Add new functions input_fd and output_fd to the select extension.

3 files changed, 79 insertions, 6 deletions

diff --git a/extension/ChangeLog b/extension/ChangeLog
index b8e68674..ba0d3bfa 100644
--- a/extension/ChangeLog
+++ b/extension/ChangeLog
@@ -1,3 +1,13 @@
+2014-11-09         Andrew J. Schorr     <aschorr@telemetry-investments.com>
+
+	* select.c (do_input_fd): New function to return the input file
+	descriptor associated with a file/command.
+	(do_output_fd): New function to return the output file descriptor
+	associated with a file/command.
+	(func_table): Add new functions "input_fd" and "output_fd".
+	* testext.c (test_get_file): Do not use __func__, since it is a C99
+	feature, and gawk does not assume C99.
+
 2014-11-06         Andrew J. Schorr     <aschorr@telemetry-investments.com>
 
 	* errno.c (do_errno2name, do_name2errno): Remove unused variable 'str'.
diff --git a/extension/select.c b/extension/select.c
index 597b3a6b..b2105b75 100644
--- a/extension/select.c
+++ b/extension/select.c
@@ -606,11 +606,74 @@ do_set_non_blocking(int nargs, awk_value_t *result)
 	return make_number(-1, result);
 }
 
+/*  do_input_fd --- Return command's input file descriptor */
+
+static awk_value_t *
+do_input_fd(int nargs, awk_value_t *result)
+{
+	awk_value_t cmd, cmdtype;
+
+	if (do_lint && nargs > 2)
+		lintwarn(ext_id, _("input_fd: called with too many arguments"));
+	/*
+	 * N.B. If called with a single "" arg, we want it to work!  In that
+	 * case, the 1st arg is an empty string, and get_argument fails on the
+	 * 2nd arg.  Note that API get_file promises not to access the type
+	 * argument if the name argument is an empty string.
+	 */
+	if (get_argument(0, AWK_STRING, & cmd) &&
+	    (get_argument(1, AWK_STRING, & cmdtype) ||
+	     (! cmd.str_value.len && (nargs == 1)))) {
+		const awk_input_buf_t *ibuf;
+		const awk_output_buf_t *obuf;
+		if (get_file(cmd.str_value.str, cmd.str_value.len, cmdtype.str_value.str, cmdtype.str_value.len, -1, &ibuf, &obuf) && ibuf)
+			return make_number(ibuf->fd, result);
+		warning(ext_id, _("input_fd: get_file(`%s', `%s') failed to return an input descriptor"), cmd.str_value.str, cmdtype.str_value.str);
+	} else if (do_lint) {
+		if (nargs < 2)
+			lintwarn(ext_id, _("input_fd: called with too few arguments"));
+		else
+			lintwarn(ext_id, _("input_fd: called with inappropriate argument(s)"));
+	}
+	return make_number(-1, result);
+}
+
+/*  do_output_fd --- Return command's output file descriptor */
+
+static awk_value_t *
+do_output_fd(int nargs, awk_value_t *result)
+{
+	awk_value_t cmd, cmdtype;
+
+	if (do_lint && nargs > 2)
+		lintwarn(ext_id, _("output_fd: called with too many arguments"));
+	/*
+	 * N.B. If called with a single "" arg, it will not work, since there
+	 * is no output fd associated the current input file.
+	 */
+	if (get_argument(0, AWK_STRING, & cmd) &&
+	    get_argument(1, AWK_STRING, & cmdtype)) {
+		const awk_input_buf_t *ibuf;
+		const awk_output_buf_t *obuf;
+		if (get_file(cmd.str_value.str, cmd.str_value.len, cmdtype.str_value.str, cmdtype.str_value.len, -1, &ibuf, &obuf) && obuf)
+			return make_number(fileno(obuf->fp), result);
+		warning(ext_id, _("output_fd: get_file(`%s', `%s') failed to return an output descriptor"), cmd.str_value.str, cmdtype.str_value.str);
+	} else if (do_lint) {
+		if (nargs < 2)
+			lintwarn(ext_id, _("output_fd: called with too few arguments"));
+		else
+			lintwarn(ext_id, _("output_fd: called with inappropriate argument(s)"));
+	}
+	return make_number(-1, result);
+}
+
 static awk_ext_func_t func_table[] = {
 	{ "select", do_select, 5 },
 	{ "select_signal", do_signal, 3 },
 	{ "set_non_blocking", do_set_non_blocking, 2 },
 	{ "kill", do_kill, 2 },
+	{ "input_fd", do_input_fd, 2 },
+	{ "output_fd", do_output_fd, 2 },
 };
 
 /* define the dl_load function using the boilerplate macro */
diff --git a/extension/testext.c b/extension/testext.c
index 3ac1f124..f00ced7d 100644
--- a/extension/testext.c
+++ b/extension/testext.c
@@ -774,28 +774,28 @@ test_get_file(int nargs, awk_value_t *result)
 	const awk_output_buf_t *obuf;
 
 	if (nargs != 2) {
-		printf("%s: nargs not right (%d should be 2)\n", __func__, nargs);
+		printf("%s: nargs not right (%d should be 2)\n", "test_get_file", nargs);
 		return make_number(-1.0, result);
 	}
 
 	if (! get_argument(0, AWK_STRING, & filename)) {
-		printf("%s: cannot get first arg\n", __func__);
+		printf("%s: cannot get first arg\n", "test_get_file");
 		return make_number(-1.0, result);
 	}
 	if (! get_argument(1, AWK_STRING, & alias)) {
-		printf("%s: cannot get first arg\n", __func__);
+		printf("%s: cannot get first arg\n", "test_get_file");
 		return make_number(-1.0, result);
 	}
 	if ((fd = open(filename.str_value.str, O_RDONLY)) < 0) {
-		printf("%s: open(%s) failed\n", __func__, filename.str_value.str);
+		printf("%s: open(%s) failed\n", "test_get_file", filename.str_value.str);
 		return make_number(-1.0, result);
 	}
 	if (! get_file(alias.str_value.str, strlen(alias.str_value.str), "<", 1, fd, &ibuf, &obuf)) {
-		printf("%s: get_file(%s) failed\n", __func__, alias.str_value.str);
+		printf("%s: get_file(%s) failed\n", "test_get_file", alias.str_value.str);
 		return make_number(-1.0, result);
 	}
 	if (! ibuf || ibuf->fd != fd) {
-		printf("%s: get_file(%s) returned fd %d instead of %d\n", __func__, alias.str_value.str, ibuf ? ibuf->fd : -1, fd);
+		printf("%s: get_file(%s) returned fd %d instead of %d\n", "test_get_file", alias.str_value.str, ibuf ? ibuf->fd : -1, fd);
 		return make_number(-1.0, result);
 	}
 	return make_number(0.0, result);