cc_open: List only supported file types

completion.c

@@ -67,10 +67,14 @@ cc_print(girara_session_t* session, char* input)
 girara_completion_t*
 cc_open(girara_session_t* session, char* input)
 {
+  g_return_val_if_fail(session != NULL, NULL);
+  g_return_val_if_fail(session->global.data != NULL, NULL);
+  zathura_t* zathura = session->global.data;
+
   girara_completion_t* completion  = girara_completion_init();
   girara_completion_group_t* group = girara_completion_group_create(session, NULL);
 
-  if (!session || !input || !completion || !group) {
+  if (!input || !completion || !group) {
     goto error_free;
   }
 
@@ -113,11 +117,30 @@ cc_open(girara_session_t* session, char* input)
     /* read files */
     char* name = NULL;
     while ((name = (char*) g_dir_read_name(dir)) != NULL) {
-      char* e_name = g_filename_display_name(name);
+      char* e_name    = g_filename_display_name(name);
+      if (e_name == NULL) {
+        goto error_free;
+      }
+
+      char* full_path = g_strdup_printf("%s/%s", path, e_name);
+      if (full_path == NULL) {
+        goto error_free;
+      }
+
+      if (file_valid_extension(zathura, full_path) == true) {
+        girara_completion_group_add_element(group, full_path, NULL);
+      }
+
+      g_free(full_path);
       g_free(e_name);
     }
 
     g_dir_close(dir);
+  /* given path is a file */
+  } else if (g_file_test(path, G_FILE_TEST_IS_REGULAR) == TRUE) {
+    if (file_valid_extension(zathura, path) == true) {
+      girara_completion_group_add_element(group, path, NULL);
+    }
   }
 
   g_free(path);

utils.c

@@ -48,6 +48,31 @@ file_get_extension(const char* path)
   return path + i + 1;
 }
 
+bool
+file_valid_extension(zathura_t* zathura, const char* path)
+{
+  if (path == NULL) {
+    return false;
+  }
+
+  const char* file_extension = file_get_extension(path);
+
+  girara_list_iterator_t* iter = girara_list_iterator(zathura->plugins.plugins);
+  if (iter == NULL) {
+    return false;
+  }
+
+  do {
+    zathura_document_plugin_t* plugin = (zathura_document_plugin_t*) girara_list_iterator_data(iter);
+    if (!strcmp(file_extension, plugin->file_extension)) {
+      return true;
+    }
+  } while (girara_list_iterator_next(iter));
+  girara_list_iterator_free(iter);
+
+  return false;
+}
+
 bool
 execute_command(char* const argv[], char** output)
 {

utils.h

@@ -31,6 +31,16 @@ bool file_exists(const char* path);
  */
 const char* file_get_extension(const char* path);
 
+/**
+ * This function checks if the file has a valid extension. A extension is
+ * evaluated as valid if it matches a supported filetype.
+ *
+ * @param zathura Zathura object
+ * @param path The path to the file
+ * @return true if the extension is valid, otherwise false
+ */
+bool file_valid_extension(zathura_t* zathura, const char* path);
+
 /**
  * Executes a system command and saves its output into output
  *