content/browser/geolocation/wifi_data_provider_common.cc

   1 // Copyright (c) 2012 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 #include "content/browser/geolocation/wifi_data_provider_common.h"
   6
   7 #include "base/bind.h"
   8 #include "base/location.h"
   9 #include "base/single_thread_task_runner.h"
  10 #include "base/strings/stringprintf.h"
  11 #include "base/strings/utf_string_conversions.h"
  12
  13 namespace content {
  14
  15 base::string16 MacAddressAsString16(const uint8 mac_as_int[6]) {
  16   // mac_as_int is big-endian. Write in byte chunks.
  17   // Format is XX-XX-XX-XX-XX-XX.
  18   static const char* const kMacFormatString =
  19       "%02x-%02x-%02x-%02x-%02x-%02x";
  20   return base::ASCIIToUTF16(base::StringPrintf(kMacFormatString,
  21                                                mac_as_int[0],
  22                                                mac_as_int[1],
  23                                                mac_as_int[2],
  24                                                mac_as_int[3],
  25                                                mac_as_int[4],
  26                                                mac_as_int[5]));
  27 }
  28
  29 WifiDataProviderCommon::WifiDataProviderCommon()
  30     : is_first_scan_complete_(false),
  31       weak_factory_(this) {
  32 }
  33
  34 WifiDataProviderCommon::~WifiDataProviderCommon() {
  35 }
  36
  37 void WifiDataProviderCommon::StartDataProvider() {
  38   DCHECK(wlan_api_ == NULL);
  39   wlan_api_.reset(NewWlanApi());
  40   if (wlan_api_ == NULL) {
  41     // Error! Can't do scans, so don't try and schedule one.
  42     is_first_scan_complete_ = true;
  43     return;
  44   }
  45
  46   DCHECK(polling_policy_ == NULL);
  47   polling_policy_.reset(NewPollingPolicy());
  48   DCHECK(polling_policy_ != NULL);
  49
  50   // Perform first scan ASAP regardless of the polling policy. If this scan
  51   // fails we'll retry at a rate in line with the polling policy.
  52   ScheduleNextScan(0);
  53 }
  54
  55 void WifiDataProviderCommon::StopDataProvider() {
  56   wlan_api_.reset();
  57   polling_policy_.reset();
  58 }
  59
  60 bool WifiDataProviderCommon::GetData(WifiData* data) {
  61   *data = wifi_data_;
  62   // If we've successfully completed a scan, indicate that we have all of the
  63   // data we can get.
  64   return is_first_scan_complete_;
  65 }
  66
  67 void WifiDataProviderCommon::DoWifiScanTask() {
  68   bool update_available = false;
  69   WifiData new_data;
  70   if (!wlan_api_->GetAccessPointData(&new_data.access_point_data)) {
  71     ScheduleNextScan(polling_policy_->NoWifiInterval());
  72   } else {
  73     update_available = wifi_data_.DiffersSignificantly(new_data);
  74     wifi_data_ = new_data;
  75     polling_policy_->UpdatePollingInterval(update_available);
  76     ScheduleNextScan(polling_policy_->PollingInterval());
  77   }
  78   if (update_available || !is_first_scan_complete_) {
  79     is_first_scan_complete_ = true;
  80     RunCallbacks();
  81   }
  82 }
  83
  84 void WifiDataProviderCommon::ScheduleNextScan(int interval) {
  85   client_loop()->task_runner()->PostDelayedTask(
  86       FROM_HERE, base::Bind(&WifiDataProviderCommon::DoWifiScanTask,
  87                             weak_factory_.GetWeakPtr()),
  88       base::TimeDelta::FromMilliseconds(interval));
  89 }
  90
  91 }  // namespace content