michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=2 et sw=2 tw=80: */
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: #ifndef mozilla_a11y_relation_h_
michael@0: #define mozilla_a11y_relation_h_
michael@0: 
michael@0: #include "AccIterator.h"
michael@0: 
michael@0: #include "mozilla/Move.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace a11y {
michael@0: 
michael@0: /**
michael@0:  * A collection of relation targets of a certain type.  Targets are computed
michael@0:  * lazily while enumerating.
michael@0:  */
michael@0: class Relation
michael@0: {
michael@0: public:
michael@0:   Relation() : mFirstIter(nullptr), mLastIter(nullptr) { }
michael@0: 
michael@0:   Relation(AccIterable* aIter) :
michael@0:     mFirstIter(aIter), mLastIter(aIter) { }
michael@0: 
michael@0:   Relation(Accessible* aAcc) :
michael@0:     mFirstIter(nullptr), mLastIter(nullptr)
michael@0:     { AppendTarget(aAcc); }
michael@0: 
michael@0:   Relation(DocAccessible* aDocument, nsIContent* aContent) :
michael@0:     mFirstIter(nullptr), mLastIter(nullptr)
michael@0:     { AppendTarget(aDocument, aContent); }
michael@0: 
michael@0:   Relation(Relation&& aOther) :
michael@0:     mFirstIter(Move(aOther.mFirstIter)), mLastIter(aOther.mLastIter)
michael@0:   {
michael@0:     aOther.mLastIter = nullptr;
michael@0:   }
michael@0: 
michael@0:   Relation& operator = (Relation&& aRH)
michael@0:   {
michael@0:     mFirstIter = Move(aRH.mFirstIter);
michael@0:     mLastIter = aRH.mLastIter;
michael@0:     aRH.mLastIter = nullptr;
michael@0:     return *this;
michael@0:   }
michael@0: 
michael@0:   inline void AppendIter(AccIterable* aIter)
michael@0:   {
michael@0:     if (mLastIter)
michael@0:       mLastIter->mNextIter = aIter;
michael@0:     else
michael@0:       mFirstIter = aIter;
michael@0: 
michael@0:     mLastIter = aIter;
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Append the given accessible to the set of related accessibles.
michael@0:    */
michael@0:   inline void AppendTarget(Accessible* aAcc)
michael@0:   {
michael@0:     if (aAcc)
michael@0:       AppendIter(new SingleAccIterator(aAcc));
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * Append the one accessible for this content node to the set of related
michael@0:    * accessibles.
michael@0:    */
michael@0:   void AppendTarget(DocAccessible* aDocument, nsIContent* aContent)
michael@0:   {
michael@0:     if (aContent)
michael@0:       AppendTarget(aDocument->GetAccessible(aContent));
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * compute and return the next related accessible.
michael@0:    */
michael@0:   inline Accessible* Next()
michael@0:   {
michael@0:     Accessible* target = nullptr;
michael@0: 
michael@0:     // a trick nsAutoPtr deletes what it used to point to when assigned to
michael@0:     while (mFirstIter && !(target = mFirstIter->Next()))
michael@0:       mFirstIter = mFirstIter->mNextIter;
michael@0: 
michael@0:     if (!mFirstIter)
michael@0:       mLastIter = nullptr;
michael@0: 
michael@0:     return target;
michael@0:   }
michael@0: 
michael@0: private:
michael@0:   Relation& operator = (const Relation&) MOZ_DELETE;
michael@0:   Relation(const Relation&) MOZ_DELETE;
michael@0: 
michael@0:   nsAutoPtr<AccIterable> mFirstIter;
michael@0:   AccIterable* mLastIter;
michael@0: };
michael@0: 
michael@0: } // namespace a11y
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif
michael@0: