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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 "chrome/browser/predictors/resource_prefetch_predictor.h"
#include <map>
#include <set>
#include <utility>
#include "base/command_line.h"
#include "base/metrics/histogram.h"
#include "base/stl_util.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/stringprintf.h"
#include "base/time/time.h"
#include "chrome/browser/chrome_notification_types.h"
#include "chrome/browser/history/history_database.h"
#include "chrome/browser/history/history_db_task.h"
#include "chrome/browser/history/history_notifications.h"
#include "chrome/browser/history/history_service.h"
#include "chrome/browser/history/history_service_factory.h"
#include "chrome/browser/predictors/predictor_database.h"
#include "chrome/browser/predictors/predictor_database_factory.h"
#include "chrome/browser/predictors/resource_prefetcher_manager.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/common/url_constants.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/navigation_controller.h"
#include "content/public/browser/notification_service.h"
#include "content/public/browser/notification_source.h"
#include "content/public/browser/notification_types.h"
#include "content/public/browser/resource_request_info.h"
#include "content/public/browser/web_contents.h"
#include "net/base/mime_util.h"
#include "net/http/http_response_headers.h"
#include "net/url_request/url_request.h"
#include "net/url_request/url_request_context_getter.h"
using content::BrowserThread;
namespace {
// For reporting whether a subresource is handled or not, and for what reasons.
enum ResourceStatus {
RESOURCE_STATUS_HANDLED = 0,
RESOURCE_STATUS_NOT_HTTP_PAGE = 1,
RESOURCE_STATUS_NOT_HTTP_RESOURCE = 2,
RESOURCE_STATUS_UNSUPPORTED_MIME_TYPE = 4,
RESOURCE_STATUS_NOT_GET = 8,
RESOURCE_STATUS_URL_TOO_LONG = 16,
RESOURCE_STATUS_NOT_CACHEABLE = 32,
RESOURCE_STATUS_HEADERS_MISSING = 64,
RESOURCE_STATUS_MAX = 128,
};
// For reporting various interesting events that occur during the loading of a
// single main frame.
enum NavigationEvent {
NAVIGATION_EVENT_REQUEST_STARTED = 0,
NAVIGATION_EVENT_REQUEST_REDIRECTED = 1,
NAVIGATION_EVENT_REQUEST_REDIRECTED_EMPTY_URL = 2,
NAVIGATION_EVENT_REQUEST_EXPIRED = 3,
NAVIGATION_EVENT_RESPONSE_STARTED = 4,
NAVIGATION_EVENT_ONLOAD = 5,
NAVIGATION_EVENT_ONLOAD_EMPTY_URL = 6,
NAVIGATION_EVENT_ONLOAD_UNTRACKED_URL = 7,
NAVIGATION_EVENT_ONLOAD_TRACKED_URL = 8,
NAVIGATION_EVENT_SHOULD_TRACK_URL = 9,
NAVIGATION_EVENT_SHOULD_NOT_TRACK_URL = 10,
NAVIGATION_EVENT_URL_TABLE_FULL = 11,
NAVIGATION_EVENT_HAVE_PREDICTIONS_FOR_URL = 12,
NAVIGATION_EVENT_NO_PREDICTIONS_FOR_URL = 13,
NAVIGATION_EVENT_MAIN_FRAME_URL_TOO_LONG = 14,
NAVIGATION_EVENT_HOST_TOO_LONG = 15,
NAVIGATION_EVENT_COUNT = 16,
};
// For reporting events of interest that are not tied to any navigation.
enum ReportingEvent {
REPORTING_EVENT_ALL_HISTORY_CLEARED = 0,
REPORTING_EVENT_PARTIAL_HISTORY_CLEARED = 1,
REPORTING_EVENT_COUNT = 2
};
void RecordNavigationEvent(NavigationEvent event) {
UMA_HISTOGRAM_ENUMERATION("ResourcePrefetchPredictor.NavigationEvent",
event,
NAVIGATION_EVENT_COUNT);
}
} // namespace
namespace predictors {
////////////////////////////////////////////////////////////////////////////////
// History lookup task.
// Used to fetch the visit count for a URL from the History database.
class GetUrlVisitCountTask : public history::HistoryDBTask {
public:
typedef ResourcePrefetchPredictor::URLRequestSummary URLRequestSummary;
typedef base::Callback<void(
int, // Visit count.
const NavigationID&,
const std::vector<URLRequestSummary>&)> VisitInfoCallback;
GetUrlVisitCountTask(
const NavigationID& navigation_id,
std::vector<URLRequestSummary>* requests,
VisitInfoCallback callback)
: visit_count_(0),
navigation_id_(navigation_id),
requests_(requests),
callback_(callback) {
DCHECK(requests_.get());
}
virtual bool RunOnDBThread(history::HistoryBackend* backend,
history::HistoryDatabase* db) OVERRIDE {
history::URLRow url_row;
if (db->GetRowForURL(navigation_id_.main_frame_url, &url_row))
visit_count_ = url_row.visit_count();
return true;
}
virtual void DoneRunOnMainThread() OVERRIDE {
callback_.Run(visit_count_, navigation_id_, *requests_);
}
private:
virtual ~GetUrlVisitCountTask() { }
int visit_count_;
NavigationID navigation_id_;
scoped_ptr<std::vector<URLRequestSummary> > requests_;
VisitInfoCallback callback_;
DISALLOW_COPY_AND_ASSIGN(GetUrlVisitCountTask);
};
////////////////////////////////////////////////////////////////////////////////
// ResourcePrefetchPredictor static functions.
