[sync] Add typed url sync metadata to the history db

components/history/core/browser/typed_url_sync_metadata_database.cc

Index: components/history/core/browser/typed_url_sync_metadata_database.cc
diff --git a/components/history/core/browser/typed_url_sync_metadata_database.cc b/components/history/core/browser/typed_url_sync_metadata_database.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4bc1e7789de4956add1e14dcb939ea15e5ca6739
--- /dev/null
+++ b/components/history/core/browser/typed_url_sync_metadata_database.cc
@@ -0,0 +1,161 @@
+// Copyright (c) 2017 The Chromium Authors. All rights reserved.

[sky, 2017/03/01 04:15:24]

no (c)

[Gang Wu, 2017/03/02 05:41:12]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/history/core/browser/typed_url_sync_metadata_database.h"
+
+#include "sql/statement.h"
+
+namespace history {
+
+TypedURLSyncMetadataDatabase::TypedURLSyncMetadataDatabase() {}
+
+TypedURLSyncMetadataDatabase::~TypedURLSyncMetadataDatabase() {}
+
+bool TypedURLSyncMetadataDatabase::GetAllSyncMetadata(
+    syncer::ModelType model_type,
+    syncer::MetadataBatch* metadata_batch) {
+  DCHECK_EQ(model_type, syncer::TYPED_URLS)
+      << "Only the TYPED_URLS model type is supported";
+  syncer::EntityMetadataMap metadata_records;
+  if (GetAllSyncEntityMetadata(model_type, &metadata_records)) {
+    for (const auto& pair : metadata_records) {

[sky, 2017/03/01 04:15:24]

no {}

[Gang Wu, 2017/03/02 05:41:12]

Done.

+      metadata_batch->AddMetadata(pair.first, pair.second);

[sky, 2017/03/01 04:15:24]

Using std::pair for this class makes for hard to understand code. I have no idea
what pair.first or pair.second is. Please use a locally defined structure to
make this code readable.

[Gang Wu, 2017/03/02 05:41:12]

This is C++ STL auto iterator for std::map, I cannot change .first and .second
for it, but I changed variable name for easy understand, a little better?  or do
you have other suggestions?

+    }
+  } else {
+    return false;
+  }
+
+  sync_pb::ModelTypeState model_type_state;
+  if (GetModelTypeState(model_type, &model_type_state)) {
+    metadata_batch->SetModelTypeState(model_type_state);
+  } else {
+    return false;
+  }
+
+  return true;
+}
+
+bool TypedURLSyncMetadataDatabase::UpdateSyncMetadata(
+    syncer::ModelType model_type,
+    const std::string& storage_key,
+    const sync_pb::EntityMetadata& metadata) {
+  DCHECK_EQ(model_type, syncer::TYPED_URLS)
+      << "Only the TYPED_URLS model type is supported";
+
+  sql::Statement s(GetDB().GetUniqueStatement(
+      "INSERT OR REPLACE INTO typed_url_sync_metadata "
+      "(storage_key, value) VALUES(?, ?)"));
+  s.BindString(0, storage_key);
+  s.BindString(1, metadata.SerializeAsString());

[sky, 2017/03/01 04:15:24]

Who handles versioning of this string?

[Gang Wu, 2017/03/02 05:41:12]

protobuf will control backward compatibility for metadata serialize and
deserialize.
for metadata itself, if we update the definition of EntityMetadata, we will
update version of database version to handle it.

