1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/layout/style/nsIMediaList.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,213 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + *
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +/*
1.11 + * representation of media lists used when linking to style sheets or by
1.12 + * @media rules
1.13 + */
1.14 +
1.15 +#ifndef nsIMediaList_h_
1.16 +#define nsIMediaList_h_
1.17 +
1.18 +#include "nsIDOMMediaList.h"
1.19 +#include "nsTArray.h"
1.20 +#include "nsIAtom.h"
1.21 +#include "nsCSSValue.h"
1.22 +#include "nsWrapperCache.h"
1.23 +#include "mozilla/Attributes.h"
1.24 +#include "mozilla/ErrorResult.h"
1.25 +
1.26 +class nsPresContext;
1.27 +class nsCSSStyleSheet;
1.28 +class nsAString;
1.29 +struct nsMediaFeature;
1.30 +
1.31 +struct nsMediaExpression {
1.32 + enum Range { eMin, eMax, eEqual };
1.33 +
1.34 + const nsMediaFeature *mFeature;
1.35 + Range mRange;
1.36 + nsCSSValue mValue;
1.37 +
1.38 + // aActualValue must be obtained from mFeature->mGetter
1.39 + bool Matches(nsPresContext* aPresContext,
1.40 + const nsCSSValue& aActualValue) const;
1.41 +};
1.42 +
1.43 +/**
1.44 + * An nsMediaQueryResultCacheKey records what feature/value combinations
1.45 + * a set of media query results are valid for. This allows the caller
1.46 + * to quickly learn whether a prior result of media query evaluation is
1.47 + * still valid (e.g., due to a window size change) without rerunning all
1.48 + * of the evaluation and rebuilding the list of rules.
1.49 + *
1.50 + * This object may not be used after any media rules in any of the
1.51 + * sheets it was given to have been modified. However, this is
1.52 + * generally not a problem since ClearRuleCascades is called on the
1.53 + * sheet whenever this happens, and these objects are stored inside the
1.54 + * rule cascades. (FIXME: We're not actually doing this all the time.)
1.55 + *
1.56 + * The implementation could be further optimized in the future to store
1.57 + * ranges (combinations of less-than, less-than-or-equal, greater-than,
1.58 + * greater-than-or-equal, equal, not-equal, present, not-present) for
1.59 + * each feature rather than simply storing the list of expressions.
1.60 + * However, this requires combining any such ranges.
1.61 + */
1.62 +class nsMediaQueryResultCacheKey {
1.63 +public:
1.64 + nsMediaQueryResultCacheKey(nsIAtom* aMedium)
1.65 + : mMedium(aMedium)
1.66 + {}
1.67 +
1.68 + /**
1.69 + * Record that aExpression was tested while building the cached set
1.70 + * that this cache key is for, and that aExpressionMatches was whether
1.71 + * it matched.
1.72 + */
1.73 + void AddExpression(const nsMediaExpression* aExpression,
1.74 + bool aExpressionMatches);
1.75 + bool Matches(nsPresContext* aPresContext) const;
1.76 +private:
1.77 + struct ExpressionEntry {
1.78 + // FIXME: if we were better at maintaining invariants about clearing
1.79 + // rule cascades when media lists change, this could be a |const
1.80 + // nsMediaExpression*| instead.
1.81 + nsMediaExpression mExpression;
1.82 + bool mExpressionMatches;
1.83 + };
1.84 + struct FeatureEntry {
1.85 + const nsMediaFeature *mFeature;
1.86 + InfallibleTArray<ExpressionEntry> mExpressions;
1.87 + };
1.88 + nsCOMPtr<nsIAtom> mMedium;
1.89 + nsTArray<FeatureEntry> mFeatureCache;
1.90 +};
1.91 +
1.92 +class nsMediaQuery {
1.93 +public:
1.94 + nsMediaQuery()
1.95 + : mNegated(false)
1.96 + , mHasOnly(false)
1.97 + , mTypeOmitted(false)
1.98 + , mHadUnknownExpression(false)
1.99 + {
1.100 + }
1.101 +
1.102 +private:
1.103 + // for Clone only
1.104 + nsMediaQuery(const nsMediaQuery& aOther)
1.105 + : mNegated(aOther.mNegated)
1.106 + , mHasOnly(aOther.mHasOnly)
1.107 + , mTypeOmitted(aOther.mTypeOmitted)
1.108 + , mHadUnknownExpression(aOther.mHadUnknownExpression)
1.109 + , mMediaType(aOther.mMediaType)
1.110 + , mExpressions(aOther.mExpressions)
1.111 + {
1.112 + MOZ_ASSERT(mExpressions.Length() == aOther.mExpressions.Length());
1.113 + }
1.114 +
1.115 +public:
1.116 +
1.117 + void SetNegated() { mNegated = true; }
1.118 + void SetHasOnly() { mHasOnly = true; }
1.119 + void SetTypeOmitted() { mTypeOmitted = true; }
1.120 + void SetHadUnknownExpression() { mHadUnknownExpression = true; }
1.121 + void SetType(nsIAtom* aMediaType) {
1.122 + NS_ASSERTION(aMediaType,
1.123 + "expected non-null");
1.124 + mMediaType = aMediaType;
1.125 + }
1.126 +
1.127 + // Return a new nsMediaExpression in the array for the caller to fill
1.128 + // in. The caller must either fill it in completely, or call
1.129 + // SetHadUnknownExpression on this nsMediaQuery.