// static
bool ResourcePrefetchPredictor::ShouldRecordRequest(
net::URLRequest* request,
ResourceType::Type resource_type) {
return resource_type == ResourceType::MAIN_FRAME &&
IsHandledMainPage(request);
}
// static
bool ResourcePrefetchPredictor::ShouldRecordResponse(
net::URLRequest* response) {
const content::ResourceRequestInfo* request_info =
content::ResourceRequestInfo::ForRequest(response);
if (!request_info)
return false;
return request_info->GetResourceType() == ResourceType::MAIN_FRAME ?
IsHandledMainPage(response) : IsHandledSubresource(response);
}
// static
bool ResourcePrefetchPredictor::ShouldRecordRedirect(
net::URLRequest* response) {
const content::ResourceRequestInfo* request_info =
content::ResourceRequestInfo::ForRequest(response);
if (!request_info)
return false;
return request_info->GetResourceType() == ResourceType::MAIN_FRAME &&
IsHandledMainPage(response);
}
// static
bool ResourcePrefetchPredictor::IsHandledMainPage(net::URLRequest* request) {
return request->original_url().scheme() == content::kHttpScheme;
}
// static
bool ResourcePrefetchPredictor::IsHandledSubresource(
net::URLRequest* response) {
int resource_status = 0;
if (response->first_party_for_cookies().scheme() != content::kHttpScheme)
resource_status |= RESOURCE_STATUS_NOT_HTTP_PAGE;
if (response->original_url().scheme() != content::kHttpScheme)
resource_status |= RESOURCE_STATUS_NOT_HTTP_RESOURCE;
std::string mime_type;
response->GetMimeType(&mime_type);
if (!mime_type.empty() &&
!net::IsSupportedImageMimeType(mime_type.c_str()) &&
!net::IsSupportedJavascriptMimeType(mime_type.c_str()) &&
!net::MatchesMimeType("text/css", mime_type)) {
resource_status |= RESOURCE_STATUS_UNSUPPORTED_MIME_TYPE;
}
if (response->method() != "GET")
resource_status |= RESOURCE_STATUS_NOT_GET;
if (response->original_url().spec().length() >
ResourcePrefetchPredictorTables::kMaxStringLength) {
resource_status |= RESOURCE_STATUS_URL_TOO_LONG;
}
if (!response->response_info().headers.get())
resource_status |= RESOURCE_STATUS_HEADERS_MISSING;
if (!IsCacheable(response))
resource_status |= RESOURCE_STATUS_NOT_CACHEABLE;
UMA_HISTOGRAM_ENUMERATION("ResourcePrefetchPredictor.ResourceStatus",
resource_status,
RESOURCE_STATUS_MAX);
return resource_status == 0;
}
// static
bool ResourcePrefetchPredictor::IsCacheable(const net::URLRequest* response) {
if (response->was_cached())
return true;
// For non cached responses, we will ensure that the freshness lifetime is
// some sane value.
const net::HttpResponseInfo& response_info = response->response_info();
if (!response_info.headers.get())
return false;
base::Time response_time(response_info.response_time);
response_time += base::TimeDelta::FromSeconds(1);
base::TimeDelta freshness = response_info.headers->GetFreshnessLifetime(
response_time);
return freshness > base::TimeDelta();
}
// static
ResourceType::Type ResourcePrefetchPredictor::GetResourceTypeFromMimeType(
const std::string& mime_type,
ResourceType::Type fallback) {
if (net::IsSupportedImageMimeType(mime_type.c_str()))
return ResourceType::IMAGE;
else if (net::IsSupportedJavascriptMimeType(mime_type.c_str()))
return ResourceType::SCRIPT;
else if (net::MatchesMimeType("text/css", mime_type))
return ResourceType::STYLESHEET;
else
return fallback;
}
////////////////////////////////////////////////////////////////////////////////
// ResourcePrefetchPredictor structs.
ResourcePrefetchPredictor::URLRequestSummary::URLRequestSummary()
: resource_type(ResourceType::LAST_TYPE),
was_cached(false) {
}
ResourcePrefetchPredictor::URLRequestSummary::URLRequestSummary(
const URLRequestSummary& other)
: navigation_id(other.navigation_id),
resource_url(other.resource_url),
resource_type(other.resource_type),
mime_type(other.mime_type),
was_cached(other.was_cached),
redirect_url(other.redirect_url) {
}
ResourcePrefetchPredictor::URLRequestSummary::~URLRequestSummary() {
}
ResourcePrefetchPredictor::Result::Result(
PrefetchKeyType i_key_type,
ResourcePrefetcher::RequestVector* i_requests)
: key_type(i_key_type),
requests(i_requests) {
}
ResourcePrefetchPredictor::Result::~Result() {
}
////////////////////////////////////////////////////////////////////////////////
// ResourcePrefetchPredictor.
ResourcePrefetchPredictor::ResourcePrefetchPredictor(
const ResourcePrefetchPredictorConfig& config,
Profile* profile)
: profile_(profile),
config_(config),
initialization_state_(NOT_INITIALIZED),
tables_(PredictorDatabaseFactory::GetForProfile(
profile)->resource_prefetch_tables()),
results_map_deleter_(&results_map_) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
// Some form of learning has to be enabled.
