Revert of Add Store+Sync to reading list.

ios/chrome/browser/reading_list/reading_list_store.cc

Index: ios/chrome/browser/reading_list/reading_list_store.cc
diff --git a/ios/chrome/browser/reading_list/reading_list_store.cc b/ios/chrome/browser/reading_list/reading_list_store.cc
deleted file mode 100644
index 0c4ca2b0314d69ded9ffadecb5e40c2ea90d8438..0000000000000000000000000000000000000000
--- a/ios/chrome/browser/reading_list/reading_list_store.cc
+++ /dev/null
@@ -1,461 +0,0 @@
-// Copyright 2016 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 "ios/chrome/browser/reading_list/reading_list_store.h"
-
-#include "base/bind.h"
-#include "base/logging.h"
-#include "base/memory/ptr_util.h"
-#include "components/sync/model/entity_change.h"
-#include "components/sync/model/metadata_batch.h"
-#include "components/sync/model/metadata_change_list.h"
-#include "components/sync/model/model_type_change_processor.h"
-#include "components/sync/model/mutable_data_batch.h"
-#include "components/sync/model_impl/accumulating_metadata_change_list.h"
-#include "components/sync/protocol/model_type_state.pb.h"
-#include "ios/chrome/browser/reading_list/proto/reading_list.pb.h"
-#include "ios/chrome/browser/reading_list/reading_list_model_impl.h"
-#include "ios/web/public/web_thread.h"
-
-ReadingListStore::ReadingListStore(
-    StoreFactoryFunction create_store_callback,
-    const ChangeProcessorFactory& change_processor_factory)
-    : ModelTypeSyncBridge(change_processor_factory, syncer::READING_LIST),
-      create_store_callback_(create_store_callback),
-      pending_transaction_count_(0) {}
-
-ReadingListStore::~ReadingListStore() {
-  DCHECK(pending_transaction_count_ == 0);
-}
-
-void ReadingListStore::SetReadingListModel(ReadingListModel* model,
-                                           ReadingListStoreDelegate* delegate) {
-  DCHECK(CalledOnValidThread());
-  model_ = model;
-  delegate_ = delegate;
-  create_store_callback_.Run(
-      base::Bind(&ReadingListStore::OnStoreCreated, base::AsWeakPtr(this)));
-}
-
-std::unique_ptr<ReadingListModelStorage::ScopedBatchUpdate>
-ReadingListStore::EnsureBatchCreated() {
-  return base::WrapUnique<ReadingListModelStorage::ScopedBatchUpdate>(
-      new ScopedBatchUpdate(this));
-}
-
-ReadingListStore::ScopedBatchUpdate::ScopedBatchUpdate(ReadingListStore* store)
-    : store_(store) {
-  store_->BeginTransaction();
-}
-
-ReadingListStore::ScopedBatchUpdate::~ScopedBatchUpdate() {
-  store_->CommitTransaction();
-}
-
-void ReadingListStore::BeginTransaction() {
-  DCHECK(CalledOnValidThread());
-  pending_transaction_count_++;
-  if (pending_transaction_count_ == 1) {
-    batch_ = store_->CreateWriteBatch();
-  }
-}
-
-void ReadingListStore::CommitTransaction() {
-  DCHECK(CalledOnValidThread());
-  pending_transaction_count_--;
-  if (pending_transaction_count_ == 0) {
-    store_->CommitWriteBatch(
-        std::move(batch_),
-        base::Bind(&ReadingListStore::OnDatabaseSave, base::AsWeakPtr(this)));
-    batch_.reset();
-  }
-}
-
-void ReadingListStore::SaveEntry(const ReadingListEntry& entry, bool read) {
-  DCHECK(CalledOnValidThread());
-  auto token = EnsureBatchCreated();
-
-  std::unique_ptr<reading_list::ReadingListLocal> pb_entry =
-      entry.AsReadingListLocal(read);
-
-  batch_->WriteData(entry.URL().spec(), pb_entry->SerializeAsString());
-
-  if (!change_processor()->IsTrackingMetadata()) {
-    return;
-  }
-  std::unique_ptr<sync_pb::ReadingListSpecifics> pb_entry_sync =
