Refactoring AutocompleteActionPredictor Database.

chrome/browser/predictors/predictor_database.cc

+// Copyright (c) 2012 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 "chrome/browser/predictors/predictor_database.h"
+
+#include "base/bind.h"
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/stringprintf.h"
+#include "base/metrics/histogram.h"
+#include "chrome/browser/predictors/autocomplete_action_predictor_table.h"
+#include "chrome/browser/profiles/profile.h"
+#include "content/public/browser/browser_thread.h"
+#include "sql/connection.h"
+#include "sql/statement.h"
+
+namespace {
+
+// FIXME: This should move to a more generic name.

[dominich, 2012/05/08 20:35:28]

TODO(shishir) instead?

[Shishir, 2012/05/08 21:49:03]

Done.

+const FilePath::CharType kPredictorDatabaseName[] =
+    FILE_PATH_LITERAL("Network Action Predictor");
+
+}  // namespace
+
+namespace predictors {
+
+// Refcounted as it is created, initialized and destroyed on a different thread
+// to the DB thread that is required for all methods performing database access.
+class PredictorDatabaseInternal
+    : public base::RefCountedThreadSafe<PredictorDatabaseInternal> {
+ private:
+  friend class base::RefCountedThreadSafe<PredictorDatabaseInternal>;
+  friend class PredictorDatabase;
+
+  explicit PredictorDatabaseInternal(Profile* profile);
+  virtual ~PredictorDatabaseInternal();
+
+  // Opens the database file from the profile path. Separated from the
+  // constructor to ease construction/destruction of this object on one thread
+  // but database access on the DB thread.
+  void Initialize();
+  void LogDatabaseStats();  //  DB Thread.
+
+  // Cancels pending DB transactions. Should only be called on the UI thread.
+  void SetCancelled();
+

[dominich, 2012/05/08 20:35:28]

remove extra line

[Shishir, 2012/05/08 21:49:03]

Done.

+
+  FilePath db_path_;
+  sql::Connection db_;
+  scoped_refptr<AutocompleteActionPredictorTable> autocomplete_table_;
+
+  DISALLOW_COPY_AND_ASSIGN(PredictorDatabaseInternal);
+};
+
+
+PredictorDatabaseInternal::PredictorDatabaseInternal(Profile* profile)
+    : db_path_(profile->GetPath().Append(kPredictorDatabaseName)),
+      autocomplete_table_(new AutocompleteActionPredictorTable()) {
+}
+
+PredictorDatabaseInternal::~PredictorDatabaseInternal() {
+}
+
+void PredictorDatabaseInternal::Initialize() {
+  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::DB));
+
+  db_.set_exclusive_locking();
+  bool success = db_.Open(db_path_);
+
+  if (!success)
+    return;
+
+  autocomplete_table_->Initialize(&db_);
+
+  LogDatabaseStats();
+}
+
+void PredictorDatabaseInternal::SetCancelled() {
+  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+
+  autocomplete_table_->cancelled_.Set();
+}
+
+void PredictorDatabaseInternal::LogDatabaseStats() {
+  CHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::DB));
+
+  int64 db_size;
+  bool success = file_util::GetFileSize(db_path_, &db_size);
+  DCHECK(success) << "Failed to get file size for " << db_path_.value();
+  UMA_HISTOGRAM_MEMORY_KB("Predictor.DatabaseSizeKB",
+                          static_cast<int>(db_size / 1024));
+
+  autocomplete_table_->LogDatabaseStats();
+}
+
+
+PredictorDatabase::PredictorDatabase(Profile* profile)
+    : db_(new PredictorDatabaseInternal(profile)) {
+  content::BrowserThread::PostTask(content::BrowserThread::DB, FROM_HERE,

[dominich, 2012/05/08 20:35:28]

what stops users getting access to the table before this task runs?

[Shishir, 2012/05/08 21:49:03]

Even if they have access to the table, the underlying db_ pointer will be null
so all database ops will be NoOp. The db_ pointers get set on line 75 when this
function comes back. Sounds reasonable?

[dominich, 2012/05/08 22:49:39]

Fine.

+      base::Bind(&PredictorDatabaseInternal::Initialize, db_));
+}
+
+PredictorDatabase::~PredictorDatabase() {
+}
+
+void PredictorDatabase::Shutdown() {
+  db_->SetCancelled();
+}
+
+AutocompleteActionPredictorTable* PredictorDatabase::autocomplete_table() {
+  return db_->autocomplete_table_.get();
+}
+
+sql::Connection* PredictorDatabase::GetDatabase() {
+  return &db_->db_;
+}
+
+}  // namespace predictors