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Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this
9 * list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
23 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <Kernel/FileSystem/Inode.h>
28#include <Kernel/FileSystem/InodeWatcher.h>
29
30namespace Kernel {
31
32NonnullRefPtr<InodeWatcher> InodeWatcher::create(Inode& inode)
33{
34 return adopt(*new InodeWatcher(inode));
35}
36
37InodeWatcher::InodeWatcher(Inode& inode)
38 : m_inode(inode.make_weak_ptr())
39{
40 inode.register_watcher({}, *this);
41}
42
43InodeWatcher::~InodeWatcher()
44{
45 if (RefPtr<Inode> safe_inode = m_inode.ptr())
46 safe_inode->unregister_watcher({}, *this);
47}
48
49bool InodeWatcher::can_read(const FileDescription&) const
50{
51 return !m_queue.is_empty() || !m_inode;
52}
53
54bool InodeWatcher::can_write(const FileDescription&) const
55{
56 return true;
57}
58
59ssize_t InodeWatcher::read(FileDescription&, u8* buffer, ssize_t buffer_size)
60{
61 ASSERT(!m_queue.is_empty() || !m_inode);
62
63 if (!m_inode)
64 return 0;
65
66 // FIXME: What should we do if the output buffer is too small?
67 ASSERT(buffer_size >= (int)sizeof(Event));
68 auto event = m_queue.dequeue();
69 memcpy(buffer, &event, sizeof(event));
70 return sizeof(event);
71}
72
73ssize_t InodeWatcher::write(FileDescription&, const u8*, ssize_t)
74{
75 return -EIO;
76}
77
78String InodeWatcher::absolute_path(const FileDescription&) const
79{
80 if (!m_inode)
81 return "InodeWatcher:(gone)";
82 return String::format("InodeWatcher:%s", m_inode->identifier().to_string().characters());
83}
84
85void InodeWatcher::notify_inode_event(Badge<Inode>, Event::Type event_type)
86{
87 m_queue.enqueue({ event_type });
88}
89
90}