Ticket #2662: support extended mouse clicks beyond 223.

The ancient way of reporting mouse coordinates only supports coordinates
up to 231, so if your terminal is wider (or taller, but that's unlikely),
you cannot use your mouse in the rightmost columns.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

AUTHORS

@@ -61,6 +61,7 @@ Antonio Palama, DOS port <palama@posso.dm.unipi.it>
 
 Egmont Koblinger <egmont@gmail.com>
         Support of 256 colors
+        Support of extended mouse clicks beyond 223
 
 Erwin van Eijk <wabbit@corner.iaf.nl>
 

lib/tty/key.c

@@ -517,6 +517,8 @@ static int *seq_append = NULL;
 
 static int *pending_keys = NULL;
 
+static int mouse_btn, mouse_x, mouse_y;
+
 #ifdef __QNXNTO__
 ph_dv_f ph_attach;
 ph_ov_f ph_input_group;
@@ -707,18 +709,14 @@ getch_with_delay (void)
 static void
 xmouse_get_event (Gpm_Event * ev)
 {
-    int btn;
     static struct timeval tv1 = { 0, 0 };       /* Force first click as single */
     static struct timeval tv2;
     static int clicks = 0;
     static int last_btn = 0;
+    int btn = mouse_btn;
 
     /* Decode Xterm mouse information to a GPM style event */
 
-    /* Variable btn has following meaning: */
-    /* 0 = btn1 dn, 1 = btn2 dn, 2 = btn3 dn, 3 = btn up */
-    btn = tty_lowlevel_getch () - 32;
-
     /* There seems to be no way of knowing which button was released */
     /* So we assume all the buttons were released */
 
@@ -796,10 +794,8 @@ xmouse_get_event (Gpm_Event * ev)
         }
         last_btn = ev->buttons;
     }
-    /* Coordinates are 33-based */
-    /* Transform them to 1-based */
-    ev->x = tty_lowlevel_getch () - 32;
-    ev->y = tty_lowlevel_getch () - 32;
+    ev->x = mouse_x;
+    ev->y = mouse_y;
 }
 
 /* --------------------------------------------------------------------------------------------- */
@@ -933,6 +929,134 @@ push_char (int c)
     return ret;
 }
 
