Alexandria 2.25.0
SDC-CH common library for the Euclid project
FileHandler.icpp
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1/*
2 * Copyright (C) 2012-2021 Euclid Science Ground Segment
3 *
4 * This library is free software; you can redistribute it and/or modify it under
5 * the terms of the GNU Lesser General Public License as published by the Free
6 * Software Foundation; either version 3.0 of the License, or (at your option)
7 * any later version.
8 *
9 * This library is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
11 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
12 * details.
13 *
14 * You should have received a copy of the GNU Lesser General Public License
15 * along with this library; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19#ifndef FILEHANDLER_IMPL
20#error "This file should not be included directly! Use FileHandler.h instead"
21#else
22
23namespace Euclid {
24namespace FilePool {
25
26template <typename TFD>
27auto FileHandler::getWriteAccessor(bool try_lock) -> std::unique_ptr<FileAccessor<TFD>> {
28 auto manager = m_file_manager.lock();
29 assert(manager);
30
31 UniqueLock unique_lock(m_file_mutex, boost::defer_lock);
32 if (try_lock && !unique_lock.try_lock()) {
33 return nullptr;
34 } else {
35 unique_lock.lock();
36 }
37
38 std::unique_ptr<FdWrapper> fd_ptr;
39 {
40 std::unique_lock<std::mutex> this_lock(m_handler_mutex);
41
42 // If we have changed mode, we need to close all existing fd
43 if (m_is_readonly) {
44 for (auto& fd : m_available_fd) {
45 fd.second->close();
46 }
47 m_available_fd.clear();
48 m_is_readonly = false;
49 }
50
51 assert(m_available_fd.size() <= 1);
52
53 // If there is one, but of a different type, close it
54 if (!m_available_fd.empty()) {
55 auto typed_ptr = dynamic_cast<TypedFdWrapper<TFD>*>(m_available_fd.begin()->second.get());
56 if (!typed_ptr) {
57 m_available_fd.clear();
58 }
59 }
60
61 // Open one file if we need
62 if (m_available_fd.empty()) {
63 this_lock.unlock();
64 auto fd = manager->open<TFD>(m_path, true, [this](FileManager::FileId id) { return this->close(id); });
65 this_lock.lock();
66 m_available_fd[fd.first].reset(new TypedFdWrapper<TFD>(fd.first, std::move(fd.second), manager.get()));
67 }
68
69 assert(m_available_fd.size() == 1);
70
71 // Build and return accessor
72 fd_ptr = std::move(m_available_fd.begin()->second);
73 m_available_fd.clear();
74 }
75
76 auto typed_ptr = dynamic_cast<TypedFdWrapper<TFD>*>(fd_ptr.get());
77 assert(typed_ptr != nullptr);
78 auto fd = std::move(typed_ptr->m_fd);
79 auto id = typed_ptr->m_id;
80
81 auto return_callback = [this, id, manager](TFD&& returned_fd) {
82 std::lock_guard<std::mutex> lambda_this_lock(m_handler_mutex);
83 m_available_fd[id] =
84 std::unique_ptr<TypedFdWrapper<TFD>>(new TypedFdWrapper<TFD>(id, std::move(returned_fd), manager.get()));
85 };
86
87 manager->notifyUsed(id);
88 return std::unique_ptr<FileWriteAccessor<TFD>>(
89 new FileWriteAccessor<TFD>(std::move(fd), return_callback, std::move(unique_lock)));
90}
91
92template <typename TFD>
93auto FileHandler::getReadAccessor(bool try_lock) -> std::unique_ptr<FileAccessor<TFD>> {
94 auto manager = m_file_manager.lock();
95 assert(manager);
96
97 SharedLock shared_lock(m_file_mutex, boost::defer_lock);
98 if (try_lock && !shared_lock.try_lock()) {
99 return nullptr;
100 } else {
101 shared_lock.lock();
102 }
103
104 std::unique_ptr<FdWrapper> fd_ptr = nullptr;
105 {
106 std::unique_lock<std::mutex> this_lock(m_handler_mutex);
107
108 // If we have changed mode, we need to close all existing fd
109 if (!m_is_readonly) {
110 for (auto& fd : m_available_fd) {
111 fd.second->close();
112 }
113 m_available_fd.clear();
114 m_is_readonly = true;
115 }
116
117 // Find the first with a matching type
118 auto avail_i = m_available_fd.begin();
119 TypedFdWrapper<TFD>* typed_ptr = nullptr;
120 while (typed_ptr == nullptr && avail_i != m_available_fd.end()) {
121 if ((typed_ptr = dynamic_cast<TypedFdWrapper<TFD>*>(avail_i->second.get())) == nullptr)
122 ++avail_i;
123 }
124
125 // Open one file if we need
126 if (!typed_ptr) {
127 this_lock.unlock();
128 auto fd = manager->open<TFD>(m_path, false, [this](FileManager::FileId id) { return this->close(id); });
129 typed_ptr = new TypedFdWrapper<TFD>(fd.first, std::move(fd.second), manager.get());
130 this_lock.lock();
131 avail_i = m_available_fd.emplace(fd.first, std::unique_ptr<TypedFdWrapper<TFD>>(typed_ptr)).first;
132 }
133
134 assert(typed_ptr && avail_i != m_available_fd.end());
135
136 fd_ptr = std::move(avail_i->second);
137 m_available_fd.erase(avail_i);
138 }
139
140 // Build and return accessor
141 TypedFdWrapper<TFD>* typed_ptr = dynamic_cast<TypedFdWrapper<TFD>*>(fd_ptr.get());
142 assert(typed_ptr != nullptr);
143 auto fd = std::move(typed_ptr->m_fd);
144 auto id = typed_ptr->m_id;
145
146 auto return_callback = [this, id, manager](TFD&& returned_fd) {
147 std::lock_guard<std::mutex> lambda_this_lock(m_handler_mutex);
148 m_available_fd[id] =
149 std::unique_ptr<TypedFdWrapper<TFD>>(new TypedFdWrapper<TFD>(id, std::move(returned_fd), manager.get()));
150 };
151
152 manager->notifyUsed(id);
153 return std::unique_ptr<FileReadAccessor<TFD>>(
154 new FileReadAccessor<TFD>(std::move(fd), return_callback, std::move(shared_lock)));
155}
156
157template <typename TFD>
158auto FileHandler::getAccessor(Mode mode) -> std::unique_ptr<FileAccessor<TFD>> {
159 bool write_bool = mode & kWrite;
160 bool try_bool = mode & kTry;
161
162 if (write_bool) {
163 return getWriteAccessor<TFD>(try_bool);
164 }
165 return getReadAccessor<TFD>(try_bool);
166}
167
168} // namespace FilePool
169} // namespace Euclid
170
171#endif