Rethink the whole line discipline architecture. Instead of having

multiple switchable line disciplines, we now have a single unified
one which changes its behaviour based on option settings. Each
option setting can be suggested by the back end and/or the terminal
handler, and can be forcibly overridden by the configuration. Local
echo and local line editing are separate, independently switchable,
options.

[originally from svn r895]

1 files changed, 132 insertions, 110 deletions

diff --git a/ldisc.c b/ldisc.c
index 80659cca..1ab832dd 100644
--- a/ldisc.c
+++ b/ldisc.c
@@ -1,21 +1,27 @@
+/*
+ * ldisc.c: PuTTY line discipline. Sits between the input coming
+ * from keypresses in the window, and the output channel leading to
+ * the back end. Implements echo and/or local line editing,
+ * depending on what's currently configured.
+ */
+
 #include <windows.h>
 #include <stdio.h>
 #include <ctype.h>
 
 #include "putty.h"
 
-/*
- * ldisc.c: PuTTY line disciplines
- */
+#define ECHOING (cfg.localecho == LD_YES || \
+                 (cfg.localecho == LD_BACKEND && \
+                      (back->ldisc(LD_ECHO) || term_ldisc(LD_ECHO))))
+#define EDITING (cfg.localedit == LD_YES || \
+                 (cfg.localedit == LD_BACKEND && \
+                      (back->ldisc(LD_EDIT) || term_ldisc(LD_EDIT))))
 
 static void c_write (char *buf, int len) {
     from_backend(0, buf, len);
 }
 
-static void c_write1 (char c) {
-    c_write(&c, 1);
-}
-
 static char *term_buf = NULL;
 static int term_buflen = 0, term_bufsiz = 0, term_quotenext = 0;
 
@@ -32,7 +38,7 @@ static int plen(unsigned char c) {
 static void pwrite(unsigned char c) {
     if ((c >= 32 && c <= 126) ||
         (c >= 160)) {
-        c_write1(c);
+        c_write(&c, 1);
     } else if (c < 128) {
         char cc[2];
         cc[1] = (c == 127 ? '?' : c + 0x40);
@@ -52,108 +58,124 @@ static void bsb(int n) {
 
 #define CTRL(x) (x^'@')
 
