Revert of Add Store+Sync to reading list.

ios/chrome/browser/reading_list/reading_list_model_impl.cc

 // 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_model_impl.h"
 
-#include "base/bind.h"
-#include "base/logging.h"
-#include "base/memory/ptr_util.h"
 #include "base/strings/string_util.h"
 #include "components/prefs/pref_service.h"
 #include "ios/chrome/browser/reading_list/reading_list_model_storage.h"
 #include "ios/chrome/browser/reading_list/reading_list_pref_names.h"
 #include "url/gurl.h"
 
 ReadingListModelImpl::ReadingListModelImpl()
     : ReadingListModelImpl(nullptr, nullptr) {}
 
 ReadingListModelImpl::ReadingListModelImpl(
     std::unique_ptr<ReadingListModelStorage> storage,
     PrefService* pref_service)
-    : pref_service_(pref_service),
-      has_unseen_(false),
-      loaded_(false),
-      weak_ptr_factory_(this) {
-  DCHECK(CalledOnValidThread());
+    : pref_service_(pref_service), has_unseen_(false) {
   if (storage) {
     storage_layer_ = std::move(storage);
-    storage_layer_->SetReadingListModel(this, this);
-  } else {
-    loaded_ = true;
-    read_ = base::MakeUnique<ReadingListEntries>();
-    unread_ = base::MakeUnique<ReadingListEntries>();
+    read_ = storage_layer_->LoadPersistentReadList();
+    unread_ = storage_layer_->LoadPersistentUnreadList();
+    has_unseen_ = GetPersistentHasUnseen();
   }
-  has_unseen_ = GetPersistentHasUnseen();
+  loaded_ = true;
 }
 
 ReadingListModelImpl::~ReadingListModelImpl() {}
 
-void ReadingListModelImpl::StoreLoaded(
-    std::unique_ptr<ReadingListEntries> unread,
-    std::unique_ptr<ReadingListEntries> read) {
-  DCHECK(CalledOnValidThread());
-  read_ = std::move(read);
-  unread_ = std::move(unread);
-  loaded_ = true;
-  SortEntries();
-  for (auto& observer : observers_)
-    observer.ReadingListModelLoaded(this);
-}
-
 void ReadingListModelImpl::Shutdown() {
-  DCHECK(CalledOnValidThread());
   for (auto& observer : observers_)
     observer.ReadingListModelBeingDeleted(this);
   loaded_ = false;
 }
 
 bool ReadingListModelImpl::loaded() const {
-  DCHECK(CalledOnValidThread());
   return loaded_;
 }
 
 size_t ReadingListModelImpl::unread_size() const {
-  DCHECK(CalledOnValidThread());
-  if (!loaded())
-    return 0;
-  return unread_->size();
+  DCHECK(loaded());
+  return unread_.size();
 }
 
 size_t ReadingListModelImpl::read_size() const {
-  DCHECK(CalledOnValidThread());
-  if (!loaded())
-    return 0;
-  return read_->size();
+  DCHECK(loaded());
+  return read_.size();
 }
 
 bool ReadingListModelImpl::HasUnseenEntries() const {
-  DCHECK(CalledOnValidThread());
-  if (!loaded())
-    return false;
+  DCHECK(loaded());
   return unread_size() && has_unseen_;
 }
 
 void ReadingListModelImpl::ResetUnseenEntries() {
-  DCHECK(CalledOnValidThread());
   DCHECK(loaded());
   has_unseen_ = false;
-  if (!IsPerformingBatchUpdates())
+  if (storage_layer_ && !IsPerformingBatchUpdates())
     SetPersistentHasUnseen(false);
 }
 
 const ReadingListEntry& ReadingListModelImpl::GetUnreadEntryAtIndex(
     size_t index) const {
-  DCHECK(CalledOnValidThread());
   DCHECK(loaded());
-  return unread_->at(index);
+  return unread_[index];
 }
 
