Refactor FakeAttachmentStore

Refactor FakeAttachmentStore into AttachmentStoreProxy and
InMemoryAttachmentStore backend. Break AttachmentStore interface into
AttachmentStoreBase (common interface for backends) and AttachmentStore
(referenced by datatype and AttachmentService).

BUG=
R=maniscalco@chromium.org

Review URL: https://codereview.chromium.org/601553004

Cr-Commit-Position: refs/heads/master@{#297339}

5 files changed, 33 insertions, 449 deletions

diff --git a/sync/api/attachments/attachment_store.cc b/sync/api/attachments/attachment_store.cc
index e22b040..ad4489e 100644
--- a/sync/api/attachments/attachment_store.cc
+++ b/sync/api/attachments/attachment_store.cc
@@ -4,9 +4,24 @@
 
 #include "sync/api/attachments/attachment_store.h"
 
+#include "base/thread_task_runner_handle.h"
+#include "sync/internal_api/public/attachments/attachment_store_handle.h"
+#include "sync/internal_api/public/attachments/in_memory_attachment_store.h"
+
 namespace syncer {
 
+AttachmentStoreBase::AttachmentStoreBase() {}
+AttachmentStoreBase::~AttachmentStoreBase() {}
+
 AttachmentStore::AttachmentStore() {}
 AttachmentStore::~AttachmentStore() {}
 
+scoped_refptr<AttachmentStore> AttachmentStore::CreateInMemoryStore() {
+  // Both frontend and backend of attachment store will live on current thread.
+  scoped_ptr<AttachmentStoreBase> backend(
+      new InMemoryAttachmentStore(base::ThreadTaskRunnerHandle::Get()));
+  return scoped_refptr<AttachmentStore>(new AttachmentStoreHandle(
+      backend.Pass(), base::ThreadTaskRunnerHandle::Get()));
+}
+
 }  // namespace syncer
diff --git a/sync/api/attachments/attachment_store.h b/sync/api/attachments/attachment_store.h
index d487f8c..45ccaf9 100644
--- a/sync/api/attachments/attachment_store.h
+++ b/sync/api/attachments/attachment_store.h
@@ -25,10 +25,8 @@ class AttachmentId;
 //
 // Destroying this object does not necessarily cancel outstanding async
 // operations. If you need cancel like semantics, use WeakPtr in the callbacks.
-class SYNC_EXPORT AttachmentStore : public base::RefCounted<AttachmentStore> {
+class SYNC_EXPORT AttachmentStoreBase {
  public:
-  AttachmentStore();
-
   // TODO(maniscalco): Consider udpating Read and Write methods to support
   // resumable transfers (bug 353292).
 
@@ -43,6 +41,9 @@ class SYNC_EXPORT AttachmentStore : public base::RefCounted<AttachmentStore> {
   typedef base::Callback<void(const Result&)> WriteCallback;
   typedef base::Callback<void(const Result&)> DropCallback;
 
+  AttachmentStoreBase();
+  virtual ~AttachmentStoreBase();
+
   // Asynchronously reads the attachments identified by |ids|.
   //
   // |callback| will be invoked when finished. AttachmentStore will attempt to
@@ -81,9 +82,22 @@ class SYNC_EXPORT AttachmentStore : public base::RefCounted<AttachmentStore> {
   // successfully.
   virtual void Drop(const AttachmentIdList& ids,
                     const DropCallback& callback) = 0;
+};
+
+// AttachmentStore is an interface exposed to data type and AttachmentService
+// code. Also contains factory methods for default implementations.
+class SYNC_EXPORT AttachmentStore
+    : public AttachmentStoreBase,
+      public base::RefCountedThreadSafe<AttachmentStore> {
+ public:
+  AttachmentStore();
+
+  // Creates an AttachmentStoreHandle backed by in-memory implementation of
+  // attachment store. For now frontend lives on the same thread as backend.
+  static scoped_refptr<AttachmentStore> CreateInMemoryStore();
 
  protected:
-  friend class base::RefCounted<AttachmentStore>;
+  friend class base::RefCountedThreadSafe<AttachmentStore>;
   virtual ~AttachmentStore();
 };
 
