Replace integer context2 encoding in conf_editbox_handler.

I was just about to add another ordinary edit box control, and found I
couldn't remember what went in the context2 argument to conf_editbox.
When I looked it up, I realised it was one of those horrid integer
encodings of the form '1 means this, -1 means that, less than -1 means
some parametrised property where the parameter is obtained by negating
the encoded integer'.

Those are always awkward to remember, and worse to extend. So I've
replaced the integer context2 used with conf_editbox_handler with a
pointer to a small struct type in which the types and parameters have
sensible names and are documented.

(To avoid annoying const warnings everywhere, this also meant
extending the 'intorptr' union to have a const void * branch as well
as a 'void *'. Surprised I haven't needed that before. But if I
introduce any more of these parameter structures, it'll come in useful
again.)

config.c

@@ -104,27 +104,23 @@ void conf_checkbox_handler(dlgcontrol *ctrl, dlgparam *dlg,
     }
 }
 
+const struct conf_editbox_handler_type conf_editbox_str = {.type = EDIT_STR};
+const struct conf_editbox_handler_type conf_editbox_int = {.type = EDIT_INT};
+
 void conf_editbox_handler(dlgcontrol *ctrl, dlgparam *dlg,
                           void *data, int event)
 {
     /*
-     * The standard edit-box handler expects the main `context'
+     * The standard edit-box handler expects the main `context' field
-     * field to contain the primary key. The secondary `context2'
+     * to contain the primary key. The secondary `context2' field is a
-     * field indicates the type of this field:
+     * pointer to the struct conf_editbox_handler_type defined in
-     *
+     * putty.h.
-     *  - if context2 > 0, the field is a string.
-     *  - if context2 == -1, the field is an int and the edit box
-     *    is numeric.
-     *  - if context2 < -1, the field is an int and the edit box is
-     *    _floating_, and (-context2) gives the scale. (E.g. if
-     *    context2 == -1000, then typing 1.2 into the box will set
-     *    the field to 1200.)
      */
     int key = ctrl->context.i;
-    int length = ctrl->context2.i;
+    const struct conf_editbox_handler_type *type = ctrl->context2.cp;
     Conf *conf = (Conf *)data;
 
-    if (length > 0) {
+    if (type->type == EDIT_STR) {
         if (event == EVENT_REFRESH) {
             char *field = conf_get_str(conf, key);
             dlg_editbox_set(ctrl, dlg, field);
@@ -133,21 +129,21 @@ void conf_editbox_handler(dlgcontrol *ctrl, dlgparam *dlg,
             conf_set_str(conf, key, field);
             sfree(field);
         }
-    } else if (length < 0) {
+    } else {
         if (event == EVENT_REFRESH) {
             char str[80];
             int value = conf_get_int(conf, key);
-            if (length == -1)
+            if (type->type == EDIT_INT)
                 sprintf(str, "%d", value);
             else
-                sprintf(str, "%g", (double)value / (double)(-length));
+                sprintf(str, "%g", (double)value / type->denominator);
             dlg_editbox_set(ctrl, dlg, str);
         } else if (event == EVENT_VALCHANGE) {
             char *str = dlg_editbox_get(ctrl, dlg);
-            if (length == -1)
+            if (type->type == EDIT_INT)
                 conf_set_int(conf, key, atoi(str));
             else
-                conf_set_int(conf, key, (int)((-length) * atof(str)));
+                conf_set_int(conf, key, (int)(type->denominator * atof(str)));
             sfree(str);
         }
     }
@@ -2039,7 +2035,7 @@ void setup_config_box(struct controlbox *b, bool midsession,
                   conf_checkbox_handler, I(CONF_blinktext));
     ctrl_editbox(s, "Answerback to ^E:", 's', 100,
                  HELPCTX(terminal_answerback),
-                 conf_editbox_handler, I(CONF_answerback), I(1));
+                 conf_editbox_handler, I(CONF_answerback), ED_STR);
 
