Promote watch to other.

1 files changed, 186 insertions, 0 deletions

diff --git a/toys/other/watch.c b/toys/other/watch.c
new file mode 100644
index 00000000..ab51148c
--- /dev/null
+++ b/toys/other/watch.c
@@ -0,0 +1,186 @@
+/* watch.c - Execute a program periodically
+ *
+ * Copyright 2013 Sandeep Sharma <sandeep.jack2756@gmail.com>
+ * Copyright 2013 Kyungwan Han <asura321@gmail.com>
+ *
+ * No standard. See http://man7.org/linux/man-pages/man1/watch.1.html
+ *
+ * TODO: trailing combining characters
+USE_WATCH(NEWTOY(watch, "^<1n%<100=2000tebx", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_LOCALE))
+
+config WATCH
+  bool "watch"
+  default y
+  help
+    usage: watch [-teb] [-n SEC] PROG ARGS
+
+    Run PROG every -n seconds, showing output. Hit q to quit.
+
+    -n  Loop period in seconds (default 2)
+    -t  Don't print header
+    -e  Exit on error
+    -b  Beep on command error
+    -x	Exec command directly (vs "sh -c")
+*/
+
+#define FOR_watch
+#include "toys.h"
+
+GLOBALS(
+  int n;
+
+  pid_t pid, oldpid;
+)
+
+// When a child process exits, stop tracking them. Handle errors for -be
+void watch_child(int sig)
+{
+  int status;
+  pid_t pid = wait(&status);
+
+  status = WIFEXITED(status) ? WEXITSTATUS(status) : WTERMSIG(status)+127;
+  if (status) {
+    // TODO should this be beep()?
+    if (toys.optflags&FLAG_b) putchar('\b');
+    if (toys.optflags&FLAG_e) {
+      printf("Exit status %d\r\n", status);
+      tty_reset();
+      _exit(status);
+    }
+  }
+
+  if (pid == TT.oldpid) TT.oldpid = 0;
+  else if (pid == TT.pid) TT.pid = 0;
+}
+
+// Return early for low-ascii characters with special behavior,
+// discard remaining low ascii, escape other unprintable chars normally
+int watch_escape(FILE *out, int cols, int wc)
+{
+  if (wc==27 || (wc>=7 && wc<=13)) return -1;
+  if (wc < 32) return 0;
+
+  return crunch_escape(out, cols, wc);
+}
+
+void watch_main(void)
+{
+  char *cmdv[] = {"/bin/sh", "-c", 0, 0}, *cmd, *ss;
+  long long now, then = millitime();
+  unsigned width, height, i, cmdlen, len, xx = xx, yy = yy, active = active;
+  struct pollfd pfd[2];
+  pid_t pid = 0;
+  int fds[2], cc;
+
+  // Assemble header line in cmd, cmdlen, and cmdv
+  for (i = TT.n%1000, len = i ? 3 : 1; i && !(i%10); i /= 10) len--;
+  len = sprintf(toybuf, "Every %u.%0*us:", TT.n/1000, len, i)+1;
+  cmdlen = len;
+  for (i = 0; toys.optargs[i]; i++) len += strlen(toys.optargs[i])+1;
+  ss = stpcpy(cmd = xmalloc(len), toybuf);
+  cmdv[2] = cmd+cmdlen;
+  for (i = 0; toys.optargs[i]; i++) ss += sprintf(ss, " %s",toys.optargs[i]);
+  cmdlen = ss-cmd;
+
+  // Need to poll on process output and stdin
+  memset(pfd, 0, sizeof(pfd));
+  pfd[0].events = pfd[1].events = POLLIN;
+
+  xsignal_flags(SIGCHLD, watch_child, SA_RESTART|SA_NOCLDSTOP);
+
+  for (;;) {
+
+    // Time for a new period?
+    if ((now = millitime())>=then) {
+
+      // Incrementing then instead of adding offset to now avoids drift,
+      // loop is in case we got suspend/resumed and need to skip periods
+      while ((then += TT.n)<=now);
+      start_redraw(&width, &height);
+
+      // redraw the header
+      if (!(toys.optflags&FLAG_t)) {
+        time_t t = time(0);
+        int pad, ctimelen;
+
+        // Get and measure time string, trimming gratuitous \n
+        ctimelen = strlen(ss = ctime(&t));
+        if (ss[ctimelen-1]=='\n') ss[--ctimelen] = 0;
+ 
+        // print cmdline, then * or ' ' (showing truncation), then ctime 
+        pad = width-++ctimelen;
+        if (pad>0) draw_trim(cmd, -pad, pad);
+        printf("%c", pad<cmdlen ? '*' : ' ');
+        if (width) xputs(ss+(width>ctimelen ? 0 : width-1));
+        if (yy>=3) xprintf("\r\n");
+        xx = 0;
+        yy = 2;
+      }
+
+      // If child didn't exit, send TERM signal to current and KILL to previous
+      if (TT.oldpid>0) kill(TT.oldpid, SIGKILL);
+      if (TT.pid>0) kill(TT.pid, SIGTERM);
+      TT.oldpid = pid;
+      if (fds[0]>0) close(fds[0]);
+      if (fds[1]>0) close(fds[1]);
+
+      // Spawn child process
+      memset(fds, 0, sizeof(fds));
+      TT.pid = xpopen_both((toys.optflags&FLAG_x) ? toys.optargs : cmdv, fds);
+      pfd[1].fd = fds[1];
+      active = 1;
+    }
+
+    // Fetch data from child process or keyboard, with timeout
+    len = 0;
+    xpoll(pfd, 1+(active && yy<height), then-now);
+    if (pfd[0].revents&POLLIN) {
+      memset(toybuf, 0, 16);
+      cc = scan_key_getsize(toybuf, 0, &width, &height);
+      // TODO: ctrl-Z suspend
+      // TODO if (cc == -3) redraw();
+      if (cc == 3 || tolower(cc) == 'q') xexit();
+    }
+    if (pfd[0].revents&POLLHUP) xexit();
+    if (active) {
+      if (pfd[1].revents&POLLIN) len = read(fds[1], toybuf, sizeof(toybuf)-1);
+      if (pfd[1].revents&POLLHUP) active = 0;
+    }
+
+    // Measure output, trim to available display area. Escape low ascii so
+    // we don't have to try to parse ansi escapes. TODO: parse ansi escapes.
+    if (len<1) continue;
+    ss = toybuf;
+    toybuf[len] = 0;
+    while (yy<height) {
+      if (xx==width) {
+        xx = 0;
+        if (++yy>=height) break;
+      }
+      xx += crunch_str(&ss, width-xx, stdout, 0, watch_escape);
+      if (xx==width) {
+        xx = 0;
+        if (++yy>=height) break;
+        continue;
+      }
+
+      if (ss-toybuf==len || *ss>27) break;
+      cc = *ss++;
+      if (cc==27) continue; // TODO
+
+      // Handle BEL BS HT LF VT FF CR
+      if (cc>=10 && cc<=12) {
+        if (++yy>=height) break;
+        if (cc=='\n') putchar('\r'), xx = 0;
+      }
+      putchar(cc);
+      if (cc=='\b' && xx) xx--;
+      else if (cc=='\t') {
+        xx = (xx|7)+1;
+        if (xx>width-1) xx = width-1;
+      }
+    }
+  }
+
+  if (CFG_TOYBOX_FREE) free(cmd);
+}