girepository: Move library path functions over from gitypelib.c

This means they’re implemented in the same file as the typelib search
path, so it’s easier to refactor the code.

This adds `gi_repository_get_library_path()` to expose the library path,
both publicly and to internal users in `gitypelib.c`. And unit tests.

Signed-off-by: Philip Withnall <pwithnall@gnome.org>

girepository/girepository.c

@@ -77,6 +77,7 @@
 
 static GIRepository *default_repository = NULL;
 static GPtrArray *typelib_search_path = NULL;
+static GPtrArray *library_paths = NULL;  /* (element-type filename) (owned) */
 
 typedef struct {
   size_t n_interfaces;
@@ -241,6 +242,9 @@ init_globals (void)
       g_ptr_array_add (typelib_search_path, g_steal_pointer (&typelib_dir));
     }
 
+  if (library_paths == NULL)
+    library_paths = g_ptr_array_new_null_terminated (1, g_free, TRUE);
+
   g_once_init_leave (&initialized, 1);
 }
 
@@ -306,6 +310,67 @@ gi_repository_get_search_path (size_t *n_paths_out)
   return (const char * const *) typelib_search_path->pdata;
 }
 
+/**
+ * gi_repository_prepend_library_path:
+ * @directory: (type filename): a single directory to scan for shared libraries
+ *
+ * Prepends @directory to the search path that is used to
+ * search shared libraries referenced by imported namespaces.
+ *
+ * Multiple calls to this function all contribute to the final
+ * list of paths.
+ *
+ * The list of paths is unique and shared for all
+ * [class@GIRepository.Repository] instances across the process, but it doesn’t
+ * affect namespaces imported before the call.
+ *
+ * If the library is not found in the directories configured
+ * in this way, loading will fall back to the system library
+ * path (i.e. `LD_LIBRARY_PATH` and `DT_RPATH` in ELF systems).
+ * See the documentation of your dynamic linker for full details.
+ *
+ * Since: 2.80
+ */
+void
+gi_repository_prepend_library_path (const char *directory)
+{
+  init_globals ();
+  g_ptr_array_insert (library_paths, 0, g_strdup (directory));
+}
+
+/**
+ * gi_repository_get_library_path:
+ * @n_paths_out: (optional) (out): The number of library paths returned.
+ *
+ * Returns the current search path [class@GIRepository.Repository] will use when
+ * loading shared libraries referenced by imported namespaces.
+ *
+ * The list is internal to [class@GIRepository.Repository] and should not be
+ * freed, nor should its string elements.
+ *
+ * Returns: (element-type filename) (transfer none) (array length=n_paths_out): list of search paths, most
+ *   important first
+ * Since: 2.80
+ */
+const char * const *
+gi_repository_get_library_path (size_t *n_paths_out)
+{
+  if G_UNLIKELY (!library_paths || !library_paths->pdata)
+    {
+      static const char * const empty_search_path[] = {NULL};
+
+      if (n_paths_out)
+        *n_paths_out = 0;
+
+      return empty_search_path;
+    }
+
+  if (n_paths_out)
+    *n_paths_out = library_paths->len;
+
+  return (const char * const *) library_paths->pdata;
+}
+
 static char *
 build_typelib_key (const char *name, const char *source)
 {

girepository/girepository.h

@@ -91,6 +91,9 @@ void          gi_repository_prepend_library_path (const char *directory);
 GI_AVAILABLE_IN_ALL
 const char * const * gi_repository_get_search_path (size_t *n_paths_out);
 
+GI_AVAILABLE_IN_ALL
+const char * const *gi_repository_get_library_path (size_t *n_paths_out);
+
 GI_AVAILABLE_IN_ALL
 const char *  gi_repository_load_typelib  (GIRepository           *repository,
                                            GITypelib              *typelib,

