sync: Expose sync functionality as functions

sync/engine/syncer.h

 // Copyright (c) 2012 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.
 
 #ifndef SYNC_ENGINE_SYNCER_H_
 #define SYNC_ENGINE_SYNCER_H_
 
 #include <utility>
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/synchronization/lock.h"
 #include "sync/base/sync_export.h"
 #include "sync/engine/conflict_resolver.h"
 #include "sync/engine/syncer_types.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/sessions/sync_session.h"
 #include "sync/util/extensions_activity_monitor.h"
 
 namespace syncer {
 
-namespace syncable {
-class Entry;
-class MutableEntry;
-}  // namespace syncable
-
-enum SyncerStep {
-  SYNCER_BEGIN,
-  DOWNLOAD_UPDATES,
-  PROCESS_UPDATES,
-  STORE_TIMESTAMPS,
-  APPLY_UPDATES,
-  COMMIT,
-  SYNCER_END
-};
-
 // A Syncer provides a control interface for driving the individual steps
 // of the sync cycle.  Each cycle (hopefully) moves the client into closer
 // synchronization with the server.  The individual steps are modeled
 // as SyncerCommands, and the ordering of the steps is expressed using
 // the SyncerStep enum.
 //
 // A Syncer instance expects to run on a dedicated thread.  Calls
 // to SyncShare() may take an unbounded amount of time, as SyncerCommands
 // may block on network i/o, on lock contention, or on tasks posted to
 // other threads.
 class SYNC_EXPORT_PRIVATE Syncer {
  public:
   typedef std::vector<int64> UnsyncedMetaHandles;
 
   Syncer();
   virtual ~Syncer();
 
   // Called by other threads to tell the syncer to stop what it's doing
   // and return early from SyncShare, if possible.
   bool ExitRequested();
   void RequestEarlyExit();
 
-  // Runs a sync cycle from |first_step| to |last_step|.
-  // Returns true if the cycle completed with |last_step|, and false
-  // if it terminated early due to error / exit requested.
-  virtual bool SyncShare(sessions::SyncSession* session,
-                         SyncerStep first_step,
-                         SyncerStep last_step);
+  virtual bool NormalSyncShare(ModelTypeSet request_types,
+                               const sessions::NudgeTracker& nudge_tracker,
+                               sessions::SyncSession* session);
+  virtual bool ConfigureSyncShare(ModelTypeSet request_types,
+                                  sessions::SyncSession* session);
+  virtual bool PollSyncShare(ModelTypeSet request_types,
+                             sessions::SyncSession* session);
 
  private:
+  void ApplyUpdates(sessions::SyncSession* session);
+  bool DownloadAndApplyUpdates(
+      sessions::SyncSession* session,
+      base::Callback<SyncerError(void)> download_fn);
+
+  void HandleCycleBegin(sessions::SyncSession* session);
+  bool HandleCycleEnd(sessions::SyncSession* session);
+
   bool early_exit_requested_;
   base::Lock early_exit_requested_lock_;
 
   friend class SyncerTest;
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, NameClashWithResolver);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, IllegalAndLegalUpdates);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingAndNewParent);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest,
                            TestCommitListOrderingAndNewParentAndChild);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingCounterexample);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingWithNesting);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestCommitListOrderingWithNewItems);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestGetUnsyncedAndSimpleCommit);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestPurgeWhileUnsynced);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, TestPurgeWhileUnapplied);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, UnappliedUpdateDuringCommit);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, DeletingEntryInFolder);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest,
                            LongChangelistCreatesFakeOrphanedEntries);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, QuicklyMergeDualCreatedHierarchy);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, LongChangelistWithApplicationConflict);
   FRIEND_TEST_ALL_PREFIXES(SyncerTest, DeletingEntryWithLocalEdits);
   FRIEND_TEST_ALL_PREFIXES(EntryCreatedInNewFolderTest,
                            EntryCreatedInNewFolderMidSync);
 
   DISALLOW_COPY_AND_ASSIGN(Syncer);
 };
 
-// Utility function declarations.
-void CopyServerFields(syncable::Entry* src, syncable::MutableEntry* dest);
-const char* SyncerStepToString(const SyncerStep);
-
 }  // namespace syncer
 
 #endif  // SYNC_ENGINE_SYNCER_H_