Revert of delete the levelDB storage implementation.

components/offline_pages/offline_page_metadata_store_impl.cc

Index: components/offline_pages/offline_page_metadata_store_impl.cc
diff --git a/components/offline_pages/offline_page_metadata_store_impl.cc b/components/offline_pages/offline_page_metadata_store_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ead3fbe3e0369d187c1c300f0e9991384fae3781
--- /dev/null
+++ b/components/offline_pages/offline_page_metadata_store_impl.cc
@@ -0,0 +1,319 @@
+// Copyright 2015 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 "components/offline_pages/offline_page_metadata_store_impl.h"
+
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/location.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/sequenced_task_runner.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "build/build_config.h"
+#include "components/leveldb_proto/proto_database_impl.h"
+#include "components/offline_pages/offline_page_item.h"
+#include "components/offline_pages/offline_page_model.h"
+#include "components/offline_pages/proto/offline_pages.pb.h"
+#include "third_party/leveldatabase/env_chromium.h"
+#include "third_party/leveldatabase/src/include/leveldb/db.h"
+#include "url/gurl.h"
+
+using leveldb_proto::ProtoDatabase;
+
+namespace {
+// Statistics are logged to UMA with this string as part of histogram name. They
+// can all be found under LevelDB.*.OfflinePageMetadataStore. Changing this
+// needs to synchronize with histograms.xml, AND will also become incompatible
+// with older browsers still reporting the previous values.
+const char kDatabaseUMAClientName[] = "OfflinePageMetadataStore";
+}
+
+namespace offline_pages {
+namespace {
+
+void OfflinePageItemToEntry(const OfflinePageItem& item,
+                            offline_pages::OfflinePageEntry* item_proto) {
+  DCHECK(item_proto);
+  item_proto->set_url(item.url.spec());
+  item_proto->set_offline_id(item.offline_id);
+  item_proto->set_version(item.version);
+  std::string path_string;
+#if defined(OS_POSIX)
+  path_string = item.file_path.value();
+#elif defined(OS_WIN)
+  path_string = base::WideToUTF8(item.file_path.value());
+#endif
+  item_proto->set_file_path(path_string);
+  item_proto->set_file_size(item.file_size);
+  item_proto->set_creation_time(item.creation_time.ToInternalValue());
+  item_proto->set_last_access_time(item.last_access_time.ToInternalValue());
+  item_proto->set_access_count(item.access_count);
+  item_proto->set_flags(
+      static_cast<::offline_pages::OfflinePageEntry_Flags>(item.flags));
+  item_proto->set_client_id_name_space(item.client_id.name_space);
+  item_proto->set_client_id(item.client_id.id);
+}
+
+bool OfflinePageItemFromEntry(const offline_pages::OfflinePageEntry& item_proto,
+                              OfflinePageItem* item) {
+  DCHECK(item);
+  bool has_offline_id =
+      item_proto.has_offline_id() || item_proto.has_deprecated_bookmark_id();
+  if (!item_proto.has_url() || !has_offline_id || !item_proto.has_version() ||
+      !item_proto.has_file_path()) {
+    return false;
+  }
+  item->url = GURL(item_proto.url());
+  item->offline_id = item_proto.offline_id();
+  item->version = item_proto.version();
+#if defined(OS_POSIX)
+  item->file_path = base::FilePath(item_proto.file_path());
+#elif defined(OS_WIN)
+  item->file_path = base::FilePath(base::UTF8ToWide(item_proto.file_path()));
+#endif
+  if (item_proto.has_file_size()) {
+    item->file_size = item_proto.file_size();
+  }
+  if (item_proto.has_creation_time()) {
+    item->creation_time =
+        base::Time::FromInternalValue(item_proto.creation_time());
+  }
+  if (item_proto.has_last_access_time()) {
+    item->last_access_time =
+        base::Time::FromInternalValue(item_proto.last_access_time());
+  }
+  if (item_proto.has_access_count()) {
+    item->access_count = item_proto.access_count();
+  }
+  if (item_proto.has_flags()) {
+    item->flags = static_cast<OfflinePageItem::Flags>(item_proto.flags());
+  }
+  item->client_id.name_space = item_proto.client_id_name_space();
+  item->client_id.id = item_proto.client_id();
+
+  return true;
+}
+
+}  // namespace
+
+OfflinePageMetadataStoreImpl::OfflinePageMetadataStoreImpl(
+    scoped_refptr<base::SequencedTaskRunner> background_task_runner,
+    const base::FilePath& database_dir)
+    : background_task_runner_(background_task_runner),
+      database_dir_(database_dir),
+      weak_ptr_factory_(this) {
+}
+
+OfflinePageMetadataStoreImpl::~OfflinePageMetadataStoreImpl() {
+}
+
+void OfflinePageMetadataStoreImpl::Load(const LoadCallback& callback) {
+  // First initialize the database.