diff --git a/sync/api/attachments/fake_attachment_store.cc b/sync/api/attachments/fake_attachment_store.cc
deleted file mode 100644
index d20a9b5..0000000
--- a/sync/api/attachments/fake_attachment_store.cc
+++ /dev/null
@@ -1,128 +0,0 @@
-// 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/api/attachments/fake_attachment_store.h"
-
-#include "base/bind.h"
-#include "base/location.h"
-#include "base/memory/ref_counted_memory.h"
-#include "base/sequenced_task_runner.h"
-#include "base/single_thread_task_runner.h"
-#include "base/thread_task_runner_handle.h"
-#include "sync/api/attachments/attachment.h"
-
-namespace syncer {
-
-// Backend is where all the work happens.
-class FakeAttachmentStore::Backend
-    : public base::RefCountedThreadSafe<FakeAttachmentStore::Backend> {
- public:
-  // Construct a Backend that posts its results to |frontend_task_runner|.
-  Backend(
-      const scoped_refptr<base::SingleThreadTaskRunner>& frontend_task_runner);
-
-  void Read(const AttachmentIdList& ids, const ReadCallback& callback);
-  void Write(const AttachmentList& attachments, const WriteCallback& callback);
-  void Drop(const AttachmentIdList& ids, const DropCallback& callback);
-
- private:
-  friend class base::RefCountedThreadSafe<Backend>;
-
-  ~Backend();
-
-  scoped_refptr<base::SingleThreadTaskRunner> frontend_task_runner_;
-  AttachmentMap attachments_;
-};
-
-FakeAttachmentStore::Backend::Backend(
-    const scoped_refptr<base::SingleThreadTaskRunner>& frontend_task_runner)
-    : frontend_task_runner_(frontend_task_runner) {}
-
-FakeAttachmentStore::Backend::~Backend() {}
-
-void FakeAttachmentStore::Backend::Read(const AttachmentIdList& ids,
-                                        const ReadCallback& callback) {
-  Result result_code = SUCCESS;
-  AttachmentIdList::const_iterator id_iter = ids.begin();
-  AttachmentIdList::const_iterator id_end = ids.end();
-  scoped_ptr<AttachmentMap> result_map(new AttachmentMap);
-  scoped_ptr<AttachmentIdList> unavailable_attachments(new AttachmentIdList);
-  for (; id_iter != id_end; ++id_iter) {
-    const AttachmentId& id = *id_iter;
-    syncer::AttachmentMap::iterator attachment_iter =
-        attachments_.find(*id_iter);
-    if (attachment_iter != attachments_.end()) {
-      const Attachment& attachment = attachment_iter->second;
-      result_map->insert(std::make_pair(id, attachment));
-    } else {
-      unavailable_attachments->push_back(id);
-    }
-  }
-  if (!unavailable_attachments->empty()) {
-    result_code = UNSPECIFIED_ERROR;
-  }
-  frontend_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(callback,
-                 result_code,
-                 base::Passed(&result_map),
-                 base::Passed(&unavailable_attachments)));
-}
-
-void FakeAttachmentStore::Backend::Write(const AttachmentList& attachments,
-                                         const WriteCallback& callback) {
-  AttachmentList::const_iterator iter = attachments.begin();
-  AttachmentList::const_iterator end = attachments.end();
-  for (; iter != end; ++iter) {
-    attachments_.insert(std::make_pair(iter->GetId(), *iter));
-  }
-  frontend_task_runner_->PostTask(FROM_HERE, base::Bind(callback, SUCCESS));
-}
-
-void FakeAttachmentStore::Backend::Drop(const AttachmentIdList& ids,
-                                        const DropCallback& callback) {
-  Result result = SUCCESS;
-  AttachmentIdList::const_iterator ids_iter = ids.begin();
-  AttachmentIdList::const_iterator ids_end = ids.end();
-  for (; ids_iter != ids_end; ++ids_iter) {
-    AttachmentMap::iterator attachments_iter = attachments_.find(*ids_iter);
-    if (attachments_iter != attachments_.end()) {
-      attachments_.erase(attachments_iter);
-    }
-  }
-  frontend_task_runner_->PostTask(FROM_HERE, base::Bind(callback, result));
-}
-
-FakeAttachmentStore::FakeAttachmentStore(
-    const scoped_refptr<base::SequencedTaskRunner>& backend_task_runner)
-    : backend_(new Backend(base::ThreadTaskRunnerHandle::Get())),