DCHECK(config_.IsLearningEnabled());
if (config_.IsURLPrefetchingEnabled())
DCHECK(config_.IsURLLearningEnabled());
if (config_.IsHostPrefetchingEnabled())
DCHECK(config_.IsHostLearningEnabled());
}
ResourcePrefetchPredictor::~ResourcePrefetchPredictor() {
}
void ResourcePrefetchPredictor::RecordURLRequest(
const URLRequestSummary& request) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
if (initialization_state_ != INITIALIZED)
return;
CHECK_EQ(request.resource_type, ResourceType::MAIN_FRAME);
OnMainFrameRequest(request);
}
void ResourcePrefetchPredictor::RecordURLResponse(
const URLRequestSummary& response) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
if (initialization_state_ != INITIALIZED)
return;
if (response.resource_type == ResourceType::MAIN_FRAME)
OnMainFrameResponse(response);
else
OnSubresourceResponse(response);
}
void ResourcePrefetchPredictor::RecordURLRedirect(
const URLRequestSummary& response) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
if (initialization_state_ != INITIALIZED)
return;
CHECK_EQ(response.resource_type, ResourceType::MAIN_FRAME);
OnMainFrameRedirect(response);
}
void ResourcePrefetchPredictor::RecordMainFrameLoadComplete(
const NavigationID& navigation_id) {
switch (initialization_state_) {
case NOT_INITIALIZED:
StartInitialization();
break;
case INITIALIZING:
break;
case INITIALIZED: {
RecordNavigationEvent(NAVIGATION_EVENT_ONLOAD);
// WebContents can return an empty URL if the navigation entry
// corresponding to the navigation has not been created yet.
if (navigation_id.main_frame_url.is_empty())
RecordNavigationEvent(NAVIGATION_EVENT_ONLOAD_EMPTY_URL);
else
OnNavigationComplete(navigation_id);
break;
}
default:
NOTREACHED() << "Unexpected initialization_state_: "
<< initialization_state_;
}
}
void ResourcePrefetchPredictor::FinishedPrefetchForNavigation(
const NavigationID& navigation_id,
PrefetchKeyType key_type,
ResourcePrefetcher::RequestVector* requests) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
Result* result = new Result(key_type, requests);
// Add the results to the results map.
if (!results_map_.insert(std::make_pair(navigation_id, result)).second) {
DLOG(FATAL) << "Returning results for existing navigation.";
delete result;
}
}
void ResourcePrefetchPredictor::Observe(
int type,
const content::NotificationSource& source,
const content::NotificationDetails& details) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
switch (type) {
case chrome::NOTIFICATION_HISTORY_LOADED: {
DCHECK_EQ(initialization_state_, INITIALIZING);
notification_registrar_.Remove(this,
chrome::NOTIFICATION_HISTORY_LOADED,
content::Source<Profile>(profile_));
OnHistoryAndCacheLoaded();
break;
}
case chrome::NOTIFICATION_HISTORY_URLS_DELETED: {
DCHECK_EQ(initialization_state_, INITIALIZED);
const content::Details<const history::URLsDeletedDetails>
urls_deleted_details =
content::Details<const history::URLsDeletedDetails>(details);
if (urls_deleted_details->all_history) {
DeleteAllUrls();
UMA_HISTOGRAM_ENUMERATION("ResourcePrefetchPredictor.ReportingEvent",
REPORTING_EVENT_ALL_HISTORY_CLEARED,
REPORTING_EVENT_COUNT);
} else {
DeleteUrls(urls_deleted_details->rows);
UMA_HISTOGRAM_ENUMERATION("ResourcePrefetchPredictor.ReportingEvent",
REPORTING_EVENT_PARTIAL_HISTORY_CLEARED,
REPORTING_EVENT_COUNT);
}
break;
}
default:
NOTREACHED() << "Unexpected notification observed.";
break;
}
}
void ResourcePrefetchPredictor::Shutdown() {
if (prefetch_manager_.get()) {
prefetch_manager_->ShutdownOnUIThread();
prefetch_manager_ = NULL;
}
}
void ResourcePrefetchPredictor::OnMainFrameRequest(
const URLRequestSummary& request) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
DCHECK_EQ(INITIALIZED, initialization_state_);
RecordNavigationEvent(NAVIGATION_EVENT_REQUEST_STARTED);
StartPrefetching(request.navigation_id);
// Cleanup older navigations.
CleanupAbandonedNavigations(request.navigation_id);
// New empty navigation entry.
inflight_navigations_.insert(std::make_pair(
request.navigation_id,
make_linked_ptr(new std::vector<URLRequestSummary>())));
}
void ResourcePrefetchPredictor::OnMainFrameResponse(
const URLRequestSummary& response) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
if (initialization_state_ != INITIALIZED)
return;
RecordNavigationEvent(NAVIGATION_EVENT_RESPONSE_STARTED);
StopPrefetching(response.navigation_id);
}
void ResourcePrefetchPredictor::OnMainFrameRedirect(
const URLRequestSummary& response) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
RecordNavigationEvent(NAVIGATION_EVENT_REQUEST_REDIRECTED);
// TODO(shishir): There are significant gains to be had here if we can use the
// start URL in a redirect chain as the key to start prefetching. We can save
// of redirect times considerably assuming that the redirect chains do not
// change.
// Stop any inflight prefetching. Remove the older navigation.
StopPrefetching(response.navigation_id);
inflight_navigations_.erase(response.navigation_id);
// A redirect will not lead to another OnMainFrameRequest call, so record the
// redirect url as a new navigation.
// The redirect url may be empty if the url was invalid.
if (response.redirect_url.is_empty()) {
RecordNavigationEvent(NAVIGATION_EVENT_REQUEST_REDIRECTED_EMPTY_URL);
return;
}
NavigationID navigation_id(response.navigation_id);
navigation_id.main_frame_url = response.redirect_url;
inflight_navigations_.insert(std::make_pair(
navigation_id,
make_linked_ptr(new std::vector<URLRequestSummary>())));
}
void ResourcePrefetchPredictor::OnSubresourceResponse(
const URLRequestSummary& response) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
if (inflight_navigations_.find(response.navigation_id) ==
inflight_navigations_.end()) {
return;
}
inflight_navigations_[response.navigation_id]->push_back(response);
}
void ResourcePrefetchPredictor::OnNavigationComplete(
const NavigationID& navigation_id) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
NavigationMap::const_iterator nav_it =
inflight_navigations_.find(navigation_id);
if (nav_it == inflight_navigations_.end()) {
RecordNavigationEvent(NAVIGATION_EVENT_ONLOAD_UNTRACKED_URL);
return;
}
RecordNavigationEvent(NAVIGATION_EVENT_ONLOAD_TRACKED_URL);
// Report any stats.
if (prefetch_manager_.get()) {
ResultsMap::iterator results_it = results_map_.find(navigation_id);
bool have_prefetch_results = results_it != results_map_.end();
UMA_HISTOGRAM_BOOLEAN("ResourcePrefetchPredictor.HavePrefetchResults",
have_prefetch_results);
if (have_prefetch_results) {
ReportAccuracyStats(results_it->second->key_type,
*(nav_it->second),
results_it->second->requests.get());
}
} else {
scoped_ptr<ResourcePrefetcher::RequestVector> requests(
new ResourcePrefetcher::RequestVector);
PrefetchKeyType key_type;
if (GetPrefetchData(navigation_id, requests.get(), &key_type)){
RecordNavigationEvent(NAVIGATION_EVENT_HAVE_PREDICTIONS_FOR_URL);
ReportPredictedAccuracyStats(key_type,
*(nav_it->second),
*requests);
} else {
RecordNavigationEvent(NAVIGATION_EVENT_NO_PREDICTIONS_FOR_URL);
}
}
// Remove the navigation from the inflight navigations.
std::vector<URLRequestSummary>* requests =
inflight_navigations_[navigation_id].release();
inflight_navigations_.erase(navigation_id);
// Kick off history lookup to determine if we should record the URL.
HistoryService* history_service = HistoryServiceFactory::GetForProfile(
profile_, Profile::EXPLICIT_ACCESS);
DCHECK(history_service);
history_service->ScheduleDBTask(
new GetUrlVisitCountTask(
navigation_id,
requests,
base::Bind(&ResourcePrefetchPredictor::OnVisitCountLookup,
AsWeakPtr())),
&history_lookup_consumer_);
}
bool ResourcePrefetchPredictor::GetPrefetchData(
const NavigationID& navigation_id,
ResourcePrefetcher::RequestVector* prefetch_requests,
PrefetchKeyType* key_type) {
DCHECK(prefetch_requests);
DCHECK(key_type);
*key_type = PREFETCH_KEY_TYPE_URL;
const GURL& main_frame_url = navigation_id.main_frame_url;
bool use_url_data = config_.IsPrefetchingEnabled() ?
config_.IsURLPrefetchingEnabled() : config_.IsURLLearningEnabled();
if (use_url_data) {
PrefetchDataMap::const_iterator iterator =
url_table_cache_->find(main_frame_url.spec());
if (iterator != url_table_cache_->end())
PopulatePrefetcherRequest(iterator->second, prefetch_requests);
}
if (!prefetch_requests->empty())
return true;
bool use_host_data = config_.IsPrefetchingEnabled() ?
config_.IsHostPrefetchingEnabled() : config_.IsHostLearningEnabled();
if (use_host_data) {
PrefetchDataMap::const_iterator iterator =
host_table_cache_->find(main_frame_url.host());
if (iterator != host_table_cache_->end()) {
*key_type = PREFETCH_KEY_TYPE_HOST;
PopulatePrefetcherRequest(iterator->second, prefetch_requests);
}
}
return !prefetch_requests->empty();
}
void ResourcePrefetchPredictor::PopulatePrefetcherRequest(
const PrefetchData& data,
ResourcePrefetcher::RequestVector* requests) {
for (ResourceRows::const_iterator it = data.resources.begin();
it != data.resources.end(); ++it) {
float confidence = static_cast<float>(it->number_of_hits) /
(it->number_of_hits + it->number_of_misses);
if (confidence < config_.min_resource_confidence_to_trigger_prefetch ||
it->number_of_hits < config_.min_resource_hits_to_trigger_prefetch) {
continue;
}
ResourcePrefetcher::Request* req = new ResourcePrefetcher::Request(
it->resource_url);
requests->push_back(req);
}
}
void ResourcePrefetchPredictor::StartPrefetching(
const NavigationID& navigation_id) {
if (!prefetch_manager_.get()) // Prefetching not enabled.
return;
// Prefer URL based data first.
scoped_ptr<ResourcePrefetcher::RequestVector> requests(
new ResourcePrefetcher::RequestVector);
PrefetchKeyType key_type;
if (!GetPrefetchData(navigation_id, requests.get(), &key_type)) {
// No prefetching data at host or URL level.
return;
}
BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
base::Bind(&ResourcePrefetcherManager::MaybeAddPrefetch,
prefetch_manager_,
navigation_id,
key_type,
base::Passed(&requests)));
}
void ResourcePrefetchPredictor::StopPrefetching(
const NavigationID& navigation_id) {
if (!prefetch_manager_.get()) // Not enabled.
return;
BrowserThread::PostTask(
BrowserThread::IO, FROM_HERE,
base::Bind(&ResourcePrefetcherManager::MaybeRemovePrefetch,
prefetch_manager_,
navigation_id));
}
void ResourcePrefetchPredictor::StartInitialization() {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
DCHECK_EQ(initialization_state_, NOT_INITIALIZED);
initialization_state_ = INITIALIZING;
// Create local caches using the database as loaded.
