[evolution] Bug 793915 - Option to convert UTC time to local time in Reply credits

[Milan Crha <mcrha src gnome org>]

commit ae559e669ce7dcd277d379737e4bbfc75416cd06
Author: Milan Crha <mcrha redhat com>
Date:   Mon Mar 12 14:26:31 2018 +0100

    Bug 793915 - Option to convert UTC time to local time in Reply credits

 data/org.gnome.evolution.mail.gschema.xml.in |    5 +++++
 src/mail/em-composer-utils.c                 |   25 ++++++++++++++++++++++++-
 2 files changed, 29 insertions(+), 1 deletions(-)
---
diff --git a/data/org.gnome.evolution.mail.gschema.xml.in b/data/org.gnome.evolution.mail.gschema.xml.in
index 24f997c..7d4d02d 100644
--- a/data/org.gnome.evolution.mail.gschema.xml.in
+++ b/data/org.gnome.evolution.mail.gschema.xml.in
@@ -220,6 +220,11 @@
       <_summary>Wrap quoted text in replies</_summary>
       <_description>If set to “true” quoted text in replies will be wrapped.</_description>
     </key>
+    <key name="composer-reply-credits-utc-to-localtime" type="b">
+      <default>false</default>
+      <_summary>Convert UTC time in reply credits to local time</_summary>
+      <_description>Whether the time in reply credits should be converted to local time when it's in UTC in 
the message.</_description>
+    </key>
     <key name="display-content-disposition-inline" type="b">
       <default>true</default>
       <_summary>Whether to obey Content-Disposition:inline message header hint</_summary>
diff --git a/src/mail/em-composer-utils.c b/src/mail/em-composer-utils.c
index 7ab04b4..c710512 100644
--- a/src/mail/em-composer-utils.c
+++ b/src/mail/em-composer-utils.c
@@ -54,9 +54,13 @@
 #ifdef gmtime_r
 #undef gmtime_r
 #endif
+#ifdef localtime_r
+#undef localtime_r
+#endif
 
-/* The gmtime() in Microsoft's C library is MT-safe */
+/* The gmtime() and localtime() in Microsoft's C library are MT-safe */
 #define gmtime_r(tp,tmp) (gmtime(tp)?(*(tmp)=*gmtime(tp),(tmp)):0)
+#define localtime_r(tp,tmp) (localtime(tp)?(*(tmp)=*localtime(tp),(tmp)):0)
 #endif
 
 typedef struct _AsyncContext AsyncContext;
@@ -3325,6 +3329,25 @@ attribution_format (CamelMimeMessage *message)
                /* That didn't work either, use current time */
                time (&date);
                tzone = 0;
+       } else if (tzone == 0) {
+               GSettings *settings;
+
+               settings = e_util_ref_settings ("org.gnome.evolution.mail");
+
+               if (g_settings_get_boolean (settings, "composer-reply-credits-utc-to-localtime")) {
+                       struct tm gmtm, lctm;
+                       time_t gmtt, lctt;
+
+                       gmtime_r (&date, &gmtm);
+                       localtime_r (&date, &lctm);
+
+                       gmtt = mktime (&gmtm);
+                       lctt = mktime (&lctm);
+
+                       tzone = (lctt - gmtt) * 100 / 3600;
+               }
+
+               g_clear_object (&settings);
        }
 
        /* Convert to UTC */