[gnome-software/uajain/free-space-checks] flatpak: Introduce success/failure heuristics for app install

[Umang Jain <uajain src gnome org>]

commit bc70ae32df6db5ecc19176d45bdaf1772ccc3010
Author: Umang Jain <umang endlessm com>
Date:   Mon May 6 17:18:47 2019 +0530

    flatpak: Introduce success/failure heuristics for app install
    
    We want to pro-actively fail the install operations if we are
    sure that we are running low on disk-space. This saves the network
    bandwidth for user and reduce this cycle:
    online fetch -> detect low disk free space -> cleanup.
    
    * For app install:
      We make sure that there is enough space for app's download size +
      min-free-space (flatpak defaults to 500MB right now).
    
    We might be interested to do similar for app updates and autoupdates
    in following commits

 meson.build                         |  2 +-
 plugins/flatpak/gs-plugin-flatpak.c | 65 +++++++++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index f71ad139..54eb06ed 100644
--- a/meson.build
+++ b/meson.build
@@ -154,7 +154,7 @@ if get_option('fwupd')
 endif
 
 if get_option('flatpak')
-  flatpak = dependency('flatpak', version : '>= 1.0.4')
+  flatpak = dependency('flatpak', version : '>= 1.1.0')
 endif
 
 if get_option('rpm_ostree')
diff --git a/plugins/flatpak/gs-plugin-flatpak.c b/plugins/flatpak/gs-plugin-flatpak.c
index 3844ca97..2203cd5a 100644
--- a/plugins/flatpak/gs-plugin-flatpak.c
+++ b/plugins/flatpak/gs-plugin-flatpak.c
@@ -531,6 +531,60 @@ app_has_local_source (GsApp *app)
        return url != NULL && g_str_has_prefix (url, "file://");
 }
 
+static gboolean
+get_installation_dir_free_space (GsFlatpak *flatpak, guint64 *free_space, GError **error)
+{
+       g_autoptr (GFile) installation_dir = NULL;
+       g_autoptr (GFileInfo) info = NULL;
+
+       installation_dir = flatpak_installation_get_path (gs_flatpak_get_installation (flatpak));
+
+       info = g_file_query_filesystem_info (installation_dir,
+                                            G_FILE_ATTRIBUTE_FILESYSTEM_FREE,
+                                            NULL,
+                                            error);
+       if (info == NULL)
+               return FALSE;
+
+       *free_space = g_file_info_get_attribute_uint64 (info, G_FILE_ATTRIBUTE_FILESYSTEM_FREE);
+       return TRUE;
+}
+
+static gboolean
+gs_flatpak_has_space_to_install (GsFlatpak *flatpak, GsApp *app)
+{
+       g_autoptr(GError) error = NULL;
+       guint64 free_space = 0;
+       guint64 min_free_space = 0;
+       guint64 space_required = 0;
+
+       space_required = gs_app_get_size_download (app);
+       if (space_required == GS_APP_SIZE_UNKNOWABLE) {
+               g_warning ("Failed to query download size: %s", gs_app_get_unique_id (app));
+               space_required = 0;
+       }
+       if (!flatpak_installation_get_min_free_space_bytes (gs_flatpak_get_installation (flatpak),
+                                                           &min_free_space,
+                                                           &error)) {
+               g_autoptr(GFile) installation_file = flatpak_installation_get_path 
(gs_flatpak_get_installation (flatpak));
+               g_autofree gchar *path = g_file_get_path (installation_file);
+               g_warning ("Error getting min-free-space config value of OSTree repo at %s:%s", path, 
error->message);
+               g_clear_error (&error);
+       }
+       space_required = space_required + min_free_space;
+
+       if (!get_installation_dir_free_space (flatpak, &free_space, &error)) {
+               g_warning ("Error getting the free space available for installing %s: %s",
+                          gs_app_get_unique_id (app), error->message);
+               /* Even if we fail to get free space, we don't want to block this user-intiated
+                * install action. It might happen that there is enough space to install but
+                * an error happened during querying the filesystem info. */
+               return TRUE;
+       }
+
+       return free_space >= space_required;
+}
+
 gboolean
 gs_plugin_app_install (GsPlugin *plugin,
                       GsApp *app,
@@ -574,6 +628,17 @@ gs_plugin_app_install (GsPlugin *plugin,
        if (gs_app_get_kind (app) == AS_APP_KIND_SOURCE)
                return gs_flatpak_app_install_source (flatpak, app, cancellable, error);
 
+       /* Check for free disk space. Take into account OSTree repo's  min-free-space-* config option */
+       if (!gs_flatpak_has_space_to_install (flatpak, app)) {
+               g_debug ("Skipping installation for %s: not enough space on disk",
+                        gs_app_get_unique_id (app));
+               gs_app_set_state_recover (app);
+               g_set_error (error, GS_PLUGIN_ERROR, GS_PLUGIN_ERROR_NO_SPACE,
+                            "You don't have enough space to install %s. Please remove apps or documents to 
create more space.",
+                            gs_app_get_unique_id (app));
+               return FALSE;
+       }
+
        /* build */
        transaction = _build_transaction (plugin, flatpak, cancellable, error);
        if (transaction == NULL) {