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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 <AK/Memory.h>
28#include <Kernel/FileSystem/Inode.h>
29#include <Kernel/FileSystem/InodeWatcher.h>
30
31namespace Kernel {
32
33NonnullRefPtr<InodeWatcher> InodeWatcher::create(Inode& inode)
34{
35 return adopt(*new InodeWatcher(inode));
36}
37
38InodeWatcher::InodeWatcher(Inode& inode)
39 : m_inode(inode.make_weak_ptr())
40{
41 inode.register_watcher({}, *this);
42}
43
44InodeWatcher::~InodeWatcher()
45{
46 if (RefPtr<Inode> safe_inode = m_inode.ptr())
47 safe_inode->unregister_watcher({}, *this);
48}
49
50bool InodeWatcher::can_read(const FileDescription&) const
51{
52 return !m_queue.is_empty() || !m_inode;
53}
54
55bool InodeWatcher::can_write(const FileDescription&) const
56{
57 return true;
58}
59
60ssize_t InodeWatcher::read(FileDescription&, u8* buffer, ssize_t buffer_size)
61{
62 ASSERT(!m_queue.is_empty() || !m_inode);
63
64 if (!m_inode)
65 return 0;
66
67 // FIXME: What should we do if the output buffer is too small?
68 ASSERT(buffer_size >= (int)sizeof(Event));
69 auto event = m_queue.dequeue();
70 memcpy(buffer, &event, sizeof(event));
71 return sizeof(event);
72}
73
74ssize_t InodeWatcher::write(FileDescription&, const u8*, ssize_t)
75{
76 return -EIO;
77}
78
79String InodeWatcher::absolute_path(const FileDescription&) const
80{
81 if (!m_inode)
82 return "InodeWatcher:(gone)";
83 return String::format("InodeWatcher:%s", m_inode->identifier().to_string().characters());
84}
85
86void InodeWatcher::notify_inode_event(Badge<Inode>, Event::Type event_type)
87{
88 m_queue.enqueue({ event_type });
89}
90
91}