gecko-dev/layout/style/SheetLoadData.h

/* -*- 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 mozilla_css_SheetLoadData_h
#define mozilla_css_SheetLoadData_h

#include "mozilla/css/Loader.h"
#include "mozilla/css/SheetParsingMode.h"
#include "mozilla/Encoding.h"
#include "mozilla/NotNull.h"
#include "nsIThreadInternal.h"
#include "nsProxyRelease.h"

namespace mozilla {
class StyleSheet;
}
class nsICSSLoaderObserver;
class nsINode;
class nsIPrincipal;
class nsIURI;

namespace mozilla {
namespace css {

/*********************************************
 * Data needed to properly load a stylesheet *
 *********************************************/

static_assert(eAuthorSheetFeatures == 0 && eUserSheetFeatures == 1 &&
                eAgentSheetFeatures == 2,
              "sheet parsing mode constants won't fit "
              "in SheetLoadData::mParsingMode");

class SheetLoadData final
  : public nsIRunnable
  , public nsIThreadObserver
{
  typedef nsIStyleSheetLinkingElement::MediaMatched MediaMatched;
  typedef nsIStyleSheetLinkingElement::IsAlternate IsAlternate;
protected:
  virtual ~SheetLoadData();

public:
  // Data for loading a sheet linked from a document
  SheetLoadData(Loader* aLoader,
                const nsAString& aTitle,
                nsIURI* aURI,
                StyleSheet* aSheet,
                bool aSyncLoad,
                nsIStyleSheetLinkingElement* aOwningElement,
                IsAlternate aIsAlternate,
                MediaMatched aMediaMatched,
                nsICSSLoaderObserver* aObserver,
                nsIPrincipal* aLoaderPrincipal,
                nsINode* aRequestingNode);

  // Data for loading a sheet linked from an @import rule
  SheetLoadData(Loader* aLoader,
                nsIURI* aURI,
                StyleSheet* aSheet,
                SheetLoadData* aParentData,
                nsICSSLoaderObserver* aObserver,
                nsIPrincipal* aLoaderPrincipal,
                nsINode* aRequestingNode);

  // Data for loading a non-document sheet
  SheetLoadData(Loader* aLoader,
                nsIURI* aURI,
                StyleSheet* aSheet,
                bool aSyncLoad,
                bool aUseSystemPrincipal,
                const Encoding* aPreloadEncoding,
                nsICSSLoaderObserver* aObserver,
                nsIPrincipal* aLoaderPrincipal,
                nsINode* aRequestingNode);

  already_AddRefed<nsIURI> GetReferrerURI();

  void ScheduleLoadEventIfNeeded();

  NotNull<const Encoding*> DetermineNonBOMEncoding(nsACString const& aSegment,
                                                   nsIChannel* aChannel);

  // The caller may have the bytes for the stylesheet split across two strings,
  // so aBytes1 and aBytes2 refer to those pieces.
  nsresult VerifySheetReadyToParse(nsresult aStatus,
                                   const nsACString& aBytes1,
                                   const nsACString& aBytes2,
                                   nsIChannel* aChannel);

  void SetReferrerPolicyFromHeader(nsIChannel* aChannel);

  NS_DECL_ISUPPORTS
  NS_DECL_NSIRUNNABLE
  NS_DECL_NSITHREADOBSERVER

  // Hold a ref to the CSSLoader so we can call back to it to let it
  // know the load finished
  RefPtr<Loader> mLoader;

  // Title needed to pull datas out of the pending datas table when
  // the preferred title is changed
  nsString mTitle;

  // The encoding we decided to use for the sheet
  const Encoding* mEncoding;

  // URI we're loading.  Null for inline sheets
  nsCOMPtr<nsIURI> mURI;

  // Should be 1 for non-inline sheets.
  uint32_t mLineNumber;

  // The sheet we're loading data for
  RefPtr<StyleSheet> mSheet;

  // Linked list of datas for the same URI as us
  SheetLoadData* mNext; // strong ref

  // Load data for the sheet that @import-ed us if we were @import-ed
  // during the parse
  RefPtr<SheetLoadData> mParentData;