 const ReadingListEntry& ReadingListModelImpl::GetReadEntryAtIndex(
     size_t index) const {
-  DCHECK(CalledOnValidThread());
   DCHECK(loaded());
-  return read_->at(index);
+  return read_[index];
 }
 
 const ReadingListEntry* ReadingListModelImpl::GetEntryFromURL(
-    const GURL& gurl,
-    bool* read) const {
-  DCHECK(CalledOnValidThread());
+    const GURL& gurl) const {
   DCHECK(loaded());
-  return GetMutableEntryFromURL(gurl, read);
-}
-
-ReadingListEntry* ReadingListModelImpl::GetMutableEntryFromURL(
-    const GURL& gurl,
-    bool* read) const {
-  DCHECK(CalledOnValidThread());
-  DCHECK(loaded());
-  bool is_read;
   ReadingListEntry entry(gurl, std::string());
-  auto it = std::find(read_->begin(), read_->end(), entry);
-  is_read = true;
-  if (it == read_->end()) {
-    it = std::find(unread_->begin(), unread_->end(), entry);
-    is_read = false;
-    if (it == unread_->end())
+  auto it = std::find(read_.begin(), read_.end(), entry);
+  if (it == read_.end()) {
+    it = std::find(unread_.begin(), unread_.end(), entry);
+    if (it == unread_.end())
       return nullptr;
   }
-  if (read) {
-    *read = is_read;
-  }
   return &(*it);
 }
 
 bool ReadingListModelImpl::CallbackEntryURL(
     const GURL& url,
     base::Callback<void(const ReadingListEntry&)> callback) const {
-  DCHECK(CalledOnValidThread());
   DCHECK(loaded());
-  const ReadingListEntry* entry = GetMutableEntryFromURL(url, nullptr);
+  const ReadingListEntry* entry = GetEntryFromURL(url);
   if (entry) {
     callback.Run(*entry);
     return true;
   }
   return false;
 }
 
-void ReadingListModelImpl::MoveEntryFrom(ReadingListEntries* entries,
-                                         const ReadingListEntry& entry,
-                                         bool read) {
-  auto result = std::find(entries->begin(), entries->end(), entry);
-  DCHECK(result != entries->end());
-  int index = std::distance(entries->begin(), result);
-  for (auto& observer : observers_)
-    observer.ReadingListWillMoveEntry(this, index, read);
-  entries->erase(result);
-}
-
-void ReadingListModelImpl::SyncAddEntry(std::unique_ptr<ReadingListEntry> entry,
-                                        bool read) {
-  DCHECK(CalledOnValidThread());
-  DCHECK(loaded());
-  // entry must not already exist.
-  DCHECK(GetMutableEntryFromURL(entry->URL(), nullptr) == nullptr);
-  if (read) {
-    for (auto& observer : observers_)
-      observer.ReadingListWillAddReadEntry(this, *entry);
-    read_->insert(read_->begin(), std::move(*entry));
-  } else {
-    for (auto& observer : observers_)
-      observer.ReadingListWillAddUnreadEntry(this, *entry);
-    has_unseen_ = true;
-    SetPersistentHasUnseen(true);
-    unread_->insert(unread_->begin(), std::move(*entry));
-  }
-  for (auto& observer : observers_)
-    observer.ReadingListDidApplyChanges(this);
-}
-
-ReadingListEntry* ReadingListModelImpl::SyncMergeEntry(
-    std::unique_ptr<ReadingListEntry> entry,
-    bool read) {
-  DCHECK(CalledOnValidThread());
-  DCHECK(loaded());
-  bool is_existing_entry_read;
-  ReadingListEntry* existing_entry =
-      GetMutableEntryFromURL(entry->URL(), &is_existing_entry_read);
-
-  DCHECK(existing_entry);
-  DCHECK(existing_entry->UpdateTime() < entry->UpdateTime());
-
-  // Merge local data in new entry.
-  entry->MergeLocalStateFrom(*existing_entry);
-
-  if (is_existing_entry_read) {
-    MoveEntryFrom(read_.get(), *existing_entry, true);
-  } else {
-    MoveEntryFrom(unread_.get(), *existing_entry, false);
-  }
-
-  ReadingListEntries::iterator added_iterator;
-  if (read) {
-    read_->push_back(std::move(*entry));
-    added_iterator = read_->end() - 1;
-  } else {
-    unread_->push_back(std::move(*entry));
-    added_iterator = unread_->end() - 1;
-  }
-  for (auto& observer : observers_)
-    observer.ReadingListDidApplyChanges(this);
-
-  ReadingListEntry& merged_entry = *added_iterator;
-  return &merged_entry;
-}
-
-void ReadingListModelImpl::SyncRemoveEntry(const GURL& url) {
-  RemoveEntryByURLImpl(url, true);
-}
-
 void ReadingListModelImpl::RemoveEntryByURL(const GURL& url) {
-  RemoveEntryByURLImpl(url, false);
-}
-
-void ReadingListModelImpl::RemoveEntryByURLImpl(const GURL& url,
-                                                bool from_sync) {
-  DCHECK(CalledOnValidThread());
   DCHECK(loaded());
   const ReadingListEntry entry(url, std::string());
 
