PreloadService.h - mozsearch

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* 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 PreloadService_h__

#define PreloadService_h__

#include "nsIContentPolicy.h"

#include "nsIURI.h"

#include "nsRefPtrHashtable.h"

#include "mozilla/PreloadHashKey.h"

class nsINode;

namespace mozilla {

class PreloaderBase;

namespace dom {

class HTMLLinkElement;

class Document;

enum class ReferrerPolicy : uint8_t;

}  // namespace dom

/**

 * Intended to scope preloads

 * (https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/rel/preload)

 * and speculative loads initiated by the parser under one roof.  This class

 * is intended to be a member of dom::Document. Provides registration of

 * speculative loads via a `key` which is defined to consist of the URL,

 * resource type, and resource-specific attributes that are further

 * distinguishing loads with otherwise same type and url.

*/

class PreloadService {

 public:

  explicit PreloadService(dom::Document*);

  ~PreloadService();

  // Called by resource loaders to register a running resource load.  This is

  // called for a speculative load when it's started the first time, being it

  // either regular speculative load or a preload.

//

  // Returns false and does nothing if a preload is already registered under

  // this key, true otherwise.

  bool RegisterPreload(const PreloadHashKey& aKey, PreloaderBase* aPreload);

  // Called when the load is about to be cancelled.  Exact behavior is to be

  // determined yet.

  void DeregisterPreload(const PreloadHashKey& aKey);

  // Called when the scope is to go away.

  void ClearAllPreloads();

  // True when there is a preload registered under the key.

  bool PreloadExists(const PreloadHashKey& aKey);

  // Returns an existing preload under the key or null, when there is none

  // registered under the key.

  already_AddRefed<PreloaderBase> LookupPreload(

      const PreloadHashKey& aKey) const;

  void SetSpeculationBase(nsIURI* aURI) { mSpeculationBaseURI = aURI; }

  already_AddRefed<nsIURI> GetPreloadURI(const nsAString& aURL);

  already_AddRefed<PreloaderBase> PreloadLinkElement(

      dom::HTMLLinkElement* aLink, nsContentPolicyType aPolicyType);

  // a non-zero aEarlyHintPreloaderId tells this service that a preload for this

  // link was started by the EarlyHintPreloader and the preloaders should

  // connect back by setting earlyHintPreloaderId in nsIChannelInternal before

  // AsyncOpen.

  void PreloadLinkHeader(nsIURI* aURI, const nsAString& aURL,

                         nsContentPolicyType aPolicyType, const nsAString& aAs,

                         const nsAString& aType, const nsAString& aNonce,

                         const nsAString& aIntegrity, const nsAString& aSrcset,

                         const nsAString& aSizes, const nsAString& aCORS,

                         const nsAString& aReferrerPolicy,

                         uint64_t aEarlyHintPreloaderId,

                         const nsAString& aFetchPriority);

  void PreloadScript(nsIURI* aURI, const nsAString& aType,

                     const nsAString& aCharset, const nsAString& aCrossOrigin,

                     const nsAString& aReferrerPolicy, const nsAString& aNonce,

                     const nsAString& aFetchPriority,

                     const nsAString& aIntegrity, bool aScriptFromHead,

                     uint64_t aEarlyHintPreloaderId);

  void PreloadImage(nsIURI* aURI, const nsAString& aCrossOrigin,

                    const nsAString& aImageReferrerPolicy, bool aIsImgSet,

                    uint64_t aEarlyHintPreloaderId,

                    const nsAString& aFetchPriority);

  void PreloadFont(nsIURI* aURI, const nsAString& aCrossOrigin,

                   const nsAString& aReferrerPolicy,

                   uint64_t aEarlyHintPreloaderId,

                   const nsAString& aFetchPriority);

  void PreloadFetch(nsIURI* aURI, const nsAString& aCrossOrigin,

                    const nsAString& aReferrerPolicy,

                    uint64_t aEarlyHintPreloaderId,

                    const nsAString& aFetchPriority);

  static void NotifyNodeEvent(nsINode* aNode, bool aSuccess);

  void SetEarlyHintUsed() { mEarlyHintUsed = true; }

  bool GetEarlyHintUsed() const { return mEarlyHintUsed; }

 private:

  dom::ReferrerPolicy PreloadReferrerPolicy(const nsAString& aReferrerPolicy);

  nsIURI* BaseURIForPreload();

  struct PreloadOrCoalesceResult {

    RefPtr<PreloaderBase> mPreloader;

    bool mAlreadyComplete;

};

  PreloadOrCoalesceResult PreloadOrCoalesce(

      nsIURI* aURI, const nsAString& aURL, nsContentPolicyType aPolicyType,

      const nsAString& aAs, const nsAString& aType, const nsAString& aCharset,

      const nsAString& aSrcset, const nsAString& aSizes,

      const nsAString& aNonce, const nsAString& aIntegrity,

      const nsAString& aCORS, const nsAString& aReferrerPolicy,

      const nsAString& aFetchPriority, bool aFromHeader,

      uint64_t aEarlyHintPreloaderId);

 private:

  nsRefPtrHashtable<PreloadHashKey, PreloaderBase> mPreloads;

  // Raw pointer only, we are intended to be a direct member of dom::Document

  dom::Document* mDocument;

  // Set by `nsHtml5TreeOpExecutor::SetSpeculationBase`.

  nsCOMPtr<nsIURI> mSpeculationBaseURI;

  bool mEarlyHintUsed = false;

};

}  // namespace mozilla

#endif