[gnome-shell] extensions-tool: Handle NULL input when prompting for metadata

[Florian Müllner <fmuellner src gnome org>]

commit b6262f06669a6b2e27b302b32765a83acba55c1b
Author: Florian Müllner <fmuellner gnome org>
Date:   Tue Apr 7 01:49:30 2020 +0200

    extensions-tool: Handle NULL input when prompting for metadata
    
    g_data_input_stream_read_line_utf8() may return NULL, for example
    when interrupting the prompt with ^D. Handle that case and keep
    prompting until we got a line.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/812

 subprojects/extensions-tool/src/command-create.c | 30 +++++++++++++++++-------
 1 file changed, 21 insertions(+), 9 deletions(-)
---
diff --git a/subprojects/extensions-tool/src/command-create.c 
b/subprojects/extensions-tool/src/command-create.c
index 7fb5d7a78f..2ee1369f6b 100644
--- a/subprojects/extensions-tool/src/command-create.c
+++ b/subprojects/extensions-tool/src/command-create.c
@@ -188,42 +188,54 @@ prompt_metadata (char **uuid, char **name, char **description)
 
   if (name != NULL && *name == NULL)
     {
-      char *line;
+      char *line = NULL;
 
       g_print (
         _("Name should be a very short (ideally descriptive) string.\n"
           "Examples are: %s"),
         "“Click To Focus”, “Adblock”, “Shell Window Shrinker”\n");
-      g_print ("%s: ", _("Name"));
 
-      line = g_data_input_stream_read_line_utf8 (istream, NULL, NULL, NULL);
+      while (line == NULL)
+        {
+          g_print ("%s: ", _("Name"));
+
+          line = g_data_input_stream_read_line_utf8 (istream, NULL, NULL, NULL);
+        }
       *name = g_strdelimit (line, "\n", '\0');
     }
 
   if (description != NULL && *description == NULL)
     {
-      char *line;
+      char *line = NULL;
 
       g_print (
         _("Description is a single-sentence explanation of what your extension does.\n"
           "Examples are: %s"),
         "“Make windows visible on click”, “Block advertisement popups”, “Animate windows shrinking on 
minimize”\n");
-      g_print ("%s: ", _("Description"));
 
-      line = g_data_input_stream_read_line_utf8 (istream, NULL, NULL, NULL);
+      while (line == NULL)
+        {
+          g_print ("%s: ", _("Description"));
+
+          line = g_data_input_stream_read_line_utf8 (istream, NULL, NULL, NULL);
+        }
       *description = g_strdelimit (line, "\n", '\0');
     }
 
   if (uuid != NULL && *uuid == NULL)
     {
-      char *line;
+      char *line = NULL;
 
       g_print (
         _("UUID is a globally-unique identifier for your extension.\n"
           "This should be in the format of an email address (clicktofocus janedoe example com)\n"));
-      g_print ("UUID: ");
 
-      line = g_data_input_stream_read_line_utf8 (istream, NULL, NULL, NULL);
+      while (line == NULL)
+        {
+          g_print ("UUID: ");
+
+          line = g_data_input_stream_read_line_utf8 (istream, NULL, NULL, NULL);
+        }
       *uuid = g_strdelimit (line, "\n", '\0');
     }
 }