fune/parser/html/nsHtml5TreeOpExecutor.h
Frédéric Wang b005b82248 Bug 1872657 - Add fetchpriority support for <link rel=preload as=image>. r=valentin,smaug,manuel
This patch adds fetchpriority support for `<link rel=preload as=image>`
and equivalent HTTP Link header. The fetchpriority value is passed from
where the link is parsed down to `NewImageChannel` where the priority
is initially set. Currently, the default equals PRIORITY_LOW, but is
decreased a bit if LOAD_BACKGROUND flag is set (this is always the case
for link preload images, see `imgLoader::LoadImage`). Later, the
priority can be increased again depending on the category (see
`imgRequest::BoostPriority`).

In order to minimize the changes, the new calculation is to keep the
initial setting to PRIORITY_LOW, adjust it using a new
`network.fetchpriority.adjustments.*` preference depending on the
fetchpriority attributes, and then preserve further adjustments for
LOAD_BACKGROUND and `BoostPriority`.

For the default value `fetchpriority=auto`, there is no adjustment
i.e. we continue to start with PRIORITY_LOW. `fetchpriority=low/high`
are respectively mapped to PRIORITY_LOW/PRIORITY_HIGH which is simple
and consistent with the "Image" cases from Google's web.dev article
https://web.dev/articles/fetch-priority. These values could of course
be revised in the future after more experiments.

This change is covered by the following tests below. The expectations
is modified to match what is described above (i.e. map to PRIORITY_LOW
or PRIORITY_HIGH with adjustment due to LOAD_BACKGROUND):
- `link-initial-preload-image.h2.html`
- `link-dynamic-preload-image.h2.html`
- `kPipeHeaderPreloadImageLinks`

Based on a patch by Mirko Brodesser (mbrodesser@igalia.com)

Differential Revision: https://phabricator.services.mozilla.com/D197493
2024-02-27 06:33:48 +00:00

