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e2ab7927 MV |
1 | /* extensions.c - registering and loading extensions. |
2 | * | |
08969a24 | 3 | * Copyright (C) 2001, 2006, 2009, 2010, 2011 Free Software Foundation, Inc. |
e2ab7927 | 4 | * |
73be1d9e | 5 | * This library is free software; you can redistribute it and/or |
53befeb7 NJ |
6 | * modify it under the terms of the GNU Lesser General Public License |
7 | * as published by the Free Software Foundation; either version 3 of | |
8 | * the License, or (at your option) any later version. | |
e2ab7927 | 9 | * |
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10 | * This library is distributed in the hope that it will be useful, but |
11 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
73be1d9e MV |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | * Lesser General Public License for more details. | |
e2ab7927 | 14 | * |
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15 | * You should have received a copy of the GNU Lesser General Public |
16 | * License along with this library; if not, write to the Free Software | |
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17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
18 | * 02110-1301 USA | |
73be1d9e | 19 | */ |
e2ab7927 | 20 | |
dbb605f5 | 21 | #ifdef HAVE_CONFIG_H |
c0fc1089 RB |
22 | # include <config.h> |
23 | #endif | |
24 | ||
fbbdb121 GH |
25 | #include <string.h> |
26 | ||
e2ab7927 MV |
27 | #include "libguile/_scm.h" |
28 | #include "libguile/strings.h" | |
29 | #include "libguile/gc.h" | |
30 | #include "libguile/dynl.h" | |
4695c759 | 31 | #include "libguile/dynwind.h" |
e2ab7927 MV |
32 | |
33 | #include "libguile/extensions.h" | |
34 | ||
1be6b49c ML |
35 | typedef struct extension_t |
36 | { | |
37 | struct extension_t *next; | |
e2ab7927 MV |
38 | const char *lib; |
39 | const char *init; | |
40 | void (*func)(void *); | |
41 | void *data; | |
1be6b49c | 42 | } extension_t; |
e2ab7927 | 43 | |
f45eccff | 44 | static extension_t *registered_extensions = NULL; |
877514da | 45 | static scm_i_pthread_mutex_t ext_lock = SCM_I_PTHREAD_MUTEX_INITIALIZER; |
e2ab7927 | 46 | |
bef38a17 MV |
47 | /* Register a LIB/INIT pair for use by `scm_load_extension'. LIB is |
48 | allowed to be NULL and then only INIT is used to identify the | |
49 | registered entry. This is useful when you don't know the library | |
50 | name (which isn't really relevant anyway in a completely linked | |
51 | program) and you are sure that INIT is unique (which it must be for | |
52 | static linking). Hmm, given this reasoning, what use is LIB | |
53 | anyway? | |
54 | */ | |
55 | ||
e2ab7927 MV |
56 | void |
57 | scm_c_register_extension (const char *lib, const char *init, | |
58 | void (*func) (void *), void *data) | |
59 | { | |
4c9419ac | 60 | extension_t *ext = scm_malloc (sizeof(extension_t)); |
bef38a17 | 61 | if (lib) |
4c9419ac | 62 | ext->lib = scm_strdup (lib); |
bef38a17 MV |
63 | else |
64 | ext->lib = NULL; | |
4c9419ac | 65 | ext->init = scm_strdup (init); |
e2ab7927 MV |
66 | ext->func = func; |
67 | ext->data = data; | |
68 | ||
877514da | 69 | scm_i_pthread_mutex_lock (&ext_lock); |
e2ab7927 MV |
70 | ext->next = registered_extensions; |
71 | registered_extensions = ext; | |
877514da | 72 | scm_i_pthread_mutex_unlock (&ext_lock); |
e2ab7927 MV |
73 | } |
74 | ||
75 | static void | |
76 | load_extension (SCM lib, SCM init) | |
77 | { | |
877514da AW |
78 | extension_t *head; |
79 | ||
80 | scm_i_pthread_mutex_lock (&ext_lock); | |
81 | head = registered_extensions; | |
82 | scm_i_pthread_mutex_unlock (&ext_lock); | |
83 | ||
e2ab7927 | 84 | /* Search the registry. */ |
877514da | 85 | if (head != NULL) |
4695c759 MV |
86 | { |