-  auto result = std::find(unread_->begin(), unread_->end(), entry);
-  if (result != unread_->end()) {
-    for (auto& observer : observers_)
+  auto result = std::find(unread_.begin(), unread_.end(), entry);
+  if (result != unread_.end()) {
+    for (auto& observer : observers_) {
       observer.ReadingListWillRemoveUnreadEntry(
-          this, std::distance(unread_->begin(), result));
-
-    if (storage_layer_ && !from_sync) {
-      storage_layer_->RemoveEntry(*result);
+          this, std::distance(unread_.begin(), result));
     }
-    unread_->erase(result);
-
+    unread_.erase(result);
+    if (storage_layer_ && !IsPerformingBatchUpdates())
+      storage_layer_->SavePersistentUnreadList(unread_);
     for (auto& observer : observers_)
       observer.ReadingListDidApplyChanges(this);
     return;
   }
 
-  result = std::find(read_->begin(), read_->end(), entry);
-  if (result != read_->end()) {
-    for (auto& observer : observers_)
+  result = std::find(read_.begin(), read_.end(), entry);
+  if (result != read_.end()) {
+    for (auto& observer : observers_) {
       observer.ReadingListWillRemoveReadEntry(
-          this, std::distance(read_->begin(), result));
-    if (storage_layer_ && !from_sync) {
-      storage_layer_->RemoveEntry(*result);
+          this, std::distance(read_.begin(), result));
     }
-    read_->erase(result);
-
+    read_.erase(result);
+    if (storage_layer_ && !IsPerformingBatchUpdates())
+      storage_layer_->SavePersistentReadList(read_);
     for (auto& observer : observers_)
       observer.ReadingListDidApplyChanges(this);
     return;
   }
 }
 
 const ReadingListEntry& ReadingListModelImpl::AddEntry(
     const GURL& url,
     const std::string& title) {
-  DCHECK(CalledOnValidThread());
   DCHECK(loaded());
   RemoveEntryByURL(url);
 
   std::string trimmedTitle(title);
   base::TrimWhitespaceASCII(trimmedTitle, base::TRIM_ALL, &trimmedTitle);
 
   ReadingListEntry entry(url, trimmedTitle);
   for (auto& observer : observers_)
     observer.ReadingListWillAddUnreadEntry(this, entry);
+  unread_.insert(unread_.begin(), std::move(entry));
   has_unseen_ = true;
-  SetPersistentHasUnseen(true);
-  if (storage_layer_) {
-    storage_layer_->SaveEntry(entry, false);
+  if (storage_layer_ && !IsPerformingBatchUpdates()) {
+    storage_layer_->SavePersistentUnreadList(unread_);
+    SetPersistentHasUnseen(true);
   }
-  unread_->insert(unread_->begin(), std::move(entry));
-
   for (auto& observer : observers_)
     observer.ReadingListDidApplyChanges(this);
-  return *unread_->begin();
+  return *unread_.begin();
 }
 
