sync: Report GetUpdate triggers to the server

sync/sessions/nudge_tracker.h

Index: sync/sessions/nudge_tracker.h
diff --git a/sync/sessions/nudge_tracker.h b/sync/sessions/nudge_tracker.h
index 0128ce096efa4075383b579b502f44eafcd75297..c0932506e8baf63e9e48b347b67a2e50cafa0edb 100644
--- a/sync/sessions/nudge_tracker.h
+++ b/sync/sessions/nudge_tracker.h
@@ -7,11 +7,14 @@
 #ifndef SYNC_SESSIONS_NUDGE_TRACKER_H_
 #define SYNC_SESSIONS_NUDGE_TRACKER_H_
 
-#include <vector>
+#include <list>
+#include <map>
 
 #include "base/compiler_specific.h"
 #include "sync/base/sync_export.h"
-#include "sync/internal_api/public/sessions/sync_source_info.h"
+#include "sync/internal_api/public/base/model_type.h"
+#include "sync/internal_api/public/base/model_type_invalidation_map.h"
+#include "sync/protocol/sync.pb.h"
 
 namespace syncer {
 namespace sessions {
@@ -20,30 +23,107 @@ struct SyncSourceInfo;
 
 class SYNC_EXPORT_PRIVATE NudgeTracker {
  public:
+  static size_t kDefaultMaxPayloadsPerType;
+
   NudgeTracker();
   ~NudgeTracker();
 
-  // Merges in the information from another nudge.
-  void CoalesceSources(const SyncSourceInfo& source);
+  // Returns true if there is a good reason for performing a sync cycle.
+  // This does not take into account whether or not this is a good *time* to
+  // perform a sync cycle; that's the scheduler's job.
+  bool IsSyncRequired();
+
+  // Tells this class that all required update fetching and committing has
+  // completed successfully.
+  void RecordSuccessfulSyncCycle();
+
+  // Takes note of a local change.
+  void RecordLocalChange(ModelTypeSet types);
+
+  // Takes note of a locally issued request to refresh a data type.
+  void RecordLocalRefreshRequest(ModelTypeSet types);
 
-  // Returns true if there are no unserviced nudges.
-  bool IsEmpty();
+  // Takes note of the receipt of an invalidation notice from the server.
+  void RecordRemoteInvalidation(
+      const ModelTypeInvalidationMap& invalidation_map);
 
-  // Clear all unserviced nudges.
-  void Reset();
+  // These functions should be called to keep this class informed of the status
+  // of the connection to the invalidations server.
+  void OnInvalidationsEnabled();
+  void OnInvalidationsDisabled();
 
-  // Returns the coalesced source info.
-  const SyncSourceInfo& source_info() const {
-    return source_info_;
-  }
+  // A helper to return an old-style source info.  Used only to maintain
+  // compatibility with some old code.
+  SyncSourceInfo GetSourceInfo() const;
 
-  // Returns the set of locally modified types, according to our tracked source
-  // infos.  The result is often wrong; see implementation comment for details.
+  // Returns the set of locally modified types, according to the nudges received
+  // since the last successful sync cycle.
   ModelTypeSet GetLocallyModifiedTypes() const;
 
+  // Returns the 'source' of the GetUpdate request.
+  //
+  // This flag is deprecated, but still used by the server.  There can be more
+  // than one reason to perform a particular sync cycle.  The GetUpdatesTrigger
+  // message will contain more reliable information about the reasons for
+  // performing a sync.
+  //
+  // See the implementation for important information about the coalesce logic.
+  sync_pb::GetUpdatesCallerInfo::GetUpdatesSource updates_source() const;
+
+  // Fills a ProgressMarker for the next GetUpdates request.  This is used by
+  // the DownloadUpdatesCommand to dump lots of useful per-type state
+  // information into the GetUpdate request before sending it off to the server.
+  void FillProtoMessage(
+      ModelType type,
+      sync_pb::GetUpdateTriggers* msg) const;
+
+  // Adjusts the number of hints that can be stored locally.
+  void SetHintBufferSize(size_t size);
+
  private:
-  // Merged source info for the nudge(s).
-  SyncSourceInfo source_info_;
+  typedef std::list<std::string> PayloadList;
+  typedef std::map<ModelType, PayloadList> PayloadListMap;
+  typedef std::map<ModelType, int> NudgeMap;
+
+  // Merged updates source.  This should be obsolete, but the server still
+  // relies on it for some heuristics.
+  sync_pb::GetUpdatesCallerInfo::GetUpdatesSource updates_source_;
+
+  // The number of times each type has been locally nudged since the last
+  // successful sync cycle.  If a type is not in the map, the count is zero.
+  NudgeMap local_nudge_counts_;
+
+  // The number of times a refresh was requested each type, since the last
+  // successful sync cycle.  If a type is not in the map, the count is zero.
+  NudgeMap refresh_requested_counts_;
+
+  // A map of datatypes to lists of hints.  The hints are ordered from least
+  // recent to most recent.
+  PayloadListMap payload_list_map_;
+
+  // Tracks the types for which the list of pending hints has overflowed,
+  // causing us to drop the oldest hints.
+  ModelTypeSet locally_dropped_payload_types_;
+
+  // Tracks the types for which the invalidation server has notified us that it
+  // dropped some of its payloads.
+  ModelTypeSet server_dropped_payload_types_;
+
+  // Tracks whether or not invalidations are currently enabled.
+  bool invalidations_enabled_;
+
+  // This flag is set if suspect that some technical malfunction or known bug
+  // may have left us with some unserviced invalidations.
+  //
+  // Keeps track of whether or not we're fully in sync with the invalidation
+  // server.  This can be false even if invalidations are enabled and working
+  // correctly.  For example, until we get ack-tracking working properly, we
+  // won't persist invalidations between restarts, so we may be out of sync when
+  // we restart.  The only way to get back into sync is to have invalidations
+  // enabled, then complete a sync cycle to make sure we're fully up to date.
+  bool invalidations_out_of_sync_;
+
+  size_t num_payloads_per_type_;
 
   DISALLOW_COPY_AND_ASSIGN(NudgeTracker);
 };