-      backend_task_runner_(backend_task_runner) {}
-
-FakeAttachmentStore::~FakeAttachmentStore() {}
-
-void FakeAttachmentStore::Read(const AttachmentIdList& ids,
-                               const ReadCallback& callback) {
-  backend_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&FakeAttachmentStore::Backend::Read, backend_, ids, callback));
-}
-
-void FakeAttachmentStore::Write(const AttachmentList& attachments,
-                                const WriteCallback& callback) {
-  backend_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&FakeAttachmentStore::Backend::Write,
-                 backend_,
-                 attachments,
-                 callback));
-}
-
-void FakeAttachmentStore::Drop(const AttachmentIdList& ids,
-                               const DropCallback& callback) {
-  backend_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&FakeAttachmentStore::Backend::Drop, backend_, ids, callback));
-}
-
-}  // namespace syncer
diff --git a/sync/api/attachments/fake_attachment_store.h b/sync/api/attachments/fake_attachment_store.h
deleted file mode 100644
index 9ac7006..0000000
--- a/sync/api/attachments/fake_attachment_store.h
+++ /dev/null
@@ -1,60 +0,0 @@
-// 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_API_ATTACHMENTS_FAKE_ATTACHMENT_STORE_H_
-#define SYNC_API_ATTACHMENTS_FAKE_ATTACHMENT_STORE_H_
-
-#include <map>
-
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/stl_util.h"
-#include "sync/api/attachments/attachment_store.h"
-#include "sync/base/sync_export.h"
-
-namespace base {
-class SequencedTaskRunner;
-class SingleThreadTaskRunner;
-}  // namespace base
-
-namespace sync_pb {
-class AttachmentId;
-}  // namespace sync_pb
-
-namespace syncer {
-
-class Attachment;
-
-// A in-memory only implementation of AttachmentStore used for testing.
-//
-// Requires that the current thread has a MessageLoop.
-class SYNC_EXPORT FakeAttachmentStore : public AttachmentStore {
- public:
-  // Construct a FakeAttachmentStore whose "IO" will be performed in
-  // |backend_task_runner|.
-  explicit FakeAttachmentStore(
-      const scoped_refptr<base::SequencedTaskRunner>& backend_task_runner);
-
-  // AttachmentStore implementation.
-  virtual void Read(const AttachmentIdList& id,
-                    const ReadCallback& callback) OVERRIDE;
-  virtual void Write(const AttachmentList& attachments,
-                     const WriteCallback& callback) OVERRIDE;
-  virtual void Drop(const AttachmentIdList& id,
-                    const DropCallback& callback) OVERRIDE;
-
- private:
-  class Backend;
-
-  virtual ~FakeAttachmentStore();
-
-  scoped_refptr<Backend> backend_;
-  scoped_refptr<base::SequencedTaskRunner> backend_task_runner_;
-
-  DISALLOW_COPY_AND_ASSIGN(FakeAttachmentStore);
-};
-
-}  // namespace syncer
-
-#endif  // SYNC_API_ATTACHMENTS_FAKE_ATTACHMENT_STORE_H_
diff --git a/sync/api/attachments/fake_attachment_store_unittest.cc b/sync/api/attachments/fake_attachment_store_unittest.cc
deleted file mode 100644
index 71b9e50..0000000
--- a/sync/api/attachments/fake_attachment_store_unittest.cc
+++ /dev/null
@@ -1,257 +0,0 @@
-// 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/api/attachments/fake_attachment_store.h"
-
-#include "base/bind.h"
-#include "base/memory/ref_counted_memory.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/message_loop/message_loop.h"
-#include "base/thread_task_runner_handle.h"
-#include "sync/api/attachments/attachment.h"
-#include "sync/protocol/sync.pb.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace syncer {
-
-const char kTestData1[] = "test data 1";
-const char kTestData2[] = "test data 2";
-
-class FakeAttachmentStoreTest : public testing::Test {
- protected:
-  base::MessageLoop message_loop;
-  scoped_refptr<FakeAttachmentStore> store;
-  AttachmentStore::Result result;
-  scoped_ptr<AttachmentMap> attachments;
-  scoped_ptr<AttachmentIdList> failed_attachment_ids;
-
-  AttachmentStore::ReadCallback read_callback;
