sync: Support nudges from non-blocking sync types

Implements support for receiving nudges from the non-blocking sync
engine.  When a non-blocking sync type requests a commit, it will also
send a request to the sync scheduler asking it to schedule
a sync cycle for some time in the future.

Adds some of the code required to support refresh requests, but does not
include an interface to allow clients of the non-blocking sync API to
access it.

Adds basic support for the initial download nudge.  When a non-blocking
type starts syncing for the first time, it sends a request to the
scheduler asking it to download any data available on the server.  This
allows it to complete initial sync quickly and without putting the
scheduler into configure mode.  For now, this looks like
a refresh request in the sync protocol.  This will be changed in
a future CL.

BUG=351005

Review URL: https://codereview.chromium.org/375023002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282439 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 93 insertions, 4 deletions

diff --git a/sync/engine/model_type_sync_worker_impl.cc b/sync/engine/model_type_sync_worker_impl.cc
index 090db11..a5402c2 100644
--- a/sync/engine/model_type_sync_worker_impl.cc
+++ b/sync/engine/model_type_sync_worker_impl.cc
@@ -20,12 +20,18 @@ namespace syncer {
 ModelTypeSyncWorkerImpl::ModelTypeSyncWorkerImpl(
     ModelType type,
     const DataTypeState& initial_state,
+    NudgeHandler* nudge_handler,
     scoped_ptr<ModelTypeSyncProxy> type_sync_proxy)
     : type_(type),
       data_type_state_(initial_state),
       type_sync_proxy_(type_sync_proxy.Pass()),
+      nudge_handler_(nudge_handler),
       entities_deleter_(&entities_),
       weak_ptr_factory_(this) {
+  // Request an initial sync if it hasn't been completed yet.
+  if (!data_type_state_.initial_sync_done) {
+    nudge_handler_->NudgeForInitialDownload(type_);
+  }
 }
 
 ModelTypeSyncWorkerImpl::~ModelTypeSyncWorkerImpl() {
@@ -217,7 +223,8 @@ void ModelTypeSyncWorkerImpl::StorePendingCommit(
                           request.specifics);
   }
 
-  // TODO: Nudge SyncScheduler.
+  if (CanCommitItems())
+    nudge_handler_->NudgeForCommit(type_);
 }
 
 void ModelTypeSyncWorkerImpl::OnCommitResponse(
diff --git a/sync/engine/model_type_sync_worker_impl.h b/sync/engine/model_type_sync_worker_impl.h
index 5837222..69d4156 100644
--- a/sync/engine/model_type_sync_worker_impl.h
+++ b/sync/engine/model_type_sync_worker_impl.h
@@ -12,6 +12,7 @@
 #include "sync/engine/commit_contributor.h"
 #include "sync/engine/model_type_sync_worker.h"
 #include "sync/engine/non_blocking_sync_common.h"
+#include "sync/engine/nudge_handler.h"
 #include "sync/engine/update_handler.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/protocol/sync.pb.h"
@@ -52,6 +53,7 @@ class SYNC_EXPORT ModelTypeSyncWorkerImpl : public UpdateHandler,
  public:
   ModelTypeSyncWorkerImpl(ModelType type,
                           const DataTypeState& initial_state,
+                          NudgeHandler* nudge_handler,
                           scoped_ptr<ModelTypeSyncProxy> type_sync_proxy);
   virtual ~ModelTypeSyncWorkerImpl();
 
@@ -109,6 +111,9 @@ class SYNC_EXPORT ModelTypeSyncWorkerImpl : public UpdateHandler,
   // This is NULL when no proxy is connected..
   scoped_ptr<ModelTypeSyncProxy> type_sync_proxy_;
 
+  // Interface used to access and send nudges to the sync scheduler.  Not owned.
+  NudgeHandler* nudge_handler_;
+
   // A map of per-entity information known to this object.
   //
   // When commits are pending, their information is stored here.  This
diff --git a/sync/engine/model_type_sync_worker_impl_unittest.cc b/sync/engine/model_type_sync_worker_impl_unittest.cc
index 09b47ad..3aaaf3a 100644
--- a/sync/engine/model_type_sync_worker_impl_unittest.cc
+++ b/sync/engine/model_type_sync_worker_impl_unittest.cc
@@ -12,6 +12,7 @@
 #include "sync/sessions/status_controller.h"
 #include "sync/syncable/syncable_util.h"
 #include "sync/test/engine/mock_model_type_sync_proxy.h"
+#include "sync/test/engine/mock_nudge_handler.h"
 #include "sync/test/engine/single_type_mock_server.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
@@ -132,6 +133,12 @@ class ModelTypeSyncWorkerImplTest : public ::testing::Test {
   CommitResponseData GetCommitResponseOnModelThread(
       const std::string& tag) const;
 