-      entry.AsReadingListSpecifics(read);
-
-  std::unique_ptr<syncer::MetadataChangeList> metadata_change_list =
-      CreateMetadataChangeList();
-
-  std::unique_ptr<syncer::EntityData> entity_data(new syncer::EntityData());
-  *entity_data->specifics.mutable_reading_list() = *pb_entry_sync;
-  entity_data->non_unique_name = pb_entry_sync->entry_id();
-
-  change_processor()->Put(entry.URL().spec(), std::move(entity_data),
-                          metadata_change_list.get());
-  batch_->TransferMetadataChanges(std::move(metadata_change_list));
-}
-
-void ReadingListStore::RemoveEntry(const ReadingListEntry& entry) {
-  DCHECK(CalledOnValidThread());
-  auto token = EnsureBatchCreated();
-
-  batch_->DeleteData(entry.URL().spec());
-  if (!change_processor()->IsTrackingMetadata()) {
-    return;
-  }
-  std::unique_ptr<syncer::MetadataChangeList> metadata_change_list =
-      CreateMetadataChangeList();
-
-  change_processor()->Delete(entry.URL().spec(), metadata_change_list.get());
-  batch_->TransferMetadataChanges(std::move(metadata_change_list));
-}
-
-void ReadingListStore::OnDatabaseLoad(
-    syncer::ModelTypeStore::Result result,
-    std::unique_ptr<syncer::ModelTypeStore::RecordList> entries) {
-  DCHECK(CalledOnValidThread());
-  if (result != syncer::ModelTypeStore::Result::SUCCESS) {
-    change_processor()->OnMetadataLoaded(
-        change_processor()->CreateAndUploadError(
-            FROM_HERE, "Cannot load Reading List Database."),
-        nullptr);
-    return;
-  }
-  auto read = base::MakeUnique<ReadingListEntries>();
-  auto unread = base::MakeUnique<ReadingListEntries>();
-
-  for (const syncer::ModelTypeStore::Record& r : *entries.get()) {
-    // for (const reading_list::ReadingListLocal& pb_entry : *entries) {
-    reading_list::ReadingListLocal proto;
-    if (!proto.ParseFromString(r.value)) {
-      continue;
-      // TODO(skym, crbug.com/582460): Handle unrecoverable initialization
-      // failure.
-    }
-
-    std::unique_ptr<ReadingListEntry> entry(
-        ReadingListEntry::FromReadingListLocal(proto));
-    if (!entry) {
-      continue;
-    }
-    if (proto.status() == reading_list::ReadingListLocal::READ) {
-      read->push_back(std::move(*entry));
-    } else {
-      unread->push_back(std::move(*entry));
-    }
-  }
-
-  delegate_->StoreLoaded(std::move(unread), std::move(read));
-
-  store_->ReadAllMetadata(
-      base::Bind(&ReadingListStore::OnReadAllMetadata, base::AsWeakPtr(this)));
-}
-
-void ReadingListStore::OnReadAllMetadata(
-    syncer::SyncError sync_error,
-    std::unique_ptr<syncer::MetadataBatch> metadata_batch) {
-  DCHECK(CalledOnValidThread());
-  change_processor()->OnMetadataLoaded(sync_error, std::move(metadata_batch));
-}
-
-void ReadingListStore::OnDatabaseSave(syncer::ModelTypeStore::Result result) {
-  return;
-}
-
-void ReadingListStore::OnStoreCreated(
-    syncer::ModelTypeStore::Result result,
-    std::unique_ptr<syncer::ModelTypeStore> store) {
-  DCHECK(CalledOnValidThread());
-  if (result != syncer::ModelTypeStore::Result::SUCCESS) {
-    // TODO(crbug.com/664926): handle store creation error.
-    return;
-  }
-  store_ = std::move(store);
-  store_->ReadAllData(
-      base::Bind(&ReadingListStore::OnDatabaseLoad, base::AsWeakPtr(this)));
-  return;
-}
-
-syncer::ModelTypeSyncBridge* ReadingListStore::GetModelTypeSyncBridge() {
-  return this;
-}
-
-// Creates an object used to communicate changes in the sync metadata to the
-// model type store.