+
+  return s.Run();
+}
+
+bool TypedURLSyncMetadataDatabase::ClearSyncMetadata(
+    syncer::ModelType model_type,
+    const std::string& storage_key) {
+  DCHECK_EQ(model_type, syncer::TYPED_URLS)
+      << "Only the TYPED_URLS model type is supported";
+
+  sql::Statement s(GetDB().GetUniqueStatement(
+      "DELETE FROM typed_url_sync_metadata WHERE storage_key=?"));
+  s.BindString(0, storage_key);
+
+  return s.Run();
+}
+
+bool TypedURLSyncMetadataDatabase::UpdateModelTypeState(
+    syncer::ModelType model_type,
+    const sync_pb::ModelTypeState& model_type_state) {
+  DCHECK_EQ(model_type, syncer::TYPED_URLS)
+      << "Only the TYPED_URLS model type is supported";
+
+  // Hardcode the id to force a collision, ensuring that there remains only a
+  // single entry.
+  sql::Statement s(GetDB().GetUniqueStatement(
+      "INSERT OR REPLACE INTO typed_url_model_type_state (id, value) "
+      "VALUES(1,?)"));
+  s.BindString(0, model_type_state.SerializeAsString());
+
+  return s.Run();
+}
+
+bool TypedURLSyncMetadataDatabase::ClearModelTypeState(
+    syncer::ModelType model_type) {
+  DCHECK_EQ(model_type, syncer::TYPED_URLS)
+      << "Only the TYPED_URLS model type is supported";
+
+  sql::Statement s(GetDB().GetUniqueStatement(
+      "DELETE FROM typed_url_model_type_state WHERE id=1"));
+
+  return s.Run();
+}
+
+bool TypedURLSyncMetadataDatabase::InitSyncTable() {
+  return InitTypedURLSyncMetadataTable() && InitModelTypeStateTable();
+}
+
+bool TypedURLSyncMetadataDatabase::InitTypedURLSyncMetadataTable() {
+  if (!GetDB().DoesTableExist("typed_url_sync_metadata")) {
+    if (!GetDB().Execute("CREATE TABLE typed_url_sync_metadata ("
+                         "storage_key VARCHAR PRIMARY KEY NOT NULL,"

[sky, 2017/03/01 04:15:23]

Document what storage_key is. In fact please document the scheme at the top of
the file such as other classes in this directory do.

[Gang Wu, 2017/03/02 05:41:12]

Done.

+                         "value BLOB)")) {
+      NOTREACHED();
+      return false;
+    }
+  }
+  return true;
+}
+
+bool TypedURLSyncMetadataDatabase::InitModelTypeStateTable() {
+  if (!GetDB().DoesTableExist("typed_url_model_type_state")) {
+    if (!GetDB().Execute("CREATE TABLE typed_url_model_type_state (id INTEGER "
+                         "PRIMARY KEY, value BLOB)")) {
+      NOTREACHED();
+      return false;
+    }
+  }
+  return true;
+}
+
+bool TypedURLSyncMetadataDatabase::GetAllSyncEntityMetadata(
+    syncer::ModelType model_type,
+    syncer::EntityMetadataMap* metadata_records) {
+  DCHECK_EQ(model_type, syncer::TYPED_URLS)
+      << "Only the TYPED_URLS model type is supported";
+
+  sql::Statement s(GetDB().GetUniqueStatement(
+      "SELECT storage_key, value FROM typed_url_sync_metadata"));
+
+  while (s.Step()) {
+    std::string storage_key = s.ColumnString(0);
+    std::string serialized_metadata = s.ColumnString(1);
+    sync_pb::EntityMetadata metadata_record;
+    if (metadata_record.ParseFromString(serialized_metadata)) {
+      metadata_records->insert(std::make_pair(storage_key, metadata_record));
+    } else {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool TypedURLSyncMetadataDatabase::GetModelTypeState(
+    syncer::ModelType model_type,
+    sync_pb::ModelTypeState* state) {
+  DCHECK_EQ(model_type, syncer::TYPED_URLS)
+      << "Only the TYPED_URLS model type is supported";
+
+  sql::Statement s(GetDB().GetUniqueStatement(
+      "SELECT value FROM typed_url_model_type_state WHERE id=1"));
+
+  if (!s.Step()) {
+    return true;
+  }
+
+  std::string serialized_state = s.ColumnString(0);
+  return state->ParseFromString(serialized_state);
+}
+
+}  // namespace history