jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#include <AK/StdLibExtras.h>
8#include <Kernel/KBufferBuilder.h>
9
10namespace Kernel {
11
12inline bool KBufferBuilder::check_expand(size_t size)
13{
14 if (!m_buffer)
15 return false;
16 if ((m_size + size) < m_buffer->capacity())
17 return true;
18 if (Checked<size_t>::addition_would_overflow(m_size, size))
19 return false;
20 size_t new_buffer_size = m_size + size;
21 if (Checked<size_t>::addition_would_overflow(new_buffer_size, 1 * MiB))
22 return false;
23 auto rounded_new_buffer_size_or_error = Memory::page_round_up(new_buffer_size + 1 * MiB);
24 if (rounded_new_buffer_size_or_error.is_error()) {
25 return false;
26 }
27 auto new_buffer_or_error = KBuffer::try_create_with_size("KBufferBuilder"sv, rounded_new_buffer_size_or_error.value());
28 if (new_buffer_or_error.is_error())
29 return false;
30 auto new_buffer = new_buffer_or_error.release_value();
31 memcpy(new_buffer->data(), m_buffer->data(), m_buffer->size());
32 m_buffer = move(new_buffer);
33 return true;
34}
35
36bool KBufferBuilder::flush()
37{
38 if (!m_buffer)
39 return false;
40 m_buffer->set_size(m_size);
41 return true;
42}
43
44OwnPtr<KBuffer> KBufferBuilder::build()
45{
46 if (!flush())
47 return {};
48
49 return move(m_buffer);
50}
51
52ErrorOr<KBufferBuilder> KBufferBuilder::try_create()
53{
54 auto buffer = TRY(KBuffer::try_create_with_size("KBufferBuilder"sv, 4 * MiB, Memory::Region::Access::ReadWrite));
55 return KBufferBuilder { move(buffer) };
56}
57
58KBufferBuilder::KBufferBuilder(NonnullOwnPtr<KBuffer> buffer)
59 : m_buffer(move(buffer))
60{
61}
62
63ErrorOr<void> KBufferBuilder::append_bytes(ReadonlyBytes bytes)
64{
65 if (!check_expand(bytes.size()))
66 return ENOMEM;
67 memcpy(insertion_ptr(), bytes.data(), bytes.size());
68 m_size += bytes.size();
69 return {};
70}
71
72ErrorOr<void> KBufferBuilder::append(StringView str)
73{
74 if (str.is_empty())
75 return {};
76 if (!check_expand(str.length()))
77 return ENOMEM;
78 memcpy(insertion_ptr(), str.characters_without_null_termination(), str.length());
79 m_size += str.length();
80 return {};
81}
82
83ErrorOr<void> KBufferBuilder::append(char const* characters, int length)
84{
85 if (!length)
86 return {};
87 if (!check_expand(length))
88 return ENOMEM;
89 memcpy(insertion_ptr(), characters, length);
90 m_size += length;
91 return {};
92}
93
94ErrorOr<void> KBufferBuilder::append(char ch)
95{
96 if (!check_expand(1))
97 return ENOMEM;
98 insertion_ptr()[0] = ch;
99 m_size += 1;
100 return {};
101}
102
103ErrorOr<void> KBufferBuilder::append_escaped_for_json(StringView string)
104{
105 for (auto ch : string) {
106 switch (ch) {
107 case '\b':
108 TRY(append("\\b"sv));
109 break;
110 case '\n':
111 TRY(append("\\n"sv));
112 break;
113 case '\t':
114 TRY(append("\\t"sv));
115 break;
116 case '\"':
117 TRY(append("\\\""sv));
118 break;
119 case '\\':
120 TRY(append("\\\\"sv));
121 break;
122 default:
123 if (ch >= 0 && ch <= 0x1f)
124 TRY(appendff("\\u{:04x}", ch));
125 else
126 TRY(append(ch));
127 }
128 }
129 return {};
130}
131
132}