324 lines
8.8 KiB
C++

/* 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 nsHtml5TreeOpExecutor_h
#define nsHtml5TreeOpExecutor_h
#include "nsAtom.h"
#include "nsTraceRefcnt.h"
#include "nsHtml5TreeOperation.h"
#include "nsHtml5SpeculativeLoad.h"
#include "nsTArray.h"
#include "nsContentSink.h"
#include "nsNodeInfoManager.h"
#include "nsHtml5DocumentMode.h"
#include "nsIScriptElement.h"
#include "nsIParser.h"
#include "nsAHtml5TreeOpSink.h"
#include "nsHtml5TreeOpStage.h"
#include "nsIURI.h"
#include "nsTHashSet.h"
#include "nsHashKeys.h"
#include "mozilla/LinkedList.h"
#include "nsHtml5DocumentBuilder.h"
#include "nsCharsetSource.h"
class nsHtml5Parser;
class nsHtml5StreamParser;
class nsIContent;
namespace mozilla {
namespace dom {
class Document;
}
} // namespace mozilla
class nsHtml5TreeOpExecutor final
: public nsHtml5DocumentBuilder,
public nsIContentSink,
public nsAHtml5TreeOpSink,
public mozilla::LinkedListElement<nsHtml5TreeOpExecutor> {
friend class nsHtml5FlushLoopGuard;
typedef mozilla::dom::ReferrerPolicy ReferrerPolicy;
using Encoding = mozilla::Encoding;
template <typename T>
using NotNull = mozilla::NotNull<T>;
public:
NS_DECL_ISUPPORTS_INHERITED
private:
#ifdef DEBUG
static uint32_t sAppendBatchMaxSize;
static uint32_t sAppendBatchSlotsExamined;
static uint32_t sAppendBatchExaminations;
static uint32_t sLongestTimeOffTheEventLoop;
static uint32_t sTimesFlushLoopInterrupted;
#endif
/**
* Whether EOF needs to be suppressed
*/
bool mSuppressEOF;
bool mReadingFromStage;
nsTArray<nsHtml5TreeOperation> mOpQueue;
nsHtml5StreamParser* mStreamParser;
/**
* URLs already preloaded/preloading.
*/
nsTHashSet<nsCString> mPreloadedURLs;
nsCOMPtr<nsIURI> mSpeculationBaseURI;
nsCOMPtr<nsIURI> mViewSourceBaseURI;
/**
* Whether the parser has started
*/
bool mStarted;
nsHtml5TreeOpStage mStage;
bool mRunFlushLoopOnStack;
bool mCallContinueInterruptedParsingIfEnabled;
/**
* Whether this executor has already complained about matters related
* to character encoding declarations.
*/
bool mAlreadyComplainedAboutCharset;
/**
* Whether this executor has already complained about the tree being too
* deep.
*/
bool mAlreadyComplainedAboutDeepTree;
public:
nsHtml5TreeOpExecutor();
protected:
virtual ~nsHtml5TreeOpExecutor();
public:
// nsIContentSink
/**
* Unimplemented. For interface compat only.
*/
NS_IMETHOD WillParse() override;
NS_IMETHOD WillBuildModel(nsDTDMode /* unused */) override {
return WillBuildModel();
}
nsresult WillBuildModel();
/**
* Emits EOF.
*/
NS_IMETHOD DidBuildModel(bool aTerminated) override;
/**
* Forwards to nsContentSink
*/
NS_IMETHOD WillInterrupt() override;
/**
* Unimplemented. For interface compat only.
*/
void WillResume() override;
virtual nsIContentSink* AsExecutor() override { return this; }
virtual void InitialTranslationCompleted() override;
/**
* Sets the parser.
*/
NS_IMETHOD SetParser(nsParserBase* aParser) override;
/**
* No-op for backwards compat.
*/
virtual void FlushPendingNotifications(mozilla::FlushType aType) override;
/**
* Don't call. For interface compat only.
*/
virtual void SetDocumentCharset(NotNull<const Encoding*> aEncoding) override {
MOZ_ASSERT_UNREACHABLE("No one should call this.");
}
/**
* Returns the document.
*/
virtual nsISupports* GetTarget() override;
virtual void ContinueInterruptedParsingAsync() override;
bool IsScriptExecuting() override { return IsScriptExecutingImpl(); }
// Not from interface
void SetStreamParser(nsHtml5StreamParser* aStreamParser) {
mStreamParser = aStreamParser;
}
void InitializeDocWriteParserState(nsAHtml5TreeBuilderState* aState,
int32_t aLine);
bool IsScriptEnabled();
virtual nsresult MarkAsBroken(nsresult aReason) override;
void StartLayout(bool* aInterrupted);
void PauseDocUpdate(bool* aInterrupted);
void FlushSpeculativeLoads();
void RunFlushLoop();
nsresult FlushDocumentWrite();
void CommitToInternalEncoding();
[[nodiscard]] bool TakeOpsFromStage();
void MaybeSuspend();
void Start();
void SetDocumentCharsetAndSource(NotNull<const Encoding*> aEncoding,
nsCharsetSource aCharsetSource);
void UpdateCharsetSource(nsCharsetSource aCharsetSource);
void NeedsCharsetSwitchTo(NotNull<const Encoding*> aEncoding, int32_t aSource,
uint32_t aLineNumber);
void MaybeComplainAboutCharset(const char* aMsgId, bool aError,
uint32_t aLineNumber);
void ComplainAboutBogusProtocolCharset(mozilla::dom::Document* aDoc,
bool aUnrecognized);
void MaybeComplainAboutDeepTree(uint32_t aLineNumber);
bool HasStarted() { return mStarted; }
bool IsFlushing() { return mFlushState >= eInFlush; }
#ifdef DEBUG
bool IsInFlushLoop() { return mRunFlushLoopOnStack; }
#endif
void RunScript(nsIContent* aScriptElement, bool aMayDocumentWriteOrBlock);
/**
* Flush the operations from the tree operations from the argument
* queue unconditionally. (This is for the main thread case.)
*/
[[nodiscard]] virtual bool MoveOpsFrom(
nsTArray<nsHtml5TreeOperation>& aOpQueue) override;
void ClearOpQueue();
void RemoveFromStartOfOpQueue(size_t aNumberOfOpsToRemove);
inline size_t OpQueueLength() { return mOpQueue.Length(); }
nsHtml5TreeOpStage* GetStage() { return &mStage; }
void StartReadingFromStage() { mReadingFromStage = true; }
void StreamEnded();
#ifdef DEBUG
void AssertStageEmpty() { mStage.AssertEmpty(); }
#endif
nsIURI* GetViewSourceBaseURI();
void PreloadScript(const nsAString& aURL, const nsAString& aCharset,
const nsAString& aType, const nsAString& aCrossOrigin,
const nsAString& aMedia, const nsAString& aNonce,
const nsAString& aFetchPriority,
const nsAString& aIntegrity,
ReferrerPolicy aReferrerPolicy, bool aScriptFromHead,
bool aAsync, bool aDefer, bool aLinkPreload);
void PreloadStyle(const nsAString& aURL, const nsAString& aCharset,
const nsAString& aCrossOrigin, const nsAString& aMedia,
const nsAString& aReferrerPolicy, const nsAString& aNonce,
const nsAString& aIntegrity, bool aLinkPreload,
const nsAString& aFetchPriority);
void PreloadImage(const nsAString& aURL, const nsAString& aCrossOrigin,
const nsAString& aMedia, const nsAString& aSrcset,
const nsAString& aSizes,
const nsAString& aImageReferrerPolicy, bool aLinkPreload,
const nsAString& aFetchPriority);
void PreloadOpenPicture();
void PreloadEndPicture();
void PreloadPictureSource(const nsAString& aSrcset, const nsAString& aSizes,
const nsAString& aType, const nsAString& aMedia);
void PreloadFont(const nsAString& aURL, const nsAString& aCrossOrigin,
const nsAString& aMedia, const nsAString& aReferrerPolicy,
const nsAString& aFetchPriority);
void PreloadFetch(const nsAString& aURL, const nsAString& aCrossOrigin,
const nsAString& aMedia, const nsAString& aReferrerPolicy,
const nsAString& aFetchPriority);
void SetSpeculationBase(const nsAString& aURL);
void UpdateReferrerInfoFromMeta(const nsAString& aMetaReferrer);
void AddSpeculationCSP(const nsAString& aCSP);
void AddBase(const nsAString& aURL);
private:
nsHtml5Parser* GetParser();
bool IsExternalViewSource();
/**
* Get a nsIURI for an nsString if the URL hasn't been preloaded yet.
*/
already_AddRefed<nsIURI> ConvertIfNotPreloadedYet(const nsAString& aURL);
/**
* The above, plus also checks that the media attribute applies.
*/
already_AddRefed<nsIURI> ConvertIfNotPreloadedYetAndMediaApplies(
const nsAString& aURL, const nsAString& aMedia);
/** Returns whether the given media attribute applies to mDocument */
bool MediaApplies(const nsAString& aMedia);
/**
* The base URI we would use for current preload operations
*/
nsIURI* BaseURIForPreload();
/**
* Returns true if we haven't preloaded this URI yet, and adds it to the
* list of preloaded URIs
*/
bool ShouldPreloadURI(nsIURI* aURI);
ReferrerPolicy GetPreloadReferrerPolicy(const nsAString& aReferrerPolicy);
ReferrerPolicy GetPreloadReferrerPolicy(ReferrerPolicy aReferrerPolicy);
};
#endif // nsHtml5TreeOpExecutor_h