-  AttachmentStore::WriteCallback write_callback;
-  AttachmentStore::DropCallback drop_callback;
-
-  scoped_refptr<base::RefCountedString> some_data1;
-  scoped_refptr<base::RefCountedString> some_data2;
-
-  FakeAttachmentStoreTest()
-      : store(new FakeAttachmentStore(base::ThreadTaskRunnerHandle::Get())) {}
-
-  virtual void SetUp() {
-    Clear();
-    read_callback = base::Bind(&FakeAttachmentStoreTest::CopyResultAttachments,
-                               base::Unretained(this),
-                               &result,
-                               &attachments,
-                               &failed_attachment_ids);
-    write_callback = base::Bind(
-        &FakeAttachmentStoreTest::CopyResult, base::Unretained(this), &result);
-    drop_callback = write_callback;
-
-    some_data1 = new base::RefCountedString;
-    some_data1->data() = kTestData1;
-
-    some_data2 = new base::RefCountedString;
-    some_data2->data() = kTestData2;
-  }
-
-  virtual void ClearAndPumpLoop() {
-    Clear();
-    message_loop.RunUntilIdle();
-  }
-
- private:
-  void Clear() {
-    result = AttachmentStore::UNSPECIFIED_ERROR;
-    attachments.reset();
-    failed_attachment_ids.reset();
-  }
-
-  void CopyResult(AttachmentStore::Result* destination_result,
-                  const AttachmentStore::Result& source_result) {
-    *destination_result = source_result;
-  }
-
-  void CopyResultAttachments(
-      AttachmentStore::Result* destination_result,
-      scoped_ptr<AttachmentMap>* destination_attachments,
-      scoped_ptr<AttachmentIdList>* destination_failed_attachment_ids,
-      const AttachmentStore::Result& source_result,
-      scoped_ptr<AttachmentMap> source_attachments,
-      scoped_ptr<AttachmentIdList> source_failed_attachment_ids) {
-    CopyResult(destination_result, source_result);
-    *destination_attachments = source_attachments.Pass();
-    *destination_failed_attachment_ids = source_failed_attachment_ids.Pass();
-  }
-};
-
-// Verify that we do not overwrite existing attachments and that we do not treat
-// it as an error.
-TEST_F(FakeAttachmentStoreTest, Write_NoOverwriteNoError) {
-  // Create two attachments with the same id but different data.
-  Attachment attachment1 = Attachment::Create(some_data1);
-  Attachment attachment2 =
-      Attachment::CreateWithId(attachment1.GetId(), some_data2);
-
-  // Write the first one.
-  AttachmentList some_attachments;
-  some_attachments.push_back(attachment1);
-  store->Write(some_attachments, write_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-
-  // Write the second one.
-  some_attachments.clear();
-  some_attachments.push_back(attachment2);
-  store->Write(some_attachments, write_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-
-  // Read it back and see that it was not overwritten.
-  AttachmentIdList some_attachment_ids;
-  some_attachment_ids.push_back(attachment1.GetId());
-  store->Read(some_attachment_ids, read_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-  EXPECT_EQ(attachments->size(), 1U);
-  EXPECT_EQ(failed_attachment_ids->size(), 0U);
-  AttachmentMap::const_iterator a1 = attachments->find(attachment1.GetId());
-  EXPECT_TRUE(a1 != attachments->end());
-  EXPECT_TRUE(attachment1.GetData()->Equals(a1->second.GetData()));
-}
-
-// Verify that we can write some attachments and read them back.
-TEST_F(FakeAttachmentStoreTest, Write_RoundTrip) {
-  Attachment attachment1 = Attachment::Create(some_data1);
-  Attachment attachment2 = Attachment::Create(some_data2);
-  AttachmentList some_attachments;
-  some_attachments.push_back(attachment1);
-  some_attachments.push_back(attachment2);
-
-  store->Write(some_attachments, write_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-
-  AttachmentIdList some_attachment_ids;
-  some_attachment_ids.push_back(attachment1.GetId());
-  some_attachment_ids.push_back(attachment2.GetId());
-  store->Read(some_attachment_ids, read_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-  EXPECT_EQ(attachments->size(), 2U);
