[panel] Make clock configurable via gconf

Add keys for customizing the panel clock to the gconf schema and make
the clock use them. The settings are copied from gnome-panel's clock
applet, excluding all location/weather/appointment/... keys. In addition,
'internet' is no longer a supported value for the format key.

https://bugzilla.gnome.org/show_bug.cgi?id=600276

data/gnome-shell.schemas

@@ -57,6 +57,90 @@
 	</locale>
       </schema>
 
+      <schema>
+        <key>/schemas/desktop/gnome/shell/clock/format</key>
+	<applyto>/desktop/gnome/shell/clock/format</applyto>
+	<owner>gnome-shell</owner>
+	<type>string</type>
+	<default>
+            <!-- Translators:
+               This controls whether the GNOME panel clock should display time
+               in 24 hour mode or 12 hour mode by default. The only valid values
+               for this are "24-hour" and "12-hour".
+               If your locale uses 24 hour time notation, translate this to
+               "24-hour".
+               If your locale uses 12 hour time notation with am/pm, translate
+               this to "12-hour".
+
+               Do NOT translate this into anything else than "24-hour" or
+               "12-hour". For example, if you translate this to "24 sata" or
+               anything else that isn't "24-hour" or "12-hour", things will
+               not work.
+            -->
+          24-hour
+        </default>
+	<locale name="C">
+	  <short>Hour format</short>
+	  <long>
+        This key specifies the hour format used by the panel clock.
+        Possible values are "12-hour", "24-hour", "unix" and "custom".
+        If set to "unix", the clock will display time in seconds since Epoch,
+        i.e. 1970-01-01.
+        If set to "custom", the clock will display time according to the format
+        specified in the custom_format key.
+        Note that if set to either "unix" or "custom", the show_date and
+        show_seconds keys are ignored.
+	  </long>
+	</locale>
+      </schema>
+
+      <schema>
+        <key>/schemas/desktop/gnome/shell/clock/custom_format</key>
+        <applyto>/desktop/gnome/shell/clock/custom_format</applyto>
+	<owner>gnome-shell</owner>
+	<type>string</type>
+	<default></default>
+	<locale name="C">
+	  <short>Custom format of the clock</short>
+	  <long>
+	    This key specifies the format used by the panel clock when the
+            format key is set to "custom". You can use conversion specifiers
+            understood by strftime() to obtain a specific format. See the
+            strftime() manual for more information.
+	  </long>
+	</locale>
+      </schema>
+
+      <schema>
+        <key>/schemas/desktop/gnome/shell/clock/show_seconds</key>
+	<applyto>/desktop/gnome/shell/clock/show_seconds</applyto>
+	<owner>gnome-shell</owner>
+	<type>bool</type>
+	<default>false</default>
+	<locale name="C">
+	  <short>Show time with seconds</short>
+	  <long>
+              If true and format is either "12-hour" or "24-hour",
+              display seconds in time.
+          </long>
+	</locale>
+      </schema>
+
+      <schema>
+        <key>/schemas/desktop/gnome/shell/clock/show_date</key>
+	<applyto>/desktop/gnome/shell/clock/show_date</applyto>
+	<owner>gnome-shell</owner>
+	<type>bool</type>
+	<default>false</default>
+	<locale name="C">
+	  <short>Show date in clock</short>
+	  <long>
+              If true and format is either "12-hour" or "24-hour",
+              display date in the clock, in addition to time.
+          </long>
+	</locale>
+      </schema>
+
       <schema>
         <key>/schemas/desktop/gnome/shell/disabled_extensions</key>
         <applyto>/desktop/gnome/shell/disabled_extensions</applyto>

js/ui/panel.js

@@ -33,6 +33,11 @@ const STANDARD_TRAY_ICON_IMPLEMENTATIONS = {
     'gnome-power-manager': 'battery'
 };
 
