src/chrome/browser/component_updater/component_updater_resource_throttle.cc

   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/component_updater/component_updater_resource_throttle.h"
   6
   7 #include "base/location.h"
   8 #include "base/memory/weak_ptr.h"
   9 #include "components/component_updater/component_updater_service.h"
  10 #include "content/public/browser/browser_thread.h"
  11 #include "content/public/browser/resource_controller.h"
  12 #include "content/public/browser/resource_throttle.h"
  13
  14 using content::BrowserThread;
  15
  16 namespace component_updater {
  17
  18 namespace {
  19
  20 ///////////////////////////////////////////////////////////////////////////////
  21 // In charge of blocking url requests until the |crx_id| component has been
  22 // updated. This class is touched solely from the IO thread. The UI thread
  23 // can post tasks to it via weak pointers. By default the request is blocked
  24 // unless the CrxUpdateService calls Unblock().
  25 // The lifetime is controlled by Chrome's resource loader so the component
  26 // updater cannot touch objects from this class except via weak pointers.
  27 class CUResourceThrottle : public content::ResourceThrottle,
  28                            public base::SupportsWeakPtr<CUResourceThrottle> {
  29  public:
  30   CUResourceThrottle();
  31   ~CUResourceThrottle() override;
  32
  33   // Overriden from ResourceThrottle.
  34   void WillStartRequest(bool* defer) override;
  35   void WillRedirectRequest(const GURL& new_url, bool* defer) override;
  36   const char* GetNameForLogging() const override;
  37
  38   // Component updater calls this function via PostTask to unblock the request.
  39   void Unblock();
  40
  41   typedef std::vector<base::WeakPtr<CUResourceThrottle> > WeakPtrVector;
  42
  43  private:
  44   enum State { NEW, BLOCKED, UNBLOCKED };
  45
  46   State state_;
  47 };
  48
  49 CUResourceThrottle::CUResourceThrottle() : state_(NEW) {
  50   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  51 }
  52
  53 CUResourceThrottle::~CUResourceThrottle() {
  54   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  55 }
  56
  57 void CUResourceThrottle::WillStartRequest(bool* defer) {
  58   if (state_ != UNBLOCKED) {
  59     state_ = BLOCKED;
  60     *defer = true;
  61   } else {
  62     *defer = false;
  63   }
  64 }
  65
  66 void CUResourceThrottle::WillRedirectRequest(const GURL& new_url, bool* defer) {
  67   WillStartRequest(defer);
  68 }
  69
  70 const char* CUResourceThrottle::GetNameForLogging() const {
  71   return "ComponentUpdateResourceThrottle";
  72 }
  73
  74 void CUResourceThrottle::Unblock() {
  75   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  76   if (state_ == BLOCKED)
  77     controller()->Resume();
  78   state_ = UNBLOCKED;
  79 }
  80
  81 void UnblockThrottleOnUIThread(base::WeakPtr<CUResourceThrottle> rt) {
  82   BrowserThread::PostTask(BrowserThread::IO,
  83                           FROM_HERE,
  84                           base::Bind(&CUResourceThrottle::Unblock, rt));
  85 }
  86
  87 }  // namespace
  88
  89 content::ResourceThrottle* GetOnDemandResourceThrottle(
  90     ComponentUpdateService* cus,
  91     const std::string& crx_id) {
  92   DCHECK_CURRENTLY_ON(BrowserThread::IO);
  93
  94   // We give the raw pointer to the caller, who will delete it at will
  95   // and we keep for ourselves a weak pointer to it so we can post tasks
  96   // from the UI thread without having to track lifetime directly.
  97   CUResourceThrottle* rt = new CUResourceThrottle;
  98   BrowserThread::PostTask(
  99       BrowserThread::UI,
 100       FROM_HERE,
 101       base::Bind(&ComponentUpdateService::MaybeThrottle,
 102                  base::Unretained(cus),
 103                  crx_id,
 104                  base::Bind(&UnblockThrottleOnUIThread, rt->AsWeakPtr())));
 105   return rt;
 106 }
 107
 108 }  // namespace component_updater