core: Add --link-cache option to checkout

This is a convenient way to have a lookaside directory of hard links,
which can greatly speed up checkouts.  In the future we probably want
to push this down into the repository.

src/libostree/ostree-repo.c

@@ -3567,9 +3567,6 @@ checkout_file_from_input (GFile          *file,
 
   if (mode == OSTREE_REPO_CHECKOUT_MODE_USER)
     {
-      if (g_file_info_get_file_type (finfo) == G_FILE_TYPE_SPECIAL)
-        return TRUE;
-
       temp_info = g_file_info_dup (finfo);
       
       g_file_info_set_attribute_uint32 (temp_info, "unix::uid", geteuid ());
@@ -3684,6 +3681,7 @@ static gboolean
 checkout_one_file (OstreeRepo                  *self,
                    OstreeRepoCheckoutMode    mode,
                    OstreeRepoCheckoutOverwriteMode    overwrite_mode,
+                   GFile                             *link_cache,
                    OstreeRepoFile           *src,
                    GFileInfo                *file_info,
                    GFile                    *destination,
@@ -3698,18 +3696,28 @@ checkout_one_file (OstreeRepo                  *self,
   ot_lobj GInputStream *input = NULL;
   ot_lvariant GVariant *xattrs = NULL;
 
+  /* Hack to avoid trying to create device files as a user */
+  if (mode == OSTREE_REPO_CHECKOUT_MODE_USER
+      && g_file_info_get_file_type (file_info) == G_FILE_TYPE_SPECIAL)
+    return TRUE;
+
   checksum = ostree_repo_file_get_checksum ((OstreeRepoFile*)src);
 
   if (priv->mode == OSTREE_REPO_MODE_BARE && mode == OSTREE_REPO_CHECKOUT_MODE_NONE)
     {
       possible_loose_path = ostree_repo_get_object_path (self, checksum, OSTREE_OBJECT_TYPE_FILE);
     }
+  else if (link_cache)
+    {
+      ot_lfree char *relpath = ostree_get_relative_object_path (checksum, OSTREE_OBJECT_TYPE_FILE);
+      possible_loose_path = g_file_resolve_relative_path (link_cache, relpath);
+    }
 
   if (possible_loose_path && lstat (ot_gfile_get_path_cached (possible_loose_path), &stbuf) >= 0)
     {
       /* If we found one, we can just hardlink */
       if (!checkout_file_hardlink (self, mode, overwrite_mode, possible_loose_path, destination,
-                                   cancellable, error) < 0)
+                                   cancellable, error))
         goto out;
     }
   else
@@ -3720,6 +3728,23 @@ checkout_one_file (OstreeRepo                  *self,
       if (!checkout_file_from_input (destination, mode, overwrite_mode, file_info, xattrs, 
                                      input, cancellable, error))
         goto out;
+
+      if (link_cache)
+        {
+          ot_lobj GFile *parent;
+          g_assert (possible_loose_path);
+
+          parent = g_file_get_parent (possible_loose_path);
+          if (!ot_gfile_ensure_directory (parent, TRUE, error))
+            goto out;
+
+          if (link (ot_gfile_get_path_cached (destination),
+                    ot_gfile_get_path_cached (possible_loose_path)) < 0)
+            {
+              ot_util_set_error_from_errno (error, errno);
+              goto out;
+            }
+        }
     }
 
   ret = TRUE;
@@ -3731,6 +3756,7 @@ gboolean
 ostree_repo_checkout_tree (OstreeRepo               *self,
                            OstreeRepoCheckoutMode    mode,
                            OstreeRepoCheckoutOverwriteMode    overwrite_mode,
+                           GFile                    *link_cache,
                            GFile                    *destination,
                            OstreeRepoFile           *source,
                            GFileInfo                *source_info,
@@ -3778,14 +3804,14 @@ ostree_repo_checkout_tree (OstreeRepo               *self,
 
       if (type == G_FILE_TYPE_DIRECTORY)
         {
-          if (!ostree_repo_checkout_tree (self, mode, overwrite_mode,
+          if (!ostree_repo_checkout_tree (self, mode, overwrite_mode, link_cache,
                                           dest_path, (OstreeRepoFile*)src_child, file_info,
                                           cancellable, error))
             goto out;
         }
       else
         {
-          if (!checkout_one_file (self, mode, overwrite_mode,
+          if (!checkout_one_file (self, mode, overwrite_mode, link_cache,
                                   (OstreeRepoFile*)src_child, file_info, 
                                   dest_path, cancellable, error))
             goto out;

src/libostree/ostree-repo.h

@@ -310,6 +310,7 @@ gboolean
 ostree_repo_checkout_tree (OstreeRepo               *self,
                            OstreeRepoCheckoutMode    mode,
                            OstreeRepoCheckoutOverwriteMode    overwrite_mode,
+                           GFile                    *link_cache,
                            GFile                    *destination,
                            OstreeRepoFile           *source,
                            GFileInfo                *source_info,

src/ostree/ot-builtin-checkout.c

@@ -29,6 +29,7 @@
 
 #include <glib/gi18n.h>
 
+static char *opt_link_cache;
 static gboolean opt_user_mode;
 static gboolean opt_atomic_retarget;
 static gboolean opt_no_triggers;
@@ -37,6 +38,7 @@ static gboolean opt_union;
 static gboolean opt_from_stdin;
 