 void ReadingListModelImpl::MarkUnreadByURL(const GURL& url) {
-  DCHECK(CalledOnValidThread());
   DCHECK(loaded());
   ReadingListEntry entry(url, std::string());
-  auto result = std::find(read_->begin(), read_->end(), entry);
-  if (result == read_->end())
+  auto result = std::find(read_.begin(), read_.end(), entry);
+  if (result == read_.end())
     return;
 
   for (ReadingListModelObserver& observer : observers_) {
-    observer.ReadingListWillMoveEntry(
-        this, std::distance(read_->begin(), result), true);
+    observer.ReadingListWillMoveEntry(this,
+                                      std::distance(read_.begin(), result));
   }
 
-  result->MarkEntryUpdated();
-  if (storage_layer_) {
-    storage_layer_->SaveEntry(*result, false);
+  unread_.insert(unread_.begin(), std::move(*result));
+  read_.erase(result);
+
+  if (storage_layer_ && !IsPerformingBatchUpdates()) {
+    storage_layer_->SavePersistentUnreadList(read_);
+    storage_layer_->SavePersistentReadList(unread_);
   }
-
-  unread_->insert(unread_->begin(), std::move(*result));
-  read_->erase(result);
-
   for (ReadingListModelObserver& observer : observers_) {
     observer.ReadingListDidApplyChanges(this);
   }
 }
 
 void ReadingListModelImpl::MarkReadByURL(const GURL& url) {
-  DCHECK(CalledOnValidThread());
   DCHECK(loaded());
   ReadingListEntry entry(url, std::string());
-  auto result = std::find(unread_->begin(), unread_->end(), entry);
-  if (result == unread_->end())
+  auto result = std::find(unread_.begin(), unread_.end(), entry);
+  if (result == unread_.end())
     return;
 
-  for (auto& observer : observers_)
-    observer.ReadingListWillMoveEntry(
-        this, std::distance(unread_->begin(), result), false);
-
-  result->MarkEntryUpdated();
-  if (storage_layer_) {
-    storage_layer_->SaveEntry(*result, true);
+  for (auto& observer : observers_) {
+    observer.ReadingListWillMoveEntry(this,
+                                      std::distance(unread_.begin(), result));
   }
 
-  read_->insert(read_->begin(), std::move(*result));
-  unread_->erase(result);
+  read_.insert(read_.begin(), std::move(*result));
+  unread_.erase(result);
 
+  if (storage_layer_ && !IsPerformingBatchUpdates()) {
+    storage_layer_->SavePersistentUnreadList(unread_);
+    storage_layer_->SavePersistentReadList(read_);
+  }
   for (auto& observer : observers_)
     observer.ReadingListDidApplyChanges(this);
 }
 
 void ReadingListModelImpl::SetEntryTitle(const GURL& url,
                                          const std::string& title) {
-  DCHECK(CalledOnValidThread());
   DCHECK(loaded());
   const ReadingListEntry entry(url, std::string());
 
-  auto result = std::find(unread_->begin(), unread_->end(), entry);
-  if (result != unread_->end()) {
-    for (auto& observer : observers_)
+  auto result = std::find(unread_.begin(), unread_.end(), entry);
+  if (result != unread_.end()) {
+    for (auto& observer : observers_) {
       observer.ReadingListWillUpdateUnreadEntry(
-          this, std::distance(unread_->begin(), result));
+          this, std::distance(unread_.begin(), result));
+    }
     result->SetTitle(title);
-
-    if (storage_layer_) {
-      storage_layer_->SaveEntry(*result, false);
-    }
+    if (storage_layer_ && !IsPerformingBatchUpdates())
+      storage_layer_->SavePersistentUnreadList(unread_);
     for (auto& observer : observers_)
       observer.ReadingListDidApplyChanges(this);
     return;
   }
 
