Do not use argparge for parsing --env and --cwd

It took 2/3 of do_render call according to profiler. New variant takes only 1/6.

WARNING: This commit will break all powerline installations with running daemon
because it changes communication protocol. You must kill and restart all your
powerline daemons for powerline to function properly.

Highlight @kovidgoyal

client/powerline.c

@@ -60,6 +60,7 @@ int main(int argc, char *argv[]) {
 	struct sockaddr_un server;
 	char address[ADDRESS_SIZE];
 	const char eof[2] = "\0\0";
+	char num_args[NUM_ARGS_SIZE];
 	char buf[BUF_SIZE];
 	char *newargv[NEW_ARGV_SIZE];
 	char *wd = NULL;
@@ -90,24 +91,26 @@ int main(int argc, char *argv[]) {
 		execvp("powerline-render", newargv);
 	}
 
+	snprintf(num_args, NUM_ARGS_SIZE, "%x", argc - 1);
+	do_write(sd, num_args, strlen(num_args));
+	do_write(sd, eof, 1);
+
 	for (i = 1; i < argc; i++) {
 		do_write(sd, argv[i], strlen(argv[i]));
 		do_write(sd, eof, 1);
 	}
 
-	for(envp=environ; *envp; envp++) {
-		do_write(sd, "--env=", 6);
-		do_write(sd, *envp, strlen(*envp));
-		do_write(sd, eof, 1);
-	}
-
 	wd = getcwd(NULL, 0);
 	if (wd != NULL) {
-		do_write(sd, "--cwd=", 6);
 		do_write(sd, wd, strlen(wd));
 		free(wd); wd = NULL;
 	}
 
+	for(envp=environ; *envp; envp++) {
+		do_write(sd, *envp, strlen(*envp));
+		do_write(sd, eof, 1);
+	}
+
 	do_write(sd, eof, 2);
 
 	i = -1;

client/powerline.py

@@ -42,7 +42,8 @@ fenc = sys.getfilesystemencoding() or 'utf-8'
 if fenc == 'ascii':
 	fenc = 'utf-8'
 
-args = [x.encode(fenc) if isinstance(x, type('')) else x for x in sys.argv[1:]]
+args = [bytes('%x' % (len(sys.argv) - 1))]
+args.extend((x.encode(fenc) if isinstance(x, type('')) else x for x in sys.argv[1:]))
 
 try:
 	cwd = os.getcwd()
@@ -51,17 +52,17 @@ except EnvironmentError:
 else:
 	if isinstance(cwd, type('')):
 		cwd = cwd.encode(fenc)
-	args.append(b'--cwd=' + cwd)
+	args.append(cwd)
 
 
 env = (k + b'=' + v for k, v in os.environ.items())
 env = (x if isinstance(x, bytes) else x.encode(fenc, 'replace') for x in env)
-args.extend((b'--env=' + x for x in env))
+args.extend(env)
 
 EOF = b'\0\0'
 
 for a in args:
-	eintr_retry_call(sock.sendall, a + EOF[0])
+	eintr_retry_call(sock.sendall, a + b'\0')
 
 eintr_retry_call(sock.sendall, EOF)
 
@@ -74,4 +75,4 @@ while True:
 
 sock.close()
 
-print (b''.join(received))
+sys.stdout.write(b''.join(received))

client/powerline.sh

@@ -5,11 +5,12 @@ ADDRESS="powerline-ipc-${UID:-`id -u`}"
 # Warning: env -0 does not work in busybox. Consider switching to parsing 
 # `set` output in this case
 (
+	printf '%x\0' "$#"
 	for argv in "$@" ; do
 		printf '%s\0' "$argv"
 	done
-	env -0 | sed 's/\(\x00\)\([^\x00]\)\|^/\1--env=\2/g'
-	printf -- '--cwd=%s\0' "$PWD"
+	printf '%s\0' "$PWD"
+	env -0
 ) | socat -lf/dev/null -t 10 - abstract-client:"$ADDRESS"
 
 if test $? -ne 0 ; then

scripts/powerline-daemon

@@ -48,8 +48,6 @@ class NonInteractiveArgParser(ArgumentParser):
 
 
 parser = get_argparser(parser=NonInteractiveArgParser, description='powerline daemon')
-parser.add_argument('--cwd', metavar='PATH')
-parser.add_argument('--env', action='append')
 
 EOF = b'EOF\0\0'
 
@@ -67,11 +65,10 @@ class PowerlineDaemon(ShellPowerline):
 		return super(PowerlineDaemon, self).get_log_handler()
 
 
-def render(args):
+def render(args, environ, cwd):
 	global logger
 	global config_loader
-	environ = dict(((k, v) for k, v in (x.partition('=')[0::2] for x in args.env)))
-	cwd = environ.get('PWD', args.cwd or '/')
+	cwd = cwd or environ.get('PWD', '/')
 	segment_info = {
 		'getcwd': lambda: cwd,
 		'home': environ.get('HOME', home),
@@ -175,11 +172,18 @@ def safe_bytes(o, encoding=encoding):
 		return safe_bytes(str(e), encoding)
 
 
+def parse_args(req):
+	args = [x.decode(encoding) for x in req.split(b'\0') if x]
+	numargs = int(args[0], 16)
+	shell_args = parser.parse_args(args[1:numargs + 1])
+	cwd = args[numargs + 1]
+	environ = dict(((k, v) for k, v in (x.partition('=')[0::2] for x in args[numargs + 2:])))
+	return shell_args, environ, cwd
+
+
 def do_render(req):
 	try:
-		args = [x.decode(encoding) for x in req.split(b'\0') if x]
-		args = parser.parse_args(args)
-		return safe_bytes(render(args))
+		return safe_bytes(render(*parse_args(req)))
 	except Exception as e:
 		return safe_bytes(str(e))