[RFCv3 41/43] module: Create pa_module_exists()

[jprvita@xxxxxxxxx (jprvita@xxxxxxxxx)]

From: Jo?o Paulo Rechi Vita <jprvita@xxxxxxxxxxxxx>

This new function checks if a certain module name is available in the
system.
---
 src/pulsecore/module.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/pulsecore/module.h |  2 ++
 2 files changed, 51 insertions(+)

diff --git a/src/pulsecore/module.c b/src/pulsecore/module.c
index 16582b3..3708fae 100644
--- a/src/pulsecore/module.c
+++ b/src/pulsecore/module.c
@@ -28,6 +28,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <ltdl.h>
 
 #include <pulse/xmalloc.h>
 #include <pulse/proplist.h>
@@ -47,6 +48,54 @@
 #define PA_SYMBOL_GET_N_USED "pa__get_n_used"
 #define PA_SYMBOL_GET_DEPRECATE "pa__get_deprecated"
 
+bool pa_module_exists(const char *name) {
+    const char *paths, *state = NULL;
+    char *p, *pathname;
+    bool result;
+
+    pa_assert(name);
+
+    if (name[0] == PA_PATH_SEP_CHAR) {
+        result = access(name, F_OK) == 0 ? true : false;
+        pa_log_debug("Checking for existence of '%s': %s", name, result ? "success" : "failure");
+        if (result)
+            return true;
+    }
+
+    if (!(paths = lt_dlgetsearchpath()))
+        return false;
+
+    /* strip .so from the end of name, if present */
+    p = rindex(name, '.');
+    if (pa_streq(p, ".so"))
+        p[0] = 0;
+
+    while ((p = pa_split(paths, ":", &state))) {
+        pathname = pa_sprintf_malloc("%s" PA_PATH_SEP "%s.so", p, name);
+        result = access(pathname, F_OK) == 0 ? true : false;
+        pa_log_debug("Checking for existence of '%s': %s", pathname, result ? "success" : "failure");
+        pa_xfree(pathname);
+        pa_xfree(p);
+        if (result)
+            return true;
+    }
+
+    state = NULL;
+    if (PA_UNLIKELY(pa_run_from_build_tree())) {
+        while ((p = pa_split(paths, ":", &state))) {
+            pathname = pa_sprintf_malloc("%s" PA_PATH_SEP ".libs" PA_PATH_SEP "%s.so", p, name);
+            result = access(pathname, F_OK) == 0 ? true : false;
+            pa_log_debug("Checking for existence of '%s': %s", pathname, result ? "success" : "failure");
+            pa_xfree(pathname);
+            pa_xfree(p);
+            if (result)
+                return true;
+        }
+    }
+
+    return false;
+}
+
 pa_module* pa_module_load(pa_core *c, const char *name, const char *argument) {
     pa_module *m = NULL;
     bool (*load_once)(void);
diff --git a/src/pulsecore/module.h b/src/pulsecore/module.h
index 5a330c6..af4e9d2 100644
--- a/src/pulsecore/module.h
+++ b/src/pulsecore/module.h
@@ -50,6 +50,8 @@ struct pa_module {
     pa_proplist *proplist;
 };
 
+bool pa_module_exists(const char *name);
+
 pa_module* pa_module_load(pa_core *c, const char *name, const char *argument);
 
 void pa_module_unload(pa_core *c, pa_module *m, bool force);
-- 
1.8.3.1