1 files changed, 91 insertions, 0 deletions
diff --git a/layout/style/nsMediaFeatures.h b/layout/style/nsMediaFeatures.h
new file mode 100644
index 000000000..76e94837d
--- /dev/null
+++ b/layout/style/nsMediaFeatures.h
@@ -0,0 +1,91 @@
+/* -*- 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/. */
+
+/* the features that media queries can test */
+
+#ifndef nsMediaFeatures_h_
+#define nsMediaFeatures_h_
+
+#include "nsCSSProps.h"
+
+class nsIAtom;
+class nsPresContext;
+class nsCSSValue;
+
+struct nsMediaFeature;
+typedef nsresult
+(* nsMediaFeatureValueGetter)(nsPresContext* aPresContext,
+                              const nsMediaFeature* aFeature,
+                              nsCSSValue& aResult);
+
+struct nsMediaFeature
+{
+  nsIAtom **mName; // extra indirection to point to nsGkAtoms members
+
+  enum RangeType { eMinMaxAllowed, eMinMaxNotAllowed };
+  RangeType mRangeType;
+
+  enum ValueType {
+    // All value types allow eCSSUnit_Null to indicate that no value
+    // was given (in addition to the types listed below).
+    eLength,     // values are such that nsCSSValue::IsLengthUnit() is true
+    eInteger,    // values are eCSSUnit_Integer
+    eFloat,      // values are eCSSUnit_Number
+    eBoolInteger,// values are eCSSUnit_Integer (0, -0, or 1 only)
+    eIntRatio,   // values are eCSSUnit_Array of two eCSSUnit_Integer
+    eResolution, // values are in eCSSUnit_Inch (for dpi),
+                 //   eCSSUnit_Pixel (for dppx), or
+                 //   eCSSUnit_Centimeter (for dpcm)
+    eEnumerated, // values are eCSSUnit_Enumerated (uses keyword table)
+    eIdent       // values are eCSSUnit_Ident
+    // Note that a number of pieces of code (both for parsing and
+    // for matching of valueless expressions) assume that all numeric
+    // value types cannot be negative.  The parsing code also does
+    // not allow zeros in eIntRatio types.
+  };
+  ValueType mValueType;
+
+  enum RequirementFlags : uint8_t {
+    // Bitfield of requirements that must be satisfied in order for this
+    // media feature to be active.
+    eNoRequirements = 0,
+    eHasWebkitPrefix = 1 << 0, // Feature name must start w/ "-webkit-", even
+                               // before any "min-"/"max-" qualifier.
+
+    // Feature is only supported if the pref
+    // "layout.css.prefixes.device-pixel-ratio-webkit" is enabled.
+    // (Should only be used for -webkit-device-pixel-ratio.)
+    eWebkitDevicePixelRatioPrefEnabled = 1 << 1
+  };
+  uint8_t mReqFlags;
+
+  union {
+    // In static arrays, it's the first member that's initialized.  We
+    // need that to be void* so we can initialize both other types.
+    // This member should never be accessed by name.
+    const void* mInitializer_;
+    // If mValueType == eEnumerated:  const int32_t*: keyword table in
+    //   the same format as the keyword tables in nsCSSProps.
+    const nsCSSProps::KTableEntry* mKeywordTable;
+    // If mGetter == GetSystemMetric (which implies mValueType ==
+    //   eBoolInteger): nsIAtom * const *, for the system metric.
+    nsIAtom * const * mMetric;
+  } mData;
+
+  // A function that returns the current value for this feature for a
+  // given presentation.  If it returns eCSSUnit_Null, the feature is
+  // not present.
+  nsMediaFeatureValueGetter mGetter;
+};
+
+class nsMediaFeatures
+{
+public:
+  // Terminated with an entry whose mName is null.
+  static const nsMediaFeature features[];
+};
+
+#endif /* !defined(nsMediaFeatures_h_) */