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      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 // Provides wifi scan API binding for chromeos, using proprietary APIs.
      6 
      7 #include "content/browser/geolocation/wifi_data_provider_chromeos.h"
      8 
      9 #include "base/bind.h"
     10 #include "base/strings/utf_string_conversions.h"
     11 #include "chromeos/network/geolocation_handler.h"
     12 #include "content/public/browser/browser_thread.h"
     13 
     14 namespace content {
     15 
     16 namespace {
     17 
     18 // The time periods between successive polls of the wifi data.
     19 const int kDefaultPollingIntervalMilliseconds = 10 * 1000;  // 10s
     20 const int kNoChangePollingIntervalMilliseconds = 2 * 60 * 1000;  // 2 mins
     21 const int kTwoNoChangePollingIntervalMilliseconds = 10 * 60 * 1000;  // 10 mins
     22 const int kNoWifiPollingIntervalMilliseconds = 20 * 1000; // 20s
     23 
     24 }  // namespace
     25 
     26 WifiDataProviderChromeOs::WifiDataProviderChromeOs() : started_(false) {
     27 }
     28 
     29 WifiDataProviderChromeOs::~WifiDataProviderChromeOs() {
     30 }
     31 
     32 void WifiDataProviderChromeOs::StartDataProvider() {
     33   DCHECK(CalledOnClientThread());
     34 
     35   DCHECK(polling_policy_ == NULL);
     36   polling_policy_.reset(
     37       new GenericWifiPollingPolicy<kDefaultPollingIntervalMilliseconds,
     38                                    kNoChangePollingIntervalMilliseconds,
     39                                    kTwoNoChangePollingIntervalMilliseconds,
     40                                    kNoWifiPollingIntervalMilliseconds>);
     41 
     42   ScheduleStart();
     43 }
     44 
     45 void WifiDataProviderChromeOs::StopDataProvider() {
     46   DCHECK(CalledOnClientThread());
     47 
     48   polling_policy_.reset();
     49   ScheduleStop();
     50 }
     51 
     52 bool WifiDataProviderChromeOs::GetData(WifiData* data) {
     53   DCHECK(CalledOnClientThread());
     54   DCHECK(data);
     55   *data = wifi_data_;
     56   return is_first_scan_complete_;
     57 }
     58 
     59 void WifiDataProviderChromeOs::DoStartTaskOnUIThread() {
     60   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     61   DoWifiScanTaskOnUIThread();
     62 }
     63 
     64 void WifiDataProviderChromeOs::DoWifiScanTaskOnUIThread() {
     65   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     66 
     67   // This method could be scheduled after a ScheduleStop.
     68   if (!started_)
     69     return;
     70 
     71   WifiData new_data;
     72 
     73   if (GetAccessPointData(&new_data.access_point_data)) {
     74     client_loop()->PostTask(
     75         FROM_HERE,
     76         base::Bind(&WifiDataProviderChromeOs::DidWifiScanTask, this, new_data));
     77   } else {
     78     client_loop()->PostTask(
     79         FROM_HERE,
     80         base::Bind(&WifiDataProviderChromeOs::DidWifiScanTaskNoResults, this));
     81   }
     82 }
     83 
     84 void WifiDataProviderChromeOs::DidWifiScanTaskNoResults() {
     85   DCHECK(CalledOnClientThread());
     86   // Schedule next scan if started (StopDataProvider could have been called
     87   // in between DoWifiScanTaskOnUIThread and this method).
     88   if (started_)
     89     ScheduleNextScan(polling_policy_->NoWifiInterval());
     90 }
     91 
     92 void WifiDataProviderChromeOs::DidWifiScanTask(const WifiData& new_data) {
     93   DCHECK(CalledOnClientThread());
     94   bool update_available = wifi_data_.DiffersSignificantly(new_data);
     95   wifi_data_ = new_data;
     96   // Schedule next scan if started (StopDataProvider could have been called
     97   // in between DoWifiScanTaskOnUIThread and this method).
     98   if (started_) {
     99     polling_policy_->UpdatePollingInterval(update_available);
    100     ScheduleNextScan(polling_policy_->PollingInterval());
    101   }
    102 
    103   if (update_available || !is_first_scan_complete_) {
    104     is_first_scan_complete_ = true;
    105     RunCallbacks();
    106   }
    107 }
    108 
    109 void WifiDataProviderChromeOs::ScheduleNextScan(int interval) {
    110   DCHECK(CalledOnClientThread());
    111   DCHECK(started_);
    112   BrowserThread::PostDelayedTask(
    113       BrowserThread::UI,
    114       FROM_HERE,
    115       base::Bind(&WifiDataProviderChromeOs::DoWifiScanTaskOnUIThread, this),
    116       base::TimeDelta::FromMilliseconds(interval));
    117 }
    118 
    119 void WifiDataProviderChromeOs::ScheduleStop() {
    120   DCHECK(CalledOnClientThread());
    121   DCHECK(started_);
    122   started_ = false;
    123 }
    124 
    125 void WifiDataProviderChromeOs::ScheduleStart() {
    126   DCHECK(CalledOnClientThread());
    127   DCHECK(!started_);
    128   started_ = true;
    129   // Perform first scan ASAP regardless of the polling policy. If this scan
    130   // fails we'll retry at a rate in line with the polling policy.
    131   BrowserThread::PostTask(
    132       BrowserThread::UI,
    133       FROM_HERE,
    134       base::Bind(&WifiDataProviderChromeOs::DoStartTaskOnUIThread, this));
    135 }
    136 
    137 bool WifiDataProviderChromeOs::GetAccessPointData(
    138     WifiData::AccessPointDataSet* result) {
    139   // If wifi isn't enabled, we've effectively completed the task.
    140   // Return true to indicate an empty access point list.
    141   if (!chromeos::NetworkHandler::Get()->geolocation_handler()->wifi_enabled())
    142     return true;
    143 
    144   chromeos::WifiAccessPointVector access_points;
    145   int64 age_ms = 0;
    146   if (!chromeos::NetworkHandler::Get()->geolocation_handler()->
    147       GetWifiAccessPoints(&access_points, &age_ms)) {
    148     return false;
    149   }
    150   for (chromeos::WifiAccessPointVector::const_iterator i
    151            = access_points.begin();
    152        i != access_points.end(); ++i) {
    153     AccessPointData ap_data;
    154     ap_data.mac_address = ASCIIToUTF16(i->mac_address);
    155     ap_data.radio_signal_strength = i->signal_strength;
    156     ap_data.channel = i->channel;
    157     ap_data.signal_to_noise = i->signal_to_noise;
    158     ap_data.ssid = UTF8ToUTF16(i->ssid);
    159     result->insert(ap_data);
    160   }
    161   // If the age is significantly longer than our long polling time, assume the
    162   // data is stale and return false which will trigger a faster update.
    163   if (age_ms > kTwoNoChangePollingIntervalMilliseconds * 2)
    164     return false;
    165   return true;
    166 }
    167 
    168 // static
    169 WifiDataProviderImplBase* WifiDataProvider::DefaultFactoryFunction() {
    170   return new WifiDataProviderChromeOs();
    171 }
    172 
    173 }  // namespace content
    174