tor-browser

The Tor Browser
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Relation.h (2620B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef mozilla_a11y_relation_h_
      8 #define mozilla_a11y_relation_h_
      9 
     10 #include "AccIterator.h"
     11 
     12 #include <memory>
     13 
     14 namespace mozilla {
     15 namespace a11y {
     16 
     17 /**
     18 * A collection of relation targets of a certain type.  Targets are computed
     19 * lazily while enumerating.
     20 */
     21 class Relation {
     22 public:
     23  Relation() : mFirstIter(nullptr), mLastIter(nullptr) {}
     24 
     25  explicit Relation(AccIterable* aIter) : mFirstIter(aIter), mLastIter(aIter) {}
     26 
     27  explicit Relation(Accessible* aAcc)
     28      : mFirstIter(nullptr), mLastIter(nullptr) {
     29    AppendTarget(aAcc);
     30  }
     31 
     32  Relation(DocAccessible* aDocument, nsIContent* aContent)
     33      : mFirstIter(nullptr), mLastIter(nullptr) {
     34    AppendTarget(aDocument, aContent);
     35  }
     36 
     37  Relation(Relation&& aOther)
     38      : mFirstIter(std::move(aOther.mFirstIter)), mLastIter(aOther.mLastIter) {
     39    aOther.mLastIter = nullptr;
     40  }
     41 
     42  Relation& operator=(Relation&& aRH) {
     43    mFirstIter = std::move(aRH.mFirstIter);
     44    mLastIter = aRH.mLastIter;
     45    aRH.mLastIter = nullptr;
     46    return *this;
     47  }
     48 
     49  inline void AppendIter(AccIterable* aIter) {
     50    if (mLastIter) {
     51      mLastIter->mNextIter.reset(aIter);
     52    } else {
     53      mFirstIter.reset(aIter);
     54    }
     55 
     56    mLastIter = aIter;
     57  }
     58 
     59  /**
     60   * Append the given accessible to the set of related accessibles.
     61   */
     62  inline void AppendTarget(Accessible* aAcc) {
     63    if (aAcc) AppendIter(new SingleAccIterator(aAcc));
     64  }
     65 
     66  /**
     67   * Append the one accessible for this content node to the set of related
     68   * accessibles.
     69   */
     70  void AppendTarget(DocAccessible* aDocument, nsIContent* aContent) {
     71    if (aContent) AppendTarget(aDocument->GetAccessible(aContent));
     72  }
     73 
     74  /**
     75   * compute and return the next related accessible.
     76   */
     77  inline Accessible* Next() {
     78    Accessible* target = nullptr;
     79 
     80    while (mFirstIter && !(target = mFirstIter->Next())) {
     81      mFirstIter = std::move(mFirstIter->mNextIter);
     82    }
     83 
     84    if (!mFirstIter) mLastIter = nullptr;
     85 
     86    return target;
     87  }
     88 
     89  inline LocalAccessible* LocalNext() {
     90    Accessible* next = Next();
     91    return next ? next->AsLocal() : nullptr;
     92  }
     93 
     94 private:
     95  Relation& operator=(const Relation&) = delete;
     96  Relation(const Relation&) = delete;
     97 
     98  std::unique_ptr<AccIterable> mFirstIter;
     99  AccIterable* mLastIter;
    100 };
    101 
    102 }  // namespace a11y
    103 }  // namespace mozilla
    104 
    105 #endif