scoped_ptr<PrefetchDataMap> url_data_map(new PrefetchDataMap());
scoped_ptr<PrefetchDataMap> host_data_map(new PrefetchDataMap());
PrefetchDataMap* url_data_ptr = url_data_map.get();
PrefetchDataMap* host_data_ptr = host_data_map.get();
BrowserThread::PostTaskAndReply(
BrowserThread::DB, FROM_HERE,
base::Bind(&ResourcePrefetchPredictorTables::GetAllData,
tables_, url_data_ptr, host_data_ptr),
base::Bind(&ResourcePrefetchPredictor::CreateCaches, AsWeakPtr(),
base::Passed(&url_data_map), base::Passed(&host_data_map)));
}
void ResourcePrefetchPredictor::CreateCaches(
scoped_ptr<PrefetchDataMap> url_data_map,
scoped_ptr<PrefetchDataMap> host_data_map) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
DCHECK_EQ(initialization_state_, INITIALIZING);
DCHECK(!url_table_cache_);
DCHECK(!host_table_cache_);
DCHECK(inflight_navigations_.empty());
url_table_cache_.reset(url_data_map.release());
host_table_cache_.reset(host_data_map.release());
UMA_HISTOGRAM_COUNTS("ResourcePrefetchPredictor.UrlTableMainFrameUrlCount",
url_table_cache_->size());
UMA_HISTOGRAM_COUNTS("ResourcePrefetchPredictor.HostTableHostCount",
host_table_cache_->size());
// Add notifications for history loading if it is not ready.
HistoryService* history_service = HistoryServiceFactory::GetForProfile(
profile_, Profile::EXPLICIT_ACCESS);
if (!history_service) {
notification_registrar_.Add(this, chrome::NOTIFICATION_HISTORY_LOADED,
content::Source<Profile>(profile_));
} else {
OnHistoryAndCacheLoaded();
}
}
void ResourcePrefetchPredictor::OnHistoryAndCacheLoaded() {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
DCHECK_EQ(initialization_state_, INITIALIZING);
notification_registrar_.Add(this,
chrome::NOTIFICATION_HISTORY_URLS_DELETED,
content::Source<Profile>(profile_));
// Initialize the prefetch manager only if prefetching is enabled.
if (config_.IsPrefetchingEnabled()) {
prefetch_manager_ = new ResourcePrefetcherManager(
this, config_, profile_->GetRequestContext());
}
initialization_state_ = INITIALIZED;
}
void ResourcePrefetchPredictor::CleanupAbandonedNavigations(
const NavigationID& navigation_id) {
static const base::TimeDelta max_navigation_age =
base::TimeDelta::FromSeconds(config_.max_navigation_lifetime_seconds);
base::TimeTicks time_now = base::TimeTicks::Now();
for (NavigationMap::iterator it = inflight_navigations_.begin();
it != inflight_navigations_.end();) {
if (it->first.IsSameRenderer(navigation_id) ||
(time_now - it->first.creation_time > max_navigation_age)) {
inflight_navigations_.erase(it++);
RecordNavigationEvent(NAVIGATION_EVENT_REQUEST_EXPIRED);
} else {
++it;
}
}
for (ResultsMap::iterator it = results_map_.begin();
it != results_map_.end();) {
if (it->first.IsSameRenderer(navigation_id) ||
(time_now - it->first.creation_time > max_navigation_age)) {
delete it->second;
results_map_.erase(it++);
} else {
++it;
}
}
}
void ResourcePrefetchPredictor::DeleteAllUrls() {
inflight_navigations_.clear();
url_table_cache_->clear();
host_table_cache_->clear();
BrowserThread::PostTask(BrowserThread::DB, FROM_HERE,
base::Bind(&ResourcePrefetchPredictorTables::DeleteAllData, tables_));
}
void ResourcePrefetchPredictor::DeleteUrls(const history::URLRows& urls) {
// Check all the urls in the database and pick out the ones that are present
// in the cache.
std::vector<std::string> urls_to_delete, hosts_to_delete;
for (history::URLRows::const_iterator it = urls.begin(); it != urls.end();
++it) {
const std::string url_spec = it->url().spec();
if (url_table_cache_->find(url_spec) != url_table_cache_->end()) {
urls_to_delete.push_back(url_spec);
url_table_cache_->erase(url_spec);
}
const std::string host = it->url().host();
if (host_table_cache_->find(host) != host_table_cache_->end()) {
hosts_to_delete.push_back(host);
host_table_cache_->erase(host);
}
}
if (!urls_to_delete.empty() || !hosts_to_delete.empty()) {
BrowserThread::PostTask(BrowserThread::DB, FROM_HERE,
base::Bind(&ResourcePrefetchPredictorTables::DeleteData,
tables_,
urls_to_delete,
hosts_to_delete));
}
}
void ResourcePrefetchPredictor::RemoveOldestEntryInPrefetchDataMap(
PrefetchKeyType key_type,
PrefetchDataMap* data_map) {
if (data_map->empty())
return;
base::Time oldest_time;
std::string key_to_delete;
for (PrefetchDataMap::iterator it = data_map->begin();
it != data_map->end(); ++it) {
if (key_to_delete.empty() || it->second.last_visit < oldest_time) {
key_to_delete = it->first;
oldest_time = it->second.last_visit;
}
}
data_map->erase(key_to_delete);
BrowserThread::PostTask(BrowserThread::DB, FROM_HERE,
base::Bind(&ResourcePrefetchPredictorTables::DeleteSingleDataPoint,
tables_,
key_to_delete,
key_type));
}
void ResourcePrefetchPredictor::OnVisitCountLookup(
int visit_count,
const NavigationID& navigation_id,
const std::vector<URLRequestSummary>& requests) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
UMA_HISTOGRAM_COUNTS("ResourcePrefetchPredictor.HistoryVisitCountForUrl",
visit_count);
// URL level data - merge only if we are already saving the data, or we it
// meets the cutoff requirement.