-  result = std::find(read_->begin(), read_->end(), entry);
-  if (result != read_->end()) {
-    for (auto& observer : observers_)
+  result = std::find(read_.begin(), read_.end(), entry);
+  if (result != read_.end()) {
+    for (auto& observer : observers_) {
       observer.ReadingListWillUpdateReadEntry(
-          this, std::distance(read_->begin(), result));
+          this, std::distance(read_.begin(), result));
+    }
     result->SetTitle(title);
-    if (storage_layer_) {
-      storage_layer_->SaveEntry(*result, true);
-    }
+    if (storage_layer_ && !IsPerformingBatchUpdates())
+      storage_layer_->SavePersistentReadList(read_);
     for (auto& observer : observers_)
       observer.ReadingListDidApplyChanges(this);
     return;
   }
 }
 
 void ReadingListModelImpl::SetEntryDistilledPath(
     const GURL& url,
     const base::FilePath& distilled_path) {
-  DCHECK(CalledOnValidThread());
   DCHECK(loaded());
   const ReadingListEntry entry(url, std::string());
 
-  auto result = std::find(unread_->begin(), unread_->end(), entry);
-  if (result != unread_->end()) {
-    for (auto& observer : observers_)
+  auto result = std::find(unread_.begin(), unread_.end(), entry);
+  if (result != unread_.end()) {
+    for (auto& observer : observers_) {
       observer.ReadingListWillUpdateUnreadEntry(
-          this, std::distance(unread_->begin(), result));
+          this, std::distance(unread_.begin(), result));
+    }
     result->SetDistilledPath(distilled_path);
-    if (storage_layer_) {
-      storage_layer_->SaveEntry(*result, false);
-    }
+    if (storage_layer_ && !IsPerformingBatchUpdates())
+      storage_layer_->SavePersistentUnreadList(unread_);
     for (auto& observer : observers_)
       observer.ReadingListDidApplyChanges(this);
     return;
   }
 
-  result = std::find(read_->begin(), read_->end(), entry);
-  if (result != read_->end()) {
-    for (auto& observer : observers_)
+  result = std::find(read_.begin(), read_.end(), entry);
+  if (result != read_.end()) {
+    for (auto& observer : observers_) {
       observer.ReadingListWillUpdateReadEntry(
-          this, std::distance(read_->begin(), result));
+          this, std::distance(read_.begin(), result));
+    }
     result->SetDistilledPath(distilled_path);
-    if (storage_layer_) {
-      storage_layer_->SaveEntry(*result, true);
-    }
+    if (storage_layer_ && !IsPerformingBatchUpdates())
+      storage_layer_->SavePersistentReadList(read_);
     for (auto& observer : observers_)
       observer.ReadingListDidApplyChanges(this);
     return;
   }
 }
 
 void ReadingListModelImpl::SetEntryDistilledState(
     const GURL& url,
     ReadingListEntry::DistillationState state) {
-  DCHECK(CalledOnValidThread());
   DCHECK(loaded());
   const ReadingListEntry entry(url, std::string());
 
-  auto result = std::find(unread_->begin(), unread_->end(), entry);
-  if (result != unread_->end()) {
-    for (auto& observer : observers_)
+  auto result = std::find(unread_.begin(), unread_.end(), entry);
+  if (result != unread_.end()) {
+    for (auto& observer : observers_) {
       observer.ReadingListWillUpdateUnreadEntry(
-          this, std::distance(unread_->begin(), result));
+          this, std::distance(unread_.begin(), result));
+    }
     result->SetDistilledState(state);
-    if (storage_layer_) {
-      storage_layer_->SaveEntry(*result, false);
-    }
+    if (storage_layer_ && !IsPerformingBatchUpdates())
+      storage_layer_->SavePersistentUnreadList(unread_);
     for (auto& observer : observers_)
       observer.ReadingListDidApplyChanges(this);
     return;
   }
 