-std::unique_ptr<syncer::MetadataChangeList>
-ReadingListStore::CreateMetadataChangeList() {
-  return syncer::ModelTypeStore::WriteBatch::CreateMetadataChangeList();
-}
-
-// Perform the initial merge between local and sync data. This should only be
-// called when a data type is first enabled to start syncing, and there is no
-// sync metadata. Best effort should be made to match local and sync data. The
-// keys in the |entity_data_map| will have been created via GetClientTag(...),
-// and if a local and sync data should match/merge but disagree on tags, the
-// service should use the sync data's tag. Any local pieces of data that are
-// not present in sync should immediately be Put(...) to the processor before
-// returning. The same MetadataChangeList that was passed into this function
-// can be passed to Put(...) calls. Delete(...) can also be called but should
-// not be needed for most model types. Durable storage writes, if not able to
-// combine all change atomically, should save the metadata after the data
-// changes, so that this merge will be re-driven by sync if is not completely
-// saved during the current run.
-syncer::SyncError ReadingListStore::MergeSyncData(
-    std::unique_ptr<syncer::MetadataChangeList> metadata_change_list,
-    syncer::EntityDataMap entity_data_map) {
-  DCHECK(CalledOnValidThread());
-  auto token = EnsureBatchCreated();
-  // Keep track of the last update of each item.
-  std::set<std::string> synced_entries;
-  std::unique_ptr<ReadingListModel::ScopedReadingListBatchUpdate>
-      model_batch_updates = model_->BeginBatchUpdates();
-
-  // Merge sync to local data.
-  for (const auto& kv : entity_data_map) {
-    synced_entries.insert(kv.first);
-    const sync_pb::ReadingListSpecifics& specifics =
-        kv.second.value().specifics.reading_list();
-    // Deserialize entry.
-    bool read = specifics.status() == sync_pb::ReadingListSpecifics::READ;
-    std::unique_ptr<ReadingListEntry> entry(
-        ReadingListEntry::FromReadingListSpecifics(specifics));
-
-    bool was_read;
-    const ReadingListEntry* existing_entry =
-        model_->GetEntryFromURL(entry->URL(), &was_read);
-
-    if (!existing_entry) {
-      // This entry is new. Add it to the store and model.
-      // Convert to local store format and write to store.
-      std::unique_ptr<reading_list::ReadingListLocal> entry_pb =
-          entry->AsReadingListLocal(read);
-      batch_->WriteData(entry->URL().spec(), entry_pb->SerializeAsString());
-
-      // Notify model about updated entry.
-      delegate_->SyncAddEntry(std::move(entry), read);
-    } else if (existing_entry->UpdateTime() < entry->UpdateTime()) {
-      // The entry from sync is more recent.
-      // Merge the local data to it and store it.
-      ReadingListEntry* merged_entry =
-          delegate_->SyncMergeEntry(std::move(entry), read);
-
-      // Write to the store.
-      std::unique_ptr<reading_list::ReadingListLocal> entry_local_pb =
-          merged_entry->AsReadingListLocal(read);
-      batch_->WriteData(entry->URL().spec(),
-                        entry_local_pb->SerializeAsString());
-
-      // Send to sync
-      std::unique_ptr<sync_pb::ReadingListSpecifics> entry_sync_pb =
-          merged_entry->AsReadingListSpecifics(read);
-      auto entity_data = base::MakeUnique<syncer::EntityData>();
-      *(entity_data->specifics.mutable_reading_list()) = *entry_sync_pb;
-      entity_data->non_unique_name = entry_sync_pb->entry_id();
-
-      // TODO(crbug.com/666232): Investigate if there is a risk of sync
-      // ping-pong.
-      change_processor()->Put(entry_sync_pb->entry_id(), std::move(entity_data),
-                              metadata_change_list.get());
-
-    } else {
-      // The entry from sync is out of date.
-      // Send back the local more recent entry.
-      // No need to update
-      std::unique_ptr<sync_pb::ReadingListSpecifics> entry_pb =
-          existing_entry->AsReadingListSpecifics(was_read);
-      auto entity_data = base::MakeUnique<syncer::EntityData>();
-      *(entity_data->specifics.mutable_reading_list()) = *entry_pb;
-      entity_data->non_unique_name = entry_pb->entry_id();
-
-      change_processor()->Put(entry_pb->entry_id(), std::move(entity_data),
-                              metadata_change_list.get());
-    }
-  }
-
-  // Commit local only entries to server.
