michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  *
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /*
michael@0:  * representation of media lists used when linking to style sheets or by
michael@0:  * @media rules
michael@0:  */
michael@0: 
michael@0: #ifndef nsIMediaList_h_
michael@0: #define nsIMediaList_h_
michael@0: 
michael@0: #include "nsIDOMMediaList.h"
michael@0: #include "nsTArray.h"
michael@0: #include "nsIAtom.h"
michael@0: #include "nsCSSValue.h"
michael@0: #include "nsWrapperCache.h"
michael@0: #include "mozilla/Attributes.h"
michael@0: #include "mozilla/ErrorResult.h"
michael@0: 
michael@0: class nsPresContext;
michael@0: class nsCSSStyleSheet;
michael@0: class nsAString;
michael@0: struct nsMediaFeature;
michael@0: 
michael@0: struct nsMediaExpression {
michael@0:   enum Range { eMin, eMax, eEqual };
michael@0: 
michael@0:   const nsMediaFeature *mFeature;
michael@0:   Range mRange;
michael@0:   nsCSSValue mValue;
michael@0: 
michael@0:   // aActualValue must be obtained from mFeature->mGetter
michael@0:   bool Matches(nsPresContext* aPresContext,
michael@0:                  const nsCSSValue& aActualValue) const;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * An nsMediaQueryResultCacheKey records what feature/value combinations
michael@0:  * a set of media query results are valid for.  This allows the caller
michael@0:  * to quickly learn whether a prior result of media query evaluation is
michael@0:  * still valid (e.g., due to a window size change) without rerunning all
michael@0:  * of the evaluation and rebuilding the list of rules.
michael@0:  *
michael@0:  * This object may not be used after any media rules in any of the
michael@0:  * sheets it was given to have been modified.  However, this is
michael@0:  * generally not a problem since ClearRuleCascades is called on the
michael@0:  * sheet whenever this happens, and these objects are stored inside the
michael@0:  * rule cascades.  (FIXME: We're not actually doing this all the time.)
michael@0:  *
michael@0:  * The implementation could be further optimized in the future to store
michael@0:  * ranges (combinations of less-than, less-than-or-equal, greater-than,
michael@0:  * greater-than-or-equal, equal, not-equal, present, not-present) for
michael@0:  * each feature rather than simply storing the list of expressions.
michael@0:  * However, this requires combining any such ranges.
michael@0:  */
michael@0: class nsMediaQueryResultCacheKey {
michael@0: public:
michael@0:   nsMediaQueryResultCacheKey(nsIAtom* aMedium)
michael@0:     : mMedium(aMedium)
michael@0:   {}
michael@0: 
michael@0:   /**
michael@0:    * Record that aExpression was tested while building the cached set
michael@0:    * that this cache key is for, and that aExpressionMatches was whether
michael@0:    * it matched.
michael@0:    */
michael@0:   void AddExpression(const nsMediaExpression* aExpression,
michael@0:                      bool aExpressionMatches);
michael@0:   bool Matches(nsPresContext* aPresContext) const;
michael@0: private:
michael@0:   struct ExpressionEntry {
michael@0:     // FIXME: if we were better at maintaining invariants about clearing
michael@0:     // rule cascades when media lists change, this could be a |const
michael@0:     // nsMediaExpression*| instead.
michael@0:     nsMediaExpression mExpression;
michael@0:     bool mExpressionMatches;
michael@0:   };
michael@0:   struct FeatureEntry {
michael@0:     const nsMediaFeature *mFeature;
michael@0:     InfallibleTArray<ExpressionEntry> mExpressions;
michael@0:   };
michael@0:   nsCOMPtr<nsIAtom> mMedium;
michael@0:   nsTArray<FeatureEntry> mFeatureCache;
michael@0: };
michael@0: 
michael@0: class nsMediaQuery {
michael@0: public:
michael@0:   nsMediaQuery()
michael@0:     : mNegated(false)
michael@0:     , mHasOnly(false)
michael@0:     , mTypeOmitted(false)
michael@0:     , mHadUnknownExpression(false)
michael@0:   {
michael@0:   }
michael@0: 
michael@0: private:
michael@0:   // for Clone only
michael@0:   nsMediaQuery(const nsMediaQuery& aOther)
michael@0:     : mNegated(aOther.mNegated)
michael@0:     , mHasOnly(aOther.mHasOnly)
michael@0:     , mTypeOmitted(aOther.mTypeOmitted)
michael@0:     , mHadUnknownExpression(aOther.mHadUnknownExpression)
michael@0:     , mMediaType(aOther.mMediaType)
michael@0:     , mExpressions(aOther.mExpressions)
michael@0:   {
michael@0:     MOZ_ASSERT(mExpressions.Length() == aOther.mExpressions.Length());
michael@0:   }
michael@0: 
michael@0: public:
michael@0: 
michael@0:   void SetNegated()                     { mNegated = true; }
michael@0:   void SetHasOnly()                     { mHasOnly = true; }
michael@0:   void SetTypeOmitted()                 { mTypeOmitted = true; }
michael@0:   void SetHadUnknownExpression()        { mHadUnknownExpression = true; }
michael@0:   void SetType(nsIAtom* aMediaType)     { 
michael@0:                                           NS_ASSERTION(aMediaType,
michael@0:                                                        "expected non-null");
michael@0:                                           mMediaType = aMediaType;
michael@0:                                         }
michael@0: 
michael@0:   // Return a new nsMediaExpression in the array for the caller to fill
michael@0:   // in.  The caller must either fill it in completely, or call
michael@0:   // SetHadUnknownExpression on this nsMediaQuery.
