[glib: 1/2] gdate: Add some missing error handling to GetDateFormatW() calls

[Sebastian Dröge <sdroege src gnome org>]

commit a00320599cb1b7e4a19aa37175d0c12d9b33a05a
Author: Philip Withnall <withnall endlessm com>
Date:   Fri Jun 12 11:31:47 2020 +0100

    gdate: Add some missing error handling to GetDateFormatW() calls
    
    Signed-off-by: Philip Withnall <withnall endlessm com>
    
    Closes: #1398

 glib/gdate.c | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)
---
diff --git a/glib/gdate.c b/glib/gdate.c
index 737fa54fd..9782a8899 100644
--- a/glib/gdate.c
+++ b/glib/gdate.c
@@ -2154,7 +2154,7 @@ g_date_order (GDate *date1,
 }
 
 #ifdef G_OS_WIN32
-static void
+static gboolean
 append_month_name (GArray     *result,
                   LCID        lcid,
                   SYSTEMTIME *systemtime,
@@ -2169,9 +2169,14 @@ append_month_name (GArray     *result,
     {
       base = abbreviated ? LOCALE_SABBREVMONTHNAME1 : LOCALE_SMONTHNAME1;
       n = GetLocaleInfoW (lcid, base + systemtime->wMonth - 1, NULL, 0);
+      if (n == 0)
+        return FALSE;
+
       g_array_set_size (result, result->len + n);
-      GetLocaleInfoW (lcid, base + systemtime->wMonth - 1,
-                     ((wchar_t *) result->data) + result->len - n, n);
+      if (GetLocaleInfoW (lcid, base + systemtime->wMonth - 1,
+                          ((wchar_t *) result->data) + result->len - n, n) != n)
+        return FALSE;
+
       g_array_set_size (result, result->len - 1);
     }
   else
@@ -2179,12 +2184,20 @@ append_month_name (GArray     *result,
       /* According to MSDN, this is the correct method to obtain
        * the form of the month name used when formatting a full
        * date; it must be a genitive case in some languages.
+       *
+       * (n == 0) indicates an error, whereas (n < 2) is something we’d never
+       * expect from the given format string, and would break the subsequent code.
        */
       lpFormat = abbreviated ? L"ddMMM" : L"ddMMMM";
       n = GetDateFormatW (lcid, 0, systemtime, lpFormat, NULL, 0);
+      if (n < 2)
+        return FALSE;
+
       g_array_set_size (result, result->len + n);
-      GetDateFormatW (lcid, 0, systemtime, lpFormat,
-                     ((wchar_t *) result->data) + result->len - n, n);
+      if (GetDateFormatW (lcid, 0, systemtime, lpFormat,
+                          ((wchar_t *) result->data) + result->len - n, n) != n)
+        return FALSE;
+
       /* We have obtained a day number as two digits and the month name.
        * Now let's get rid of those two digits: overwrite them with the
        * month name.
@@ -2194,6 +2207,8 @@ append_month_name (GArray     *result,
               (n - 2) * sizeof (wchar_t));
       g_array_set_size (result, result->len - 3);
     }
+
+  return TRUE;
 }
 
 static gsize
@@ -2286,12 +2301,16 @@ win32_strftime_helper (const GDate     *d,
              break;
            case 'b':
            case 'h':
-             append_month_name (result, lcid, &systemtime, TRUE,
-                                modifier == 'O');
+              if (!append_month_name (result, lcid, &systemtime, TRUE, modifier == 'O'))
+                {
+                  /* Ignore the error; this placeholder will be replaced with nothing */
+                }
              break;
            case 'B':
-             append_month_name (result, lcid, &systemtime, FALSE,
-                                modifier == 'O');
+              if (!append_month_name (result, lcid, &systemtime, FALSE, modifier == 'O'))
+                {
+                  /* Ignore the error; this placeholder will be replaced with nothing */
+                }
              break;
            case 'c':
              n = GetDateFormatW (lcid, 0, &systemtime, NULL, NULL, 0);