 static GOptionEntry options[] = {
+  { "link-cache", 0, 0, G_OPTION_ARG_STRING, &opt_link_cache, "Use directory as lookaside cache for hard links", NULL },
   { "user-mode", 'U', 0, G_OPTION_ARG_NONE, &opt_user_mode, "Do not change file ownership or initialze extended attributes", NULL },
   { "subpath", 0, 0, G_OPTION_ARG_STRING, &opt_subpath, "Checkout sub-directory PATH", "PATH" },
   { "union", 0, 0, G_OPTION_ARG_NONE, &opt_union, "Keep existing directories, overwrite existing files", NULL },
@@ -120,6 +122,7 @@ process_one_checkout (OstreeRepo           *repo,
                       const char           *resolved_commit,
                       const char           *subpath,
                       GFile                *target,
+                      GFile                *link_cache,
                       GCancellable         *cancellable,
                       GError              **error)
 {
@@ -145,7 +148,7 @@ process_one_checkout (OstreeRepo           *repo,
 
   if (!ostree_repo_checkout_tree (repo, opt_user_mode ? OSTREE_REPO_CHECKOUT_MODE_USER : 0,
                                   opt_union ? OSTREE_REPO_CHECKOUT_OVERWRITE_UNION_FILES : 0,
-                                  target, subtree, file_info, cancellable, error))
+                                  link_cache, target, subtree, file_info, cancellable, error))
     goto out;
                       
   ret = TRUE;
@@ -155,6 +158,7 @@ process_one_checkout (OstreeRepo           *repo,
 
 static gboolean
 process_many_checkouts (OstreeRepo         *repo,
+                        GFile              *link_cache,
                         GFile              *target,
                         GCancellable       *cancellable,
                         GError            **error)
@@ -194,7 +198,7 @@ process_many_checkouts (OstreeRepo         *repo,
       if (!ostree_repo_resolve_rev (repo, revision, FALSE, &resolved_commit, error))
         goto out;
 
-      if (!process_one_checkout (repo, resolved_commit, subpath, target,
+      if (!process_one_checkout (repo, resolved_commit, subpath, target, link_cache,
                                  cancellable, error))
         goto out;
 
@@ -225,6 +229,7 @@ ostree_builtin_checkout (int argc, char **argv, GFile *repo_path, GError **error
   ot_lfree char *resolved_commit = NULL;
   ot_lfree char *suffixed_destination = NULL;
   ot_lfree char *tmp_destination = NULL;
+  ot_lobj GFile *link_cache = NULL;
   ot_lobj GFileInfo *symlink_file_info = NULL;
   ot_lobj GFile *checkout_target = NULL;
   ot_lobj GFile *checkout_target_tmp = NULL;
@@ -250,6 +255,9 @@ ostree_builtin_checkout (int argc, char **argv, GFile *repo_path, GError **error
       goto out;
     }
 
+  if (opt_link_cache)
+    link_cache = ot_gfile_new_for_path (opt_link_cache);
+
   if (opt_from_stdin)
     {
       if (opt_atomic_retarget)
@@ -262,7 +270,7 @@ ostree_builtin_checkout (int argc, char **argv, GFile *repo_path, GError **error
       destination = argv[1];
       checkout_target = ot_gfile_new_for_path (destination);
 
-      if (!process_many_checkouts (repo, checkout_target, cancellable, error))
+      if (!process_many_checkouts (repo, link_cache, checkout_target, cancellable, error))
         goto out;
       
       if (!opt_no_triggers)
@@ -321,7 +329,7 @@ ostree_builtin_checkout (int argc, char **argv, GFile *repo_path, GError **error
         {
           if (!process_one_checkout (repo, resolved_commit, opt_subpath,
                                      checkout_target_tmp ? checkout_target_tmp : checkout_target,
-                                     cancellable, error))
+                                     link_cache, cancellable, error))
             goto out;
 
           if (!opt_no_triggers)

tests/t0000-basic.sh

@@ -19,7 +19,7 @@
 
 set -e
 
-echo "1..29"
+echo "1..30"
 
 . libtest.sh
 
@@ -211,3 +211,11 @@ $OSTREE checkout --atomic-retarget test2
 cd test2
 assert_file_has_content ./yet/another/tree/green "leaf"
 echo "ok checkout short form"
+
+cd ${test_tmpdir}
+rm -rf test2
+mkdir linkcache
+$OSTREE checkout --link-cache=linkcache test2 test2-checkout-from-link-cache
+cd test2-checkout-from-link-cache
+assert_file_has_content ./yet/another/tree/green "leaf"
+echo "ok checkout link cache"

tests/t0001-archive.sh

@@ -21,7 +21,7 @@ set -e
 
 . libtest.sh
 
-echo '1..18'
+echo '1..19'
 
 setup_test_repository "archive"
 echo "ok setup"
@@ -96,3 +96,11 @@ echo "ok fsck"
 cd ${test_tmpdir}
 $OSTREE checkout test2 checkout-test2-from-unpacked
 echo "ok checkout union 2"
+
+cd ${test_tmpdir}
+rm -rf test2
+mkdir linkcache
+$OSTREE checkout --user-mode --link-cache=linkcache test2 test2
+cd test2
+assert_file_has_content baz/cow moo
+echo "ok checkout link cache"