  // Number of sheets we @import-ed that are still loading
  uint32_t mPendingChildren;

  // mSyncLoad is true when the load needs to be synchronous.
  // For LoadSheetSync, <link> to chrome stylesheets in UA Widgets,
  // and children of sync loads.
  bool mSyncLoad : 1;

  // mIsNonDocumentSheet is true if the load was triggered by LoadSheetSync or
  // LoadSheet or an @import from such a sheet.  Non-document sheet loads can
  // proceed even if we have no document.
  bool mIsNonDocumentSheet : 1;

  // mIsLoading is true from the moment we are placed in the loader's
  // "loading datas" table (right after the async channel is opened)
  // to the moment we are removed from said table (due to the load
  // completing or being cancelled).
  bool mIsLoading : 1;

  // mIsBeingParsed is true if this stylesheet is currently being parsed.
  bool mIsBeingParsed : 1;

  // mIsCancelled is set to true when a sheet load is stopped by
  // Stop() or StopLoadingSheet() (which was removed in Bug 556446).
  // SheetLoadData::OnStreamComplete() checks this to avoid parsing
  // sheets that have been cancelled and such.
  bool mIsCancelled : 1;

  // mMustNotify is true if the load data is being loaded async and
  // the original function call that started the load has returned.
  // This applies only to observer notifications; load/error events
  // are fired for any SheetLoadData that has a non-null
  // mOwningElement.
  bool mMustNotify : 1;

  // mWasAlternate is true if the sheet was an alternate when the load data was
  // created.
  bool mWasAlternate : 1;

  // mMediaMatched is true if the sheet matched its medialist when the load data
  // was created.
  bool mMediaMatched : 1;

  // mUseSystemPrincipal is true if the system principal should be used for
  // this sheet, no matter what the channel principal is.  Only true for sync
  // loads.
  bool mUseSystemPrincipal : 1;

  // If true, this SheetLoadData is being used as a way to handle
  // async observer notification for an already-complete sheet.
  bool mSheetAlreadyComplete : 1;

  // If true, the sheet is being loaded cross-origin without CORS permissions.
  // This is completely normal and CORS isn't needed for such loads.  This
  // flag is simply useful in determining whether to set mBlockResourceTiming
  // for a child sheet.
  bool mIsCrossOriginNoCORS : 1;

  // If this flag is true, LoadSheet will call SetReportResourceTiming(false)
  // on the timedChannel. This is to mark resources that are loaded by a
  // cross-origin stylesheet with a no-cors policy.
  // https://www.w3.org/TR/resource-timing/#processing-model
  bool mBlockResourceTiming : 1;

  // Boolean flag indicating whether the load has failed.  This will be set
  // to true if this load, or the load of any descendant import, fails.
  bool mLoadFailed : 1;

  // This is the element that imported the sheet.  Needed to get the
  // charset set on it and to fire load/error events.
  nsCOMPtr<nsIStyleSheetLinkingElement> mOwningElement;

  // The observer that wishes to be notified of load completion
  nsCOMPtr<nsICSSLoaderObserver> mObserver;

  // The principal that identifies who started loading us.
  nsCOMPtr<nsIPrincipal> mLoaderPrincipal;

  // The node that identifies who started loading us.
  nsCOMPtr<nsINode> mRequestingNode;

  // The encoding to use for preloading Must be empty if mOwningElement
  // is non-null.
  const Encoding* mPreloadEncoding;

  bool ShouldDefer() const
  {
    return mWasAlternate || !mMediaMatched;
  }

private:
  void FireLoadEvent(nsIThreadInternal* aThread);
};

typedef nsMainThreadPtrHolder<SheetLoadData> SheetLoadDataHolder;

} // namespace css
} // namespace mozilla

/**
 * Casting SheetLoadData to nsISupports is ambiguous.
 * This method handles that.
 */
inline nsISupports*
ToSupports(mozilla::css::SheetLoadData* p)
{
  return NS_ISUPPORTS_CAST(nsIRunnable*, p);
}

#endif // mozilla_css_SheetLoadData_h