rigctl.c: Add options to save/read command history

As commands from a previous session may not be desired, make reading the
history file at rigctl start and writing to it at rigctl close optional
by use of the -i/--read_history or -I/--save-history options.
Compilation is conditional on having Readline and Readline History
support detected at build system configuration time.

History is stored in '$HOME/.rigctl_history' by default.  An alternate
path may be specified by setting the RIGCTL_HIST_DIR environment
variable:

$ RIGCTL_HIST_DIR=~/.rigctl rigctl -iI

will temporarily set the history directory to /home/USER/.rigctl and
create .rigctl_history if it does not exist.  If the file cannot be read
or written a warning message will be given on stderr.

tests/rigctl.c

@@ -49,6 +49,8 @@ extern char *readline ();
 #endif                              /* HAVE_LIBREADLINE */
 
 #ifdef HAVE_READLINE_HISTORY
+#  include <sys/stat.h>
+#  define HST_SHRT_OPTS "iI"
 #  if defined(HAVE_READLINE_HISTORY_H)
 #    include <readline/history.h>
 #  elif defined(HAVE_HISTORY_H)
@@ -58,7 +60,9 @@ extern void add_history ();
 extern int write_history ();
 extern int read_history ();
 #  endif                            /* defined(HAVE_READLINE_HISTORY_H) */
-                                    /* no history */
+#else
+/* no history */
+#define HST_SHRT_OPTS ""
 #endif                              /* HAVE_READLINE_HISTORY */
 
 
@@ -100,6 +104,10 @@ static struct option long_options[] =
 	{"show-conf",       0, 0, 'L'},
 	{"dump-caps",       0, 0, 'u'},
 	{"vfo",             0, 0, 'o'},
+#ifdef HAVE_READLINE_HISTORY
+	{"read-history",    0, 0, 'i'},
+	{"save-history",    0, 0, 'I'},
+#endif
 	{"verbose",         0, 0, 'v'},
 	{"help",            0, 0, 'h'},
 	{"version",         0, 0, 'V'},
@@ -133,6 +141,14 @@ int main (int argc, char *argv[])
 	int verbose = 0;
 	int show_conf = 0;
 	int dump_caps_opt = 0;
+#ifdef HAVE_READLINE_HISTORY
+	int rd_hist = 0;
+	int sv_hist = 0;
+	const char *hist_dir = NULL;
+	const char hist_file[] = "/.rigctl_history";
+	char *hist_path = NULL;
+	struct stat hist_dir_stat;
+#endif
 	const char *rig_file=NULL, *ptt_file=NULL, *dcd_file=NULL;
 	ptt_type_t ptt_type = RIG_PTT_NONE;
 	dcd_type_t dcd_type = RIG_DCD_NONE;
@@ -144,7 +160,7 @@ int main (int argc, char *argv[])
 		int c;
 		int option_index = 0;
 
-		c = getopt_long (argc, argv, SHORT_OPTIONS,
+		c = getopt_long (argc, argv, SHORT_OPTIONS HST_SHRT_OPTS,
 			long_options, &option_index);
 		if (c == -1)
 			break;
@@ -262,6 +278,14 @@ int main (int argc, char *argv[])
 			case 'o':
 				vfo_mode++;
 				break;
+#ifdef HAVE_READLINE_HISTORY
+			case 'i':
+				rd_hist++;
+				break;
+			case 'I':
+				sv_hist++;
+				break;
+#endif
 			case 'v':
 				verbose++;
 				break;
@@ -361,14 +385,31 @@ int main (int argc, char *argv[])
 	exitcode = 0;
 
 #ifdef HAVE_LIBREADLINE
-
 	if (interactive && prompt && have_rl) {
 		rl_readline_name = "rigctl";
 #ifdef HAVE_READLINE_HISTORY
-		using_history();
+		using_history();	/* Initialize Readline History */
+
+		if (rd_hist || sv_hist) {
+			if (!(hist_dir = getenv("RIGCTL_HIST_DIR")))
+				hist_dir = getenv("HOME");
+
+			if (((stat(hist_dir, &hist_dir_stat) == -1) && (errno == ENOENT))
+				|| !(S_ISDIR(hist_dir_stat.st_mode))) {
+				fprintf(stderr, "Warning: %s is not a directory!\n", hist_dir);
+			}
+
+			hist_path = (char *)calloc((sizeof(char) * (strlen(hist_dir) + strlen(hist_file) + 1)), sizeof(char));
+
+			strncpy(hist_path, hist_dir, strlen(hist_dir));
+			strncat(hist_path, hist_file, strlen(hist_file));
+		}
+
+		if (rd_hist && hist_path)
+			if (read_history(hist_path) == ENOENT)
+				fprintf(stderr, "Warning: Could not read history from %s\n", hist_path);
 #endif
 	}
-
 #endif	/* HAVE_LIBREADLINE */
 
 	do {
@@ -378,6 +419,20 @@ int main (int argc, char *argv[])
 	}
 	while (retcode == 0 || retcode == 2);
 
+#ifdef HAVE_LIBREADLINE
+	if (interactive && prompt && have_rl) {
+#ifdef HAVE_READLINE_HISTORY
+		if (sv_hist && hist_path)
+			if (write_history(hist_path) == ENOENT)
+				fprintf(stderr, "\nWarning: Could not write history to %s\n", hist_path);
+
+		if ((rd_hist || sv_hist) && hist_path) {
+			free(hist_path);
+			hist_path = (char *)NULL;
+		}
+	}
+#endif
+#endif
 	rig_close(my_rig); /* close port */
 	rig_cleanup(my_rig); /* if you care about memory */
 
@@ -406,6 +461,10 @@ void usage(void)
 	"  -l, --list                 list all model numbers and exit\n"
 	"  -u, --dump-caps            dump capabilities and exit\n"
 	"  -o, --vfo                  do not default to VFO_CURR, require extra vfo arg\n"
+#ifdef HAVE_READLINE_HISTORY
+	"  -i, --read-history         read prior interactive session history\n"
+	"  -I, --save-history         save current interactive session history\n"
+#endif
 	"  -v, --verbose              set verbose mode, cumulative\n"
 	"  -h, --help                 display this help and exit\n"
 	"  -V, --version              output version information and exit\n\n"