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// Copyright (c) 2012 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 "content/browser/geolocation/network_location_provider.h"
#include "base/bind.h"
#include "base/strings/utf_string_conversions.h"
#include "base/time/time.h"
#include "content/public/browser/access_token_store.h"
namespace content {
namespace {
// The maximum period of time we'll wait for a complete set of wifi data
// before sending the request.
const int kDataCompleteWaitSeconds = 2;
} // namespace
// static
const size_t NetworkLocationProvider::PositionCache::kMaximumSize = 10;
NetworkLocationProvider::PositionCache::PositionCache() {}
NetworkLocationProvider::PositionCache::~PositionCache() {}
bool NetworkLocationProvider::PositionCache::CachePosition(
const WifiData& wifi_data,
const Geoposition& position) {
// Check that we can generate a valid key for the wifi data.
base::string16 key;
if (!MakeKey(wifi_data, &key)) {
return false;
}
// If the cache is full, remove the oldest entry.
if (cache_.size() == kMaximumSize) {
DCHECK(cache_age_list_.size() == kMaximumSize);
CacheAgeList::iterator oldest_entry = cache_age_list_.begin();
DCHECK(oldest_entry != cache_age_list_.end());
cache_.erase(*oldest_entry);
cache_age_list_.erase(oldest_entry);
}
DCHECK_LT(cache_.size(), kMaximumSize);
// Insert the position into the cache.
std::pair<CacheMap::iterator, bool> result =
cache_.insert(std::make_pair(key, position));
if (!result.second) {
NOTREACHED(); // We never try to add the same key twice.
CHECK_EQ(cache_.size(), cache_age_list_.size());
return false;
}
cache_age_list_.push_back(result.first);
DCHECK_EQ(cache_.size(), cache_age_list_.size());
return true;
}
// Searches for a cached position response for the current WiFi data. Returns
// the cached position if available, NULL otherwise.
const Geoposition* NetworkLocationProvider::PositionCache::FindPosition(
const WifiData& wifi_data) {
base::string16 key;
if (!MakeKey(wifi_data, &key)) {
return NULL;
}
CacheMap::const_iterator iter = cache_.find(key);
return iter == cache_.end() ? NULL : &iter->second;
}
// Makes the key for the map of cached positions, using the available data.
// Returns true if a good key was generated, false otherwise.
//
// static
bool NetworkLocationProvider::PositionCache::MakeKey(
const WifiData& wifi_data,
base::string16* key) {
// Currently we use only WiFi data and base the key only on the MAC addresses.
DCHECK(key);
key->clear();
const size_t kCharsPerMacAddress = 6 * 3 + 1; // e.g. "11:22:33:44:55:66|"
key->reserve(wifi_data.access_point_data.size() * kCharsPerMacAddress);
const base::string16 separator(base::ASCIIToUTF16("|"));
for (WifiData::AccessPointDataSet::const_iterator iter =
wifi_data.access_point_data.begin();
iter != wifi_data.access_point_data.end();
iter++) {
*key += separator;
*key += iter->mac_address;
*key += separator;
}
// If the key is the empty string, return false, as we don't want to cache a
// position for such data.
return !key->empty();
}
// NetworkLocationProvider factory function
LocationProviderBase* NewNetworkLocationProvider(
AccessTokenStore* access_token_store,
net::URLRequestContextGetter* context,
const GURL& url,
const base::string16& access_token) {
return new NetworkLocationProvider(
access_token_store, context, url, access_token);
}
// NetworkLocationProvider
NetworkLocationProvider::NetworkLocationProvider(
AccessTokenStore* access_token_store,
net::URLRequestContextGetter* url_context_getter,
const GURL& url,
const base::string16& access_token)
: access_token_store_(access_token_store),
wifi_data_provider_(NULL),
wifi_data_update_callback_(
base::Bind(&NetworkLocationProvider::OnWifiDataUpdate,
base::Unretained(this))),
is_wifi_data_complete_(false),
access_token_(access_token),
is_permission_granted_(false),
is_new_data_available_(false),
weak_factory_(this) {
// Create the position cache.
position_cache_.reset(new PositionCache());
request_.reset(new NetworkLocationRequest(
url_context_getter,
url,
base::Bind(&NetworkLocationProvider::OnLocationResponse,
base::Unretained(this))));
}
NetworkLocationProvider::~NetworkLocationProvider() {
StopProvider();
}
// LocationProvider implementation
void NetworkLocationProvider::GetPosition(Geoposition* position) {
DCHECK(position);
*position = position_;
}
void NetworkLocationProvider::RequestRefresh() {
// TODO(joth): When called via the public (base class) interface, this should
// poke each data provider to get them to expedite their next scan.
