components/precache/core/precache_database.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_PRECACHE_CORE_PRECACHE_DATABASE_H_
   6 #define COMPONENTS_PRECACHE_CORE_PRECACHE_DATABASE_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/callback.h"
  13 #include "base/containers/hash_tables.h"
  14 #include "base/memory/ref_counted.h"
  15 #include "base/memory/scoped_ptr.h"
  16 #include "base/threading/thread_checker.h"
  17 #include "components/precache/core/precache_url_table.h"
  18
  19 class GURL;
  20
  21 namespace base {
  22 class FilePath;
  23 class Time;
  24 }
  25
  26 namespace sql {
  27 class Connection;
  28 }
  29
  30 namespace precache {
  31
  32 // Class that tracks information related to precaching. This class can be
  33 // constructed or destroyed on any threads, but all other methods must be called
  34 // on the same thread (e.g. the DB thread).
  35 class PrecacheDatabase : public base::RefCountedThreadSafe<PrecacheDatabase> {
  36  public:
  37   // A PrecacheDatabase can be constructed on any thread.
  38   PrecacheDatabase();
  39
  40   // Initializes the precache database, using the specified database file path.
  41   // Init must be called before any other methods.
  42   bool Init(const base::FilePath& db_path);
  43
  44   // Deletes precache history from the precache URL table that is more than 60
  45   // days older than |current_time|.
  46   void DeleteExpiredPrecacheHistory(const base::Time& current_time);
  47
  48   // Delete all history entries from the database.
  49   void ClearHistory();
  50
  51   // Report precache-related metrics in response to a URL being fetched, where
  52   // the fetch was motivated by precaching.
  53   void RecordURLPrecached(const GURL& url, const base::Time& fetch_time,
  54                           int64 size, bool was_cached);
  55
  56   // Report precache-related metrics in response to a URL being fetched, where
  57   // the fetch was not motivated by precaching. |is_connection_cellular|
  58   // indicates whether the current network connection is a cellular network.
  59   void RecordURLFetched(const GURL& url, const base::Time& fetch_time,
  60                         int64 size, bool was_cached,
  61                         bool is_connection_cellular);
  62
  63  private:
  64   friend class base::RefCountedThreadSafe<PrecacheDatabase>;
  65   friend class PrecacheDatabaseTest;
  66
  67   ~PrecacheDatabase();
  68
  69   bool IsDatabaseAccessible() const;
  70
  71   // Flushes any buffered write operations. |buffered_writes_| will be empty
  72   // after calling this function. To maximize performance, all the buffered
  73   // writes are run in a single database transaction.
  74   void Flush();
  75
  76   // Same as Flush(), but also updates the flag |is_flush_posted_| to indicate
  77   // that a flush is no longer posted.
  78   void PostedFlush();
  79
  80   // Post a call to PostedFlush() on the current thread's MessageLoop, if
  81   // |buffered_writes_| is non-empty and there isn't already a flush call
  82   // posted.
  83   void MaybePostFlush();
  84
  85   scoped_ptr<sql::Connection> db_;
  86
  87   // Table that keeps track of URLs that are in the cache because of precaching,
  88   // and wouldn't be in the cache otherwise. If |buffered_writes_| is non-empty,
  89   // then this table will not be up to date until the next call to Flush().
  90   PrecacheURLTable precache_url_table_;
  91
  92   // A vector of write operations to be run on the database.
  93   std::vector<base::Closure> buffered_writes_;
  94
  95   // Set of URLs that have been modified in |buffered_writes_|. It's a hash set
  96   // of strings, and not GURLs, because there is no hash function on GURL.
  97   base::hash_set<std::string> buffered_urls_;
  98
  99   // Flag indicating whether or not a call to Flush() has been posted to run in
 100   // the future.
 101   bool is_flush_posted_;
 102
 103   // ThreadChecker used to ensure that all methods other than the constructor
 104   // or destructor are called on the same thread.
 105   base::ThreadChecker thread_checker_;
 106
 107   DISALLOW_COPY_AND_ASSIGN(PrecacheDatabase);
 108 };
 109
 110 }  // namespace precache
 111
 112 #endif  // COMPONENTS_PRECACHE_CORE_PRECACHE_DATABASE_H_