-  int unread_count = model_->unread_size();
-  int read_count = model_->read_size();
-  for (int index = 0; index < unread_count + read_count; index++) {
-    bool read = index >= unread_count;
-    const ReadingListEntry& entry =
-        read ? model_->GetReadEntryAtIndex(index - unread_count)
-             : model_->GetUnreadEntryAtIndex(index);
-    if (synced_entries.count(entry.URL().spec())) {
-      // Entry already exists and has been merged above.
-      continue;
-    }
-
-    // Local entry has later timestamp. It should be committed to server.
-    std::unique_ptr<sync_pb::ReadingListSpecifics> entry_pb =
-        entry.AsReadingListSpecifics(read);
-
-    auto entity_data = base::MakeUnique<syncer::EntityData>();
-    *(entity_data->specifics.mutable_reading_list()) = *entry_pb;
-    entity_data->non_unique_name = entry_pb->entry_id();
-
-    change_processor()->Put(entry_pb->entry_id(), std::move(entity_data),
-                            metadata_change_list.get());
-  }
-  batch_->TransferMetadataChanges(std::move(metadata_change_list));
-
-  return syncer::SyncError();
-}
-
-// Apply changes from the sync server locally.
-// Please note that |entity_changes| might have fewer entries than
-// |metadata_change_list| in case when some of the data changes are filtered
-// out, or even be empty in case when a commit confirmation is processed and
-// only the metadata needs to persisted.
-syncer::SyncError ReadingListStore::ApplySyncChanges(
-    std::unique_ptr<syncer::MetadataChangeList> metadata_change_list,
-    syncer::EntityChangeList entity_changes) {
-  DCHECK(CalledOnValidThread());
-  std::unique_ptr<ReadingListModel::ScopedReadingListBatchUpdate> batch =
-      model_->BeginBatchUpdates();
-  auto token = EnsureBatchCreated();
-
-  for (syncer::EntityChange& change : entity_changes) {
-    if (change.type() == syncer::EntityChange::ACTION_DELETE) {
-      batch_->DeleteData(change.storage_key());
-      // Need to notify model that entry is deleted.
-      delegate_->SyncRemoveEntry(GURL(change.storage_key()));
-    } else {
-      // Deserialize entry.
-      const sync_pb::ReadingListSpecifics& specifics =
-          change.data().specifics.reading_list();
-      bool read = specifics.status() == sync_pb::ReadingListSpecifics::READ;
-      std::unique_ptr<ReadingListEntry> entry(
-          ReadingListEntry::FromReadingListSpecifics(specifics));
-
-      bool was_read;
-      const ReadingListEntry* existing_entry =
-          model_->GetEntryFromURL(entry->URL(), &was_read);
-
-      if (!existing_entry) {
-        // This entry is new. Add it to the store and model.
-        // Convert to local store format and write to store.
-        std::unique_ptr<reading_list::ReadingListLocal> entry_pb =
-            entry->AsReadingListLocal(read);
-        batch_->WriteData(entry->URL().spec(), entry_pb->SerializeAsString());
-
-        // Notify model about updated entry.
-        delegate_->SyncAddEntry(std::move(entry), read);
-      } else if (existing_entry->UpdateTime() < entry->UpdateTime()) {
-        // The entry from sync is more recent.
-        // Merge the local data to it and store it.
-        ReadingListEntry* merged_entry =
-            delegate_->SyncMergeEntry(std::move(entry), read);
-
-        // Write to the store.
-        std::unique_ptr<reading_list::ReadingListLocal> entry_local_pb =
-            merged_entry->AsReadingListLocal(read);
-        batch_->WriteData(merged_entry->URL().spec(),
-                          entry_local_pb->SerializeAsString());
-
-        // Send to sync
-        std::unique_ptr<sync_pb::ReadingListSpecifics> entry_sync_pb =
-            merged_entry->AsReadingListSpecifics(read);
-        auto entity_data = base::MakeUnique<syncer::EntityData>();
-        *(entity_data->specifics.mutable_reading_list()) = *entry_sync_pb;
-        entity_data->non_unique_name = entry_sync_pb->entry_id();
-
-        // TODO(crbug.com/666232): Investigate if there is a risk of sync
-        // ping-pong.