// Whilst in the delayed start, only send request if all data is ready.
if (!weak_factory_.HasWeakPtrs() || is_wifi_data_complete_) {
RequestPosition();
}
}
void NetworkLocationProvider::OnPermissionGranted() {
const bool was_permission_granted = is_permission_granted_;
is_permission_granted_ = true;
if (!was_permission_granted && IsStarted()) {
RequestRefresh();
}
}
void NetworkLocationProvider::OnWifiDataUpdate(WifiDataProvider* provider) {
DCHECK(provider == wifi_data_provider_);
is_wifi_data_complete_ = wifi_data_provider_->GetData(&wifi_data_);
OnWifiDataUpdated();
}
void NetworkLocationProvider::OnLocationResponse(
const Geoposition& position,
bool server_error,
const base::string16& access_token,
const WifiData& wifi_data) {
DCHECK(CalledOnValidThread());
// Record the position and update our cache.
position_ = position;
if (position.Validate()) {
position_cache_->CachePosition(wifi_data, position);
}
// Record access_token if it's set.
if (!access_token.empty() && access_token_ != access_token) {
access_token_ = access_token;
access_token_store_->SaveAccessToken(request_->url(), access_token);
}
// Let listeners know that we now have a position available.
NotifyCallback(position_);
}
bool NetworkLocationProvider::StartProvider(bool high_accuracy) {
DCHECK(CalledOnValidThread());
if (IsStarted())
return true;
DCHECK(wifi_data_provider_ == NULL);
if (!request_->url().is_valid()) {
LOG(WARNING) << "StartProvider() : Failed, Bad URL: "
<< request_->url().possibly_invalid_spec();
return false;
}
// Registers a callback with the data provider. The first call to Register
// will create a singleton data provider and it will be deleted when the last
// callback is removed with Unregister.
wifi_data_provider_ = WifiDataProvider::Register(&wifi_data_update_callback_);
base::MessageLoop::current()->PostDelayedTask(
FROM_HERE,
base::Bind(&NetworkLocationProvider::RequestPosition,
weak_factory_.GetWeakPtr()),
base::TimeDelta::FromSeconds(kDataCompleteWaitSeconds));
// Get the wifi data.
is_wifi_data_complete_ = wifi_data_provider_->GetData(&wifi_data_);
if (is_wifi_data_complete_)
OnWifiDataUpdated();
return true;
}
void NetworkLocationProvider::OnWifiDataUpdated() {
DCHECK(CalledOnValidThread());
wifi_data_updated_timestamp_ = base::Time::Now();
is_new_data_available_ = is_wifi_data_complete_;
RequestRefresh();
}
void NetworkLocationProvider::StopProvider() {
DCHECK(CalledOnValidThread());
if (IsStarted()) {
wifi_data_provider_->Unregister(&wifi_data_update_callback_);
}
wifi_data_provider_ = NULL;
weak_factory_.InvalidateWeakPtrs();
}
// Other methods
void NetworkLocationProvider::RequestPosition() {
DCHECK(CalledOnValidThread());
if (!is_new_data_available_)
return;
const Geoposition* cached_position =
position_cache_->FindPosition(wifi_data_);
DCHECK(!wifi_data_updated_timestamp_.is_null()) <<
"Timestamp must be set before looking up position";
if (cached_position) {
DCHECK(cached_position->Validate());
// Record the position and update its timestamp.
position_ = *cached_position;
// The timestamp of a position fix is determined by the timestamp
// of the source data update. (The value of position_.timestamp from
// the cache could be from weeks ago!)
position_.timestamp = wifi_data_updated_timestamp_;
is_new_data_available_ = false;
// Let listeners know that we now have a position available.
NotifyCallback(position_);
return;
}
// Don't send network requests until authorized. http://crbug.com/39171
if (!is_permission_granted_)
return;
weak_factory_.InvalidateWeakPtrs();
is_new_data_available_ = false;
// TODO(joth): Rather than cancel pending requests, we should create a new
// NetworkLocationRequest for each and hold a set of pending requests.
if (request_->is_request_pending()) {
DVLOG(1) << "NetworkLocationProvider - pre-empting pending network request "
"with new data. Wifi APs: "
<< wifi_data_.access_point_data.size();
}
request_->MakeRequest(access_token_, wifi_data_,
wifi_data_updated_timestamp_);
}
bool NetworkLocationProvider::IsStarted() const {
return wifi_data_provider_ != NULL;
}
} // namespace content