colorize: use isatty module

* bootstrap.conf: Add isatty module.
* gnulib: Update to latest.
* lib/colorize.h: Remove argument from should_colorize.
* lib/ms/colorize.h: Likewise.
* lib/colorize-impl.c: Factor isatty call out of here...
* lib/ms/colorize-impl.c: ... and here...
* src/main.c: ... into here.

4 files changed, 12 insertions, 25 deletions

diff --git a/lib/colorize-impl.c b/lib/colorize-impl.c
index b7c0a3ff..e9d5c730 100644
--- a/lib/colorize-impl.c
+++ b/lib/colorize-impl.c
@@ -27,13 +27,8 @@
 /* Return non-zero if we should highlight matches in output to file
    descriptor FD.  */
 int
-should_colorize (int fd)
+should_colorize (void)
 {
-  if (! isatty (fd))
-    return 0;
-  else
-    {
-      char const *t = getenv ("TERM");
-      return t && strcmp (t, "dumb") != 0;
-    }
+  char const *t = getenv ("TERM");
+  return t && strcmp (t, "dumb") != 0;
 }
diff --git a/lib/colorize.h b/lib/colorize.h
index 104f7a03..93f3b10f 100644
--- a/lib/colorize.h
+++ b/lib/colorize.h
@@ -19,7 +19,7 @@
 #include <stdio.h>
 
 static inline void init_colorize (void) { }
-extern int should_colorize (int);
+extern int should_colorize (void);
 
 /* Start a colorized text attribute on stdout using the SGR_START
    format; the attribute is specified by SGR_SEQ.  */
diff --git a/lib/ms/colorize-impl.c b/lib/ms/colorize-impl.c
index d9d9b959..7341fe20 100644
--- a/lib/ms/colorize-impl.c
+++ b/lib/ms/colorize-impl.c
@@ -49,22 +49,14 @@ init_colorize (void)
 
 /* Return non-zero if we should highlight matches in output.  */
 int
-should_colorize (int fd)
+should_colorize (void)
 {
-  if (! isatty (fd))
-    return 0;
-  /* Windows isatty returns non-zero for the null device too.  */
-  else if (lseek (fd, SEEK_CUR, 0) != -1)
-    return 0;
-  else
-    {
-      /* $TERM is not normally defined on DOS/Windows, so don't require
-         it for highlighting.  But some programs, like Emacs, do define
-         it when running Grep as a subprocess, so make sure they don't
-         set TERM=dumb.  */
-      char const *t = getenv ("TERM");
-      return ! (t && strcmp (t, "dumb") == 0);
-    }
+  /* $TERM is not normally defined on DOS/Windows, so don't require
+     it for highlighting.  But some programs, like Emacs, do define
+     it when running Grep as a subprocess, so make sure they don't
+     set TERM=dumb.  */
+  char const *t = getenv ("TERM");
+  return ! (t && strcmp (t, "dumb") == 0);
 }
 
 /* Convert a color spec, a semi-colon separated list of the form
diff --git a/lib/ms/colorize.h b/lib/ms/colorize.h
index c49657d6..bb94e763 100644
--- a/lib/ms/colorize.h
+++ b/lib/ms/colorize.h
@@ -1,4 +1,4 @@
 extern void colorize_init (void);
-extern int should_colorize (int);
+extern int should_colorize (void);
 extern void print_start_colorize (char const *, char const *);
 extern void print_end_colorize (char const *);