michael@0: /* vim: set shiftwidth=4 tabstop=8 autoindent cindent expandtab: */
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: /* the features that media queries can test */
michael@0: 
michael@0: #ifndef nsMediaFeatures_h_
michael@0: #define nsMediaFeatures_h_
michael@0: 
michael@0: #include "nsError.h"
michael@0: #include "nsCSSProps.h"
michael@0: 
michael@0: class nsIAtom;
michael@0: class nsPresContext;
michael@0: class nsCSSValue;
michael@0: 
michael@0: struct nsMediaFeature;
michael@0: typedef nsresult
michael@0: (* nsMediaFeatureValueGetter)(nsPresContext* aPresContext,
michael@0:                               const nsMediaFeature* aFeature,
michael@0:                               nsCSSValue& aResult);
michael@0: 
michael@0: struct nsMediaFeature {
michael@0:     nsIAtom **mName; // extra indirection to point to nsGkAtoms members
michael@0: 
michael@0:     enum RangeType { eMinMaxAllowed, eMinMaxNotAllowed };
michael@0:     RangeType mRangeType;
michael@0: 
michael@0:     enum ValueType {
michael@0:         // All value types allow eCSSUnit_Null to indicate that no value
michael@0:         // was given (in addition to the types listed below).
michael@0:         eLength,     // values are such that nsCSSValue::IsLengthUnit() is true
michael@0:         eInteger,    // values are eCSSUnit_Integer
michael@0:         eFloat,      // values are eCSSUnit_Number
michael@0:         eBoolInteger,// values are eCSSUnit_Integer (0, -0, or 1 only)
michael@0:         eIntRatio,   // values are eCSSUnit_Array of two eCSSUnit_Integer
michael@0:         eResolution, // values are in eCSSUnit_Inch (for dpi),
michael@0:                      //   eCSSUnit_Pixel (for dppx), or
michael@0:                      //   eCSSUnit_Centimeter (for dpcm)
michael@0:         eEnumerated, // values are eCSSUnit_Enumerated (uses keyword table)
michael@0:         eIdent       // values are eCSSUnit_Ident
michael@0:         // Note that a number of pieces of code (both for parsing and
michael@0:         // for matching of valueless expressions) assume that all numeric
michael@0:         // value types cannot be negative.  The parsing code also does
michael@0:         // not allow zeros in eIntRatio types.
michael@0:     };
michael@0:     ValueType mValueType;
michael@0: 
michael@0:     union {
michael@0:       // In static arrays, it's the first member that's initialized.  We
michael@0:       // need that to be void* so we can initialize both other types.
michael@0:       // This member should never be accessed by name.
michael@0:       const void* mInitializer_;
michael@0:       // If mValueType == eEnumerated:  const int32_t*: keyword table in
michael@0:       //   the same format as the keyword tables in nsCSSProps.
michael@0:       const nsCSSProps::KTableValue* mKeywordTable;
michael@0:       // If mGetter == GetSystemMetric (which implies mValueType ==
michael@0:       //   eBoolInteger): nsIAtom * const *, for the system metric.
michael@0:       nsIAtom * const * mMetric;
michael@0:     } mData;
michael@0: 
michael@0:     // A function that returns the current value for this feature for a
michael@0:     // given presentation.  If it returns eCSSUnit_Null, the feature is
michael@0:     // not present.
michael@0:     nsMediaFeatureValueGetter mGetter;
michael@0: };
michael@0: 
michael@0: class nsMediaFeatures {
michael@0: public:
michael@0:     // Terminated with an entry whose mName is null.
michael@0:     static const nsMediaFeature features[];
michael@0: };
michael@0: 
michael@0: #endif /* !defined(nsMediaFeatures_h_) */