+const CLOCK_FORMAT_KEY        = 'clock/format';
+const CLOCK_CUSTOM_FORMAT_KEY = 'clock/custom_format';
+const CLOCK_SHOW_DATE_KEY     = 'clock/show_date';
+const CLOCK_SHOW_SECONDS_KEY  = 'clock/show_seconds';
+
 function TextShadower() {
     this._init();
 }
@@ -478,6 +483,9 @@ Panel.prototype = {
 
         Main.chrome.addActor(this.actor, { visibleInOverview: true });
 
+        let gconf = Shell.GConf.get_default();
+        gconf.connect('changed', Lang.bind(this, this._updateClock));
+
         // Start the clock
         this._updateClock();
     },
@@ -544,29 +552,68 @@ Panel.prototype = {
     },
 
     _updateClock: function() {
+        let gconf = Shell.GConf.get_default();
+        let format = gconf.get_string(CLOCK_FORMAT_KEY);
+        let showDate = gconf.get_boolean(CLOCK_SHOW_DATE_KEY);
+        let showSeconds = gconf.get_boolean(CLOCK_SHOW_SECONDS_KEY);
+
+        let clockFormat;
+        switch (format) {
+            case 'unix':
+                // force updates every second
+                showSeconds = true;
+                clockFormat = "%s";
+                break;
+            case 'custom':
+                // force updates every second
+                showSeconds = true;
+                clockFormat = gconf.get_string(CLOCK_CUSTOM_FORMAT_KEY);
+                break;
+            case '24-hour':
+                if (showDate)
+	            /* Translators: This is the time format with date used
+                       in 24-hour mode. */
+                    clockFormat = showSeconds ? _("%a %b %e, %R:%S")
+                                              : _("%a %b %e, %R");
+                else
+	            /* Translators: This is the time format without date used
+                       in 24-hour mode. */
+                    clockFormat = showSeconds ? _("%a %R:%S")
+                                              : _("%a %R");
+                break;
+            case '12-hour':
+            default:
+                if (showDate)
+	            /* Translators: This is a time format with date used
+                       for AM/PM. */
+                    clockFormat = showSeconds ? _("%a %b %e, %l:%M:%S %p")
+                                              : _("%a %b %e, %l:%M %p");
+                else
+	            /* Translators: This is a time format without date used
+                       for AM/PM. */
+                    clockFormat = showSeconds ? _("%a %l:%M:%S %p")
+                                              : _("%a %l:%M %p");
+                break;
+        }
+
         let displayDate = new Date();
-        let msecRemaining = 60000 - (1000 * displayDate.getSeconds() +
+        let msecRemaining;
+        if (showSeconds) {
+            msecRemaining = 1000 - displayDate.getMilliseconds();
+            if (msecRemaining < 50) {
+                displayDate.setSeconds(displayDate.getSeconds() + 1);
+                msecRemaining += 1000;
+            }
+        } else {
+            msecRemaining = 60000 - (1000 * displayDate.getSeconds() +
                                      displayDate.getMilliseconds());
             if (msecRemaining < 500) {
                 displayDate.setMinutes(displayDate.getMinutes() + 1);
                 msecRemaining += 60000;
             }
-
-        // if the locale representations of 05:00 and 17:00 do not
-        // start with the same 2 digits, it must be a 24h clock
-        let fiveAm = new Date();
-        fiveAm.setHours(5);
-        let fivePm = new Date();
-        fivePm.setHours(17);
-        let isTime24h = fiveAm.toLocaleFormat("%X").substr(0,2) !=
-                        fivePm.toLocaleFormat("%X").substr(0,2);
-        if (isTime24h) {
-            /* Translators: This is the time format used in 24-hour mode. */
-            this._clock.set_text(displayDate.toLocaleFormat(_("%a %R")));
-        } else {
-            /* Translators: This is a time format used for AM/PM. */
-            this._clock.set_text(displayDate.toLocaleFormat(_("%a %l:%M %p")));
         }
+
+        this._clock.set_text(displayDate.toLocaleFormat(clockFormat));
         Mainloop.timeout_add(msecRemaining, Lang.bind(this, this._updateClock));
         return false;
     },