     s = ctrl_getset(b, "Terminal", "ldisc", "Line discipline options");
     ctrl_radiobuttons(s, "Local echo:", 'l', 3,
@@ -2129,17 +2125,21 @@ void setup_config_box(struct controlbox *b, bool midsession,
                   conf_checkbox_handler, I(CONF_bellovl));
     ctrl_editbox(s, "Over-use means this many bells...", 'm', 20,
                  HELPCTX(bell_overload),
-                 conf_editbox_handler, I(CONF_bellovl_n), I(-1));
+                 conf_editbox_handler, I(CONF_bellovl_n), ED_INT);
+
+    static const struct conf_editbox_handler_type conf_editbox_tickspersec = {
+        .type = EDIT_FIXEDPOINT, .denominator = TICKSPERSEC};
+
     ctrl_editbox(s, "... in this many seconds", 't', 20,
                  HELPCTX(bell_overload),
                  conf_editbox_handler, I(CONF_bellovl_t),
-                 I(-TICKSPERSEC));
+                 CP(&conf_editbox_tickspersec));
     ctrl_text(s, "The bell is re-enabled after a few seconds of silence.",
               HELPCTX(bell_overload));
     ctrl_editbox(s, "Seconds of silence required", 's', 20,
                  HELPCTX(bell_overload),
                  conf_editbox_handler, I(CONF_bellovl_s),
-                 I(-TICKSPERSEC));
+                 CP(&conf_editbox_tickspersec));
 
     /*
      * The Terminal/Features panel.
@@ -2208,11 +2208,11 @@ void setup_config_box(struct controlbox *b, bool midsession,
         ctrl_columns(s, 2, 50, 50);
         c = ctrl_editbox(s, "Columns", 'm', 100,
                          HELPCTX(window_size),
-                         conf_editbox_handler, I(CONF_width), I(-1));
+                         conf_editbox_handler, I(CONF_width), ED_INT);
         c->column = 0;
         c = ctrl_editbox(s, "Rows", 'r', 100,
                          HELPCTX(window_size),
-                         conf_editbox_handler, I(CONF_height),I(-1));
+                         conf_editbox_handler, I(CONF_height),ED_INT);
         c->column = 1;
         ctrl_columns(s, 1, 100);
     }
@@ -2221,7 +2221,7 @@ void setup_config_box(struct controlbox *b, bool midsession,
                     "Control the scrollback in the window");
     ctrl_editbox(s, "Lines of scrollback", 's', 50,
                  HELPCTX(window_scrollback),
-                 conf_editbox_handler, I(CONF_savelines), I(-1));
+                 conf_editbox_handler, I(CONF_savelines), ED_INT);
     ctrl_checkbox(s, "Display scrollbar", 'd',
                   HELPCTX(window_scrollback),
                   conf_checkbox_handler, I(CONF_scrollbar));
@@ -2273,7 +2273,7 @@ void setup_config_box(struct controlbox *b, bool midsession,
     ctrl_editbox(s, "Gap between text and window edge:", 'e', 20,
                  HELPCTX(appearance_border),
                  conf_editbox_handler,
-                 I(CONF_window_border), I(-1));
+                 I(CONF_window_border), ED_INT);
 
     /*
      * The Window/Behaviour panel.
@@ -2286,7 +2286,7 @@ void setup_config_box(struct controlbox *b, bool midsession,
                     "Adjust the behaviour of the window title");
     ctrl_editbox(s, "Window title:", 't', 100,
                  HELPCTX(appearance_title),
-                 conf_editbox_handler, I(CONF_wintitle), I(1));
+                 conf_editbox_handler, I(CONF_wintitle), ED_STR);
     ctrl_checkbox(s, "Separate window and icon titles", 'i',
                   HELPCTX(appearance_title),
                   conf_checkbox_handler,
@@ -2465,8 +2465,7 @@ void setup_config_box(struct controlbox *b, bool midsession,
                         "Sending of null packets to keep session active");
         ctrl_editbox(s, "Seconds between keepalives (0 to turn off)", 'k', 20,
                      HELPCTX(connection_keepalive),
-                     conf_editbox_handler, I(CONF_ping_interval),
+                     conf_editbox_handler, I(CONF_ping_interval), ED_INT);
-                     I(-1));
 
         if (!midsession) {
             s = ctrl_getset(b, "Connection", "tcp",
@@ -2499,7 +2498,7 @@ void setup_config_box(struct controlbox *b, bool midsession,
                                 "Logical name of remote host");
                 ctrl_editbox(s, label, 'm', 100,
                              HELPCTX(connection_loghost),
-                             conf_editbox_handler, I(CONF_loghost), I(1));
+                             conf_editbox_handler, I(CONF_loghost), ED_STR);
             }
         }
 