+  database_.reset(new leveldb_proto::ProtoDatabaseImpl<OfflinePageEntry>(
+      background_task_runner_));
+  database_->Init(kDatabaseUMAClientName, database_dir_,
+                  base::Bind(&OfflinePageMetadataStoreImpl::LoadContinuation,
+                             weak_ptr_factory_.GetWeakPtr(),
+                             callback));
+}
+
+void OfflinePageMetadataStoreImpl::LoadContinuation(
+    const LoadCallback& callback,
+    bool success) {
+  if (!success) {
+    NotifyLoadResult(callback,
+                     STORE_INIT_FAILED,
+                     std::vector<OfflinePageItem>());
+    return;
+  }
+
+  // After initialization, start to load the data.
+  database_->LoadEntries(
+      base::Bind(&OfflinePageMetadataStoreImpl::LoadDone,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 callback));
+}
+
+void OfflinePageMetadataStoreImpl::LoadDone(
+    const LoadCallback& callback,
+    bool success,
+    std::unique_ptr<std::vector<OfflinePageEntry>> entries) {
+  DCHECK(entries);
+
+  std::vector<OfflinePageItem> result;
+  std::unique_ptr<ProtoDatabase<OfflinePageEntry>::KeyEntryVector>
+      entries_to_update(new ProtoDatabase<OfflinePageEntry>::KeyEntryVector());
+  std::unique_ptr<std::vector<std::string>> keys_to_remove(
+      new std::vector<std::string>());
+
+  LoadStatus status = LOAD_SUCCEEDED;
+
+  if (success) {
+    for (auto& entry : *entries) {
+      OfflinePageItem item;
+      // We don't want to fail the entire database if one item is corrupt,
+      // so log error and keep going.
+      if (!OfflinePageItemFromEntry(entry, &item)) {
+        LOG(ERROR) << "failed to parse entry: " << entry.url() << " skipping.";
+        continue;
+      }
+      // Legacy storage.  We upgrade them to the new offline_id keyed storage.
+      // TODO(bburns): Remove this eventually when we are sure everyone is
+      // upgraded.
+      if (!entry.has_offline_id()) {
+        item.offline_id = OfflinePageModel::GenerateOfflineId();
+
+        if (!entry.has_deprecated_bookmark_id()) {
+          LOG(ERROR) << "unexpected entry missing bookmark id";
+          continue;
+        }
+        item.client_id.name_space = offline_pages::kBookmarkNamespace;
+        item.client_id.id = base::Int64ToString(entry.deprecated_bookmark_id());
+
+        OfflinePageEntry upgraded_entry;
+        OfflinePageItemToEntry(item, &upgraded_entry);
+        entries_to_update->push_back(
+            std::make_pair(base::Int64ToString(upgraded_entry.offline_id()),
+                           upgraded_entry));
+        // Remove the old entry that is indexed with deprecated id.
+        keys_to_remove->push_back(item.client_id.id);
+      }
+      result.push_back(item);
+    }
+  } else {
+    status = STORE_LOAD_FAILED;
+  }
+
+  // If we couldn't load _anything_ report a parse failure.