-  result = std::find(read_->begin(), read_->end(), entry);
-  if (result != read_->end()) {
-    for (auto& observer : observers_)
+  result = std::find(read_.begin(), read_.end(), entry);
+  if (result != read_.end()) {
+    for (auto& observer : observers_) {
       observer.ReadingListWillUpdateReadEntry(
-          this, std::distance(read_->begin(), result));
+          this, std::distance(read_.begin(), result));
+    }
     result->SetDistilledState(state);
-    if (storage_layer_) {
-      storage_layer_->SaveEntry(*result, true);
-    }
+    if (storage_layer_ && !IsPerformingBatchUpdates())
+      storage_layer_->SavePersistentReadList(read_);
     for (auto& observer : observers_)
       observer.ReadingListDidApplyChanges(this);
     return;
   }
 };
 
-std::unique_ptr<ReadingListModel::ScopedReadingListBatchUpdate>
-ReadingListModelImpl::CreateBatchToken() {
-  return base::MakeUnique<ReadingListModelImpl::ScopedReadingListBatchUpdate>(
-      this);
-}
-
-ReadingListModelImpl::ScopedReadingListBatchUpdate::
-    ScopedReadingListBatchUpdate(ReadingListModelImpl* model)
-    : ReadingListModel::ScopedReadingListBatchUpdate::
-          ScopedReadingListBatchUpdate(model) {
-  if (model->StorageLayer()) {
-    storage_token_ = model->StorageLayer()->EnsureBatchCreated();
+void ReadingListModelImpl::EndBatchUpdates() {
+  ReadingListModel::EndBatchUpdates();
+  if (IsPerformingBatchUpdates() || !storage_layer_) {
+    return;
   }
-}
-
-ReadingListModelImpl::ScopedReadingListBatchUpdate::
-    ~ScopedReadingListBatchUpdate() {
-  storage_token_.reset();
-}
-
-void ReadingListModelImpl::LeavingBatchUpdates() {
-  DCHECK(CalledOnValidThread());
-  if (storage_layer_) {
-    SetPersistentHasUnseen(has_unseen_);
-    SortEntries();
-  }
-  ReadingListModel::LeavingBatchUpdates();
-}
-
-void ReadingListModelImpl::EnteringBatchUpdates() {
-  DCHECK(CalledOnValidThread());
-  ReadingListModel::EnteringBatchUpdates();
+  storage_layer_->SavePersistentUnreadList(unread_);
+  storage_layer_->SavePersistentReadList(read_);
+  SetPersistentHasUnseen(has_unseen_);
 }
 
 void ReadingListModelImpl::SetPersistentHasUnseen(bool has_unseen) {
-  DCHECK(CalledOnValidThread());
   if (!pref_service_) {
     return;
   }
   pref_service_->SetBoolean(reading_list::prefs::kReadingListHasUnseenEntries,
                             has_unseen);
 }
 
 bool ReadingListModelImpl::GetPersistentHasUnseen() {
-  DCHECK(CalledOnValidThread());
   if (!pref_service_) {
     return false;
   }
   return pref_service_->GetBoolean(
       reading_list::prefs::kReadingListHasUnseenEntries);
 }
-
-syncer::ModelTypeSyncBridge* ReadingListModelImpl::GetModelTypeSyncBridge() {
-  DCHECK(loaded());
-  if (!storage_layer_)
-    return nullptr;
-  return storage_layer_->GetModelTypeSyncBridge();
-}
-
-void ReadingListModelImpl::SortEntries() {
-  DCHECK(CalledOnValidThread());
-  DCHECK(loaded());
-  std::sort(read_->begin(), read_->end(),
-            ReadingListEntry::CompareEntryUpdateTime);
-  std::sort(unread_->begin(), unread_->end(),
-            ReadingListEntry::CompareEntryUpdateTime);
-}
-
-ReadingListModelStorage* ReadingListModelImpl::StorageLayer() {
-  return storage_layer_.get();
-}