dom/html/nsHTMLDNSPrefetch.h
author Valentin Gosu <valentin.gosu@gmail.com>
Fri, 15 Dec 2017 15:46:24 -0600
changeset 396786 9b69f2b7d37346a5ac8aff8aeec2fe23673fe566
parent 367722 6a629adbb62a299d7208373d1c6f375149d2afdb
child 436992 7aa742bff8fbae4338e258a4477d5397d0d6f7ad
permissions -rw-r--r--
Bug 1424834 - Replace nsHostRecord.callbacks with LinkedList<RefPtr<nsResolveHostCallback>> r=mayhemer * nsResolveHostCallback extends nsISupports (for addref-ing and because nsDNSAsyncRequest implements nsICancelable) * nsResolveHostCallback extends LinkedListElement<RefPtr<nsResolveHostCallback>> so the list can properly manage references * nsDNSAsyncRequest and nsDNSSyncRequest properly implement nsISupports and use RefPtr to manage lifetimes MozReview-Commit-ID: 5NvBcWZzfyN

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef nsHTMLDNSPrefetch_h___
#define nsHTMLDNSPrefetch_h___

#include "nsCOMPtr.h"
#include "nsString.h"

#include "nsIDNSListener.h"
#include "nsIWebProgressListener.h"
#include "nsWeakReference.h"
#include "nsIObserver.h"

class nsIDocument;
class nsITimer;
namespace mozilla {
namespace dom {
class Link;
} // namespace dom
} // namespace mozilla

namespace mozilla {
namespace net {
class NeckoParent;
} // namespace net
} // namespace mozilla

class nsHTMLDNSPrefetch
{
public:
  // The required aDocument parameter is the context requesting the prefetch - under
  // certain circumstances (e.g. headers, or security context) associated with
  // the context the prefetch will not be performed.
  static bool     IsAllowed(nsIDocument *aDocument);

  static nsresult Initialize();
  static nsresult Shutdown();

  // Call one of the Prefetch* methods to start the lookup.
  //
  // The URI versions will defer DNS lookup until pageload is
  // complete, while the string versions submit the lookup to
  // the DNS system immediately. The URI version is somewhat lighter
  // weight, but its request is also more likely to be dropped due to a
  // full queue and it may only be used from the main thread.

  static nsresult PrefetchHigh(mozilla::dom::Link *aElement);
  static nsresult PrefetchMedium(mozilla::dom::Link *aElement);
  static nsresult PrefetchLow(mozilla::dom::Link *aElement);
  static nsresult PrefetchHigh(const nsAString &host,
                               const mozilla::OriginAttributes &aOriginAttributes);
  static nsresult PrefetchMedium(const nsAString &host,
                                 const mozilla::OriginAttributes &aOriginAttributes);
  static nsresult PrefetchLow(const nsAString &host,
                              const mozilla::OriginAttributes &aOriginAttributes);
  static nsresult CancelPrefetchLow(const nsAString &host,
                                    const mozilla::OriginAttributes &aOriginAttributes,
                                    nsresult aReason);
  static nsresult CancelPrefetchLow(mozilla::dom::Link *aElement,
                                    nsresult aReason);

  static void LinkDestroyed(mozilla::dom::Link* aLink);

private:
  static nsresult Prefetch(const nsAString &host,
                           const mozilla::OriginAttributes &aOriginAttributes,
                           uint16_t flags);
  static nsresult Prefetch(mozilla::dom::Link *aElement, uint16_t flags);
  static nsresult CancelPrefetch(const nsAString &hostname,
                                 const mozilla::OriginAttributes &aOriginAttributes,
                                 uint16_t flags,
                                 nsresult aReason);
  static nsresult CancelPrefetch(mozilla::dom::Link *aElement,
                                 uint16_t flags,
                                 nsresult aReason);

public:
  class nsListener final : public nsIDNSListener
  {
    // This class exists to give a safe callback no-op DNSListener
  public:
    NS_DECL_THREADSAFE_ISUPPORTS
    NS_DECL_NSIDNSLISTENER

    nsListener()  {}
  private:
    ~nsListener() {}
  };

  class nsDeferrals final: public nsIWebProgressListener
                         , public nsSupportsWeakReference
                         , public nsIObserver
  {
  public:
    NS_DECL_ISUPPORTS
    NS_DECL_NSIWEBPROGRESSLISTENER
    NS_DECL_NSIOBSERVER

    nsDeferrals();

    void Activate();
    nsresult Add(uint16_t flags, mozilla::dom::Link *aElement);

    void RemoveUnboundLinks();

  private:
    ~nsDeferrals();
    void Flush();

    void SubmitQueue();

    uint16_t                  mHead;
    uint16_t                  mTail;
    uint32_t                  mActiveLoaderCount;

    nsCOMPtr<nsITimer>        mTimer;
    bool                      mTimerArmed;
    static void Tick(nsITimer *aTimer, void *aClosure);

    static const int          sMaxDeferred = 512;  // keep power of 2 for masking
    static const int          sMaxDeferredMask = (sMaxDeferred - 1);

    struct deferred_entry
    {
      uint16_t                         mFlags;
      // Link implementation clears this raw pointer in its destructor.
      mozilla::dom::Link*              mElement;
    } mEntries[sMaxDeferred];
  };

  friend class mozilla::net::NeckoParent;
};

#endif