@@ -2514,7 +2513,7 @@ void setup_config_box(struct controlbox *b, bool midsession,
                             "Login details");
             ctrl_editbox(s, "Auto-login username", 'u', 50,
                          HELPCTX(connection_username),
-                         conf_editbox_handler, I(CONF_username), I(1));
+                         conf_editbox_handler, I(CONF_username), ED_STR);
             {
                 /* We assume the local username is sufficiently stable
                  * to include on the dialog box. */
@@ -2535,10 +2534,10 @@ void setup_config_box(struct controlbox *b, bool midsession,
                             "Terminal details");
             ctrl_editbox(s, "Terminal-type string", 't', 50,
                          HELPCTX(connection_termtype),
-                         conf_editbox_handler, I(CONF_termtype), I(1));
+                         conf_editbox_handler, I(CONF_termtype), ED_STR);
             ctrl_editbox(s, "Terminal speeds", 's', 50,
                          HELPCTX(connection_termspeed),
-                         conf_editbox_handler, I(CONF_termspeed), I(1));
+                         conf_editbox_handler, I(CONF_termspeed), ED_STR);
 
             s = ctrl_getset(b, "Connection/Data", "env",
                             "Environment variables");
@@ -2588,19 +2587,19 @@ void setup_config_box(struct controlbox *b, bool midsession,
         c = ctrl_editbox(s, "Proxy hostname", 'y', 100,
                          HELPCTX(proxy_main),
                          conf_editbox_handler,
-                         I(CONF_proxy_host), I(1));
+                         I(CONF_proxy_host), ED_STR);
         c->column = 0;
         c = ctrl_editbox(s, "Port", 'p', 100,
                          HELPCTX(proxy_main),
                          conf_editbox_handler,
                          I(CONF_proxy_port),
-                         I(-1));
+                         ED_INT);
         c->column = 1;
         ctrl_columns(s, 1, 100);
         ctrl_editbox(s, "Exclude Hosts/IPs", 'e', 100,
                      HELPCTX(proxy_exclude),
                      conf_editbox_handler,
-                     I(CONF_proxy_exclude_list), I(1));
+                     I(CONF_proxy_exclude_list), ED_STR);
         ctrl_checkbox(s, "Consider proxying local host connections", 'x',
                       HELPCTX(proxy_exclude),
                       conf_checkbox_handler,
@@ -2615,16 +2614,16 @@ void setup_config_box(struct controlbox *b, bool midsession,
         ctrl_editbox(s, "Username", 'u', 60,
                      HELPCTX(proxy_auth),
                      conf_editbox_handler,
-                     I(CONF_proxy_username), I(1));
+                     I(CONF_proxy_username), ED_STR);
         c = ctrl_editbox(s, "Password", 'w', 60,
                          HELPCTX(proxy_auth),
                          conf_editbox_handler,
-                         I(CONF_proxy_password), I(1));
+                         I(CONF_proxy_password), ED_STR);
         c->editbox.password = true;
         ctrl_editbox(s, "Command to send to proxy (for some types)", 'm', 100,
                      HELPCTX(proxy_command),
                      conf_editbox_handler,
-                     I(CONF_proxy_telnet_command), I(1));
+                     I(CONF_proxy_telnet_command), ED_STR);
 
         ctrl_radiobuttons(s, "Print proxy diagnostics "
                           "in the terminal window", 'r', 5,
@@ -2674,7 +2673,7 @@ void setup_config_box(struct controlbox *b, bool midsession,
                             "Data to send to the server");
             ctrl_editbox(s, "Remote command:", 'r', 100,
                          HELPCTX(ssh_command),
-                         conf_editbox_handler, I(CONF_remote_cmd), I(1));
+                         conf_editbox_handler, I(CONF_remote_cmd), ED_STR);
 
