Refactor: sysroot.bootloader: Store enum value rather than string

It's easier to extend and it centralises the config parsing.  In other
places we will no longer need to use `g_str_equal` to match these values,
a `switch` statement will be sufficient.

src/libostree/ostree-repo-private.h

@@ -110,6 +110,22 @@ typedef enum {
   _OSTREE_FEATURE_YES,
 } _OstreeFeatureSupport;
 
+/* Possible values for the sysroot.bootloader configuration variable */
+typedef enum {
+  CFG_SYSROOT_BOOTLOADER_OPT_AUTO = 0,
+  CFG_SYSROOT_BOOTLOADER_OPT_NONE,
+  CFG_SYSROOT_BOOTLOADER_OPT_ZIPL,
+  /* Non-exhaustive */
+} OstreeCfgSysrootBootloaderOpt;
+
+static const char* const CFG_SYSROOT_BOOTLOADER_OPTS_STR[] = {
+  /* This must be kept in the same order as the enum */
+  "auto",
+  "none",
+  "zipl",
+  NULL,
+};
+
 /**
  * OstreeRepo:
  *
@@ -193,7 +209,7 @@ struct OstreeRepo {
   guint64 payload_link_threshold;
   gint fs_support_reflink; /* The underlying filesystem has support for ioctl (FICLONE..) */
   gchar **repo_finders;
-  gchar *bootloader; /* Configure which bootloader to use. */
+  OstreeCfgSysrootBootloaderOpt bootloader; /* Configure which bootloader to use. */
 
   OstreeRepo *parent_repo;
 };

src/libostree/ostree-repo.c

@@ -1048,7 +1048,6 @@ ostree_repo_finalize (GObject *object)
   g_mutex_clear (&self->txn_lock);
   g_free (self->collection_id);
   g_strfreev (self->repo_finders);
-  g_free (self->bootloader);
 
   g_clear_pointer (&self->remotes, g_hash_table_destroy);
   g_mutex_clear (&self->remotes_lock);
@@ -3186,7 +3185,7 @@ reload_sysroot_config (OstreeRepo          *self,
                        GCancellable        *cancellable,
                        GError             **error)
 {
-  { g_autofree char *bootloader = NULL;
+  g_autofree char *bootloader = NULL;
 
   if (!ot_keyfile_get_value_with_default_group_optional (self->config, "sysroot",
                                                          "bootloader", "auto",
@@ -3197,17 +3196,17 @@ reload_sysroot_config (OstreeRepo          *self,
    * binary "x" in /usr/lib/ostree/bootloaders/x). See:
    * https://github.com/ostreedev/ostree/issues/1719
    * https://github.com/ostreedev/ostree/issues/1801
-     * Also, dedup these strings with the bootloader implementations
    */
-    if (!(g_str_equal (bootloader, "auto") || g_str_equal (bootloader, "none")
+  for (int i = 0; CFG_SYSROOT_BOOTLOADER_OPTS_STR[i]; i++)
-          || g_str_equal (bootloader, "zipl")))
+    {
-      return glnx_throw (error, "Invalid bootloader configuration: '%s'", bootloader);
+      if (g_str_equal (bootloader, CFG_SYSROOT_BOOTLOADER_OPTS_STR[i]))
-
+        {
-    g_free (self->bootloader);
+          self->bootloader = (OstreeCfgSysrootBootloaderOpt) i;
-    self->bootloader = g_steal_pointer (&bootloader);
+          return TRUE;
+        }
     }
 
-  return TRUE;
+  return glnx_throw (error, "Invalid bootloader configuration: '%s'", bootloader);
 }
 
 /**
@@ -6331,7 +6330,7 @@ ostree_repo_get_bootloader (OstreeRepo   *self)
 {
   g_return_val_if_fail (OSTREE_IS_REPO (self), NULL);
 
-  return self->bootloader;
+  return CFG_SYSROOT_BOOTLOADER_OPTS_STR[self->bootloader];
 }
 
 

src/libostree/ostree-sysroot.c

@@ -1340,23 +1340,24 @@ _ostree_sysroot_query_bootloader (OstreeSysroot     *sysroot,
                                   GError           **error)
 {
   OstreeRepo *repo = ostree_sysroot_repo (sysroot);
-  g_autofree gchar *bootloader_config = ostree_repo_get_bootloader (repo);
+  OstreeCfgSysrootBootloaderOpt bootloader_config = repo->bootloader;
 
-  g_debug ("Using bootloader configuration: %s", bootloader_config);
+  g_debug ("Using bootloader configuration: %s",
+      CFG_SYSROOT_BOOTLOADER_OPTS_STR[bootloader_config]);
 
   g_autoptr(OstreeBootloader) ret_loader = NULL;
-  if (g_str_equal (bootloader_config, "none"))
+  switch (repo->bootloader)
     {
+    case CFG_SYSROOT_BOOTLOADER_OPT_NONE:
       /* No bootloader specified; do not query bootloaders to run. */
       ret_loader = NULL;
-    }
+      break;
-  else if (g_str_equal (bootloader_config, "zipl"))
+    case CFG_SYSROOT_BOOTLOADER_OPT_ZIPL:
-    {
       /* We never consider zipl as active by default, so it can only be created
        * if it's explicitly requested in the config */
       ret_loader = (OstreeBootloader*) _ostree_bootloader_zipl_new (sysroot);
-    }
+      break;
-  else if (g_str_equal (bootloader_config, "auto"))
+    case CFG_SYSROOT_BOOTLOADER_OPT_AUTO:
       {
         gboolean is_active;
         ret_loader = (OstreeBootloader*)_ostree_bootloader_syslinux_new (sysroot);
@@ -1381,9 +1382,11 @@ _ostree_sysroot_query_bootloader (OstreeSysroot     *sysroot,
           }
         if (!is_active)
           g_clear_object (&ret_loader);
+        break;
       }
-  else
+    default:
       g_assert_not_reached ();
+    }
 
   ot_transfer_out_value(out_bootloader, &ret_loader);
   return TRUE;