Refactor WifiDataProviderChromeOs to implement WifiDataProviderImplBase directly.

content/browser/geolocation/wifi_data_provider_chromeos.cc

 // Copyright (c) 2010 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.
 
 // Provides wifi scan API binding for chromeos, using proprietary APIs.
 
 #include "content/browser/geolocation/wifi_data_provider_chromeos.h"
 
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/chromeos/cros/cros_library.h"
 #include "chrome/browser/chromeos/cros/network_library.h"
+#include "content/browser/browser_thread.h"
 
 namespace {
 // The time periods between successive polls of the wifi data.
 const int kDefaultPollingIntervalMilliseconds = 10 * 1000;  // 10s
 const int kNoChangePollingIntervalMilliseconds = 2 * 60 * 1000;  // 2 mins
 const int kTwoNoChangePollingIntervalMilliseconds = 10 * 60 * 1000;  // 10 mins
 const int kNoWifiPollingIntervalMilliseconds = 20 * 1000; // 20s
 }
 
 namespace chromeos {
@@ skipping 43 matching lines @@
 }
 
 }  // namespace
 }  // namespace chromeos
 
 template<>
 WifiDataProviderImplBase* WifiDataProvider::DefaultFactoryFunction() {
   return new WifiDataProviderChromeOs();
 }
 
-WifiDataProviderChromeOs::WifiDataProviderChromeOs() {
+WifiDataProviderChromeOs::WifiDataProviderChromeOs() :
+    started_(false) {
 }
 
 WifiDataProviderChromeOs::~WifiDataProviderChromeOs() {
 }
 
+bool WifiDataProviderChromeOs::StartDataProvider() {
+  DCHECK(CalledOnClientThread());
+  DCHECK(!started_);
+  started_ = true;
+
+  wlan_api_.reset(NewWlanApi());
+  if (wlan_api_ == NULL) {
+    // Error! Can't do scans, so don't try and schedule one.
+    is_first_scan_complete_ = true;
+    return false;
+  }
+
+  DCHECK(polling_policy_ == NULL);
+  polling_policy_.reset(NewPollingPolicy());
+  DCHECK(polling_policy_ != NULL);
+
+  // Perform first scan ASAP regardless of the polling policy. If this scan
+  // fails we'll retry at a rate in line with the polling policy.
+  ScheduleNextScan(0);
+  return true;
+}
+
+void WifiDataProviderChromeOs::StopDataProvider() {
+  DCHECK(CalledOnClientThread());
+  started_ = false;
+  wlan_api_.reset();
+  polling_policy_.reset();
+}
+
+bool WifiDataProviderChromeOs::GetData(WifiData *data) {

[bulach, 2011/03/16 18:01:00]

nit: WifiData* data

[John Knottenbelt, 2011/03/16 18:20:14]

Done.

+  DCHECK(CalledOnClientThread());
+  DCHECK(data);
+  *data = wifi_data_;
+  return is_first_scan_complete_;
+}
+
 WifiDataProviderCommon::WlanApiInterface*
     WifiDataProviderChromeOs::NewWlanApi(chromeos::NetworkLibrary* lib) {
   return new chromeos::NetworkLibraryWlanApi(lib);
 }
 
 WifiDataProviderCommon::WlanApiInterface*
     WifiDataProviderChromeOs::NewWlanApi() {
   chromeos::CrosLibrary* cros_lib = chromeos::CrosLibrary::Get();
   DCHECK(cros_lib);
   if (!cros_lib->EnsureLoaded())
     return NULL;
   return NewWlanApi(cros_lib->GetNetworkLibrary());
 }
 
 PollingPolicyInterface* WifiDataProviderChromeOs::NewPollingPolicy() {
   return new GenericPollingPolicy<kDefaultPollingIntervalMilliseconds,
                                   kNoChangePollingIntervalMilliseconds,
                                   kTwoNoChangePollingIntervalMilliseconds,
                                   kNoWifiPollingIntervalMilliseconds>;
 }
+
+void WifiDataProviderChromeOs::DoWifiScanTask() {
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  scoped_ptr<WifiData> new_data(new WifiData);
+  if (!wlan_api_->GetAccessPointData(&new_data->access_point_data))
+    new_data.reset();
+
+  client_loop_->PostTask(FROM_HERE, NewRunnableMethod(
+      this, &WifiDataProviderChromeOs::DidWifiScanTask,
+      new_data.release()));

[bulach, 2011/03/16 18:01:00]

heh, the thing is that whilst in flight, new_data has will be orphan and leak if
the task gets cancelled before running..
but fear not! :) afaict WifiData is a simple copy-constructable struct, so
instead of a ptr, just pass by value...

and as we chatted, have another method for "DidEmptyWifiScan", or something..

[John Knottenbelt, 2011/03/16 18:20:14]

Done.

+}
+
+void WifiDataProviderChromeOs::DidWifiScanTask(WifiData* new_data) {

[bulach, 2011/03/16 18:01:00]

and this can be come a const WifiData& new_data

[John Knottenbelt, 2011/03/16 18:20:14]

Done.

+  DCHECK(CalledOnClientThread());
+  scoped_ptr<WifiData> delete_new_data(new_data);
+
+  bool update_available = false;
+  if (!new_data)
+    ScheduleNextScan(polling_policy_->NoWifiInterval());
+  else {
+    update_available = wifi_data_.DiffersSignificantly(*new_data);
+    wifi_data_ = *new_data;
+
+    polling_policy_->UpdatePollingInterval(update_available);
+    ScheduleNextScan(polling_policy_->PollingInterval());
+  }
+  if (update_available || !is_first_scan_complete_) {
+    is_first_scan_complete_ = true;
+    NotifyListeners();
+  }
+}
+
+void WifiDataProviderChromeOs::ScheduleNextScan(int interval) {
+  DCHECK(CalledOnClientThread());
+  if (started_) {
+    BrowserThread::PostDelayedTask(
+        BrowserThread::UI,
+        FROM_HERE,
+        NewRunnableMethod(this,
+                          &WifiDataProviderChromeOs::DoWifiScanTask),
+        interval);
+  }
+}