Installation: Add flatpak_installation_get_min_free_space_bytes

A convenience wrapper around ostree_repo_get_min_free_space_bytes().
Clients programs like gnome-software can get the value of minimum free
space as defined in the OSTree repo. This can be useful in various
disk-space checks these client program can implement.

At Endless, we have downstream heuristics in gnome-software which
determine the success/failure likelihood of an install/update
operation to some extend. Depending upon the likelihood of the
success/failure we dispatch install/update/auto-update operations.

With client programs gaining features such as auto-updates, it makes
sense to have a min-free-space API so that these programs can check
free-space availablity vs minimum free space defined by user inside
OSTree's repo before auto-updating. Although, OSTree will certainly
fail operations over-stepping min-free-space's value; It's just a
matter of convenience to provide a way to query the value to client
programs as well.

Closes: #2274
Approved by: matthiasclasen

4 files changed, 41 insertions, 1 deletions

diff --git a/common/flatpak-installation.c b/common/flatpak-installation.c
index a3650d66..68397bae 100644
--- a/common/flatpak-installation.c
+++ b/common/flatpak-installation.c
@@ -1520,6 +1520,42 @@ flatpak_installation_get_config (FlatpakInstallation *self,
 }
 
 /**
+ * flatpak_installation_get_min_free_space_bytes:
+ * @self: a #FlatpakInstallation
+ * @out_bytes: (out): Location to store the result
+ * @error: Return location for a #GError
+ *
+ * Returns the min-free-space config value from the OSTree repository of this installation.
+ *
+ * Applications can use this value, together with information about the available
+ * disk space and the size of pending updates or installs, to estimate whether a
+ * pull operation will fail due to running out of disk space.
+ *
+ * Returns: %TRUE on success, or %FALSE on error.
+ * Since: 1.1
+ */
+gboolean
+flatpak_installation_get_min_free_space_bytes (FlatpakInstallation *self,
+                                               guint64             *out_bytes,
+                                               GError             **error)
+{
+  g_autoptr(FlatpakDir) dir = NULL;
+  g_autoptr(FlatpakDir) dir_clone = NULL;
+
+  dir = flatpak_installation_get_dir (self, NULL);
+  if (dir == NULL)
+    return FALSE;
+
+  /* We clone the dir here to make sure we re-read the latest ostree repo config, in case
+     it has local changes */
+  dir_clone = flatpak_dir_clone (dir);
+  if (!flatpak_dir_ensure_repo (dir_clone, NULL, error))
+    return FALSE;
+
+  return ostree_repo_get_min_free_space_bytes (flatpak_dir_get_repo (dir_clone), out_bytes, error);
+}
+
+/**
  * flatpak_installation_update_remote_sync:
  * @self: a #FlatpakInstallation
  * @name: the name of the remote to update
diff --git a/common/flatpak-installation.h b/common/flatpak-installation.h
index 1950e71f..6720794b 100644
--- a/common/flatpak-installation.h
+++ b/common/flatpak-installation.h
@@ -261,6 +261,9 @@ FLATPAK_EXTERN gboolean              flatpak_installation_set_config_sync (Flatp
                                                                            const char          *value,
                                                                            GCancellable        *cancellable,
                                                                            GError             **error);
+FLATPAK_EXTERN gboolean              flatpak_installation_get_min_free_space_bytes (FlatpakInstallation *self,
+                                                                                    guint64             *out_bytes,
+                                                                                    GError             **error);
 FLATPAK_EXTERN char *                flatpak_installation_get_config (FlatpakInstallation *self,
                                                                       const char          *key,
                                                                       GCancellable        *cancellable,
diff --git a/configure.ac b/configure.ac
index 78c98edc..042c8b1c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -32,7 +32,7 @@ AC_INIT([Flatpak],
 GLIB_REQS=2.44
 SYSTEM_BWRAP_REQS=0.2.1
 SYSTEM_DBUS_PROXY_REQS=0.1.0
-OSTREE_REQS=2018.7
+OSTREE_REQS=2018.9
 
 AC_USE_SYSTEM_EXTENSIONS
 AC_SYS_LARGEFILE
diff --git a/doc/reference/flatpak-sections.txt b/doc/reference/flatpak-sections.txt
index 062766e2..db9c9912 100644
--- a/doc/reference/flatpak-sections.txt
+++ b/doc/reference/flatpak-sections.txt
@@ -21,6 +21,7 @@ flatpak_installation_get_current_installed_app
 flatpak_installation_get_display_name
 flatpak_installation_get_id
 flatpak_installation_get_installed_ref
+flatpak_installation_get_min_free_space_bytes
 flatpak_installation_get_priority
 flatpak_installation_get_storage_type
 flatpak_installation_list_installed_refs