87 | extension_t *ext; | |
88 | char *clib, *cinit; | |
a5fc6570 | 89 | int found = 0; |
4695c759 | 90 | |
661ae7ab | 91 | scm_dynwind_begin (0); |
4695c759 MV |
92 | |
93 | clib = scm_to_locale_string (lib); | |
661ae7ab | 94 | scm_dynwind_free (clib); |
4695c759 | 95 | cinit = scm_to_locale_string (init); |
661ae7ab | 96 | scm_dynwind_free (cinit); |
4695c759 | 97 | |
877514da | 98 | for (ext = head; ext; ext = ext->next) |
4695c759 MV |
99 | if ((ext->lib == NULL || !strcmp (ext->lib, clib)) |
100 | && !strcmp (ext->init, cinit)) | |
101 | { | |
102 | ext->func (ext->data); | |
a5fc6570 | 103 | found = 1; |
4695c759 MV |
104 | break; |
105 | } | |
106 | ||
661ae7ab | 107 | scm_dynwind_end (); |
a5fc6570 AW |
108 | |
109 | if (found) | |
110 | return; | |
4695c759 | 111 | } |
e2ab7927 MV |
112 | |
113 | /* Dynamically link the library. */ | |
08969a24 | 114 | #if HAVE_MODULES |
e2ab7927 | 115 | scm_dynamic_call (init, scm_dynamic_link (lib)); |
08969a24 AW |
116 | #else |
117 | scm_misc_error ("load-extension", | |
118 | "extension ~S:~S not registered and dynamic-link disabled", | |
119 | scm_list_2 (init, lib)); | |
120 | #endif | |
e2ab7927 MV |
121 | } |
122 | ||
123 | void | |
124 | scm_c_load_extension (const char *lib, const char *init) | |
125 | { | |
4695c759 | 126 | load_extension (scm_from_locale_string (lib), scm_from_locale_string (init)); |
e2ab7927 MV |
127 | } |
128 | ||
129 | SCM_DEFINE (scm_load_extension, "load-extension", 2, 0, 0, | |
130 | (SCM lib, SCM init), | |
72dd0a03 | 131 | "Load and initialize the extension designated by LIB and INIT.\n" |
9401323e NJ |
132 | "When there is no pre-registered function for LIB/INIT, this is\n" |
133 | "equivalent to\n" | |
134 | "\n" | |
135 | "@lisp\n" | |
136 | "(dynamic-call INIT (dynamic-link LIB))\n" | |
137 | "@end lisp\n" | |
138 | "\n" | |
139 | "When there is a pre-registered function, that function is called\n" | |
140 | "instead.\n" | |
141 | "\n" | |
142 | "Normally, there is no pre-registered function. This option exists\n" | |
143 | "only for situations where dynamic linking is unavailable or unwanted.\n" | |
144 | "In that case, you would statically link your program with the desired\n" | |
145 | "library, and register its init function right after Guile has been\n" | |
146 | "initialized.\n" | |
147 | "\n" | |
148 | "LIB should be a string denoting a shared library without any file type\n" | |
149 | "suffix such as \".so\". The suffix is provided automatically. It\n" | |
150 | "should also not contain any directory components. Libraries that\n" | |
151 | "implement Guile Extensions should be put into the normal locations for\n" | |
152 | "shared libraries. We recommend to use the naming convention\n" | |
153 | "libguile-bla-blum for a extension related to a module `(bla blum)'.\n" | |
154 | "\n" | |
155 | "The normal way for a extension to be used is to write a small Scheme\n" | |
156 | "file that defines a module, and to load the extension into this\n" | |
157 | "module. When the module is auto-loaded, the extension is loaded as\n" | |
158 | "well. For example,\n" | |
159 | "\n" | |
160 | "@lisp\n" | |
161 | "(define-module (bla blum))\n" | |
162 | "\n" | |
163 | "(load-extension \"libguile-bla-blum\" \"bla_init_blum\")\n" | |
164 | "@end lisp") | |
e2ab7927 MV |
165 | #define FUNC_NAME s_scm_load_extension |
166 | { | |
e2ab7927 MV |
167 | load_extension (lib, init); |
168 | return SCM_UNSPECIFIED; | |
169 | } | |
170 | #undef FUNC_NAME | |
171 | ||
172 | void | |
173 | scm_init_extensions () | |
174 | { | |
e2ab7927 | 175 | #include "libguile/extensions.x" |
e2ab7927 MV |
176 | } |
177 | ||
178 | /* | |
179 | Local Variables: | |
180 | c-file-style: "gnu" | |
181 | End: | |
182 | */ |