Precache tracking database

components/precache/content/precache_manager.cc

+// Copyright 2013 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 "components/precache/content/precache_manager.h"
+
+#include "base/bind.h"
+#include "base/command_line.h"
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "base/metrics/field_trial.h"
+#include "base/time/time.h"
+#include "components/precache/core/precache_database.h"
+#include "components/precache/core/precache_switches.h"
+#include "components/precache/core/url_list_provider.h"
+#include "content/public/browser/browser_context.h"
+#include "content/public/browser/browser_thread.h"
+#include "sql/connection.h"
+
+using content::BrowserThread;
+
+namespace {
+
+const char kPrecacheFieldTrialName[] = "Precache";
+const char kPrecacheFieldTrialEnabledGroup[] = "PrecacheEnabled";
+
+const base::FilePath::CharType kPrecacheDatabaseName[] =
+    FILE_PATH_LITERAL("PrecacheDatabase");
+
+void InitPrecacheDatabaseOnDBThread(
+    base::FilePath dir_path,
+    scoped_refptr<precache::PrecacheDatabase> precache_database) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::DB));
+
+  scoped_ptr<sql::Connection> db(new sql::Connection());
+  if (!db->Open(dir_path.Append(kPrecacheDatabaseName))) {
+    DLOG(WARNING) << "Could not open precache database. No precache data will "
+                     "be tracked.";
+  }
+
+  // Initialize the precache database with the connection even if it failed to
+  // open. The precache database will take ownership of the connection.
+  precache_database->Init(db.Pass());
+}
+
+}  // namespace
+
+namespace precache {
+
+PrecacheManager::PrecacheManager(content::BrowserContext* browser_context)
+    : browser_context_(browser_context),
+      precache_database_(new PrecacheDatabase()),
+      is_precaching_(false) {
+  BrowserThread::PostTask(
+      BrowserThread::DB, FROM_HERE,
+      base::Bind(&InitPrecacheDatabaseOnDBThread, browser_context->GetPath(),
+                 precache_database_));
+}
+
+PrecacheManager::~PrecacheManager() {}
+
+// static
+bool PrecacheManager::IsPrecachingEnabled() {
+  return base::FieldTrialList::FindFullName(kPrecacheFieldTrialName) ==
+             kPrecacheFieldTrialEnabledGroup ||
+         CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnablePrecache);
+}
+
+void PrecacheManager::Shutdown() {
+  CancelPrecaching();
+}
+
+void PrecacheManager::OnDone() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  {
+    base::AutoLock lock(lock_);
+    is_precaching_ = false;
+  }
+
+  precache_fetcher_.reset();
+}
+
+void PrecacheManager::StartPrecaching(
+    URLListProvider* interesting_urls_provider) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  {
+    base::AutoLock lock(lock_);
+    if (is_precaching_) {
+      DLOG(WARNING) << "Cannot start precaching because precaching is already "
+                       "in progress.";
+      return;
+    }
+    is_precaching_ = true;
+  }
+
+  // The start of the day before today. Don't just use (base::Time::Now() -
+  // base::TimeDelta::FromDays(1)).LocalMidnight() because that wouldn't account
+  // for daylight savings, i.e. some days are 23 or 25 hours long.
+  base::Time yesterday = (base::Time::Now().LocalMidnight() -
+                          base::TimeDelta::FromHours(1)).LocalMidnight();
+
+  // Report any UMA of precache stats for days before the current date and
+  // delete expired precache history.
+  BrowserThread::PostTask(BrowserThread::DB, FROM_HERE,
+                          base::Bind(&PrecacheDatabase::ReportAndDeleteOldStats,
+                                     precache_database_, yesterday));
+
+  interesting_urls_provider->GetURLs(
+      base::Bind(&PrecacheManager::OnURLsReceived, base::Unretained(this)));
+}
+
+void PrecacheManager::CancelPrecaching() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  {
+    base::AutoLock lock(lock_);
+    if (!is_precaching_) {
+      // Do nothing if precaching is not in progress.
+      return;
+    }
+    is_precaching_ = false;
+  }
+
+  // Destroying the |precache_fetcher_| will cancel any fetch in progress.
+  precache_fetcher_.reset();
+}
+
+bool PrecacheManager::IsPrecaching() {
+  base::AutoLock lock(lock_);
+  return is_precaching_;
+}
+
+scoped_refptr<PrecacheDatabase> PrecacheManager::precache_database() {
+  return precache_database_;
+}
+
+void PrecacheManager::OnURLsReceived(const std::list<GURL>& interesting_urls) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  if (!IsPrecaching()) {
+    // Don't start precaching if it was canceled while waiting for the list of
+    // interesting URLs.
+    return;
+  }
+
+  // Start precaching.
+  precache_fetcher_.reset(new PrecacheFetcher(
+      interesting_urls, browser_context_->GetRequestContext(), this));
+  precache_fetcher_->Start();
+}
+
+}  // namespace precache