+  if (entries->size() > 0 && result.size() == 0) {
+    status = DATA_PARSING_FAILED;
+  }
+
+  if (status == LOAD_SUCCEEDED && entries_to_update->size() > 0) {
+    UpdateEntries(std::move(entries_to_update), std::move(keys_to_remove),
+                  base::Bind(&OfflinePageMetadataStoreImpl::DatabaseUpdateDone,
+                             weak_ptr_factory_.GetWeakPtr(), callback, status,
+                             std::move(result)));
+  } else {
+    NotifyLoadResult(callback, status, result);
+  }
+}
+
+void OfflinePageMetadataStoreImpl::NotifyLoadResult(
+    const LoadCallback& callback,
+    LoadStatus status,
+    const std::vector<OfflinePageItem>& result) {
+  UMA_HISTOGRAM_ENUMERATION("OfflinePages.LoadStatus",
+                            status,
+                            OfflinePageMetadataStore::LOAD_STATUS_COUNT);
+  if (status == LOAD_SUCCEEDED) {
+    UMA_HISTOGRAM_COUNTS("OfflinePages.SavedPageCount", result.size());
+  } else {
+    DVLOG(1) << "Offline pages database loading failed: " << status;
+    database_.reset();
+  }
+  callback.Run(status, result);
+}
+
+void OfflinePageMetadataStoreImpl::AddOrUpdateOfflinePage(
+    const OfflinePageItem& offline_page_item,
+    const UpdateCallback& callback) {
+  std::unique_ptr<ProtoDatabase<OfflinePageEntry>::KeyEntryVector>
+      entries_to_save(new ProtoDatabase<OfflinePageEntry>::KeyEntryVector());
+  std::unique_ptr<std::vector<std::string>> keys_to_remove(
+      new std::vector<std::string>());
+
+  OfflinePageEntry offline_page_proto;
+  OfflinePageItemToEntry(offline_page_item, &offline_page_proto);
+
+  entries_to_save->push_back(std::make_pair(
+      base::Int64ToString(offline_page_item.offline_id), offline_page_proto));
+
+  UpdateEntries(std::move(entries_to_save), std::move(keys_to_remove),
+                callback);
+}
+
+void OfflinePageMetadataStoreImpl::RemoveOfflinePages(
+    const std::vector<int64_t>& offline_ids,
+    const UpdateCallback& callback) {
+  std::unique_ptr<ProtoDatabase<OfflinePageEntry>::KeyEntryVector>
+      entries_to_save(new ProtoDatabase<OfflinePageEntry>::KeyEntryVector());
+  std::unique_ptr<std::vector<std::string>> keys_to_remove(
+      new std::vector<std::string>());
+
+  for (int64_t id : offline_ids)
+    keys_to_remove->push_back(base::Int64ToString(id));
+
+  UpdateEntries(std::move(entries_to_save), std::move(keys_to_remove),
+                callback);
+}
+
+void OfflinePageMetadataStoreImpl::UpdateEntries(
+    std::unique_ptr<ProtoDatabase<OfflinePageEntry>::KeyEntryVector>
+        entries_to_save,
+    std::unique_ptr<std::vector<std::string>> keys_to_remove,
+    const UpdateCallback& callback) {
+  if (!database_.get()) {
+    // Failing fast here, because DB is not initialized, and there is nothing
+    // that can be done about it.
+    // Callback is invoked through message loop to avoid improper retry and
+    // simplify testing.
+    DVLOG(1) << "Offline pages database not available in UpdateEntries.";
+    base::ThreadTaskRunnerHandle::Get()->PostTask(FROM_HERE,
+                                                  base::Bind(callback, false));
+    return;
+  }
+
+  database_->UpdateEntries(
+      std::move(entries_to_save), std::move(keys_to_remove),
+      base::Bind(&OfflinePageMetadataStoreImpl::UpdateDone,
+                 weak_ptr_factory_.GetWeakPtr(), callback));
+}
+
+void OfflinePageMetadataStoreImpl::UpdateDone(
+    const OfflinePageMetadataStore::UpdateCallback& callback,
+    bool success) {
+  if (!success) {
+    // TODO(fgorski): Add UMA for this case. Consider rebuilding the store.
+    DVLOG(1) << "Offline pages database update failed.";
+  }
+
+  callback.Run(success);
+}
+
+void OfflinePageMetadataStoreImpl::Reset(const ResetCallback& callback) {
+  database_->Destroy(
+      base::Bind(&OfflinePageMetadataStoreImpl::ResetDone,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 callback));
+}
+
+void OfflinePageMetadataStoreImpl::ResetDone(
+    const ResetCallback& callback,
+    bool success) {
+  database_.reset();
+  weak_ptr_factory_.InvalidateWeakPtrs();
+  callback.Run(success);
+}
+
+void OfflinePageMetadataStoreImpl::DatabaseUpdateDone(
+    const OfflinePageMetadataStore::LoadCallback& cb,
+    LoadStatus status,
+    const std::vector<OfflinePageItem>& result,
+    bool success) {
+  // If the update failed, log and keep going.  We'll try to
+  // update next time.
+  if (!success) {
+    LOG(ERROR) << "Failed to update database";
+  }
+  NotifyLoadResult(cb, status, result);
+}
+
+}  // namespace offline_pages