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
|
------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- G N A T . L O C K _ F I L E S --
-- --
-- B o d y --
-- --
-- Copyright (C) 1998-2018, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with System;
package body GNAT.Lock_Files is
Dir_Separator : Character;
pragma Import (C, Dir_Separator, "__gnat_dir_separator");
---------------
-- Lock_File --
---------------
procedure Lock_File
(Directory : Path_Name;
Lock_File_Name : Path_Name;
Wait : Duration := 1.0;
Retries : Natural := Natural'Last)
is
Dir : aliased String := Directory & ASCII.NUL;
File : aliased String := Lock_File_Name & ASCII.NUL;
function Try_Lock (Dir, File : System.Address) return Integer;
pragma Import (C, Try_Lock, "__gnat_try_lock");
begin
-- If a directory separator was provided, just remove the one we have
-- added above.
if Directory (Directory'Last) = Dir_Separator
or else Directory (Directory'Last) = '/'
then
Dir (Dir'Last - 1) := ASCII.NUL;
end if;
-- Try to lock the file Retries times
for I in 0 .. Retries loop
if Try_Lock (Dir'Address, File'Address) = 1 then
return;
end if;
exit when I = Retries;
delay Wait;
end loop;
raise Lock_Error;
end Lock_File;
---------------
-- Lock_File --
---------------
procedure Lock_File
(Lock_File_Name : Path_Name;
Wait : Duration := 1.0;
Retries : Natural := Natural'Last)
is
begin
for J in reverse Lock_File_Name'Range loop
if Lock_File_Name (J) = Dir_Separator
or else Lock_File_Name (J) = '/'
then
Lock_File
(Lock_File_Name (Lock_File_Name'First .. J - 1),
Lock_File_Name (J + 1 .. Lock_File_Name'Last),
Wait,
Retries);
return;
end if;
end loop;
Lock_File (".", Lock_File_Name, Wait, Retries);
end Lock_File;
-----------------
-- Unlock_File --
-----------------
procedure Unlock_File (Lock_File_Name : Path_Name) is
S : aliased String := Lock_File_Name & ASCII.NUL;
procedure unlink (A : System.Address);
pragma Import (C, unlink, "unlink");
begin
unlink (S'Address);
end Unlock_File;
-----------------
-- Unlock_File --
-----------------
procedure Unlock_File (Directory : Path_Name; Lock_File_Name : Path_Name) is
begin
if Directory (Directory'Last) = Dir_Separator
or else Directory (Directory'Last) = '/'
then
Unlock_File (Directory & Lock_File_Name);
else
Unlock_File (Directory & Dir_Separator & Lock_File_Name);
end if;
end Unlock_File;
end GNAT.Lock_Files;
|
