[ostree] repo: Fix bare-user file loads

[Colin Walters <walters src gnome org>]

commit 019635d9c2f89dac56fb40e3df2752ef81fedff3
Author: Colin Walters <walters verbum org>
Date:   Mon Jan 12 12:39:57 2015 -0500

    repo: Fix bare-user file loads
    
    Regression from 86764dbf007fca1e42aacb830e3c1911b198be6e
    
    This function is kind of fiendish now that we have 3 cases, each of
    which want to be optimized somewhat to only load what's necessary
    (e.g. don't open the file if we don't have an output for stream
    requested).
    
    Clean things up so that BARE_USER and BARE are separate conditionals
    that share as much as possible, and fix the bug that asserted we
    were in BARE mode.
    
    I tested this by running test-basic-user.sh by hand.

 src/libostree/ostree-repo.c |   86 ++++++++++++++++++++++++++----------------
 1 files changed, 53 insertions(+), 33 deletions(-)
---
diff --git a/src/libostree/ostree-repo.c b/src/libostree/ostree-repo.c
index d82872c..4d93a89 100644
--- a/src/libostree/ostree-repo.c
+++ b/src/libostree/ostree-repo.c
@@ -1918,10 +1918,14 @@ ostree_repo_load_file (OstreeRepo         *self,
 
       if (ret_file_info)
         {
+          found = TRUE;
+
           if (repo_mode == OSTREE_REPO_MODE_BARE_USER)
             {
+              guint32 mode;
               gs_unref_variant GVariant *metadata = NULL;
               gs_unref_bytes GBytes *bytes = NULL;
+              gs_fd_close int fd = -1;
 
               bytes = ot_lgetxattrat (self->objects_dir_fd, loose_path_buf,
                                       "user.ostreemeta", error);
@@ -1934,9 +1938,28 @@ ostree_repo_load_file (OstreeRepo         *self,
 
               ret_xattrs = set_info_from_filemeta (ret_file_info, metadata);
 
-              if (S_ISLNK (g_file_info_get_attribute_uint32 (ret_file_info, "unix::mode")))
+              mode = g_file_info_get_attribute_uint32 (ret_file_info, "unix::mode");
+
+              /* Optimize this so that we only open the file if we
+               * need to; symlinks contain their content, and we only
+               * open regular files if the caller has requested an
+               * input stream.
+               */
+              if (S_ISLNK (mode) || out_input)
+                { 
+                  if (!gs_file_openat_noatime (self->objects_dir_fd, loose_path_buf, &fd,
+                                               cancellable, error))
+                    goto out;
+                }
+
+              if (S_ISREG (mode) && out_input)
+                {
+                  g_assert (fd != -1);
+                  ret_input = g_unix_input_stream_new (fd, TRUE);
+                  fd = -1; /* Transfer ownership */
+                }
+              else if (S_ISLNK (mode))
                 {
-                  int fd = -1;
                   gs_unref_object GInputStream *target_input = NULL;
                   char targetbuf[PATH_MAX+1];
                   gsize target_size;
@@ -1944,11 +1967,8 @@ ostree_repo_load_file (OstreeRepo         *self,
                   g_file_info_set_file_type (ret_file_info, G_FILE_TYPE_SYMBOLIC_LINK);
                   g_file_info_set_size (ret_file_info, 0);
 
-                  if (!gs_file_openat_noatime (self->objects_dir_fd, loose_path_buf, &fd,
-                                               cancellable, error))
-                    goto out;
-
                   target_input = g_unix_input_stream_new (fd, TRUE);
+                  fd = -1; /* Transfer ownership */
 
                   if (!g_input_stream_read_all (target_input, targetbuf, sizeof (targetbuf),
                                                 &target_size, cancellable, error))
@@ -1957,41 +1977,41 @@ ostree_repo_load_file (OstreeRepo         *self,
                   g_file_info_set_symlink_target (ret_file_info, targetbuf);
                 }
             }
-
-          g_assert (repo_mode == OSTREE_REPO_MODE_BARE);
-
-          if (g_file_info_get_file_type (ret_file_info) == G_FILE_TYPE_REGULAR
-              && (out_input || out_xattrs))
+          else
             {
-              gs_fd_close int fd = -1;
-
-              if (!gs_file_openat_noatime (self->objects_dir_fd, loose_path_buf, &fd,
-                                           cancellable, error))
-                goto out;
+              g_assert (repo_mode == OSTREE_REPO_MODE_BARE);
 
-              if (out_xattrs)
+              if (g_file_info_get_file_type (ret_file_info) == G_FILE_TYPE_REGULAR
+                  && (out_input || out_xattrs))
                 {
-                  if (!gs_fd_get_all_xattrs (fd, &ret_xattrs,
-                                             cancellable, error))
+                  gs_fd_close int fd = -1;
+
+                  if (!gs_file_openat_noatime (self->objects_dir_fd, loose_path_buf, &fd,
+                                               cancellable, error))
                     goto out;
-                }
 
-              if (out_input)
+                  if (out_xattrs)
+                    {
+                      if (!gs_fd_get_all_xattrs (fd, &ret_xattrs,
+                                                 cancellable, error))
+                        goto out;
+                    }
+
+                  if (out_input)
+                    {
+                      ret_input = g_unix_input_stream_new (fd, TRUE);
+                      fd = -1; /* Transfer ownership */
+                    }
+                }
+              else if (g_file_info_get_file_type (ret_file_info) == G_FILE_TYPE_SYMBOLIC_LINK
+                       && out_xattrs)
                 {
-                  ret_input = g_unix_input_stream_new (fd, TRUE);
-                  fd = -1; /* Transfer ownership */
+                  if (!gs_dfd_and_name_get_all_xattrs (self->objects_dir_fd, loose_path_buf,
+                                                       &ret_xattrs,
+                                                       cancellable, error))
+                    goto out;
                 }
             }
-          else if (g_file_info_get_file_type (ret_file_info) == G_FILE_TYPE_SYMBOLIC_LINK
-                   && out_xattrs)
-            {
-              if (!gs_dfd_and_name_get_all_xattrs (self->objects_dir_fd, loose_path_buf,
-                                                   &ret_xattrs,
-                                                   cancellable, error))
-                goto out;
-            }
-          
-          found = TRUE;
         }
     }