+  // Returns the number of commit nudges sent to the mock nudge handler.
+  int GetNumCommitNudges() const;
+
+  // Returns the number of initial sync nudges sent to the mock nudge handler.
+  int GetNumInitialDownloadNudges() const;
+
   // Helpers for building various messages and structures.
   static std::string GenerateTagHash(const std::string& tag);
   static sync_pb::EntitySpecifics GenerateSpecifics(const std::string& tag,
@@ -149,6 +156,10 @@ class ModelTypeSyncWorkerImplTest : public ::testing::Test {
   // a single UpdateHandler and CommitContributor pair.  In this test
   // harness, the |worker_| is both of them.
   SingleTypeMockServer mock_server_;
+
+  // A mock to track the number of times the ModelTypeSyncWorker requests to
+  // sync.
+  MockNudgeHandler mock_nudge_handler_;
 };
 
 ModelTypeSyncWorkerImplTest::ModelTypeSyncWorkerImplTest()
@@ -178,6 +189,8 @@ void ModelTypeSyncWorkerImplTest::NormalInitialize() {
   initial_state.initial_sync_done = true;
 
   InitializeWithState(initial_state);
+
+  mock_nudge_handler_.ClearCounters();
 }
 
 void ModelTypeSyncWorkerImplTest::InitializeWithState(
@@ -188,7 +201,8 @@ void ModelTypeSyncWorkerImplTest::InitializeWithState(
   mock_type_sync_proxy_ = new MockModelTypeSyncProxy();
   scoped_ptr<ModelTypeSyncProxy> proxy(mock_type_sync_proxy_);
 
-  worker_.reset(new ModelTypeSyncWorkerImpl(kModelType, state, proxy.Pass()));
+  worker_.reset(new ModelTypeSyncWorkerImpl(
+      kModelType, state, &mock_nudge_handler_, proxy.Pass()));
 }
 
 void ModelTypeSyncWorkerImplTest::CommitRequest(const std::string& name,
@@ -379,6 +393,14 @@ CommitResponseData ModelTypeSyncWorkerImplTest::GetCommitResponseOnModelThread(
   return mock_type_sync_proxy_->GetCommitResponse(tag_hash);
 }
 
+int ModelTypeSyncWorkerImplTest::GetNumCommitNudges() const {
+  return mock_nudge_handler_.GetNumCommitNudges();
+}
+
+int ModelTypeSyncWorkerImplTest::GetNumInitialDownloadNudges() const {
+  return mock_nudge_handler_.GetNumInitialDownloadNudges();
+}
+
 std::string ModelTypeSyncWorkerImplTest::GenerateTagHash(
     const std::string& tag) {
   const std::string& client_tag_hash =
@@ -412,6 +434,8 @@ TEST_F(ModelTypeSyncWorkerImplTest, SimpleCommit) {
 
   CommitRequest("tag1", "value1");
 
+  EXPECT_EQ(1, GetNumCommitNudges());
+
   ASSERT_TRUE(WillCommit());
   DoSuccessfulCommit();
 
@@ -454,6 +478,7 @@ TEST_F(ModelTypeSyncWorkerImplTest, SimpleDelete) {
   // We can't delete an entity that was never committed.
   // Step 1 is to create and commit a new entity.
   CommitRequest("tag1", "value1");
+  EXPECT_EQ(1, GetNumCommitNudges());
   ASSERT_TRUE(WillCommit());
   DoSuccessfulCommit();
 
@@ -502,16 +527,19 @@ TEST_F(ModelTypeSyncWorkerImplTest, NoDeleteUncommitted) {
   // Request the commit of a new, never-before-seen item.
   CommitRequest("tag1", "value1");
   EXPECT_TRUE(WillCommit());
+  EXPECT_EQ(1, GetNumCommitNudges());
 
   // Request a deletion of that item before we've had a chance to commit it.
   DeleteRequest("tag1");
   EXPECT_FALSE(WillCommit());
+  EXPECT_EQ(2, GetNumCommitNudges());
 }
 
 // Verifies the sending of an "initial sync done" signal.
 TEST_F(ModelTypeSyncWorkerImplTest, SendInitialSyncDone) {
   FirstInitialize();  // Initialize with no saved sync state.
   EXPECT_EQ(0U, GetNumModelThreadUpdateResponses());
+  EXPECT_EQ(1, GetNumInitialDownloadNudges());
 
   // Receive an update response that contains only the type root node.
   TriggerTypeRootUpdateFromServer();
@@ -538,6 +566,7 @@ TEST_F(ModelTypeSyncWorkerImplTest, TwoNewItemsCommittedSeparately) {
 
   // Commit the first of two entities.
   CommitRequest("tag1", "value1");
+  EXPECT_EQ(1, GetNumCommitNudges());
   ASSERT_TRUE(WillCommit());
   DoSuccessfulCommit();
   ASSERT_EQ(1U, GetNumCommitMessagesOnServer());
@@ -548,6 +577,7 @@ TEST_F(ModelTypeSyncWorkerImplTest, TwoNewItemsCommittedSeparately) {
 