const std::string url_spec = navigation_id.main_frame_url.spec();
bool already_tracking = url_table_cache_->find(url_spec) !=
url_table_cache_->end();
bool should_track_url = already_tracking ||
(visit_count >= config_.min_url_visit_count);
if (should_track_url) {
RecordNavigationEvent(NAVIGATION_EVENT_SHOULD_TRACK_URL);
if (config_.IsURLLearningEnabled()) {
LearnNavigation(url_spec, PREFETCH_KEY_TYPE_URL, requests,
config_.max_urls_to_track, url_table_cache_.get());
}
} else {
RecordNavigationEvent(NAVIGATION_EVENT_SHOULD_NOT_TRACK_URL);
}
// Host level data - no cutoff, always learn the navigation if enabled.
if (config_.IsHostLearningEnabled()) {
LearnNavigation(navigation_id.main_frame_url.host(),
PREFETCH_KEY_TYPE_HOST,
requests,
config_.max_hosts_to_track,
host_table_cache_.get());
}
// Remove the navigation from the results map.
delete results_map_[navigation_id];
results_map_.erase(navigation_id);
}
void ResourcePrefetchPredictor::LearnNavigation(
const std::string& key,
PrefetchKeyType key_type,
const std::vector<URLRequestSummary>& new_resources,
int max_data_map_size,
PrefetchDataMap* data_map) {
CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
// If the primary key is too long reject it.
if (key.length() > ResourcePrefetchPredictorTables::kMaxStringLength) {
if (key_type == PREFETCH_KEY_TYPE_HOST)
RecordNavigationEvent(NAVIGATION_EVENT_HOST_TOO_LONG);
else
RecordNavigationEvent(NAVIGATION_EVENT_MAIN_FRAME_URL_TOO_LONG);
return;
}
PrefetchDataMap::iterator cache_entry = data_map->find(key);
if (cache_entry == data_map->end()) {
if (static_cast<int>(data_map->size()) >= max_data_map_size) {
// The table is full, delete an entry.
RemoveOldestEntryInPrefetchDataMap(key_type, data_map);
}
cache_entry = data_map->insert(std::make_pair(
key, PrefetchData(key_type, key))).first;
cache_entry->second.last_visit = base::Time::Now();
int new_resources_size = static_cast<int>(new_resources.size());
std::set<GURL> resources_seen;
for (int i = 0; i < new_resources_size; ++i) {
if (resources_seen.find(new_resources[i].resource_url) !=
resources_seen.end()) {
continue;
}
ResourceRow row_to_add;
row_to_add.resource_url = new_resources[i].resource_url;
row_to_add.resource_type = new_resources[i].resource_type;
row_to_add.number_of_hits = 1;
row_to_add.average_position = i + 1;
cache_entry->second.resources.push_back(row_to_add);
resources_seen.insert(new_resources[i].resource_url);
}
} else {
ResourceRows& old_resources = cache_entry->second.resources;
cache_entry->second.last_visit = base::Time::Now();
// Build indices over the data.
std::map<GURL, int> new_index, old_index;
int new_resources_size = static_cast<int>(new_resources.size());
for (int i = 0; i < new_resources_size; ++i) {
const URLRequestSummary& summary = new_resources[i];
// Take the first occurence of every url.
if (new_index.find(summary.resource_url) == new_index.end())
new_index[summary.resource_url] = i;
}
int old_resources_size = static_cast<int>(old_resources.size());
for (int i = 0; i < old_resources_size; ++i) {
const ResourceRow& row = old_resources[i];
DCHECK(old_index.find(row.resource_url) == old_index.end());
old_index[row.resource_url] = i;
}
// Go through the old urls and update their hit/miss counts.
for (int i = 0; i < old_resources_size; ++i) {
ResourceRow& old_row = old_resources[i];
if (new_index.find(old_row.resource_url) == new_index.end()) {
++old_row.number_of_misses;
++old_row.consecutive_misses;
} else {
const URLRequestSummary& new_row =
new_resources[new_index[old_row.resource_url]];
// Update the resource type since it could have changed.
if (new_row.resource_type != ResourceType::LAST_TYPE)
old_row.resource_type = new_row.resource_type;
int position = new_index[old_row.resource_url] + 1;
int total = old_row.number_of_hits + old_row.number_of_misses;
old_row.average_position =
((old_row.average_position * total) + position) / (total + 1);
++old_row.number_of_hits;
old_row.consecutive_misses = 0;
}
}
// Add the new ones that we have not seen before.
for (int i = 0; i < new_resources_size; ++i) {
const URLRequestSummary& summary = new_resources[i];
if (old_index.find(summary.resource_url) != old_index.end())
continue;
// Only need to add new stuff.
ResourceRow row_to_add;
row_to_add.resource_url = summary.resource_url;
row_to_add.resource_type = summary.resource_type;
row_to_add.number_of_hits = 1;
row_to_add.average_position = i + 1;
old_resources.push_back(row_to_add);
// To ensure we dont add the same url twice.
old_index[summary.resource_url] = 0;
}
}
// Trim and sort the resources after the update.
