1 files changed, 318 insertions, 0 deletions
diff --git a/layout/style/nsIMediaList.h b/layout/style/nsIMediaList.h
new file mode 100644
index 000000000..43b631ae8
--- /dev/null
+++ b/layout/style/nsIMediaList.h
@@ -0,0 +1,318 @@
+/* -*- 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 "nsAutoPtr.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 nsAString;
+struct nsMediaFeature;
+
+namespace mozilla {
+class CSSStyleSheet;
+namespace css {
+class DocumentRule;
+} // namespace css
+} // namespace mozilla
+
+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;
+
+  bool operator==(const nsMediaExpression& aOther) const {
+    return mFeature == aOther.mFeature && // pointer equality fine (atom-like)
+           mRange == aOther.mRange &&
+           mValue == aOther.mValue;
+  }
+  bool operator!=(const nsMediaExpression& aOther) const {
+    return !(*this == aOther);
+  }
+};
+
+/**
+ * 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:
+  explicit 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;
+  bool HasFeatureConditions() const {
+    return !mFeatureCache.IsEmpty();
+  }
+
+  /**
+   * An operator== that implements list equality, which isn't quite as
+   * good as set equality, but catches the trivial equality cases.
+   */
+  bool operator==(const nsMediaQueryResultCacheKey& aOther) const {
+    return mMedium == aOther.mMedium &&
+           mFeatureCache == aOther.mFeatureCache;
+  }
+  bool operator!=(const nsMediaQueryResultCacheKey& aOther) const {
+    return !(*this == aOther);
+  }
+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;
+
+    bool operator==(const ExpressionEntry& aOther) const {
+      return mExpression == aOther.mExpression &&
+             mExpressionMatches == aOther.mExpressionMatches;
+    }
+    bool operator!=(const ExpressionEntry& aOther) const {
+      return !(*this == aOther);
+    }
+  };
+  struct FeatureEntry {
+    const nsMediaFeature *mFeature;
+    InfallibleTArray<ExpressionEntry> mExpressions;
+
+    bool operator==(const FeatureEntry& aOther) const {
+      return mFeature == aOther.mFeature &&
+             mExpressions == aOther.mExpressions;
+    }
+    bool operator!=(const FeatureEntry& aOther) const {
+      return !(*this == aOther);
+    }
+  };
+  nsCOMPtr<nsIAtom> mMedium;
+  nsTArray<FeatureEntry> mFeatureCache;
+};
+
+/**
+ * nsDocumentRuleResultCacheKey is analagous to nsMediaQueryResultCacheKey
+ * and stores the result of matching the @-moz-document rules from a set
+ * of style sheets.  nsCSSRuleProcessor builds up an
+ * nsDocumentRuleResultCacheKey as it visits the @-moz-document rules
+ * while building its RuleCascadeData.
+ *
+ * Rather than represent the result using a list of both the matching and
+ * non-matching rules, we just store the matched rules.  The assumption is
+ * that in situations where we have a large number of rules -- such as the
+ * thousands added by AdBlock Plus -- that only a small number will be
+ * matched.  Thus to check if the nsDocumentRuleResultCacheKey matches a
+ * given nsPresContext, we also need the entire list of @-moz-document
+ * rules to know which rules must not match.
+ */
+class nsDocumentRuleResultCacheKey
+{
+public:
+#ifdef DEBUG
+  nsDocumentRuleResultCacheKey()
+    : mFinalized(false) {}
+#endif
+
+  bool AddMatchingRule(mozilla::css::DocumentRule* aRule);
+  bool Matches(nsPresContext* aPresContext,
+               const nsTArray<mozilla::css::DocumentRule*>& aRules) const;
+
+  bool operator==(const nsDocumentRuleResultCacheKey& aOther) const {
+    MOZ_ASSERT(mFinalized);
+    MOZ_ASSERT(aOther.mFinalized);
+    return mMatchingRules == aOther.mMatchingRules;
+  }
+  bool operator!=(const nsDocumentRuleResultCacheKey& aOther) const {
+    return !(*this == aOther);
+  }
+
+  void Swap(nsDocumentRuleResultCacheKey& aOther) {
+    mMatchingRules.SwapElements(aOther.mMatchingRules);
+#ifdef DEBUG
+    std::swap(mFinalized, aOther.mFinalized);
+#endif
+  }
+
+  void Finalize();
+
+#ifdef DEBUG
+  void List(FILE* aOut = stdout, int32_t aIndex = 0) const;
+#endif
+
+  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+
+private:
+  nsTArray<mozilla::css::DocumentRule*> mMatchingRules;
+#ifdef DEBUG
+  bool mFinalized;
+#endif
+};
+
+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 final : public nsIDOMMediaList
+                        , public nsWrapperCache
+{
+public:
+  typedef mozilla::ErrorResult ErrorResult;
+
+  nsMediaList();
+
+  virtual JSObject*
+  WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) 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);
+
+  void SetStyleSheet(mozilla::CSSStyleSheet* 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
+  mozilla::CSSStyleSheet* mStyleSheet;
+};
+#endif /* !defined(nsIMediaList_h_) */