   // Commit the second of two entities.
   CommitRequest("tag2", "value2");
+  EXPECT_EQ(2, GetNumCommitNudges());
   ASSERT_TRUE(WillCommit());
   DoSuccessfulCommit();
   ASSERT_EQ(2U, GetNumCommitMessagesOnServer());
diff --git a/sync/engine/nudge_handler.cc b/sync/engine/nudge_handler.cc
new file mode 100644
index 0000000..9c0ef7d
--- /dev/null
+++ b/sync/engine/nudge_handler.cc
@@ -0,0 +1,15 @@
+// Copyright 2014 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 "sync/engine/nudge_handler.h"
+
+namespace syncer {
+
+NudgeHandler::NudgeHandler() {
+}
+
+NudgeHandler::~NudgeHandler() {
+}
+
+}  // namespace syncer
diff --git a/sync/engine/nudge_handler.h b/sync/engine/nudge_handler.h
new file mode 100644
index 0000000..f5d18ea
--- /dev/null
+++ b/sync/engine/nudge_handler.h
@@ -0,0 +1,26 @@
+// Copyright 2014 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_NUDGE_HANDLER_H_
+#define SYNC_ENGINE_NUDGE_HANDLER_H_
+
+#include "base/compiler_specific.h"
+#include "sync/base/sync_export.h"
+#include "sync/internal_api/public/base/model_type.h"
+
+namespace syncer {
+
+class SYNC_EXPORT_PRIVATE NudgeHandler {
+ public:
+  NudgeHandler();
+  virtual ~NudgeHandler();
+
+  virtual void NudgeForInitialDownload(syncer::ModelType type) = 0;
+  virtual void NudgeForCommit(syncer::ModelType type) = 0;
+  virtual void NudgeForRefresh(syncer::ModelType type) = 0;
+};
+
+}  // namespace syncer
+
+#endif  // SYNC_ENGINE_NUDGE_HANDLER_H_
diff --git a/sync/engine/sync_scheduler_unittest.cc b/sync/engine/sync_scheduler_unittest.cc
index 8348eab..7cf7360 100644
--- a/sync/engine/sync_scheduler_unittest.cc
+++ b/sync/engine/sync_scheduler_unittest.cc
@@ -19,6 +19,7 @@
 #include "sync/test/callback_counter.h"
 #include "sync/test/engine/fake_model_worker.h"
 #include "sync/test/engine/mock_connection_manager.h"
+#include "sync/test/engine/mock_nudge_handler.h"
 #include "sync/test/engine/test_directory_setter_upper.h"
 #include "sync/test/mock_invalidation.h"
 #include "sync/util/extensions_activity.h"
@@ -131,7 +132,8 @@ class SyncSchedulerTest : public testing::Test {
                                                 &cancelation_signal_));
     connection_->SetServerReachable();
 
-    model_type_registry_.reset(new ModelTypeRegistry(workers_, directory()));
+    model_type_registry_.reset(
+        new ModelTypeRegistry(workers_, directory(), &mock_nudge_handler_));
 
     context_.reset(new SyncSessionContext(
             connection_.get(), directory(),
@@ -240,6 +242,7 @@ class SyncSchedulerTest : public testing::Test {
   scoped_ptr<ModelTypeRegistry> model_type_registry_;
   scoped_ptr<SyncSessionContext> context_;
   scoped_ptr<SyncSchedulerImpl> scheduler_;
+  MockNudgeHandler mock_nudge_handler_;
   MockSyncer* syncer_;
   MockDelayProvider* delay_;
   std::vector<scoped_refptr<ModelSafeWorker> > workers_;
diff --git a/sync/engine/syncer_unittest.cc b/sync/engine/syncer_unittest.cc
index 98cde3b..6f891e8d 100644
--- a/sync/engine/syncer_unittest.cc
+++ b/sync/engine/syncer_unittest.cc
@@ -47,6 +47,7 @@
 #include "sync/syncable/syncable_write_transaction.h"
 #include "sync/test/engine/fake_model_worker.h"
 #include "sync/test/engine/mock_connection_manager.h"
+#include "sync/test/engine/mock_nudge_handler.h"
 #include "sync/test/engine/test_directory_setter_upper.h"
 #include "sync/test/engine/test_id_factory.h"
 #include "sync/test/engine/test_syncable_utils.h"
@@ -294,7 +295,8 @@ class SyncerTest : public testing::Test,
     ModelSafeRoutingInfo routing_info;
     GetModelSafeRoutingInfo(&routing_info);
 
-    model_type_registry_.reset(new ModelTypeRegistry(workers_, directory()));
+    model_type_registry_.reset(
+        new ModelTypeRegistry(workers_, directory(), &mock_nudge_handler_));
     model_type_registry_->RegisterDirectoryTypeDebugInfoObserver(
         &debug_info_cache_);
 
@@ -584,6 +586,7 @@ class SyncerTest : public testing::Test,
 
   scoped_ptr<SyncSession> session_;
   TypeDebugInfoCache debug_info_cache_;
+  MockNudgeHandler mock_nudge_handler_;
   scoped_ptr<ModelTypeRegistry> model_type_registry_;
   scoped_ptr<SyncSessionContext> context_;
   bool saw_syncer_event_;