ResourceRows& resources = cache_entry->second.resources;
for (ResourceRows::iterator it = resources.begin();
it != resources.end();) {
it->UpdateScore();
if (it->consecutive_misses >= config_.max_consecutive_misses)
it = resources.erase(it);
else
++it;
}
std::sort(resources.begin(), resources.end(),
ResourcePrefetchPredictorTables::ResourceRowSorter());
if (static_cast<int>(resources.size()) > config_.max_resources_per_entry)
resources.resize(config_.max_resources_per_entry);
// If the row has no resources, remove it from the cache and delete the
// entry in the database. Else update the database.
if (resources.size() == 0) {
data_map->erase(key);
BrowserThread::PostTask(
BrowserThread::DB, FROM_HERE,
base::Bind(&ResourcePrefetchPredictorTables::DeleteSingleDataPoint,
tables_,
key,
key_type));
} else {
bool is_host = key_type == PREFETCH_KEY_TYPE_HOST;
PrefetchData empty_data(
!is_host ? PREFETCH_KEY_TYPE_HOST : PREFETCH_KEY_TYPE_URL,
std::string());
const PrefetchData& host_data = is_host ? cache_entry->second : empty_data;
const PrefetchData& url_data = is_host ? empty_data : cache_entry->second;
BrowserThread::PostTask(
BrowserThread::DB, FROM_HERE,
base::Bind(&ResourcePrefetchPredictorTables::UpdateData,
tables_,
url_data,
host_data));
}
}
////////////////////////////////////////////////////////////////////////////////
// Accuracy measurement.
void ResourcePrefetchPredictor::ReportAccuracyStats(
PrefetchKeyType key_type,
const std::vector<URLRequestSummary>& actual,
ResourcePrefetcher::RequestVector* prefetched) const {
// Annotate the results.
std::map<GURL, bool> actual_resources;
for (std::vector<URLRequestSummary>::const_iterator it = actual.begin();
it != actual.end(); ++it) {
actual_resources[it->resource_url] = it->was_cached;
}
int prefetch_cancelled = 0, prefetch_failed = 0, prefetch_not_started = 0;
// 'a_' -> actual, 'p_' -> predicted.
int p_cache_a_cache = 0, p_cache_a_network = 0, p_cache_a_notused = 0,
p_network_a_cache = 0, p_network_a_network = 0, p_network_a_notused = 0;
for (ResourcePrefetcher::RequestVector::iterator it = prefetched->begin();
it != prefetched->end(); ++it) {
ResourcePrefetcher::Request* req = *it;
// Set the usage states if the resource was actually used.
std::map<GURL, bool>::iterator actual_it = actual_resources.find(
req->resource_url);
if (actual_it != actual_resources.end()) {
if (actual_it->second) {
req->usage_status =
ResourcePrefetcher::Request::USAGE_STATUS_FROM_CACHE;
} else {
req->usage_status =
ResourcePrefetcher::Request::USAGE_STATUS_FROM_NETWORK;
}
}
switch (req->prefetch_status) {
// TODO(shishir): Add histogram for each cancellation reason.
case ResourcePrefetcher::Request::PREFETCH_STATUS_REDIRECTED:
case ResourcePrefetcher::Request::PREFETCH_STATUS_AUTH_REQUIRED:
case ResourcePrefetcher::Request::PREFETCH_STATUS_CERT_REQUIRED:
case ResourcePrefetcher::Request::PREFETCH_STATUS_CERT_ERROR:
case ResourcePrefetcher::Request::PREFETCH_STATUS_CANCELLED:
++prefetch_cancelled;
break;
case ResourcePrefetcher::Request::PREFETCH_STATUS_FAILED:
++prefetch_failed;
break;
case ResourcePrefetcher::Request::PREFETCH_STATUS_FROM_CACHE:
if (req->usage_status ==
ResourcePrefetcher::Request::USAGE_STATUS_FROM_CACHE)
++p_cache_a_cache;
else if (req->usage_status ==
ResourcePrefetcher::Request::USAGE_STATUS_FROM_NETWORK)
++p_cache_a_network;
else
++p_cache_a_notused;
break;
case ResourcePrefetcher::Request::PREFETCH_STATUS_FROM_NETWORK:
if (req->usage_status ==
ResourcePrefetcher::Request::USAGE_STATUS_FROM_CACHE)
++p_network_a_cache;
else if (req->usage_status ==
ResourcePrefetcher::Request::USAGE_STATUS_FROM_NETWORK)
++p_network_a_network;
else
++p_network_a_notused;
break;
case ResourcePrefetcher::Request::PREFETCH_STATUS_NOT_STARTED:
++prefetch_not_started;
break;
case ResourcePrefetcher::Request::PREFETCH_STATUS_STARTED:
DLOG(FATAL) << "Invalid prefetch status";
break;
}
}
int total_prefetched = p_cache_a_cache + p_cache_a_network + p_cache_a_notused
+ p_network_a_cache + p_network_a_network + p_network_a_notused;
std::string histogram_type = key_type == PREFETCH_KEY_TYPE_HOST ? "Host." :
"Url.";
// Macros to avoid using the STATIC_HISTOGRAM_POINTER_BLOCK in UMA_HISTOGRAM
// definitions.