+/* --------------------------------------------------------------------------------------------- */
+/* Parse extended mouse coordinates.
+   Returns -1 if pending_keys cannot be a prefix of extended mouse coordinates.
+   Returns 0 if pending_keys is a valid (but still incomplete) prefix for extended mouse
+   coordinates, e.g. "^[[32;4".
+   Returns 1 and fills the mouse_btn, mouse_x, mouse_y values if pending_keys is a complete extended
+   mouse sequence, e.g. "^[[32;42;5M"
+ */
+
+/* Technical info (Egmont Koblinger <egmont@gmail.com>):
+
+   The ancient way of reporting mouse coordinates only supports coordinates up to 231,
+   so if your terminal is wider (or taller, but that's unlikely), you cannot use your mouse
+   in the rightmost columns.
+
+   * The old way of reporting mouse coordinates is the following:
+        + Output DECSET 1000 to enable mouse
+        + Expect escape sequences in the format \e[M<action+32><x+32><y+32> whereas <action+32>,
+          <x+32> and <y+32> are single bytes. (Action is 0 for left click, 1 for middle click,
+          2 for right click, 3 for release, or something like this.)
+        + Disadvantages of this format:
+            + x and y can only go up to 231.
+            + Coordinates above 95 are not ascii-compatible, so any character set converting
+              layer (e.g. luit) messes them up.
+            + The stream is not valid UTF-8, even if everything else is.
+
+    * The first new extension, introduced by xterm-262, is the following:
+        + Output DECSET 1000 to enable mouse, followed by DECSET 1005 to activate extended mode.
+        + Expect escape sequences in the format \e[M<action+32><<x+32>><<y+32>> whereas <<x+32>>
+          and <<y+32>> each can be up to two bytes long: coordinate+32 is encoded in UTF-8.
+        + Disadvantates of this format:
+            + There's still a limit of 2015 rows/columns (okay, it's not a real life problem).
+            + Doesn't solve the luit issue.
+            + It is "horribly broken" (quoting urxvt's changelog) in terms of compatibility
+              with the previous standard. There is no way for an application to tell whether
+              the underlying terminal supports this new mode (whether DECSET 1005 did actually change
+              the behavior or not), but depending on this a completely different user action might
+              generate the same input. Example:
+                + If the terminal doesn't support this extension, then clicking at (162, 129)
+                  generates \e[M<32><194><161>.
+                + If the terminal supports this extension, then clicking at (129, 1) [bit of math:
+                  129+32 = 161, U+0161 in UTF-8 is 194 161] generates \e[M<32><194><161><33>.
+                + so there's no way to tell whether the terminal ignored the 1005 escape sequence,
+                  the user clicked on (162, 129) and then typed an exclamation mark; or whether
+                  the terminal recognized the escape, and the user clicked on (129, 1).
+                + Due to this horrible brokenness, there's no way to implement support it without
+                  explicitly asking the user (via a setting) if the terminal can speak this extension.
+
+    * The second new extension, introduced by rxvt-unicode-9.10, is the following:
+        + Output DECSET 1000 to enable mouse, followed by DECSET 1015 to activate this extended mode.
+        + Expect escape sequences in the format \e[{action+32};{x};{y}M where this time I used
+          the braces to denote spelling out the numbers in decimal, rather than using raw bytes.
+        + The only thing I don't understand is why they kept the offset of 32 at action, but other
+          than that, this format is totally okay, and solves all the weaknesses of the previous ones.
+
+    Currently, at least the following terminal emulators have support for these:
+    * xterm supports the xterm extension
+    * rxvt-unicode >= 9.10 supports both extensions
+    * iterm2 supports both extensions.
+*/
+
+static int
+parse_extended_mouse_coordinates (void)
+{
+    int c, btn = 0, x = 0, y = 0;
+    const int *p = pending_keys;
+
+    c = *p++;
+    if (c == 0)
+        return 0;
+    if (c != ESC_CHAR)
+        return -1;
+
+    c = *p++;
+    if (c == 0)
+        return 0;
+    if (c != '[')
+        return -1;
+
+    while (TRUE)
+    {
+        c = *p++;
+        if (c == 0)
+            return 0;
+        if (c == ';')
+            break;
+        if (c < '0' || c > '9')
+            return -1;
+        btn = 10 * btn + c - '0';
+    }
+    if (btn < 32)
+        return -1;
+    btn -= 32;
+
+    while (TRUE)
+    {
+        c = *p++;
+        if (c == 0)
+            return 0;
+        if (c == ';')
+            break;
+        if (c < '0' || c > '9')
+            return -1;
+        x = 10 * x + c - '0';
+    }
+    if (x < 1)
+        return -1;
+
+    while (TRUE)
+    {
+        c = *p++;
+        if (c == 0)
+            return 0;
+        if (c == 'M')
+            break;
+        if (c < '0' || c > '9')
+            return -1;
+        y = 10 * y + c - '0';
+    }
+    if (y < 1)
+        return -1;
+
+    mouse_btn = btn;
+    mouse_x = x;
+    mouse_y = y;
+    return 1;
+}
+
 /* --------------------------------------------------------------------------------------------- */
 /* Apply corrections for the keycode generated in get_key_code() */
 
