LinGui: make preset backups when import upgrades presets

And attempt to load a backup if we recognize that presets were written
with a more recent version of HandBrake than what is currently running.

1 files changed, 43 insertions, 6 deletions

diff --git a/gtk/src/presets.c b/gtk/src/presets.c
index 33757b992..122756e84 100644
--- a/gtk/src/presets.c
+++ b/gtk/src/presets.c
@@ -662,12 +662,35 @@ presets_add_config_file(const gchar *name)
     g_free(path);
     if (preset != NULL)
     {
-        hb_presets_add(preset);
-
         int hb_major, hb_minor, hb_micro;
         int major, minor, micro;
         hb_presets_version(preset, &major, &minor, &micro);
         hb_presets_current_version(&hb_major, &hb_minor, &hb_micro);
+        if (major > hb_major)
+        {
+            // Change in major indicates non-backward compatible preset changes.
+            // We can't successfully load presets that were generated by
+            // a newer version of handbrake than is currently running.
+            hb_value_free(&preset);
+            return -1;
+        }
+
+        hb_value_t *backup = hb_value_dup(preset);
+        int result = hb_presets_import(preset);
+        if (result)
+        {
+            // hb_presets_import modified the preset.  So make a backup
+            // of the original.
+            config  = ghb_get_user_config_dir(NULL);
+            path    = g_strdup_printf ("%s/presets.%d.%d.%d.json",
+                            config, major, minor, micro);
+            hb_value_write_json(backup, path);
+            g_free(config);
+            g_free(path);
+        }
+        hb_value_free(&backup);
+
+        hb_presets_add(preset);
         if (major != hb_major || minor != hb_minor || micro != hb_micro)
         {
             // Reload hb builtin presets
@@ -1524,12 +1547,26 @@ ghb_presets_load(signal_user_data_t *ud)
 {
     if (presets_add_config_file("presets.json") < 0)
     {
-        if (presets_add_config_file("presets") < 0)
+        // The above can fail if the presets file was written by a
+        // more recent version of HandBrake than is currently running.
+        // Look for a backup version that matches the currently running
+        // version.
+        gchar *name;
+        int major, minor, micro;
+
+        hb_presets_current_version(&major, &minor, &micro);
+        name = g_strdup_printf("presets.%d.%d.%d.json", major, minor, micro);
+        ghb_log("Failed to read presets file, trying backup (%s)...", name);
+        if (presets_add_config_file(name) < 0)
         {
-            ghb_log("Failed to read preset file, initailizing new presets...");
-            hb_presets_builtin_update();
-            store_presets();
+            if (presets_add_config_file("presets") < 0)
+            {
+                ghb_log("Failed to read presets file, initailizing new presets...");
+                hb_presets_builtin_update();
+                store_presets();
+            }
         }
+        g_free(name);
     }
 }