1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
|
/*
* cat.c
*
* Copyright 2022 Christian Hergert <chergert@redhat.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, see <http://www.gnu.org/licenses/>.
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
#include <unistd.h>
#include <gio/gio.h>
#include <gio/gunixinputstream.h>
#include <gio/gunixoutputstream.h>
#include "cat-util.h"
/* NOTE:
*
* `cat` from coreutils is certainly faster than this, especially if you're
* doing things like `./examples/cat foo > bar` as it will use
* copy_file_range() to avoid reading into userspace.
*
* `gio cat` is likely faster than this doing synchronous IO on the calling
* thread because it doesn't have to coordinate across thread pools.
*/
static DexFuture *
cat_read_fiber (gpointer user_data)
{
Cat *cat = user_data;
GInputStream *stream = g_unix_input_stream_new (cat->read_fd, FALSE);
Buffer *buffer = NULL;
for (;;)
{
Buffer *next;
/* Suspend while sending the buffer to the channel, which may
* help throttle reads if they get too far ahead of writes.
*/
if (buffer != NULL)
dex_await (dex_channel_send (cat->channel,
dex_future_new_for_pointer (g_steal_pointer (&buffer))),
NULL);
/* Get next buffer from the pool */
next = cat_pop_buffer (cat);
/* Suspend while reading into the buffer */
next->length = dex_await_int64 (dex_input_stream_read (stream,
next->data,
next->capacity,
G_PRIORITY_DEFAULT),
NULL);
/* If we got length <= 0, we failed or finished */
if (next->length <= 0)
{
dex_channel_close_send (cat->channel);
cat_push_buffer (cat, next);
break;
}
buffer = next;
}
/* Suspend while we close the stream */
dex_await (dex_input_stream_close (stream, 0), NULL);
g_object_unref (stream);
return dex_future_new_for_boolean (TRUE);
}
static DexFuture *
cat_write_fiber (gpointer user_data)
{
Cat *cat = user_data;
GOutputStream *stream = g_unix_output_stream_new (cat->write_fd, FALSE);
for (;;)
{
Buffer *buffer;
gssize len;
/* Suspend while we wait for another buffer (or error on channel closed) */
if (!(buffer = dex_await_pointer (dex_channel_receive (cat->channel), NULL)))
break;
/* Suspend while we write the buffer contents to output stream */
len = dex_await_int64 (dex_output_stream_write (G_OUTPUT_STREAM (stream),
buffer->data,
buffer->length,
G_PRIORITY_DEFAULT),
NULL);
/* Give the buffer back to the pool */
cat_push_buffer (cat, buffer);
/* Bail if we got a failure or empty buffer */
if (len <= 0)
break;
}
/* Asynchronously close the stream, which may cause flushing to occur. */
dex_await (dex_output_stream_close (stream, 0), NULL);
/* Release the stream, which should not block since it was closed above */
g_object_unref (stream);
return dex_future_new_for_boolean (TRUE);
}
int
main (int argc,
char *argv[])
{
GError *error = NULL;
Cat cat;
int ret = EXIT_SUCCESS;
dex_init ();
if (!cat_init (&cat, &argc, &argv, &error) ||
!cat_run (&cat,
dex_scheduler_spawn (NULL, 0, cat_read_fiber, &cat, NULL),
dex_scheduler_spawn (NULL, 0, cat_write_fiber, &cat, NULL),
&error))
{
g_printerr ("cat: %s\n", error->message);
g_clear_error (&error);
ret = EXIT_FAILURE;
}
cat_clear (&cat);
return ret;
}
|