michael@0:   // Returns null on out-of-memory.
michael@0:   nsMediaExpression* NewExpression()    { return mExpressions.AppendElement(); }
michael@0: 
michael@0:   void AppendToString(nsAString& aString) const;
michael@0: 
michael@0:   nsMediaQuery* Clone() const;
michael@0: 
michael@0:   // Does this query apply to the presentation?
michael@0:   // If |aKey| is non-null, add cache information to it.
michael@0:   bool Matches(nsPresContext* aPresContext,
michael@0:                  nsMediaQueryResultCacheKey* aKey) const;
michael@0: 
michael@0: private:
michael@0:   bool mNegated;
michael@0:   bool mHasOnly; // only needed for serialization
michael@0:   bool mTypeOmitted; // only needed for serialization
michael@0:   bool mHadUnknownExpression;
michael@0:   nsCOMPtr<nsIAtom> mMediaType;
michael@0:   nsTArray<nsMediaExpression> mExpressions;
michael@0: };
michael@0: 
michael@0: class nsMediaList MOZ_FINAL : public nsIDOMMediaList
michael@0:                             , public nsWrapperCache
michael@0: {
michael@0: public:
michael@0:   typedef mozilla::ErrorResult ErrorResult;
michael@0: 
michael@0:   nsMediaList();
michael@0: 
michael@0:   virtual JSObject*
michael@0:   WrapObject(JSContext* aCx) MOZ_OVERRIDE;
michael@0:   nsISupports* GetParentObject() const
michael@0:   {
michael@0:     return nullptr;
michael@0:   }
michael@0: 
michael@0:   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
michael@0:   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(nsMediaList)
michael@0: 
michael@0:   NS_DECL_NSIDOMMEDIALIST
michael@0: 
michael@0:   void GetText(nsAString& aMediaText);
michael@0:   void SetText(const nsAString& aMediaText);
michael@0: 
michael@0:   // Does this query apply to the presentation?
michael@0:   // If |aKey| is non-null, add cache information to it.
michael@0:   bool Matches(nsPresContext* aPresContext,
michael@0:                  nsMediaQueryResultCacheKey* aKey);
michael@0: 
michael@0:   nsresult SetStyleSheet(nsCSSStyleSheet* aSheet);
michael@0:   void AppendQuery(nsAutoPtr<nsMediaQuery>& aQuery) {
michael@0:     // Takes ownership of aQuery
michael@0:     mArray.AppendElement(aQuery.forget());
michael@0:   }
michael@0: 
michael@0:   already_AddRefed<nsMediaList> Clone();
michael@0: 
michael@0:   nsMediaQuery* MediumAt(int32_t aIndex) { return mArray[aIndex]; }
michael@0:   void Clear() { mArray.Clear(); }
michael@0: 
michael@0:   // WebIDL
michael@0:   // XPCOM GetMediaText and SetMediaText are fine.
michael@0:   uint32_t Length() { return mArray.Length(); }
michael@0:   void IndexedGetter(uint32_t aIndex, bool& aFound, nsAString& aReturn);
michael@0:   // XPCOM Item is fine.
michael@0:   void DeleteMedium(const nsAString& aMedium, ErrorResult& aRv)
michael@0:   {
michael@0:     aRv = DeleteMedium(aMedium);
michael@0:   }
michael@0:   void AppendMedium(const nsAString& aMedium, ErrorResult& aRv)
michael@0:   {
michael@0:     aRv = AppendMedium(aMedium);
michael@0:   }
michael@0: 
michael@0: protected:
michael@0:   ~nsMediaList();
michael@0: 
michael@0:   nsresult Delete(const nsAString & aOldMedium);
michael@0:   nsresult Append(const nsAString & aOldMedium);
michael@0: 
michael@0:   InfallibleTArray<nsAutoPtr<nsMediaQuery> > mArray;
michael@0:   // not refcounted; sheet will let us know when it goes away
michael@0:   // mStyleSheet is the sheet that needs to be dirtied when this medialist
michael@0:   // changes
michael@0:   nsCSSStyleSheet*         mStyleSheet;
michael@0: };
michael@0: #endif /* !defined(nsIMediaList_h_) */