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
152
153
154
155
156
157
158
159
160
161
162
163
164
|
/* Copyright(C) 2019 MariaDB Corporation.
This program is free software; you can redistribute itand /or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111 - 1301 USA*/
#ifndef _WIN32
#include <unistd.h> /* pread(), pwrite() */
#endif
#include "tpool.h"
#include "tpool_structs.h"
#include <stdlib.h>
#include <string.h>
namespace tpool
{
#ifdef _WIN32
/*
In order to be able to execute synchronous IO even on file opened
with FILE_FLAG_OVERLAPPED, and to bypass to completion port,
we use valid event handle for the hEvent member of the OVERLAPPED structure,
with its low-order bit set.
See MSDN docs for GetQueuedCompletionStatus() for description of this trick.
*/
static DWORD fls_sync_io= FLS_OUT_OF_INDEXES;
HANDLE win_get_syncio_event()
{
HANDLE h;
h= (HANDLE) FlsGetValue(fls_sync_io);
if (h)
{
return h;
}
h= CreateEventA(NULL, FALSE, FALSE, NULL);
/* Set low-order bit to keeps I/O completion from being queued */
h= (HANDLE)((uintptr_t) h | 1);
FlsSetValue(fls_sync_io, h);
return h;
}
#include <WinIoCtl.h>
static void __stdcall win_free_syncio_event(void *data)
{
if (data)
{
CloseHandle((HANDLE) data);
}
}
struct WinIoInit
{
WinIoInit()
{
fls_sync_io= FlsAlloc(win_free_syncio_event);
if(fls_sync_io == FLS_OUT_OF_INDEXES)
abort();
}
~WinIoInit() { FlsFree(fls_sync_io); }
};
static WinIoInit win_io_init;
SSIZE_T pread(const native_file_handle &h, void *buf, size_t count,
unsigned long long offset)
{
OVERLAPPED ov{};
ULARGE_INTEGER uli;
uli.QuadPart= offset;
ov.Offset= uli.LowPart;
ov.OffsetHigh= uli.HighPart;
ov.hEvent= win_get_syncio_event();
if (count > 0xFFFFFFFF)
count= 0xFFFFFFFF;
if (ReadFile(h, buf, (DWORD) count, 0, &ov) ||
(GetLastError() == ERROR_IO_PENDING))
{
DWORD n_bytes;
if (GetOverlappedResult(h, &ov, &n_bytes, TRUE))
return n_bytes;
}
return -1;
}
SSIZE_T pwrite(const native_file_handle &h, void *buf, size_t count,
unsigned long long offset)
{
OVERLAPPED ov{};
ULARGE_INTEGER uli;
uli.QuadPart= offset;
ov.Offset= uli.LowPart;
ov.OffsetHigh= uli.HighPart;
ov.hEvent= win_get_syncio_event();
if (count > 0xFFFFFFFF)
count= 0xFFFFFFFF;
if (WriteFile(h, buf, (DWORD) count, 0, &ov) ||
(GetLastError() == ERROR_IO_PENDING))
{
DWORD n_bytes;
if (GetOverlappedResult(h, &ov, &n_bytes, TRUE))
return n_bytes;
}
return -1;
}
#endif
/**
Simulated AIO.
Executes IO synchronously in worker pool
and then calls the completion routine.
*/
class simulated_aio : public aio
{
thread_pool *m_pool;
public:
simulated_aio(thread_pool *tp)
: m_pool(tp)
{
}
static void simulated_aio_callback(void *param)
{
aiocb *cb= (aiocb *) param;
synchronous(cb);
cb->m_internal_task.m_func= cb->m_callback;
thread_pool *pool= (thread_pool *)cb->m_internal;
pool->submit_task(&cb->m_internal_task);
}
virtual int submit_io(aiocb *aiocb) override
{
aiocb->m_internal_task.m_func = simulated_aio_callback;
aiocb->m_internal_task.m_arg = aiocb;
aiocb->m_internal_task.m_group = aiocb->m_group;
aiocb->m_internal = m_pool;
m_pool->submit_task(&aiocb->m_internal_task);
return 0;
}
virtual int bind(native_file_handle &fd) override { return 0; }
virtual int unbind(const native_file_handle &fd) override { return 0; }
};
aio *create_simulated_aio(thread_pool *tp)
{
return new simulated_aio(tp);
}
} // namespace tpool
|