-        change_processor()->Put(entry_sync_pb->entry_id(),
-                                std::move(entity_data),
-                                metadata_change_list.get());
-
-      } else {
-        // The entry from sync is out of date.
-        // Send back the local more recent entry.
-        // No need to update
-        std::unique_ptr<sync_pb::ReadingListSpecifics> entry_pb =
-            existing_entry->AsReadingListSpecifics(was_read);
-        auto entity_data = base::MakeUnique<syncer::EntityData>();
-        *(entity_data->specifics.mutable_reading_list()) = *entry_pb;
-        entity_data->non_unique_name = entry_pb->entry_id();
-
-        change_processor()->Put(entry_pb->entry_id(), std::move(entity_data),
-                                metadata_change_list.get());
-      }
-    }
-  }
-
-  batch_->TransferMetadataChanges(std::move(metadata_change_list));
-  return syncer::SyncError();
-}
-
-void ReadingListStore::GetData(StorageKeyList storage_keys,
-                               DataCallback callback) {
-  DCHECK(CalledOnValidThread());
-  auto batch = base::MakeUnique<syncer::MutableDataBatch>();
-  for (std::string url_string : storage_keys) {
-    bool read;
-    const ReadingListEntry* entry =
-        model_->GetEntryFromURL(GURL(url_string), &read);
-    if (entry) {
-      AddEntryToBatch(batch.get(), *entry, read);
-    }
-  }
-
-  callback.Run(syncer::SyncError(), std::move(batch));
-}
-
-void ReadingListStore::GetAllData(DataCallback callback) {
-  DCHECK(CalledOnValidThread());
-  auto batch = base::MakeUnique<syncer::MutableDataBatch>();
-  int unread_count = model_->unread_size();
-  int read_count = model_->read_size();
-  for (int index = 0; index < unread_count + read_count; index++) {
-    bool read = index >= unread_count;
-    const ReadingListEntry& entry =
-        read ? model_->GetReadEntryAtIndex(index - unread_count)
-             : model_->GetUnreadEntryAtIndex(index);
-    AddEntryToBatch(batch.get(), entry, read);
-  }
-
-  callback.Run(syncer::SyncError(), std::move(batch));
-}
-
-void ReadingListStore::AddEntryToBatch(syncer::MutableDataBatch* batch,
-                                       const ReadingListEntry& entry,
-                                       bool read) {
-  DCHECK(CalledOnValidThread());
-  std::unique_ptr<sync_pb::ReadingListSpecifics> entry_pb =
-      entry.AsReadingListSpecifics(read);
-
-  std::unique_ptr<syncer::EntityData> entity_data(new syncer::EntityData());
-  *(entity_data->specifics.mutable_reading_list()) = *entry_pb;
-  entity_data->non_unique_name = entry_pb->entry_id();
-
-  batch->Put(entry_pb->entry_id(), std::move(entity_data));
-}
-
-// Get or generate a client tag for |entity_data|. This must be the same tag
-// that was/would have been generated in the SyncableService/Directory world
-// for backward compatibility with pre-USS clients. The only time this
-// theoretically needs to be called is on the creation of local data, however
-// it is also used to verify the hash of remote data. If a data type was never
-// launched pre-USS, then method does not need to be different from
-// GetStorageKey().
-std::string ReadingListStore::GetClientTag(
-    const syncer::EntityData& entity_data) {
-  DCHECK(CalledOnValidThread());
-  return GetStorageKey(entity_data);
-}
-
-// Get or generate a storage key for |entity_data|. This will only ever be
-// called once when first encountering a remote entity. Local changes will
-// provide their storage keys directly to Put instead of using this method.
-// Theoretically this function doesn't need to be stable across multiple calls
-// on the same or different clients, but to keep things simple, it probably
-// should be.
-std::string ReadingListStore::GetStorageKey(
-    const syncer::EntityData& entity_data) {
-  DCHECK(CalledOnValidThread());
-  return entity_data.specifics.reading_list().entry_id();
-}