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      1 // Copyright 2014 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 "chrome/browser/predictors/resource_prefetcher_manager.h"
      6 
      7 #include "base/bind.h"
      8 #include "base/stl_util.h"
      9 #include "chrome/browser/predictors/resource_prefetch_predictor.h"
     10 #include "content/public/browser/browser_thread.h"
     11 #include "net/url_request/url_request.h"
     12 #include "net/url_request/url_request_context_getter.h"
     13 
     14 using content::BrowserThread;
     15 
     16 namespace predictors {
     17 
     18 ResourcePrefetcherManager::ResourcePrefetcherManager(
     19     ResourcePrefetchPredictor* predictor,
     20     const ResourcePrefetchPredictorConfig& config,
     21     net::URLRequestContextGetter* context_getter)
     22     : predictor_(predictor),
     23       config_(config),
     24       context_getter_(context_getter) {
     25   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
     26   CHECK(predictor_);
     27   CHECK(context_getter_);
     28 }
     29 
     30 ResourcePrefetcherManager::~ResourcePrefetcherManager() {
     31   DCHECK(prefetcher_map_.empty())
     32       << "Did not call ShutdownOnUIThread or ShutdownOnIOThread. "
     33          " Will leak Prefetcher pointers.";
     34 }
     35 
     36 void ResourcePrefetcherManager::ShutdownOnUIThread() {
     37   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
     38 
     39   predictor_ = NULL;
     40   BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
     41       base::Bind(&ResourcePrefetcherManager::ShutdownOnIOThread,
     42                  this));
     43 }
     44 
     45 void ResourcePrefetcherManager::ShutdownOnIOThread() {
     46   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
     47   STLDeleteContainerPairSecondPointers(prefetcher_map_.begin(),
     48                                        prefetcher_map_.end());
     49 }
     50 
     51 void ResourcePrefetcherManager::MaybeAddPrefetch(
     52     const NavigationID& navigation_id,
     53     PrefetchKeyType key_type,
     54     scoped_ptr<ResourcePrefetcher::RequestVector> requests) {
     55   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
     56 
     57   // Don't add a duplicate prefetch for the same host or URL.
     58   std::string key = key_type == PREFETCH_KEY_TYPE_HOST ?
     59       navigation_id.main_frame_url.host() : navigation_id.main_frame_url.spec();
     60   if (ContainsKey(prefetcher_map_, key))
     61     return;
     62 
     63   ResourcePrefetcher* prefetcher = new ResourcePrefetcher(
     64       this, config_, navigation_id, key_type, requests.Pass());
     65   prefetcher_map_.insert(std::make_pair(key, prefetcher));
     66   prefetcher->Start();
     67 }
     68 
     69 void ResourcePrefetcherManager::MaybeRemovePrefetch(
     70     const NavigationID& navigation_id) {
     71   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
     72 
     73   // Look for a URL based prefetch first.
     74   PrefetcherMap::iterator it = prefetcher_map_.find(
     75       navigation_id.main_frame_url.spec());
     76   if (it != prefetcher_map_.end() &&
     77       it->second->navigation_id() == navigation_id) {
     78     it->second->Stop();
     79     return;
     80   }
     81 
     82   // No URL based prefetching, look for host based.
     83   it = prefetcher_map_.find(navigation_id.main_frame_url.host());
     84   if (it != prefetcher_map_.end() &&
     85       it->second->navigation_id() == navigation_id) {
     86     it->second->Stop();
     87   }
     88 }
     89 
     90 void ResourcePrefetcherManager::ResourcePrefetcherFinished(
     91     ResourcePrefetcher* resource_prefetcher,
     92     ResourcePrefetcher::RequestVector* requests) {
     93   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
     94 
     95   // |predictor_| can only be accessed from the UI thread.
     96   scoped_ptr<ResourcePrefetcher::RequestVector> scoped_requests(requests);
     97   BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
     98       base::Bind(&ResourcePrefetcherManager::ResourcePrefetcherFinishedOnUI,
     99                  this,
    100                  resource_prefetcher->navigation_id(),
    101                  resource_prefetcher->key_type(),
    102                  base::Passed(&scoped_requests)));
    103 
    104   const GURL& main_frame_url =
    105       resource_prefetcher->navigation_id().main_frame_url;
    106   const std::string key =
    107       resource_prefetcher->key_type() == PREFETCH_KEY_TYPE_HOST ?
    108           main_frame_url.host() : main_frame_url.spec();
    109   PrefetcherMap::iterator it = prefetcher_map_.find(key);
    110   DCHECK(it != prefetcher_map_.end());
    111   delete it->second;
    112   prefetcher_map_.erase(it);
    113 }
    114 
    115 void ResourcePrefetcherManager::ResourcePrefetcherFinishedOnUI(
    116     const NavigationID& navigation_id,
    117     PrefetchKeyType key_type,
    118     scoped_ptr<ResourcePrefetcher::RequestVector> requests) {
    119   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
    120 
    121   // |predictor_| may have been set to NULL if the predictor is shutting down.
    122   if (predictor_) {
    123     predictor_->FinishedPrefetchForNavigation(navigation_id,
    124                                               key_type,
    125                                               requests.release());
    126   }
    127 }
    128 
    129 net::URLRequestContext* ResourcePrefetcherManager::GetURLRequestContext() {
    130   DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
    131 
    132   return context_getter_->GetURLRequestContext();
    133 }
    134 
    135 }  // namespace predictors
    136