@@ -1692,22 +1816,35 @@ get_key_code (int no_delay)
   pend_send:
     if (pending_keys != NULL)
     {
-        int d = *pending_keys++;
-      check_pend:
-        if (*pending_keys == 0)
+        int m;
+
+        m = parse_extended_mouse_coordinates ();
+        if (m == 1)
         {
-            pending_keys = NULL;
-            seq_append = NULL;
+            pending_keys = seq_append = NULL;
+            this = NULL;
+            return MCKEY_EXTENDED_MOUSE;
         }
-        if ((d == ESC_CHAR) && (pending_keys != NULL))
+        if (m == -1)
         {
-            d = ALT (*pending_keys++);
-            goto check_pend;
+            int d = *pending_keys++;
+          check_pend:
+            if (*pending_keys == 0)
+            {
+                pending_keys = NULL;
+                seq_append = NULL;
+            }
+            if ((d == ESC_CHAR) && (pending_keys != NULL))
+            {
+                d = ALT (*pending_keys++);
+                goto check_pend;
+            }
+            if ((d > 127 && d < 256) && use_8th_bit_as_meta)
+                d = ALT (d & 0x7f);
+            this = NULL;
+            return correct_key_code (d);
         }
-        if ((d > 127 && d < 256) && use_8th_bit_as_meta)
-            d = ALT (d & 0x7f);
-        this = NULL;
-        return correct_key_code (d);
+        /* else if (m == 0), just let it continue */
     }
 
   nodelay_try_again:
@@ -2014,9 +2151,21 @@ tty_get_event (struct Gpm_Event *event, gboolean redo_event, gboolean block)
 #ifdef KEY_MOUSE
                           || c == KEY_MOUSE
 #endif /* KEY_MOUSE */
+                          || c == MCKEY_EXTENDED_MOUSE
         ))
     {
         /* Mouse event */
+        /* In case of extended coordinates, mouse_btn, mouse_x and mouse_y are already filled in. */
+        if (c != MCKEY_EXTENDED_MOUSE)
+        {
+            /* Variable btn has following meaning: */
+            /* 0 = btn1 dn, 1 = btn2 dn, 2 = btn3 dn, 3 = btn up */
+            mouse_btn = tty_lowlevel_getch () - 32;
+            /* Coordinates are 33-based */
+            /* Transform them to 1-based */
+            mouse_x = tty_lowlevel_getch () - 32;
+            mouse_y = tty_lowlevel_getch () - 32;
+        }
         xmouse_get_event (event);
         return (event->type != 0) ? EV_MOUSE : EV_NONE;
     }

lib/tty/key.h

@@ -33,6 +33,9 @@
 /* Return code for the mouse sequence */
 #define MCKEY_MOUSE     -2
 
+/* Return code for the extended mouse sequence */
+#define MCKEY_EXTENDED_MOUSE     -3
+
 /*** enums ***************************************************************************************/
 
 /*** structures declarations (and typedefs of structures)*****************************************/

lib/tty/mouse.c

@@ -138,6 +138,9 @@ enable_mouse (void)
         /* enable mouse tracking */
         printf (ESC_STR "[?1000h");
 
+        /* enable urxvt extended mouse coordinate reporting */
+        printf (ESC_STR "[?1015h");
+
         fflush (stdout);
         mouse_enabled = TRUE;
         break;
@@ -149,6 +152,9 @@ enable_mouse (void)
         /* enable mouse tracking */
         printf (ESC_STR "[?1002h");
 
+        /* enable urxvt extended mouse coordinate reporting */
+        printf (ESC_STR "[?1015h");
+
         fflush (stdout);
         mouse_enabled = TRUE;
         break;
@@ -176,6 +182,9 @@ disable_mouse (void)
         break;
 #endif
     case MOUSE_XTERM_NORMAL_TRACKING:
+        /* disable urxvt extended mouse coordinate reporting */
+        printf (ESC_STR "[?1015l");
+
         /* disable mouse tracking */
         printf (ESC_STR "[?1000l");
 
@@ -185,6 +194,9 @@ disable_mouse (void)
         fflush (stdout);
         break;
     case MOUSE_XTERM_BUTTON_EVENT_TRACKING:
+        /* disable urxvt extended mouse coordinate reporting */
+        printf (ESC_STR "[?1015l");
+
         /* disable mouse tracking */
         printf (ESC_STR "[?1002l");