michael@0: /* vim: set shiftwidth=2 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: /* object that resolves CSS variables using specified and inherited variable
michael@0:  * values
michael@0:  */
michael@0: 
michael@0: #ifndef mozilla_CSSVariableResolver_h
michael@0: #define mozilla_CSSVariableResolver_h
michael@0: 
michael@0: #include "mozilla/DebugOnly.h"
michael@0: #include "nsCSSParser.h"
michael@0: #include "nsCSSScanner.h"
michael@0: #include "nsDataHashtable.h"
michael@0: #include "nsTArray.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: class CSSVariableDeclarations;
michael@0: class CSSVariableValues;
michael@0: class EnumerateVariableReferencesData;
michael@0: 
michael@0: class CSSVariableResolver
michael@0: {
michael@0:   friend class CSSVariableDeclarations;
michael@0:   friend class CSSVariableValues;
michael@0:   friend class EnumerateVariableReferencesData;
michael@0: public:
michael@0:   /**
michael@0:    * Creates a new CSSVariableResolver that will output a set of resolved,
michael@0:    * computed variables into aOutput.
michael@0:    */
michael@0:   CSSVariableResolver(CSSVariableValues* aOutput)
michael@0:     : mOutput(aOutput)
michael@0:     , mResolved(false)
michael@0:   {
michael@0:     MOZ_ASSERT(aOutput);
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Resolves the set of inherited variables from aInherited and the
michael@0:    * set of specified variables from aSpecified.  The resoled variables
michael@0:    * are written in to mOutput.
michael@0:    */
michael@0:   void Resolve(const CSSVariableValues* aInherited,
michael@0:                const CSSVariableDeclarations* aSpecified);
michael@0: 
michael@0: private:
michael@0:   struct Variable
michael@0:   {
michael@0:     Variable(const nsAString& aVariableName,
michael@0:              nsString aValue,
michael@0:              nsCSSTokenSerializationType aFirstToken,
michael@0:              nsCSSTokenSerializationType aLastToken,
michael@0:              bool aWasInherited)
michael@0:       : mVariableName(aVariableName)
michael@0:       , mValue(aValue)
michael@0:       , mFirstToken(aFirstToken)
michael@0:       , mLastToken(aLastToken)
michael@0:       , mWasInherited(aWasInherited)
michael@0:       , mResolved(false)
michael@0:       , mReferencesNonExistentVariable(false)
michael@0:       , mInStack(false)
michael@0:       , mIndex(0)
michael@0:       , mLowLink(0) { }
michael@0: 
michael@0:     nsString mVariableName;
michael@0:     nsString mValue;
michael@0:     nsCSSTokenSerializationType mFirstToken;
michael@0:     nsCSSTokenSerializationType mLastToken;
michael@0: 
michael@0:     // Whether this variable came from the set of inherited variables.
michael@0:     bool mWasInherited;
michael@0: 
michael@0:     // Whether this variable has been resolved yet.
michael@0:     bool mResolved;
michael@0: 
michael@0:     // Whether this variables includes any references to non-existent variables.
michael@0:     bool mReferencesNonExistentVariable;
michael@0: 
michael@0:     // Bookkeeping for the cycle remover algorithm.
michael@0:     bool mInStack;
michael@0:     size_t mIndex;
michael@0:     size_t mLowLink;
michael@0:   };
michael@0: 
michael@0:   /**
michael@0:    * Adds or modifies an existing entry in the set of variables to be resolved.
michael@0:    * This is intended to be called by the AddVariablesToResolver functions on
michael@0:    * the CSSVariableDeclarations and CSSVariableValues objects passed in to
michael@0:    * Resolve.
michael@0:    *
michael@0:    * @param aName The variable name (not including any "--" prefix that would
michael@0:    *   be part of the custom property name) whose value is to be set.
michael@0:    * @param aValue The variable value.
michael@0:    * @param aFirstToken The type of token at the start of the variable value.
michael@0:    * @param aLastToken The type of token at the en of the variable value.
michael@0:    * @param aWasInherited Whether this variable came from the set of inherited
michael@0:    *   variables.
michael@0:    */
michael@0:   void Put(const nsAString& aVariableName,
michael@0:            nsString aValue,
michael@0:            nsCSSTokenSerializationType aFirstToken,
michael@0:            nsCSSTokenSerializationType aLastToken,
michael@0:            bool aWasInherited);
michael@0: 
michael@0:   // Helper functions for Resolve.
michael@0:   void RemoveCycles(size_t aID);
michael@0:   void ResolveVariable(size_t aID);
michael@0: 
michael@0:   // A mapping of variable names to an ID that indexes into mVariables
michael@0:   // and mReferences.
michael@0:   nsDataHashtable<nsStringHashKey, size_t> mVariableIDs;
michael@0: 
michael@0:   // The set of variables.
michael@0:   nsTArray<Variable> mVariables;
michael@0: 
michael@0:   // The list of variables that each variable references.
michael@0:   nsTArray<nsTArray<size_t> > mReferences;
michael@0: 
michael@0:   // The next index to assign to a variable found during the cycle removing
michael@0:   // algorithm's traversal of the variable reference graph.
michael@0:   size_t mNextIndex;
michael@0: 
michael@0:   // Stack of variable IDs that we push to as we traverse the variable reference
michael@0:   // graph while looking for cycles.  Variable::mInStack reflects whether a
michael@0:   // given variable has its ID in mStack.
michael@0:   nsTArray<size_t> mStack;
michael@0: 
michael@0:   // CSS parser to use for parsing property values with variable references.
michael@0:   nsCSSParser mParser;
michael@0: 
michael@0:   // The object to output the resolved variables into.
michael@0:   CSSVariableValues* mOutput;
michael@0: 
michael@0:   // Whether Resolve has been called.
michael@0:   DebugOnly<bool> mResolved;
michael@0: };
michael@0: 
michael@0: }
michael@0: 
michael@0: #endif