Refactoring, moving and renaming the NetworkActionPredictor.

chrome/browser/predictors/predictor_database.h

+// Copyright (c) 2011 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.
+
+#ifndef CHROME_BROWSER_PREDICTORS_PREDICTOR_DATABASE_H_
+#define CHROME_BROWSER_PREDICTORS_PREDICTOR_DATABASE_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "base/file_path.h"
+#include "base/memory/ref_counted.h"
+#include "base/string16.h"
+#include "base/synchronization/cancellation_flag.h"
+#include "chrome/browser/profiles/refcounted_profile_keyed_service.h"
+#include "googleurl/src/gurl.h"
+#include "sql/connection.h"
+
+class Profile;
+
+namespace predictors {
+
+// Refcounted as it is created and destroyed in the UI thread, but its database
+// related functions have to be called in the DB thread.
+class PredictorTableBase

[dominich, 2012/03/13 14:55:21]

this should be in its own file.

[Shishir, 2012/03/14 21:14:37]

Done.

+    : public base::RefCountedThreadSafe<PredictorTableBase> {
+ protected:
+  PredictorTableBase();
+  virtual ~PredictorTableBase();
+  virtual void CreateTableIfNonExistent() = 0;
+
+  sql::Connection* db_;

[dominich, 2012/03/13 14:55:21]

if each table has its own pointer to the same database, and the tables are
calling db functions on that connection, is there any guarantee that there won't
be concurrent access to the connection?

I realise they should all be on the DB thread and thus implicitly
single-threaded, but maybe it's worth enforcing that by making this private and
adding a protected accessor that checks the current thread.

[Shishir, 2012/03/14 21:14:37]

Done.

+  base::CancellationFlag cancelled_;
+
+ private:
+  friend class PredictorDatabase;
+  friend class base::RefCountedThreadSafe<PredictorTableBase>;
+
+  void Initialize(sql::Connection* db);
+
+  DISALLOW_COPY_AND_ASSIGN(PredictorTableBase);
+};
+
+
+// This manages the autocomplete predictor table within the SQLite database
+// passed in to the constructor. It expects the following scheme:
+//
+// network_action_predictor
+//   id                 A unique id.
+//   user_text          What the user typed.
+//   url                The URL of the entry.
+//   number_of_hits     Number of times the entry was shown to the user and
+//                      selected.
+//   number_of_misses   Number of times the entry was shown to the user but not
+//                      selected.
+//
+// TODO(dominich): Consider adding this table to one of the history databases.
+// In memory is currently used, but adding to the on-disk visits database
+// would allow DeleteOldEntries to be cheaper through use of a join.
+class AutocompleteActionPredictorTable : public PredictorTableBase {

[dominich, 2012/03/13 14:55:21]

this should be in its own file.

[Shishir, 2012/03/14 21:14:37]

Done.

+ public:
+  struct Row {
+    // TODO(dominich): Make this 64-bit integer as an optimization. This
+    // requires some investigation into how to make sure the id is unique for
+    // each user_text/url pair.
+    // http://crbug.com/102020
+    typedef std::string Id;
+
+    Row();
+
+    // Only used by unit tests.
+    Row(const Id& id,
+        const string16& user_text,
+        const GURL& url,
+        int number_of_hits,
+        int number_of_misses);
+
+    Row(const Row& row);
+
+    Id id;
+    string16 user_text;
+    GURL url;
+    int number_of_hits;
+    int number_of_misses;
+  };
+
+  typedef std::vector<Row> Rows;
+
+  void GetRow(const Row::Id& id, Row* row);
+  void GetAllRows(Rows* row_buffer);
+
+  void AddRow(const Row& row);
+  void UpdateRow(const Row& row);
+  void AddAndUpdateRows(const Rows& rows_to_add, const Rows& rows_to_update);
+  void DeleteRow(const Row::Id& id);
+  void DeleteRows(const std::vector<Row::Id>& id_list);
+  void DeleteAllRows();
+
+ private:
+  friend class PredictorDatabase;
+
+  AutocompleteActionPredictorTable();
+  virtual ~AutocompleteActionPredictorTable();
+
+  void CreateTableIfNonExistent() OVERRIDE;
+
+  bool StepAndInitializeRow(sql::Statement* statement, Row* row);
+  void BindRowToStatement(const Row& row, sql::Statement* statement);
+
+  DISALLOW_COPY_AND_ASSIGN(AutocompleteActionPredictorTable);
+};
+
+
+// RefcountedProfileKeyedService as it is created and destroyed on a different
+// thread to the DB thread that is required for all methods performing database
+// access.
+class PredictorDatabase : public RefcountedProfileKeyedService {
+ public:
+  explicit PredictorDatabase(Profile* profile);
+  virtual ~PredictorDatabase();
+
+  // 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();
+
+  AutocompleteActionPredictorTable* autocomplete_table() {
+    return autocomplete_table_.get();
+  }
+
+ private:
+  friend class AutocompleteActionPredictorTableTest;
+
+  // RefcountedProfileKeyedService.
+  virtual void ShutdownOnUIThread() OVERRIDE;
+
+  FilePath db_path_;
+  sql::Connection db_;
+  scoped_refptr<AutocompleteActionPredictorTable> autocomplete_table_;
+
+  DISALLOW_COPY_AND_ASSIGN(PredictorDatabase);
+};
+
+}  // namespace predictors
+
+#endif  // CHROME_BROWSER_PREDICTORS_PREDICTOR_DATABASE_H_