| 1 | /* |
|---|---|
| 2 | This file is part of the KDE Baloo project. |
| 3 | SPDX-FileCopyrightText: 2015 Vishesh Handa <vhanda@kde.org> |
| 4 | |
| 5 | SPDX-License-Identifier: LGPL-2.1-or-later |
| 6 | */ |
| 7 | |
| 8 | #include "orpostingiterator.h" |
| 9 | |
| 10 | using namespace Baloo; |
| 11 | |
| 12 | OrPostingIterator::OrPostingIterator(const QVector<PostingIterator*>& iterators) |
| 13 | : m_iterators(iterators) |
| 14 | , m_docId(0) |
| 15 | , m_nextId(0) |
| 16 | { |
| 17 | /* |
| 18 | * Check for null iterators |
| 19 | * Preferably, these are not pushed to the list at all, but better be safe |
| 20 | */ |
| 21 | m_iterators.removeAll(t: nullptr); |
| 22 | |
| 23 | for (PostingIterator* iter : std::as_const(t&: m_iterators)) { |
| 24 | auto docId = iter->next(); |
| 25 | // find smallest docId |
| 26 | if (docId && (docId < m_nextId || m_nextId == 0)) { |
| 27 | m_nextId = docId; |
| 28 | } |
| 29 | } |
| 30 | } |
| 31 | |
| 32 | OrPostingIterator::~OrPostingIterator() |
| 33 | { |
| 34 | qDeleteAll(c: m_iterators); |
| 35 | } |
| 36 | |
| 37 | quint64 OrPostingIterator::docId() const |
| 38 | { |
| 39 | return m_docId; |
| 40 | } |
| 41 | |
| 42 | quint64 OrPostingIterator::skipTo(quint64 id) |
| 43 | { |
| 44 | if (m_docId >= id) { |
| 45 | return m_docId; |
| 46 | } |
| 47 | if (m_nextId == 0) { |
| 48 | m_docId = m_nextId; |
| 49 | return 0; |
| 50 | } |
| 51 | |
| 52 | if (id > m_nextId) { |
| 53 | // Fast forward - move all iterators to the lowest position |
| 54 | // greater or equal to id |
| 55 | m_nextId = 0; |
| 56 | for (PostingIterator* iter : std::as_const(t&: m_iterators)) { |
| 57 | auto docId = iter->skipTo(docId: id); |
| 58 | if (docId > 0) { |
| 59 | if (docId < m_nextId || !m_nextId) { |
| 60 | m_nextId = docId; |
| 61 | } |
| 62 | } |
| 63 | } |
| 64 | if (m_nextId == 0) { |
| 65 | m_docId = m_nextId; |
| 66 | return 0; |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | m_docId = m_nextId; |
| 71 | m_nextId = 0; |
| 72 | |
| 73 | // advance all iterators which point to the lowest docId |
| 74 | for (PostingIterator*& iter : m_iterators) { |
| 75 | auto docId = iter->docId(); |
| 76 | if (docId == m_docId) { |
| 77 | docId = iter->next(); |
| 78 | } |
| 79 | |
| 80 | if (docId == 0) { |
| 81 | // remove element if iterator has reached the end |
| 82 | delete iter; |
| 83 | iter = nullptr; |
| 84 | } else { |
| 85 | // check if the docId is the new lowest docId |
| 86 | if (docId < m_nextId || !m_nextId) { |
| 87 | m_nextId = docId; |
| 88 | } |
| 89 | } |
| 90 | } |
| 91 | auto tail = std::remove_if(first: m_iterators.begin(), last: m_iterators.end(), |
| 92 | pred: [](const PostingIterator* it) { return it == nullptr; }); |
| 93 | m_iterators.erase(abegin: tail, aend: m_iterators.end()); |
| 94 | |
| 95 | return m_docId; |
| 96 | } |
| 97 | |
| 98 | quint64 OrPostingIterator::next() |
| 99 | { |
| 100 | if (m_nextId) { |
| 101 | m_docId = skipTo(id: m_nextId); |
| 102 | } else { |
| 103 | m_docId = 0; |
| 104 | } |
| 105 | return m_docId; |
| 106 | } |
| 107 |