1 | /* Provide relocatable packages. |
2 | Copyright (C) 2003, 2005, 2008-2019 Free Software Foundation, Inc. |
3 | Written by Bruno Haible <bruno@clisp.org>, 2003. |
4 | |
5 | This program is free software: you can redistribute it and/or modify |
6 | it under the terms of the GNU General Public License as published by |
7 | the Free Software Foundation; either version 3 of the License, or |
8 | (at your option) any later version. |
9 | |
10 | This program is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
13 | GNU General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU General Public License |
16 | along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
17 | |
18 | #ifndef _RELOCATABLE_H |
19 | #define _RELOCATABLE_H |
20 | |
21 | #ifdef __cplusplus |
22 | extern "C" { |
23 | #endif |
24 | |
25 | |
26 | /* This can be enabled through the configure --enable-relocatable option. */ |
27 | #if ENABLE_RELOCATABLE |
28 | |
29 | /* When building a DLL, we must export some functions. Note that because |
30 | this is a private .h file, we don't need to use __declspec(dllimport) |
31 | in any case. */ |
32 | #if HAVE_VISIBILITY && BUILDING_DLL |
33 | # define RELOCATABLE_DLL_EXPORTED __attribute__((__visibility__("default"))) |
34 | #elif defined _MSC_VER && BUILDING_DLL |
35 | # define RELOCATABLE_DLL_EXPORTED __declspec(dllexport) |
36 | #else |
37 | # define RELOCATABLE_DLL_EXPORTED |
38 | #endif |
39 | |
40 | /* Sets the original and the current installation prefix of the package. |
41 | Relocation simply replaces a pathname starting with the original prefix |
42 | by the corresponding pathname with the current prefix instead. Both |
43 | prefixes should be directory names without trailing slash (i.e. use "" |
44 | instead of "/"). */ |
45 | extern RELOCATABLE_DLL_EXPORTED void |
46 | set_relocation_prefix (const char *orig_prefix, |
47 | const char *curr_prefix); |
48 | |
49 | /* Returns the pathname, relocated according to the current installation |
50 | directory. |
51 | The returned string is either PATHNAME unmodified or a freshly allocated |
52 | string that you can free with free() after casting it to 'char *'. */ |
53 | extern const char * relocate (const char *pathname); |
54 | |
55 | /* Returns the pathname, relocated according to the current installation |
56 | directory. |
57 | This function sets *ALLOCATEDP to the allocated memory, or to NULL if |
58 | no memory allocation occurs. So that, after you're done with the return |
59 | value, to reclaim allocated memory, you can do: free (*ALLOCATEDP). */ |
60 | extern const char * relocate2 (const char *pathname, char **allocatedp); |
61 | |
62 | /* Memory management: relocate() potentially allocates memory, because it has |
63 | to construct a fresh pathname. If this is a problem because your program |
64 | calls relocate() frequently or because you want to fix all potential memory |
65 | leaks anyway, you have three options: |
66 | 1) Use this idiom: |
67 | const char *pathname = ...; |
68 | const char *rel_pathname = relocate (pathname); |
69 | ... |
70 | if (rel_pathname != pathname) |
71 | free ((char *) rel_pathname); |
72 | 2) Use this idiom: |
73 | char *allocated; |
74 | const char *rel_pathname = relocate2 (..., &allocated); |
75 | ... |
76 | free (allocated); |
77 | 3) Think about caching the result. */ |
78 | |
79 | /* Convenience function: |
80 | Computes the current installation prefix, based on the original |
81 | installation prefix, the original installation directory of a particular |
82 | file, and the current pathname of this file. |
83 | Returns it, freshly allocated. Returns NULL upon failure. */ |
84 | extern char * compute_curr_prefix (const char *orig_installprefix, |
85 | const char *orig_installdir, |
86 | const char *curr_pathname); |
87 | |
88 | #else |
89 | |
90 | /* By default, we use the hardwired pathnames. */ |
91 | #define relocate(pathname) (pathname) |
92 | #define relocate2(pathname,allocatedp) (*(allocatedp) = NULL, (pathname)) |
93 | |
94 | #endif |
95 | |
96 | |
97 | #ifdef __cplusplus |
98 | } |
99 | #endif |
100 | |
101 | #endif /* _RELOCATABLE_H */ |
102 | |