#define RPP_HISTOGRAM_PERCENTAGE(suffix, value) \
{ \
std::string name = "ResourcePrefetchPredictor." + histogram_type + suffix; \
std::string g_name = "ResourcePrefetchPredictor." + std::string(suffix); \
base::HistogramBase* histogram = base::LinearHistogram::FactoryGet( \
name, 1, 101, 102, base::Histogram::kUmaTargetedHistogramFlag); \
histogram->Add(value); \
UMA_HISTOGRAM_PERCENTAGE(g_name, value); \
}
RPP_HISTOGRAM_PERCENTAGE("PrefetchCancelled",
prefetch_cancelled * 100.0 / total_prefetched);
RPP_HISTOGRAM_PERCENTAGE("PrefetchFailed",
prefetch_failed * 100.0 / total_prefetched);
RPP_HISTOGRAM_PERCENTAGE("PrefetchFromCacheUsedFromCache",
p_cache_a_cache * 100.0 / total_prefetched);
RPP_HISTOGRAM_PERCENTAGE("PrefetchFromCacheUsedFromNetwork",
p_cache_a_network * 100.0 / total_prefetched);
RPP_HISTOGRAM_PERCENTAGE("PrefetchFromCacheNotUsed",
p_cache_a_notused * 100.0 / total_prefetched);
RPP_HISTOGRAM_PERCENTAGE("PrefetchFromNetworkUsedFromCache",
p_network_a_cache * 100.0 / total_prefetched);
RPP_HISTOGRAM_PERCENTAGE("PrefetchFromNetworkUsedFromNetwork",
p_network_a_network * 100.0 / total_prefetched);
RPP_HISTOGRAM_PERCENTAGE("PrefetchFromNetworkNotUsed",
p_network_a_notused * 100.0 / total_prefetched);
RPP_HISTOGRAM_PERCENTAGE(
"PrefetchNotStarted",
prefetch_not_started * 100.0 / (prefetch_not_started + total_prefetched));
#undef RPP_HISTOGRAM_PERCENTAGE
}
void ResourcePrefetchPredictor::ReportPredictedAccuracyStats(
PrefetchKeyType key_type,
const std::vector<URLRequestSummary>& actual,
const ResourcePrefetcher::RequestVector& predicted) const {
std::map<GURL, bool> actual_resources;
int from_network = 0;
for (std::vector<URLRequestSummary>::const_iterator it = actual.begin();
it != actual.end(); ++it) {
actual_resources[it->resource_url] = it->was_cached;
if (!it->was_cached)
++from_network;
}
// Measure the accuracy at 25, 50 predicted resources.
ReportPredictedAccuracyStatsHelper(key_type, predicted, actual_resources,
from_network, 25);
ReportPredictedAccuracyStatsHelper(key_type, predicted, actual_resources,
from_network, 50);
}
void ResourcePrefetchPredictor::ReportPredictedAccuracyStatsHelper(
PrefetchKeyType key_type,
const ResourcePrefetcher::RequestVector& predicted,
const std::map<GURL, bool>& actual,
int total_resources_fetched_from_network,
int max_assumed_prefetched) const {
int prefetch_cached = 0, prefetch_network = 0, prefetch_missed = 0;
int num_assumed_prefetched = std::min(static_cast<int>(predicted.size()),
max_assumed_prefetched);
if (num_assumed_prefetched == 0)
return;
for (int i = 0; i < num_assumed_prefetched; ++i) {
const ResourcePrefetcher::Request& row = *(predicted[i]);
std::map<GURL, bool>::const_iterator it = actual.find(row.resource_url);
if (it == actual.end()) {
++prefetch_missed;
} else if (it->second) {
++prefetch_cached;
} else {
++prefetch_network;
}
}
std::string prefix = key_type == PREFETCH_KEY_TYPE_HOST ?
"ResourcePrefetchPredictor.Host.Predicted" :
"ResourcePrefetchPredictor.Url.Predicted";
std::string suffix = "_" + base::IntToString(max_assumed_prefetched);
// Macros to avoid using the STATIC_HISTOGRAM_POINTER_BLOCK in UMA_HISTOGRAM
// definitions.
#define RPP_PREDICTED_HISTOGRAM_COUNTS(name, value) \
{ \
std::string full_name = prefix + name + suffix; \
base::HistogramBase* histogram = base::Histogram::FactoryGet( \
full_name, 1, 1000000, 50, \
base::Histogram::kUmaTargetedHistogramFlag); \
histogram->Add(value); \
}
#define RPP_PREDICTED_HISTOGRAM_PERCENTAGE(name, value) \
{ \
std::string full_name = prefix + name + suffix; \
base::HistogramBase* histogram = base::LinearHistogram::FactoryGet( \
full_name, 1, 101, 102, base::Histogram::kUmaTargetedHistogramFlag); \
histogram->Add(value); \
}
RPP_PREDICTED_HISTOGRAM_COUNTS("PrefetchCount", num_assumed_prefetched);
RPP_PREDICTED_HISTOGRAM_COUNTS("PrefetchMisses_Count", prefetch_missed);
RPP_PREDICTED_HISTOGRAM_COUNTS("PrefetchFromCache_Count", prefetch_cached);
RPP_PREDICTED_HISTOGRAM_COUNTS("PrefetchFromNetwork_Count", prefetch_network);
RPP_PREDICTED_HISTOGRAM_PERCENTAGE(
"PrefetchMisses_PercentOfTotalPrefetched",
prefetch_missed * 100.0 / num_assumed_prefetched);
RPP_PREDICTED_HISTOGRAM_PERCENTAGE(
"PrefetchFromCache_PercentOfTotalPrefetched",
prefetch_cached * 100.0 / num_assumed_prefetched);
RPP_PREDICTED_HISTOGRAM_PERCENTAGE(
"PrefetchFromNetwork_PercentOfTotalPrefetched",
prefetch_network * 100.0 / num_assumed_prefetched);
// Measure the ratio of total number of resources prefetched from network vs
// the total number of resources fetched by the page from the network.
if (total_resources_fetched_from_network > 0) {
RPP_PREDICTED_HISTOGRAM_PERCENTAGE(
"PrefetchFromNetworkPercentOfTotalFromNetwork",
prefetch_network * 100.0 / total_resources_fetched_from_network);
}
#undef RPP_PREDICTED_HISTOGRAM_PERCENTAGE
#undef RPP_PREDICTED_HISTOGRAM_COUNTS
}
} // namespace predictors