE_CONTINUATION value to signal that it has
// been read.
SyncSourceInfo TestAndSetSource();
const std::vector<ModelSafeWorker*>& workers() const { return workers_; }
const ModelSafeRoutingInfo& routing_info() const { return routing_info_; }
const SyncSourceInfo& source() const { return source_; }
private:
// Extend the encapsulation boundary to utilities for internal member
// assignments. This way, the scope of these actions is explicit, they can't
// be overridden, and assigning is always accompanied by unassigning.
friend class ScopedSetSessionWriteTransaction;
// The context for this session, guaranteed to outlive |this|.
SyncSessionContext* const context_;
// The source for initiating this sync session.
SyncSourceInfo source_;
// Information about extensions activity since the last successful commit.
ExtensionsActivityMonitor::Records extensions_activity_;
// Used to allow various steps to share a transaction. Can be NULL.
syncable::WriteTransaction* write_transaction_;
// The delegate for this session, must never be NULL.
Delegate* delegate_;
// Our controller for various status and error counters.
scoped_ptr<StatusController> status_controller_;
// The set of active ModelSafeWorkers for the duration of this session.
// This can change if this session is Coalesce()'d with another.
std::vector<ModelSafeWorker*> workers_;
// The routing info for the duration of this session, dictating which
// datatypes should be synced and which workers should be used when working
// on those datatypes.
ModelSafeRoutingInfo routing_info_;
DISALLOW_COPY_AND_ASSIGN(SyncSession);
};
// Installs a WriteTransaction to a given session and later clears it when the
// utility falls out of scope. Transactions are not nestable, so it is an error
// to try and use one of these if the session already has a transaction.
class ScopedSetSessionWriteTransaction {
public:
ScopedSetSessionWriteTransaction(SyncSession* session,
syncable::WriteTransaction* trans)
: session_(session) {
DCHECK(!session_->write_transaction_);
session_->write_transaction_ = trans;
}
~ScopedSetSessionWriteTransaction() { session_->write_transaction_ = NULL; }
private:
SyncSession* session_;
DISALLOW_COPY_AND_ASSIGN(ScopedSetSessionWriteTransaction);
};
} // namespace sessions
} // namespace browser_sync
#endif // CHROME_BROWSER_SYNC_SESSIONS_SYNC_SESSION_H_
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