The Tor Browser: layout/style/nsIMediaList.h@7e26c7da4463 (annotated)

layout/style/nsIMediaList.h@7e26c7da4463 (annotated)

layout/style/nsIMediaList.h

Wed, 31 Dec 2014 06:55:50 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:55:50 +0100
changeset 2: 7e26c7da4463
permissions: -rw-r--r--

Added tag UPSTREAM_283F7C6 for changeset ca08bd8f51b2

 /* -*- 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/. */
 /*
  * representation of media lists used when linking to style sheets or by
  * @media rules
  */
 #ifndef nsIMediaList_h_
 #define nsIMediaList_h_
 #include "nsIDOMMediaList.h"
 #include "nsTArray.h"
 #include "nsIAtom.h"
 #include "nsCSSValue.h"
 #include "nsWrapperCache.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/ErrorResult.h"
 class nsPresContext;
 class nsCSSStyleSheet;
 class nsAString;
 struct nsMediaFeature;
 struct nsMediaExpression {
   enum Range { eMin, eMax, eEqual };
   const nsMediaFeature *mFeature;
   Range mRange;
   nsCSSValue mValue;
   // aActualValue must be obtained from mFeature->mGetter
   bool Matches(nsPresContext* aPresContext,
                  const nsCSSValue& aActualValue) const;
 };
 /**
  * An nsMediaQueryResultCacheKey records what feature/value combinations
  * a set of media query results are valid for.  This allows the caller
  * to quickly learn whether a prior result of media query evaluation is
  * still valid (e.g., due to a window size change) without rerunning all
  * of the evaluation and rebuilding the list of rules.
  *
  * This object may not be used after any media rules in any of the
  * sheets it was given to have been modified.  However, this is
  * generally not a problem since ClearRuleCascades is called on the
  * sheet whenever this happens, and these objects are stored inside the
  * rule cascades.  (FIXME: We're not actually doing this all the time.)
  *
  * The implementation could be further optimized in the future to store
  * ranges (combinations of less-than, less-than-or-equal, greater-than,
  * greater-than-or-equal, equal, not-equal, present, not-present) for
  * each feature rather than simply storing the list of expressions.
  * However, this requires combining any such ranges.
  */
 class nsMediaQueryResultCacheKey {
 public:
   nsMediaQueryResultCacheKey(nsIAtom* aMedium)
     : mMedium(aMedium)
   {}
   /**
    * Record that aExpression was tested while building the cached set
    * that this cache key is for, and that aExpressionMatches was whether
    * it matched.
    */
   void AddExpression(const nsMediaExpression* aExpression,
                      bool aExpressionMatches);
   bool Matches(nsPresContext* aPresContext) const;
 private:
   struct ExpressionEntry {
     // FIXME: if we were better at maintaining invariants about clearing
     // rule cascades when media lists change, this could be a |const
     // nsMediaExpression*| instead.
     nsMediaExpression mExpression;
     bool mExpressionMatches;
   };
   struct FeatureEntry {
     const nsMediaFeature *mFeature;
     InfallibleTArray<ExpressionEntry> mExpressions;
   };
   nsCOMPtr<nsIAtom> mMedium;
   nsTArray<FeatureEntry> mFeatureCache;
 };
 class nsMediaQuery {
 public:
   nsMediaQuery()
     : mNegated(false)
     , mHasOnly(false)
     , mTypeOmitted(false)
     , mHadUnknownExpression(false)
   {
   }
 private:
   // for Clone only
   nsMediaQuery(const nsMediaQuery& aOther)
     : mNegated(aOther.mNegated)
     , mHasOnly(aOther.mHasOnly)
     , mTypeOmitted(aOther.mTypeOmitted)
     , mHadUnknownExpression(aOther.mHadUnknownExpression)
     , mMediaType(aOther.mMediaType)
     , mExpressions(aOther.mExpressions)
   {
     MOZ_ASSERT(mExpressions.Length() == aOther.mExpressions.Length());
   }
 public:
   void SetNegated()                     { mNegated = true; }
   void SetHasOnly()                     { mHasOnly = true; }
   void SetTypeOmitted()                 { mTypeOmitted = true; }
   void SetHadUnknownExpression()        { mHadUnknownExpression = true; }
   void SetType(nsIAtom* aMediaType)     {
                                           NS_ASSERTION(aMediaType,
                                                        "expected non-null");
                                           mMediaType = aMediaType;
                                         }
   // Return a new nsMediaExpression in the array for the caller to fill
   // in.  The caller must either fill it in completely, or call
   // SetHadUnknownExpression on this nsMediaQuery.
   // Returns null on out-of-memory.
   nsMediaExpression* NewExpression()    { return mExpressions.AppendElement(); }
   void AppendToString(nsAString& aString) const;
   nsMediaQuery* Clone() const;
   // Does this query apply to the presentation?
   // If |aKey| is non-null, add cache information to it.
   bool Matches(nsPresContext* aPresContext,
                  nsMediaQueryResultCacheKey* aKey) const;
 private:
   bool mNegated;
   bool mHasOnly; // only needed for serialization
   bool mTypeOmitted; // only needed for serialization
   bool mHadUnknownExpression;
   nsCOMPtr<nsIAtom> mMediaType;
   nsTArray<nsMediaExpression> mExpressions;
 };
 class nsMediaList MOZ_FINAL : public nsIDOMMediaList
                             , public nsWrapperCache
 {
 public:
   typedef mozilla::ErrorResult ErrorResult;
   nsMediaList();
   virtual JSObject*
   WrapObject(JSContext* aCx) MOZ_OVERRIDE;
   nsISupports* GetParentObject() const
   {
     return nullptr;
   }
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(nsMediaList)
   NS_DECL_NSIDOMMEDIALIST
   void GetText(nsAString& aMediaText);
   void SetText(const nsAString& aMediaText);
   // Does this query apply to the presentation?
   // If |aKey| is non-null, add cache information to it.
   bool Matches(nsPresContext* aPresContext,
                  nsMediaQueryResultCacheKey* aKey);
   nsresult SetStyleSheet(nsCSSStyleSheet* aSheet);
   void AppendQuery(nsAutoPtr<nsMediaQuery>& aQuery) {
     // Takes ownership of aQuery
     mArray.AppendElement(aQuery.forget());
   }
   already_AddRefed<nsMediaList> Clone();
   nsMediaQuery* MediumAt(int32_t aIndex) { return mArray[aIndex]; }
   void Clear() { mArray.Clear(); }
   // WebIDL
   // XPCOM GetMediaText and SetMediaText are fine.
   uint32_t Length() { return mArray.Length(); }
   void IndexedGetter(uint32_t aIndex, bool& aFound, nsAString& aReturn);
   // XPCOM Item is fine.
   void DeleteMedium(const nsAString& aMedium, ErrorResult& aRv)
   {
     aRv = DeleteMedium(aMedium);
   }
   void AppendMedium(const nsAString& aMedium, ErrorResult& aRv)
   {
     aRv = AppendMedium(aMedium);
   }
 protected:
   ~nsMediaList();
   nsresult Delete(const nsAString & aOldMedium);
   nsresult Append(const nsAString & aOldMedium);
   InfallibleTArray<nsAutoPtr<nsMediaQuery> > mArray;
   // not refcounted; sheet will let us know when it goes away
   // mStyleSheet is the sheet that needs to be dirtied when this medialist
   // changes
   nsCSSStyleSheet*         mStyleSheet;
 };
 #endif /* !defined(nsIMediaList_h_) */

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layout/style/nsIMediaList.h@7e26c7da4463 (annotated)

layout/style/nsIMediaList.h