-static void term_send(char *buf, int len) {
-    while (len--) {
-	char c;
-        c = *buf++;
-	switch (term_quotenext ? ' ' : c) {
-	    /*
-	     * ^h/^?: delete one char and output one BSB
-	     * ^w: delete, and output BSBs, to return to last space/nonspace
-	     * boundary
-	     * ^u: delete, and output BSBs, to return to BOL
-	     * ^c: Do a ^u then send a telnet IP
-	     * ^z: Do a ^u then send a telnet SUSP
-	     * ^\: Do a ^u then send a telnet ABORT
-	     * ^r: echo "^R\n" and redraw line
-	     * ^v: quote next char
-	     * ^d: if at BOL, end of file and close connection, else send line
-	     * and reset to BOL
-	     * ^m: send line-plus-\r\n and reset to BOL
-	     */
-	  case CTRL('H'): case CTRL('?'):      /* backspace/delete */
-	    if (term_buflen > 0) {
-		bsb(plen(term_buf[term_buflen-1]));
-		term_buflen--;
-	    }
-	    break;
-	  case CTRL('W'):		       /* delete word */
-	    while (term_buflen > 0) {
-		bsb(plen(term_buf[term_buflen-1]));
-		term_buflen--;
-		if (term_buflen > 0 &&
-		    isspace(term_buf[term_buflen-1]) &&
-		    !isspace(term_buf[term_buflen]))
-		    break;
-	    }
-	    break;
-	  case CTRL('U'):	       /* delete line */
-	  case CTRL('C'):	       /* Send IP */
-	  case CTRL('\\'):	       /* Quit */
-	  case CTRL('Z'):	       /* Suspend */
-	    while (term_buflen > 0) {
-		bsb(plen(term_buf[term_buflen-1]));
-		term_buflen--;
-	    }
-	    back->special (TS_EL);
-	    if( c == CTRL('C') )  back->special (TS_IP);
-	    if( c == CTRL('Z') )  back->special (TS_SUSP);
-	    if( c == CTRL('\\') ) back->special (TS_ABORT);
-            break;
-	  case CTRL('R'):	       /* redraw line */
-	    c_write("^R\r\n", 4);
-	    {
-		int i;
-		for (i = 0; i < term_buflen; i++)
-		    pwrite(term_buf[i]);
-	    }
-	    break;
-	  case CTRL('V'):	       /* quote next char */
-	    term_quotenext = TRUE;
-	    break;
-	  case CTRL('D'):	       /* logout or send */
-	    if (term_buflen == 0) {
-		back->special (TS_EOF);
-	    } else {
-		back->send(term_buf, term_buflen);
-		term_buflen = 0;
-	    }
-	    break;
-	  case CTRL('M'):	       /* send with newline */
-	    if (term_buflen > 0)
-                back->send(term_buf, term_buflen);
-	    if (cfg.protocol == PROT_RAW)
-	        back->send("\r\n", 2);
-	    else
-	        back->send("\r", 1);
-	    c_write("\r\n", 2);
-	    term_buflen = 0;
-	    break;
-	  default:                     /* get to this label from ^V handler */
-	    if (term_buflen >= term_bufsiz) {
-		term_bufsiz = term_buflen + 256;
-		term_buf = saferealloc(term_buf, term_bufsiz);
-	    }
-	    term_buf[term_buflen++] = c;
-	    pwrite(c);
-            term_quotenext = FALSE;
-	    break;
-	}
+void ldisc_send(char *buf, int len) {
+    /*
+     * Called with len=0 when the options change. We must inform
+     * the front end in case it needs to know.
+     */
+    if (len == 0) {
+        void ldisc_update(int echo, int edit);
+        ldisc_update(ECHOING, EDITING);
     }
-}
-
-static void simple_send(char *buf, int len) {
-    if( term_buflen != 0 )
-    {
-	back->send(term_buf, term_buflen);
-	while (term_buflen > 0) {
-	    bsb(plen(term_buf[term_buflen-1]));
-	    term_buflen--;
-	}
+    /*
+     * Either perform local editing, or just send characters.
+     */
+    if (EDITING) {
+        while (len--) {
+            char c;
+            c = *buf++;
+            switch (term_quotenext ? ' ' : c) {
+                /*
+                 * ^h/^?: delete one char and output one BSB
+                 * ^w: delete, and output BSBs, to return to last
+                 * space/nonspace boundary
+                 * ^u: delete, and output BSBs, to return to BOL
+                 * ^c: Do a ^u then send a telnet IP
+                 * ^z: Do a ^u then send a telnet SUSP
+                 * ^\: Do a ^u then send a telnet ABORT
+                 * ^r: echo "^R\n" and redraw line
+                 * ^v: quote next char
+                 * ^d: if at BOL, end of file and close connection,
+                 * else send line and reset to BOL
+                 * ^m: send line-plus-\r\n and reset to BOL
+                 */
+              case CTRL('H'): case CTRL('?'):      /* backspace/delete */
+                if (term_buflen > 0) {
+                    if (ECHOING)
+                        bsb(plen(term_buf[term_buflen-1]));
+                    term_buflen--;
+                }
+                break;
+              case CTRL('W'):		       /* delete word */
+                while (term_buflen > 0) {
+                    if (ECHOING)
+                        bsb(plen(term_buf[term_buflen-1]));
+                    term_buflen--;
+                    if (term_buflen > 0 &&
+                        isspace(term_buf[term_buflen-1]) &&
+                        !isspace(term_buf[term_buflen]))
+                        break;
+                }
+                break;
+              case CTRL('U'):	       /* delete line */
+              case CTRL('C'):	       /* Send IP */
+              case CTRL('\\'):	       /* Quit */
+              case CTRL('Z'):	       /* Suspend */
+                while (term_buflen > 0) {
+                    if (ECHOING)
+                        bsb(plen(term_buf[term_buflen-1]));
+                    term_buflen--;
+                }
+                back->special (TS_EL);
+                if( c == CTRL('C') )  back->special (TS_IP);
+                if( c == CTRL('Z') )  back->special (TS_SUSP);
+                if( c == CTRL('\\') ) back->special (TS_ABORT);
+                break;
+              case CTRL('R'):	       /* redraw line */
+                if (ECHOING) {
+                    int i;
+                    c_write("^R\r\n", 4);
+                    for (i = 0; i < term_buflen; i++)
+                        pwrite(term_buf[i]);
+                }
+                break;
+              case CTRL('V'):	       /* quote next char */
+                term_quotenext = TRUE;
+                break;
+              case CTRL('D'):	       /* logout or send */
+                if (term_buflen == 0) {
+                    back->special (TS_EOF);
+                } else {
+                    back->send(term_buf, term_buflen);
+                    term_buflen = 0;
+                }
+                break;
+              case CTRL('M'):	       /* send with newline */
+                if (term_buflen > 0)
+                    back->send(term_buf, term_buflen);
+                if (cfg.protocol == PROT_RAW)
+                    back->send("\r\n", 2);
+                else
+                    back->send("\r", 1);
+                if (ECHOING)
+                    c_write("\r\n", 2);
+                term_buflen = 0;
+                break;
+              default:                     /* get to this label from ^V handler */
+                if (term_buflen >= term_bufsiz) {
+                    term_bufsiz = term_buflen + 256;
+                    term_buf = saferealloc(term_buf, term_bufsiz);
+                }
+                term_buf[term_buflen++] = c;
+                if (ECHOING)
+                    pwrite(c);
+                term_quotenext = FALSE;
+                break;
+            }
+        }
+    } else {
+        if( term_buflen != 0 )
+        {
+            back->send(term_buf, term_buflen);
+            while (term_buflen > 0) {
+                bsb(plen(term_buf[term_buflen-1]));
+                term_buflen--;
+            }
+        }
+        if (len > 0) {
+            if (ECHOING)
+                c_write(buf, len);
+            back->send(buf, len);
+        }
     }
-    if (len > 0)
-        back->send(buf, len);
 }
-
-Ldisc ldisc_term = { term_send };
-Ldisc ldisc_simple = { simple_send };