[ostree] sysroot: Sort returned boot loader configs

[Colin Walters <walters src gnome org>]

commit 3300ee6259d191199f96b5f4e04ccfded3d11b86
Author: Colin Walters <walters verbum org>
Date:   Tue May 26 18:46:47 2015 -0400

    sysroot: Sort returned boot loader configs
    
    I haven't done a full dig through the history, but it seems quite
    possible right now we've been relying on inode enumeration
    order for generating bootloader configuration.
    
    Most of the time, newer inodes (i.e. later written files) will win.
    But that's obviously not reliable.
    
    Fix this by sorting the returned configuration internally.

 src/libostree/ostree-sysroot.c |   47 ++++++++++++++++++++++++++++-----------
 1 files changed, 34 insertions(+), 13 deletions(-)
---
diff --git a/src/libostree/ostree-sysroot.c b/src/libostree/ostree-sysroot.c
index ebcb632..f12ebc5 100644
--- a/src/libostree/ostree-sysroot.c
+++ b/src/libostree/ostree-sysroot.c
@@ -361,6 +361,35 @@ _ostree_sysroot_read_current_subbootversion (OstreeSysroot *self,
   return ret;
 }
 
+static gint
+compare_boot_loader_configs (OstreeBootconfigParser     *a,
+                             OstreeBootconfigParser     *b)
+{
+  const char *a_version = ostree_bootconfig_parser_get (a, "version");
+  const char *b_version = ostree_bootconfig_parser_get (b, "version");
+
+  if (a_version && b_version)
+    {
+      int r = strverscmp (a_version, b_version);
+      /* Reverse */
+      return -r;
+    }
+  else if (a_version)
+    return -1;
+  else
+    return 1;
+}
+
+static int
+compare_loader_configs_for_sorting (gconstpointer  a_pp,
+                                    gconstpointer  b_pp)
+{
+  OstreeBootconfigParser *a = *((OstreeBootconfigParser**)a_pp);
+  OstreeBootconfigParser *b = *((OstreeBootconfigParser**)b_pp);
+
+  return compare_boot_loader_configs (a, b);
+}
+
 gboolean
 _ostree_sysroot_read_boot_loader_configs (OstreeSysroot *self,
                                           int            bootversion,
@@ -427,6 +456,9 @@ _ostree_sysroot_read_boot_loader_configs (OstreeSysroot *self,
         }
     }
 
+  /* Callers expect us to give them a sorted array */
+  g_ptr_array_sort (ret_loader_configs, compare_loader_configs_for_sorting);
+
  done:
   gs_transfer_out_value (out_loader_configs, &ret_loader_configs);
   ret = TRUE;
@@ -706,19 +738,8 @@ compare_deployments_by_boot_loader_version_reversed (gconstpointer     a_pp,
   OstreeDeployment *b = *((OstreeDeployment**)b_pp);
   OstreeBootconfigParser *a_bootconfig = ostree_deployment_get_bootconfig (a);
   OstreeBootconfigParser *b_bootconfig = ostree_deployment_get_bootconfig (b);
-  const char *a_version = ostree_bootconfig_parser_get (a_bootconfig, "version");
-  const char *b_version = ostree_bootconfig_parser_get (b_bootconfig, "version");
-  
-  if (a_version && b_version)
-    {
-      int r = strverscmp (a_version, b_version);
-      /* Reverse */
-      return -r;
-    }
-  else if (a_version)
-    return -1;
-  else
-    return 1;
+
+  return compare_boot_loader_configs (a_bootconfig, b_bootconfig);
 }
 
 /**