-  EXPECT_EQ(failed_attachment_ids->size(), 0U);
-
-  AttachmentMap::const_iterator a1 = attachments->find(attachment1.GetId());
-  EXPECT_TRUE(a1 != attachments->end());
-  EXPECT_TRUE(attachment1.GetData()->Equals(a1->second.GetData()));
-
-  AttachmentMap::const_iterator a2 = attachments->find(attachment2.GetId());
-  EXPECT_TRUE(a2 != attachments->end());
-  EXPECT_TRUE(attachment2.GetData()->Equals(a2->second.GetData()));
-}
-
-// Try to read two attachments when only one exists.
-TEST_F(FakeAttachmentStoreTest, Read_OneNotFound) {
-  Attachment attachment1 = Attachment::Create(some_data1);
-  Attachment attachment2 = Attachment::Create(some_data2);
-
-  AttachmentList some_attachments;
-  // Write attachment1 only.
-  some_attachments.push_back(attachment1);
-  store->Write(some_attachments, write_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-
-  // Try to read both attachment1 and attachment2.
-  AttachmentIdList ids;
-  ids.push_back(attachment1.GetId());
-  ids.push_back(attachment2.GetId());
-  store->Read(ids, read_callback);
-  ClearAndPumpLoop();
-
-  // See that only attachment1 was read.
-  EXPECT_EQ(result, AttachmentStore::UNSPECIFIED_ERROR);
-  EXPECT_EQ(attachments->size(), 1U);
-  EXPECT_EQ(failed_attachment_ids->size(), 1U);
-}
-
-// Try to drop two attachments when only one exists. Verify that no error occurs
-// and that the existing attachment was dropped.
-TEST_F(FakeAttachmentStoreTest, Drop_DropTwoButOnlyOneExists) {
-  // First, create two attachments.
-  Attachment attachment1 = Attachment::Create(some_data1);
-  Attachment attachment2 = Attachment::Create(some_data2);
-  AttachmentList some_attachments;
-  some_attachments.push_back(attachment1);
-  some_attachments.push_back(attachment2);
-  store->Write(some_attachments, write_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-
-  // Drop attachment1 only.
-  AttachmentIdList ids;
-  ids.push_back(attachment1.GetId());
-  store->Drop(ids, drop_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-
-  // See that attachment1 is gone.
-  store->Read(ids, read_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::UNSPECIFIED_ERROR);
-  EXPECT_EQ(attachments->size(), 0U);
-  EXPECT_EQ(failed_attachment_ids->size(), 1U);
-  EXPECT_EQ((*failed_attachment_ids)[0], attachment1.GetId());
-
-  // Drop both attachment1 and attachment2.
-  ids.clear();
-  ids.push_back(attachment1.GetId());
-  ids.push_back(attachment2.GetId());
-  store->Drop(ids, drop_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-
-  // See that attachment2 is now gone.
-  ids.clear();
-  ids.push_back(attachment2.GetId());
-  store->Read(ids, read_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::UNSPECIFIED_ERROR);
-  EXPECT_EQ(attachments->size(), 0U);
-  EXPECT_EQ(failed_attachment_ids->size(), 1U);
-  EXPECT_EQ((*failed_attachment_ids)[0], attachment2.GetId());
-}
-
-// Verify that attempting to drop an attachment that does not exist is not an
-// error.
-TEST_F(FakeAttachmentStoreTest, Drop_DoesNotExist) {
-  Attachment attachment1 = Attachment::Create(some_data1);
-  AttachmentList some_attachments;
-  some_attachments.push_back(attachment1);
-  store->Write(some_attachments, write_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-
-  // Drop the attachment.
-  AttachmentIdList ids;
-  ids.push_back(attachment1.GetId());
-  store->Drop(ids, drop_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-
-  // See that it's gone.
-  store->Read(ids, read_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::UNSPECIFIED_ERROR);
-  EXPECT_EQ(attachments->size(), 0U);
-  EXPECT_EQ(failed_attachment_ids->size(), 1U);
-  EXPECT_EQ((*failed_attachment_ids)[0], attachment1.GetId());
-
-  // Drop again, see that no error occurs.
-  ids.clear();
-  ids.push_back(attachment1.GetId());
-  store->Drop(ids, drop_callback);
-  ClearAndPumpLoop();
-  EXPECT_EQ(result, AttachmentStore::SUCCESS);
-}
-
-}  // namespace syncer