pw-cli: use readline() in interactive mode

With history and a simple command completion hook this makes the
interactive mode a lot easier to deal with.

meson.build

@@ -325,6 +325,7 @@ pthread_lib = dependency('threads')
 dbus_dep = dependency('dbus-1')
 sdl_dep = dependency('sdl2', required : get_option('sdl2'))
 summary({'SDL 2': sdl_dep.found()}, bool_yn: true, section: 'Misc dependencies')
+readline_dep = dependency('readline', required : false)
 ncurses_dep = dependency('ncursesw', required : false)
 sndfile_dep = dependency('sndfile', version : '>= 1.0.20', required : get_option('sndfile'))
 summary({'sndfile': sndfile_dep.found()}, bool_yn: true, section: 'pw-cat/pw-play/pw-dump/filter-chain')

src/tools/meson.build

@@ -1,6 +1,5 @@
 tools_sources = [
   [ 'pw-mon', [ 'pw-mon.c' ] ],
-  [ 'pw-cli', [ 'pw-cli.c' ] ],
   [ 'pw-dot', [ 'pw-dot.c' ] ],
   [ 'pw-dump', [ 'pw-dump.c' ] ],
   [ 'pw-profiler', [ 'pw-profiler.c' ] ],
@@ -18,6 +17,14 @@ foreach t : tools_sources
   )
 endforeach
 
+if readline_dep.found()
+  executable('pw-cli',
+    'pw-cli.c',
+    install: true,
+    dependencies: [pipewire_dep, readline_dep]
+  )
+endif
+
 if ncurses_dep.found()
   executable('pw-top',
 	'pw-top.c',

src/tools/pw-cli.c

@@ -32,6 +32,8 @@
 #include <alloca.h>
 #endif
 #include <getopt.h>
+#include <readline/readline.h>
+#include <readline/history.h>
 
 #define spa_debug(...) fprintf(stdout,__VA_ARGS__);fputc('\n', stdout)
 
@@ -48,6 +50,7 @@
 #include <pipewire/extensions/session-manager.h>
 
 static const char WHITESPACE[] = " \t";
+static char prompt[64];
 
 struct remote_data;
 
@@ -279,11 +282,10 @@ static void on_core_info(void *_data, const struct pw_core_info *info)
 		fprintf(stdout, "remote %d is named '%s'\n", rd->id, rd->name);
 }
 
-static void show_prompt(struct remote_data *rd)
+static void set_prompt(struct remote_data *rd)
 {
-	rd->data->monitoring = true;
-	fprintf(stdout, "%s>>", rd->name);
-	fflush(stdout);
+	snprintf(prompt, sizeof(prompt), "%s>> ", rd->name);
+	rl_set_prompt(prompt);
 }
 
 static void on_core_done(void *_data, uint32_t id, int seq)
@@ -292,10 +294,12 @@ static void on_core_done(void *_data, uint32_t id, int seq)
 	struct data *d = rd->data;
 
 	if (seq == rd->prompt_pending) {
-		if (d->interactive)
-			show_prompt(rd);
-		else
+		if (d->interactive) {
+			set_prompt(rd);
+			rd->data->monitoring = true;
+		} else {
 			pw_main_loop_quit(d->loop);
+		}
 	}
 }
 
@@ -2880,7 +2884,7 @@ usage:
 	return false;
 }
 
-static bool parse(struct data *data, char *buf, size_t size, char **error)
+static bool parse(struct data *data, char *buf, char **error)
 {
 	char *a[2];
 	int n;
@@ -2912,35 +2916,35 @@ static bool parse(struct data *data, char *buf, size_t size, char **error)
 	return false;
 }
 
-static void do_input(void *data, int fd, uint32_t mask)
+/* We need a global variable, readline doesn't have a closure arg */
+static struct data *readline_dataptr;
+
+static void readline_process_line(char *line)
 {
-	struct data *d = data;
-	char buf[4096], *error;
-	ssize_t r;
+	struct data *d = readline_dataptr;
+	char *error;
 
-	if (mask & SPA_IO_IN) {
-		while (true) {
-			r = read(fd, buf, sizeof(buf)-1);
-			if (r < 0) {
-				if (errno == EAGAIN)
-					continue;
-				perror("read");
-				r = 0;
-				break;
-			}
-			break;
-		}
-		if (r == 0) {
-			fprintf(stdout, "\n");
-			pw_main_loop_quit(d->loop);
-			return;
-		}
-		buf[r] = '\0';
+	if (!line)
+		line = strdup("quit");
 
-		if (!parse(d, buf, r, &error)) {
+	if (line[0] != '\0') {
+		add_history(line);
+		if (!parse(d, line, &error)) {
 			fprintf(stdout, "Error: \"%s\"\n", error);
 			free(error);
 		}
+	}
+	free(line);
+}
+
+static void do_input(void *data, int fd, uint32_t mask)
+{
+	struct data *d = data;
+
+	if (mask & SPA_IO_IN) {
+		readline_dataptr = d;
+		rl_callback_read_char();
+
 		if (d->current == NULL)
 			pw_main_loop_quit(d->loop);
 		else  {
@@ -2951,6 +2955,55 @@ static void do_input(void *data, int fd, uint32_t mask)
 	}
 }
 
+static char *
+readline_match_command(const char *text, int state)
+{
+	static size_t idx;
+	static int len;
+
+	if (!state) {
+		idx = 0;
+		len = strlen(text);
+	}
+
+	while (idx < SPA_N_ELEMENTS(command_list))  {
+		const char *name = command_list[idx].name;
+		const char *alias = command_list[idx].alias;
+
+		idx++;
+		if (spa_strneq(name, text, len) || spa_strneq(alias, text, len))
+			return strdup(name);
+	}
+
+	return NULL;
+}
+
+static char **
+readline_command_completion(const char *text, int start, int end)
+{
+	char **matches = NULL;
+
+	/* Only try to complete the first word in a line */
+	if (start == 0)
+		matches = rl_completion_matches(text, readline_match_command);
+
+	/* Don't fall back to filename completion */
+	rl_attempted_completion_over = true;
+
+	return matches;
+}
+
+static void readline_init()
+{
+	rl_attempted_completion_function = readline_command_completion;
+	rl_callback_handler_install(">> ", readline_process_line);
+}
+
+static void readline_cleanup()
+{
+	rl_callback_handler_remove();
+}
+
 static void do_quit_on_signal(void *data, int signal_number)
 {
 	struct data *d = data;
@@ -3046,12 +3099,16 @@ int main(int argc, char *argv[])
 	if (optind == argc) {
 		data.interactive = true;
 
-		pw_loop_add_io(l, STDIN_FILENO, SPA_IO_IN|SPA_IO_HUP, false, do_input, &data);
-
 		fprintf(stdout, "Welcome to PipeWire version %s. Type 'help' for usage.\n",
 				pw_get_library_version());
 
+		readline_init();
+
+		pw_loop_add_io(l, STDIN_FILENO, SPA_IO_IN|SPA_IO_HUP, false, do_input, &data);
+
 		pw_main_loop_run(data.loop);
+
+		readline_cleanup();
 	} else {
 		char buf[4096], *p, *error;
 
@@ -3063,7 +3120,7 @@ int main(int argc, char *argv[])
 
 		pw_main_loop_run(data.loop);
 
-		if (!parse(&data, buf, p - buf, &error)) {
+		if (!parse(&data, buf, &error)) {
 			fprintf(stdout, "Error: \"%s\"\n", error);
 			free(error);
 		}