1.130 + // Returns null on out-of-memory.
1.131 + nsMediaExpression* NewExpression() { return mExpressions.AppendElement(); }
1.132 +
1.133 + void AppendToString(nsAString& aString) const;
1.134 +
1.135 + nsMediaQuery* Clone() const;
1.136 +
1.137 + // Does this query apply to the presentation?
1.138 + // If |aKey| is non-null, add cache information to it.
1.139 + bool Matches(nsPresContext* aPresContext,
1.140 + nsMediaQueryResultCacheKey* aKey) const;
1.141 +
1.142 +private:
1.143 + bool mNegated;
1.144 + bool mHasOnly; // only needed for serialization
1.145 + bool mTypeOmitted; // only needed for serialization
1.146 + bool mHadUnknownExpression;
1.147 + nsCOMPtr<nsIAtom> mMediaType;
1.148 + nsTArray<nsMediaExpression> mExpressions;
1.149 +};
1.150 +
1.151 +class nsMediaList MOZ_FINAL : public nsIDOMMediaList
1.152 + , public nsWrapperCache
1.153 +{
1.154 +public:
1.155 + typedef mozilla::ErrorResult ErrorResult;
1.156 +
1.157 + nsMediaList();
1.158 +
1.159 + virtual JSObject*
1.160 + WrapObject(JSContext* aCx) MOZ_OVERRIDE;
1.161 + nsISupports* GetParentObject() const
1.162 + {
1.163 + return nullptr;
1.164 + }
1.165 +
1.166 + NS_DECL_CYCLE_COLLECTING_ISUPPORTS
1.167 + NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(nsMediaList)
1.168 +
1.169 + NS_DECL_NSIDOMMEDIALIST
1.170 +
1.171 + void GetText(nsAString& aMediaText);
1.172 + void SetText(const nsAString& aMediaText);
1.173 +
1.174 + // Does this query apply to the presentation?
1.175 + // If |aKey| is non-null, add cache information to it.
1.176 + bool Matches(nsPresContext* aPresContext,
1.177 + nsMediaQueryResultCacheKey* aKey);
1.178 +
1.179 + nsresult SetStyleSheet(nsCSSStyleSheet* aSheet);
1.180 + void AppendQuery(nsAutoPtr<nsMediaQuery>& aQuery) {
1.181 + // Takes ownership of aQuery
1.182 + mArray.AppendElement(aQuery.forget());
1.183 + }
1.184 +
1.185 + already_AddRefed<nsMediaList> Clone();
1.186 +
1.187 + nsMediaQuery* MediumAt(int32_t aIndex) { return mArray[aIndex]; }
1.188 + void Clear() { mArray.Clear(); }
1.189 +
1.190 + // WebIDL
1.191 + // XPCOM GetMediaText and SetMediaText are fine.
1.192 + uint32_t Length() { return mArray.Length(); }
1.193 + void IndexedGetter(uint32_t aIndex, bool& aFound, nsAString& aReturn);
1.194 + // XPCOM Item is fine.
1.195 + void DeleteMedium(const nsAString& aMedium, ErrorResult& aRv)
1.196 + {
1.197 + aRv = DeleteMedium(aMedium);
1.198 + }
1.199 + void AppendMedium(const nsAString& aMedium, ErrorResult& aRv)
1.200 + {
1.201 + aRv = AppendMedium(aMedium);
1.202 + }
1.203 +
1.204 +protected:
1.205 + ~nsMediaList();
1.206 +
1.207 + nsresult Delete(const nsAString & aOldMedium);
1.208 + nsresult Append(const nsAString & aOldMedium);
1.209 +
1.210 + InfallibleTArray<nsAutoPtr<nsMediaQuery> > mArray;
1.211 + // not refcounted; sheet will let us know when it goes away
1.212 + // mStyleSheet is the sheet that needs to be dirtied when this medialist
1.213 + // changes
1.214 + nsCSSStyleSheet* mStyleSheet;
1.215 +};
1.216 +#endif /* !defined(nsIMediaList_h_) */
