tag modules that may only be loaded once at most especially, and enforce that in the module loader

git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@2043 fefdeb5f-60dc-0310-8127-8f9354f1896f

src/pulsecore/modinfo.c

@@ -40,10 +40,12 @@
 #define PA_SYMBOL_DESCRIPTION "pa__get_description"
 #define PA_SYMBOL_USAGE "pa__get_usage"
 #define PA_SYMBOL_VERSION "pa__get_version"
+#define PA_SYMBOL_LOAD_ONCE "pa__load_once"
 
 pa_modinfo *pa_modinfo_get_by_handle(lt_dlhandle dl, const char *module_name) {
     pa_modinfo *i;
     const char* (*func)(void);
+    pa_bool_t (*func2) (void);
 
     pa_assert(dl);
 
@@ -61,6 +63,9 @@ pa_modinfo *pa_modinfo_get_by_handle(lt_dlhandle dl, const char *module_name) {
     if ((func = (const char* (*)(void)) pa_load_sym(dl, module_name, PA_SYMBOL_VERSION)))
         i->version = pa_xstrdup(func());
 
+    if ((func2 = (pa_bool_t (*)(void)) pa_load_sym(dl, module_name, PA_SYMBOL_LOAD_ONCE)))
+        i->load_once = func2();
+
     return i;
 }
 

src/pulsecore/modinfo.h

@@ -25,12 +25,14 @@
 ***/
 
 /* Some functions for reading module meta data from PulseAudio modules */
+#include <pulsecore/macro.h>
 
 typedef struct pa_modinfo {
     char *author;
     char *description;
     char *usage;
     char *version;
+    pa_bool_t load_once;
 } pa_modinfo;
 
 /* Read meta data from an libtool handle */

src/pulsecore/module.c

@@ -46,6 +46,7 @@
 
 #define PA_SYMBOL_INIT "pa__init"
 #define PA_SYMBOL_DONE "pa__done"
+#define PA_SYMBOL_LOAD_ONCE "pa__load_once"
 
 #define UNLOAD_POLL_TIME 2
 
@@ -66,6 +67,7 @@ static void timeout_callback(pa_mainloop_api *m, pa_time_event*e, PA_GCC_UNUSED
 
 pa_module* pa_module_load(pa_core *c, const char *name, const char *argument) {
     pa_module *m = NULL;
+    pa_bool_t (*load_once)(void);
 
     pa_assert(c);
     pa_assert(name);
@@ -82,6 +84,22 @@ pa_module* pa_module_load(pa_core *c, const char *name, const char *argument) {
         goto fail;
     }
 
+    if ((load_once = (pa_bool_t (*)(void)) pa_load_sym(m->dl, name, PA_SYMBOL_LOAD_ONCE))) {
+
+        if (load_once()) {
+            pa_module *i;
+            uint32_t idx;
+            /* OK, the module only wants to be loaded once, let's make sure it is */
+
+            for (i = pa_idxset_first(c->modules, &idx); i; i = pa_idxset_next(c->modules, &idx)) {
+                if (strcmp(name, i->name) == 0) {
+                    pa_log("Module \"%s\" should be loaded once at most. Refusing to load.", name);
+                    goto fail;
+                }
+            }
+        }
+    }
+
     if (!(m->init = (int (*)(pa_module*_m)) pa_load_sym(m->dl, name, PA_SYMBOL_INIT))) {
         pa_log("Failed to load module \"%s\": symbol \""PA_SYMBOL_INIT"\" not found.", name);
         goto fail;

src/pulsecore/module.h

@@ -62,10 +62,25 @@ void pa_module_unload_request(pa_module *m);
 
 void pa_module_set_used(pa_module*m, int used);
 
-#define PA_MODULE_AUTHOR(s) const char *pa__get_author(void) { return s; }
-#define PA_MODULE_DESCRIPTION(s) const char *pa__get_description(void) { return s; }
-#define PA_MODULE_USAGE(s) const char *pa__get_usage(void) { return s; }
-#define PA_MODULE_VERSION(s) const char * pa__get_version(void) { return s; }
+#define PA_MODULE_AUTHOR(s)                                     \
+    const char *pa__get_author(void) { return s; }              \
+    struct __stupid_useless_struct_to_allow_trailing_semicolon
+
+#define PA_MODULE_DESCRIPTION(s)                                \
+    const char *pa__get_description(void) { return s; }         \
+    struct __stupid_useless_struct_to_allow_trailing_semicolon
+
+#define PA_MODULE_USAGE(s)                                      \
+    const char *pa__get_usage(void) { return s; }               \
+    struct __stupid_useless_struct_to_allow_trailing_semicolon
+
+#define PA_MODULE_VERSION(s)                                    \
+    const char * pa__get_version(void) { return s; }            \
+    struct __stupid_useless_struct_to_allow_trailing_semicolon
+
+#define PA_MODULE_LOAD_ONCE(b)                                  \
+    pa_bool_t pa__load_once(void) { return b; }                 \
+    struct __stupid_useless_struct_to_allow_trailing_semicolon
 
 pa_modinfo *pa_module_get_info(pa_module *m);