Reland of land: Initialize and reset V4LocalDBManager. Instantiate V4Stores.

components/safe_browsing_db/v4_local_database_manager.cc

Index: components/safe_browsing_db/v4_local_database_manager.cc
diff --git a/components/safe_browsing_db/v4_local_database_manager.cc b/components/safe_browsing_db/v4_local_database_manager.cc
index 376d26edac729bd59e0727bb0a9588be447cd9e2..06fb383160cf1241e55ac56991c384927e95ff4e 100644
--- a/components/safe_browsing_db/v4_local_database_manager.cc
+++ b/components/safe_browsing_db/v4_local_database_manager.cc
@@ -6,6 +6,7 @@
 
 #include <vector>
 
+#include "base/callback.h"
 #include "components/safe_browsing_db/safebrowsing.pb.h"
 #include "content/public/browser/browser_thread.h"
 
@@ -13,7 +14,12 @@
 
 namespace safe_browsing {
 
-V4LocalDatabaseManager::V4LocalDatabaseManager() : enabled_(false) {}
+V4LocalDatabaseManager::V4LocalDatabaseManager(const base::FilePath& base_path)
+    : base_path_(base_path), enabled_(false) {
+  DCHECK(!base_path_.empty());
+  DVLOG(1) << "V4LocalDatabaseManager::V4LocalDatabaseManager: "
+           << "base_path_: " << base_path_.AsUTF8Unsafe();
+}
 
 V4LocalDatabaseManager::~V4LocalDatabaseManager() {
   DCHECK(!enabled_);
@@ -123,8 +129,9 @@
 bool V4LocalDatabaseManager::CheckBrowseUrl(const GURL& url, Client* client) {
   // TODO(vakh): Implement this skeleton.
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!enabled_)
+  if (!enabled_) {
     return true;
+  }
 
   // Don't defer the resource load.
   return true;
@@ -141,13 +148,23 @@
     const V4ProtocolConfig& config) {
   SafeBrowsingDatabaseManager::StartOnIOThread(request_context_getter, config);
 
-#if defined(OS_WIN) || defined (OS_LINUX) || defined (OS_MACOSX)
+  SetupUpdateProtocolManager(request_context_getter, config);
+
+  SetupDatabase();
+
+  enabled_ = true;
+}
+
+void V4LocalDatabaseManager::SetupUpdateProtocolManager(
+    net::URLRequestContextGetter* request_context_getter,
+    const V4ProtocolConfig& config) {
+#if defined(OS_WIN) || defined(OS_LINUX) || defined(OS_MACOSX)
   // TODO(vakh): Remove this if/endif block when the V4Database is implemented.
   // Filed as http://crbug.com/608075
   UpdateListIdentifier update_list_identifier;
 #if defined(OS_WIN)
   update_list_identifier.platform_type = WINDOWS_PLATFORM;
-#elif defined (OS_LINUX)
+#elif defined(OS_LINUX)
   update_list_identifier.platform_type = LINUX_PLATFORM;
 #else
   update_list_identifier.platform_type = OSX_PLATFORM;
@@ -159,28 +176,75 @@
 
   V4UpdateCallback callback = base::Bind(
       &V4LocalDatabaseManager::UpdateRequestCompleted, base::Unretained(this));
+
   v4_update_protocol_manager_ = V4UpdateProtocolManager::Create(
       request_context_getter, config, current_list_states_, callback);
-
-  enabled_ = true;
+}
+
+void V4LocalDatabaseManager::SetupDatabase() {
+  DCHECK(!base_path_.empty());
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  // Only get a new task runner if there isn't one already. If the service has
+  // previously been started and stopped, a task runner could already exist.
+  if (!task_runner_) {
+    base::SequencedWorkerPool* pool = BrowserThread::GetBlockingPool();
+    task_runner_ = pool->GetSequencedTaskRunnerWithShutdownBehavior(
+        pool->GetSequenceToken(), base::SequencedWorkerPool::SKIP_ON_SHUTDOWN);
+  }
+
+  // TODO(vakh): list_info_map should probably be a hard-coded map.
+  ListInfoMap list_info_map;
+
+  // Do not create the database on the IO thread since this may be an expensive
+  // operation. Instead, do that on the task_runner and when the new database
+  // has been created, swap it out on the IO thread.
+  NewDatabaseReadyCallback db_ready_callback = base::Bind(
+      &V4LocalDatabaseManager::DatabaseReady, base::Unretained(this));
+  V4Database::Create(task_runner_, base_path_, list_info_map,
+                     db_ready_callback);
+}
+
+void V4LocalDatabaseManager::DatabaseReady(
+    std::unique_ptr<V4Database> v4_database) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  // The following check is needed because it is possible that by the time the
+  // database is ready, StopOnIOThread has been called.
+  if (enabled_) {
+    v4_database_ = std::move(v4_database);
+
+    // The database is in place. Start fetching updates now.
+    v4_update_protocol_manager_->ScheduleNextUpdate();
+  } else {
+    // Schedule the deletion of v4_database off IO thread.
+    V4Database::Destroy(std::move(v4_database));
+  }
 }
 
 void V4LocalDatabaseManager::StopOnIOThread(bool shutdown) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
+  enabled_ = false;
+
+  // Delete the V4Database. Any pending writes to disk are completed.
+  // This operation happens on the task_runner on which v4_database_ operates
+  // and doesn't block the IO thread.
+  V4Database::Destroy(std::move(v4_database_));
 
   // Delete the V4UpdateProtocolManager.
   // This cancels any in-flight update request.
-  if (v4_update_protocol_manager_.get()) {
-    v4_update_protocol_manager_.reset();
-  }
-
-  enabled_ = false;
+  v4_update_protocol_manager_.reset();
+
   SafeBrowsingDatabaseManager::StopOnIOThread(shutdown);
 }
 
 void V4LocalDatabaseManager::UpdateRequestCompleted(
     const std::vector<ListUpdateResponse>& responses) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+
   // TODO(vakh): Updates downloaded. Store them on disk and record new state.
+  v4_update_protocol_manager_->ScheduleNextUpdate();
 }
 
 }  // namespace safe_browsing