[libgweather/benzea/wip-variant-backend] fixup! Add new GVariant schema, header and database generator

[Benjamin Berg <bberg src gnome org>]

commit 4fca0e4918ff5c4ff3edc66fbfc70b0600cd188d
Author: Benjamin Berg <bberg redhat com>
Date:   Mon Apr 27 11:30:40 2020 +0200

    fixup! Add new GVariant schema, header and database generator

 data/gen-locations-variant.py   |  6 +++++-
 libgweather/gweather-db.h       | 26 +++++++++++++++++++-------
 libgweather/gweather-location.c |  6 ++++++
 libgweather/gweather.gv         |  3 +++
 4 files changed, 33 insertions(+), 8 deletions(-)
---
diff --git a/data/gen-locations-variant.py b/data/gen-locations-variant.py
index 82278c31..76952b67 100755
--- a/data/gen-locations-variant.py
+++ b/data/gen-locations-variant.py
@@ -16,6 +16,9 @@ assert root.attrib['format'] == "1.0"
 # Maybe types are annyoing, so use an invalid idx
 INVALID_IDX = 0xffff
 
+# GWthDB01 as an integer
+magic = 0x5747687442443130
+
 levels = {
   'gweather' : 0,
   'region' : 1,
@@ -180,7 +183,8 @@ loc_by_metar_var = [(loc.findtext('code'), locations.index(loc)) for loc in loc_
 timezones_var = [(tz.get('id'), tz_variant(tz)) for tz in timezones]
 locations_var = [loc_variant(loc) for loc in locations]
 
-res = GLib.Variant("(a{sq}a{sq}a{s((ss)as)}a((ss)ss(dd)ssqyqqaqaq))", (
+res = GLib.Variant("(ta{sq}a{sq}a{s((ss)as)}a((ss)ss(dd)ssqyqqaqaq))", (
+    magic,
     loc_by_country_var,
     loc_by_metar_var,
     timezones_var,
diff --git a/libgweather/gweather-db.h b/libgweather/gweather-db.h
index 51b2a929..7a8faed7 100644
--- a/libgweather/gweather-db.h
+++ b/libgweather/gweather-db.h
@@ -1975,7 +1975,7 @@ db_arrayof_location_print (DbArrayofLocationRef v, gboolean type_annotate)
 }
 
 /************** DbWorld *******************/
-#define DB_WORLD_TYPESTRING "(a{sq}a{sq}a{s((ss)as)}a((ss)ss(dd)ssqyqqaqaq))"
+#define DB_WORLD_TYPESTRING "(ta{sq}a{sq}a{s((ss)as)}a((ss)ss(dd)ssqyqqaqaq))"
 #define DB_WORLD_TYPEFORMAT ((const GVariantType *) DB_WORLD_TYPESTRING)
 
 typedef struct {
@@ -2038,13 +2038,23 @@ db_world_from_variant (DbVariantRef v)
   return db_world_from_data (child.base, child.size);
 }
 
-#define DB_WORLD_INDEXOF_LOC_BY_COUNTRY 0
+#define DB_WORLD_INDEXOF_MAGIC 0
+
+static inline guint64
+db_world_get_magic (DbWorldRef v)
+{
+  guint offset = ((7) & (~(gsize)7)) + 0;
+  g_assert (offset + 8 < v.size);
+  return (guint64)G_STRUCT_MEMBER(guint64, v.base, offset);
+}
+
+#define DB_WORLD_INDEXOF_LOC_BY_COUNTRY 1
 
 static inline DbWorldLocByCountryRef
 db_world_get_loc_by_country (DbWorldRef v)
 {
   guint offset_size = Db_ref_get_offset_size (v.size);
-  guint offset = ((1) & (~(gsize)1)) + 0;
+  guint offset = ((7) & (~(gsize)7)) + 8;
   gsize start = offset;
   gsize end = DB_REF_READ_FRAME_OFFSET(v, 0);
   g_assert (start <= end);
@@ -2052,7 +2062,7 @@ db_world_get_loc_by_country (DbWorldRef v)
   return (DbWorldLocByCountryRef) { G_STRUCT_MEMBER_P(v.base, start), end - start };
 }
 
-#define DB_WORLD_INDEXOF_LOC_BY_METAR 1
+#define DB_WORLD_INDEXOF_LOC_BY_METAR 2
 
 static inline DbWorldLocByMetarRef
 db_world_get_loc_by_metar (DbWorldRef v)
@@ -2067,7 +2077,7 @@ db_world_get_loc_by_metar (DbWorldRef v)
   return (DbWorldLocByMetarRef) { G_STRUCT_MEMBER_P(v.base, start), end - start };
 }
 
-#define DB_WORLD_INDEXOF_TIMEZONES 2
+#define DB_WORLD_INDEXOF_TIMEZONES 3
 
 static inline DbWorldTimezonesRef
 db_world_get_timezones (DbWorldRef v)
@@ -2082,7 +2092,7 @@ db_world_get_timezones (DbWorldRef v)
   return (DbWorldTimezonesRef) { G_STRUCT_MEMBER_P(v.base, start), end - start };
 }
 
-#define DB_WORLD_INDEXOF_LOCATIONS 3
+#define DB_WORLD_INDEXOF_LOCATIONS 4
 
 static inline DbArrayofLocationRef
 db_world_get_locations (DbWorldRef v)
@@ -2100,7 +2110,9 @@ db_world_get_locations (DbWorldRef v)
 static inline GString *
 db_world_format (DbWorldRef v, GString *s, gboolean type_annotate)
 {
-  g_string_append (s, "(");
+  g_string_append_printf (s, "(%s%"G_GUINT64_FORMAT", ",
+                   type_annotate ? "uint64 " : "",
+                   db_world_get_magic (v));
   db_world_loc_by_country_format (db_world_get_loc_by_country (v), s, type_annotate);
   g_string_append (s, ", ");
   db_world_loc_by_metar_format (db_world_get_loc_by_metar (v), s, type_annotate);
diff --git a/libgweather/gweather-location.c b/libgweather/gweather-location.c
index 1780590a..fa7135e8 100644
--- a/libgweather/gweather-location.c
+++ b/libgweather/gweather-location.c
@@ -246,6 +246,12 @@ gweather_location_dup_world ()
        world_db = g_new0 (GWeatherDb, 1);
        world_db->map = map;
        world_db->world = db_world_from_data (g_mapped_file_get_contents (map), g_mapped_file_get_length 
(map));
+       /* This is GWeathDB01 */
+       if (db_world_get_magic (world_db->world) != 0x5747687442443130) {
+           g_mapped_file_unref (world_db->map);
+           g_free (world_db);
+           return NULL;
+       }
 
        world_db->locations_keepalive = g_ptr_array_new_with_free_func ((GDestroyNotify) 
_gweather_location_unref_no_check);
        world_db->timezones_keepalive = g_ptr_array_new_with_free_func ((GDestroyNotify) 
gweather_timezone_unref);
diff --git a/libgweather/gweather.gv b/libgweather/gweather.gv
index 3013399b..897ea689 100644
--- a/libgweather/gweather.gv
+++ b/libgweather/gweather.gv
@@ -35,6 +35,9 @@ type Location {
 };
 
 type World {
+  /* The magic value ends up right at the start of the file. */
+  magic: uint64;
+
   loc_by_country: [sorted string] uint16;
   loc_by_metar: [sorted string] uint16;