girepository/gitypelib.c

@@ -2213,36 +2213,6 @@ gi_typelib_error_quark (void)
   return quark;
 }
 
-static GSList *library_paths;
-
-/**
- * gi_repository_prepend_library_path:
- * @directory: (type filename): a single directory to scan for shared libraries
- *
- * Prepends @directory to the search path that is used to
- * search shared libraries referenced by imported namespaces.
- *
- * Multiple calls to this function all contribute to the final
- * list of paths.
- *
- * The list of paths is unique and shared for all
- * [class@GIRepository.Repository] instances across the process, but it doesn’t
- * affect namespaces imported before the call.
- *
- * If the library is not found in the directories configured
- * in this way, loading will fall back to the system library
- * path (i.e. `LD_LIBRARY_PATH` and `DT_RPATH` in ELF systems).
- * See the documentation of your dynamic linker for full details.
- *
- * Since: 2.80
- */
-void
-gi_repository_prepend_library_path (const char *directory)
-{
-  library_paths = g_slist_prepend (library_paths,
-                                   g_strdup (directory));
-}
-
 /* Note on the GModule flags used by this function:
 
  * Glade's autoconnect feature and OpenGL's extension mechanism
@@ -2256,7 +2226,6 @@ gi_repository_prepend_library_path (const char *directory)
 static GModule *
 load_one_shared_library (const char *shlib)
 {
-  GSList *p;
   GModule *m;
 
 #ifdef __APPLE__
@@ -2272,9 +2241,11 @@ load_one_shared_library (const char *shlib)
 #endif
     {
       /* First try in configured library paths */
-      for (p = library_paths; p; p = p->next)
+      const char * const *library_paths = gi_repository_get_library_path (NULL);
+
+      for (unsigned int i = 0; library_paths[i] != NULL; i++)
         {
-          char *path = g_build_filename (p->data, shlib, NULL);
+          char *path = g_build_filename (library_paths[i], shlib, NULL);
 
           m = g_module_open (path, G_MODULE_BIND_LAZY);
 

girepository/tests/repository-search-paths.c

@@ -99,6 +99,39 @@ test_repository_search_paths_prepend (void)
 #endif
 }
 
+static void
+test_repository_library_paths_default (void)
+{
+  const char * const *library_paths;
+  size_t n_library_paths;
+
+  library_paths = gi_repository_get_library_path (&n_library_paths);
+  g_assert_nonnull (library_paths);
+  g_assert_cmpuint (g_strv_length ((char **) library_paths), ==, 0);
+}
+
+static void
+test_repository_library_paths_prepend (void)
+{
+  const char * const *library_paths;
+  size_t n_library_paths;
+
+  gi_repository_prepend_library_path (g_test_get_dir (G_TEST_BUILT));
+  library_paths = gi_repository_get_library_path (&n_library_paths);
+  g_assert_nonnull (library_paths);
+  g_assert_cmpuint (g_strv_length ((char **) library_paths), ==, 1);
+
+  g_assert_cmpstr (library_paths[0], ==, g_test_get_dir (G_TEST_BUILT));
+
+  gi_repository_prepend_library_path (g_test_get_dir (G_TEST_DIST));
+  library_paths = gi_repository_get_library_path (&n_library_paths);
+  g_assert_nonnull (library_paths);
+  g_assert_cmpuint (g_strv_length ((char **) library_paths), ==, 2);
+
+  g_assert_cmpstr (library_paths[0], ==, g_test_get_dir (G_TEST_DIST));
+  g_assert_cmpstr (library_paths[1], ==, g_test_get_dir (G_TEST_BUILT));
+}
+
 int
 main (int   argc,
       char *argv[])
@@ -109,9 +142,11 @@ main (int   argc,
   g_setenv ("GI_TYPELIB_PATH", g_get_tmp_dir (), TRUE);
   g_setenv ("GI_GIR_PATH", g_get_user_cache_dir (), TRUE);
 
-  g_test_add_func ("/repository-search-paths/unset", test_repository_search_paths_unset);
-  g_test_add_func ("/repository-search-paths/default", test_repository_search_paths_default);
-  g_test_add_func ("/repository-search-paths/prepend", test_repository_search_paths_prepend);
+  g_test_add_func ("/repository/search-paths/unset", test_repository_search_paths_unset);
+  g_test_add_func ("/repository/search-paths/default", test_repository_search_paths_default);
+  g_test_add_func ("/repository/search-paths/prepend", test_repository_search_paths_prepend);
+  g_test_add_func ("/repository/library-paths/default", test_repository_library_paths_default);
+  g_test_add_func ("/repository/library-paths/prepend", test_repository_library_paths_prepend);
 
   return g_test_run ();
 }