             s = ctrl_getset(b, "Connection/SSH", "protocol", "Protocol options");
             ctrl_checkbox(s, "Don't start a shell or command at all", 'n',
@@ -2753,19 +2752,19 @@ void setup_config_box(struct controlbox *b, bool midsession,
                          HELPCTX(ssh_kex_repeat),
                          conf_editbox_handler,
                          I(CONF_ssh_rekey_time),
-                         I(-1));
+                         ED_INT);
 #ifndef NO_GSSAPI
             ctrl_editbox(s, "Minutes between GSS checks (0 for never)", NO_SHORTCUT, 20,
                          HELPCTX(ssh_kex_repeat),
                          conf_editbox_handler,
                          I(CONF_gssapirekey),
-                         I(-1));
+                         ED_INT);
 #endif
             ctrl_editbox(s, "Max data before rekey (0 for no limit)", 'x', 20,
                          HELPCTX(ssh_kex_repeat),
                          conf_editbox_handler,
                          I(CONF_ssh_rekey_data),
-                         I(16));
+                         ED_STR);
             ctrl_text(s, "(Use 1M for 1 megabyte, 1G for 1 gigabyte etc)",
                       HELPCTX(ssh_kex_repeat));
         }
@@ -3044,7 +3043,7 @@ void setup_config_box(struct controlbox *b, bool midsession,
                           conf_checkbox_handler,I(CONF_x11_forward));
             ctrl_editbox(s, "X display location", 'x', 50,
                          HELPCTX(ssh_tunnels_x11),
-                         conf_editbox_handler, I(CONF_x11_display), I(1));
+                         conf_editbox_handler, I(CONF_x11_display), ED_STR);
             ctrl_radiobuttons(s, "Remote X11 authentication protocol", 'u', 2,
                               HELPCTX(ssh_tunnels_x11auth),
                               conf_radiobutton_handler,
@@ -3210,22 +3209,26 @@ void setup_config_box(struct controlbox *b, bool midsession,
                             "Select a serial line");
             ctrl_editbox(s, "Serial line to connect to", 'l', 40,
                          HELPCTX(serial_line),
-                         conf_editbox_handler, I(CONF_serline), I(1));
+                         conf_editbox_handler, I(CONF_serline), ED_STR);
         }
 
         s = ctrl_getset(b, "Connection/Serial", "sercfg", "Configure the serial line");
         ctrl_editbox(s, "Speed (baud)", 's', 40,
                      HELPCTX(serial_speed),
-                     conf_editbox_handler, I(CONF_serspeed), I(-1));
+                     conf_editbox_handler, I(CONF_serspeed), ED_INT);
         ctrl_editbox(s, "Data bits", 'b', 40,
                      HELPCTX(serial_databits),
-                     conf_editbox_handler, I(CONF_serdatabits), I(-1));
+                     conf_editbox_handler, I(CONF_serdatabits), ED_INT);
         /*
          * Stop bits come in units of one half.
          */
+        static const struct conf_editbox_handler_type conf_editbox_stopbits = {
+            .type = EDIT_FIXEDPOINT, .denominator = 2};
+
         ctrl_editbox(s, "Stop bits", 't', 40,
                      HELPCTX(serial_stopbits),
-                     conf_editbox_handler, I(CONF_serstopbits), I(-2));
+                     conf_editbox_handler, I(CONF_serstopbits),
+                     CP(&conf_editbox_stopbits));
         ctrl_droplist(s, "Parity", 'p', 40,
                       HELPCTX(serial_parity), serial_parity_handler,
                       I(ser_vt->serial_parity_mask));
@@ -3279,7 +3282,7 @@ void setup_config_box(struct controlbox *b, bool midsession,
                         "Data to send to the server");
         ctrl_editbox(s, "Local username:", 'l', 50,
                      HELPCTX(rlogin_localuser),
-                     conf_editbox_handler, I(CONF_localusername), I(1));
+                     conf_editbox_handler, I(CONF_localusername), ED_STR);
 
     }
 
@@ -3295,7 +3298,7 @@ void setup_config_box(struct controlbox *b, bool midsession,
         ctrl_editbox(s, "Location string", 'l', 70,
                      HELPCTX(supdup_location),
                      conf_editbox_handler, I(CONF_supdup_location),
-                     I(1));
+                     ED_STR);
 
         ctrl_radiobuttons(s, "Extended ASCII Character set:", 'e', 4,
                           HELPCTX(supdup_ascii),

dialog.h

@@ -43,11 +43,12 @@ enum {
  * included with DEFINE_INTORPTR_FNS defined. This is a total pain,
  * but such is life.
  */
-typedef union { void *p; int i; } intorptr;
+typedef union { void *p; const void *cp; int i; } intorptr;
 
 #ifndef INLINE
 intorptr I(int i);
 intorptr P(void *p);
+intorptr CP(const void *p);
 #endif
 
 #if defined DEFINE_INTORPTR_FNS || defined INLINE
@@ -58,6 +59,7 @@ intorptr P(void *p);
 #endif
 PREFIX intorptr I(int i) { intorptr ret; ret.i = i; return ret; }
 PREFIX intorptr P(void *p) { intorptr ret; ret.p = p; return ret; }
+PREFIX intorptr CP(const void *p) { intorptr ret; ret.cp = p; return ret; }
 #undef PREFIX
 #endif
 

putty.h

@@ -2640,6 +2640,41 @@ void conf_filesel_handler(dlgcontrol *ctrl, dlgparam *dlg,
 void conf_fontsel_handler(dlgcontrol *ctrl, dlgparam *dlg,
                           void *data, int event);
 
+struct conf_editbox_handler_type {
+    /* Structure passed as context2 to conf_editbox_handler */
+    enum { EDIT_STR, EDIT_INT, EDIT_FIXEDPOINT } type;
+    union {
+        /*
+         * EDIT_STR means the edit box is connected to a string
+         * field in Conf. No further parameters needed.
+         */
+
+        /*
+         * EDIT_INT means the edit box is connected to an int field in
+         * Conf, and the input string is interpreted as decimal. No
+         * further parameters needed. (But we could add one here later
+         * if for some reason we wanted int fields in hex.)
+         */
+
+        /*
+         * EDIT_FIXEDPOINT means the edit box is connected to an int
+         * field in Conf, but the input string is interpreted as
+         * _floating point_, and converted to/from the output int by
+         * means of a fixed denominator. That is,
+         *
+         *   (floating value in edit box) * denominator = value in Conf
+         */
+        struct {
+            double denominator;
+        };
+    };
+};
+
+extern const struct conf_editbox_handler_type conf_editbox_str;
+extern const struct conf_editbox_handler_type conf_editbox_int;
+#define ED_STR CP(&conf_editbox_str)
+#define ED_INT CP(&conf_editbox_int)
+
 void setup_config_box(struct controlbox *b, bool midsession,
                       int protocol, int protcfginfo);
 

unix/config-gtk.c

@@ -112,7 +112,7 @@ void gtk_setup_config_box(struct controlbox *b, bool midsession, void *win)
               HELPCTX(no_help));
     ctrl_editbox(s, "Horizontal offset for shadow bold:", 'z', 20,
                  HELPCTX(no_help), conf_editbox_handler,
-                 I(CONF_shadowboldoffset), I(-1));
+                 I(CONF_shadowboldoffset), ED_INT);
 
     /*
      * Markus Kuhn feels, not totally unreasonably, that it's good
@@ -155,6 +155,6 @@ void gtk_setup_config_box(struct controlbox *b, bool midsession, void *win)
                         "X Window System settings");
         ctrl_editbox(s, "Window class name:", 'z', 50,
                      HELPCTX(no_help), conf_editbox_handler,
-                     I(CONF_winclass), I(1));
+                     I(CONF_winclass), ED_STR);
     }
 }