Move command spawning to separate module

Makefile

@@ -3,7 +3,7 @@
 
 include config.mk
 
-SRC = atoms.c drw.c dwm.c settings.c tags.c util.c
+SRC = atoms.c drw.c dwm.c settings.c spawn.c tags.c util.c
 OBJ = ${SRC:.c=.o}
 
 all: options polytreewm
@@ -17,7 +17,7 @@ options:
 %.o: %.c
 	${CC} -c $< -o $@ ${CFLAGS}
 
-${OBJ}: atoms.h drw.h config.def.h config.mk settings.h tags.h util.h
+${OBJ}: atoms.h drw.h config.def.h config.mk settings.h spawn.h tags.h util.h
 
 polytreewm: ${OBJ}
 	${CC} -o $@ ${OBJ} ${LDFLAGS}

config.def.h

@@ -51,18 +51,12 @@ static const Layout layouts[] = {
 	{ MODKEY|ShiftMask,             KEY,      tag,            {.ui = 1 << TAG} }, \
 	{ MODKEY|ControlMask|ShiftMask, KEY,      toggletag,      {.ui = 1 << TAG} },
 
-/* commands */
-static char dmenumon[2] = "0"; /* component of dmenucmd, manipulated in spawn() */
-static const char *dmenucmd[] = { "dmenu_run", "-m", dmenumon, "-fn", dmenufont, "-nb", col_gray1, "-nf", col_gray3, "-sb", col_cyan, "-sf", col_gray4, NULL };
-static const char *termcmd[]  = { "st", NULL };
-static const char *firefoxcmd[] = { "firefox", NULL };
-
 static Key keys[] = {
 	/* modifier                     key        function        argument */
 	{ MODKEY,                       XK_n,      nametag,        {0} },
-	{ MODKEY,                       XK_slash,  spawn,          {.v = dmenucmd } },
-	{ MODKEY|ShiftMask,             XK_Return, spawn,          {.v = termcmd } },
-	{ MODKEY|ShiftMask,             XK_f,      spawn,          {.v = firefoxcmd } },
+	{ MODKEY,                       XK_slash,  spawn,          {.v = "menu" } },
+	{ MODKEY|ShiftMask,             XK_Return, spawn,          {.v = "term" } },
+	{ MODKEY|ShiftMask,             XK_f,      spawn,          {.v = "firefox" } },
 	{ MODKEY,                       XK_b,      togglebar,      {0} },
 	{ MODKEY,                       XK_j,      focusstack,     {.i = +1 } },
 	{ MODKEY,                       XK_k,      focusstack,     {.i = -1 } },

dwm.c

@@ -28,7 +28,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <sys/types.h>
 #include <sys/wait.h>
 #include <X11/cursorfont.h>
 #include <X11/keysym.h>
@@ -44,6 +43,7 @@
 #include "atoms.h"
 #include "drw.h"
 #include "settings.h"
+#include "spawn.h"
 #include "tags.h"
 #include "util.h"
 
@@ -235,6 +235,7 @@ static void seturgent(Client *c, int urg);
 static void showhide(Client *c);
 static void sigchld(int unused);
 static void spawn(const Arg *arg);
+static void spawn_callback();
 static Monitor *systraytomon(Monitor *m);
 static void tag(const Arg *arg);
 static void tagmon(const Arg *arg);
@@ -2074,16 +2075,16 @@ sigchld(int unused)
 void
 spawn(const Arg *arg)
 {
-	if (arg->v == dmenucmd)
-		dmenumon[0] = '0' + selmon->num;
-	if (fork() == 0) {
-		if (dpy)
-			close(ConnectionNumber(dpy));
-		setsid();
-		execvp(((char **)arg->v)[0], (char **)arg->v);
-		fprintf(stderr, "polytreewm: execvp %s", ((char **)arg->v)[0]);
-		perror(" failed");
-		exit(EXIT_SUCCESS);
+	const char *const command_name = arg->v;
+
+	spawn_command(command_name, spawn_callback, selmon->num);
+}
+
+void
+spawn_callback()
+{
+	if (dpy) {
+		close(ConnectionNumber(dpy));
 	}
 }
 

spawn.c

@@ -0,0 +1,121 @@
+#include "spawn.h"
+
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define MAX_ARGS_COUNT 20
+#define ARGS_SIZE (MAX_ARGS_COUNT + 1)
+#define MON_ARG_SIZE 2
+
+struct Command {
+	const char *name;
+	size_t monitor_arg_index;
+	const char *args[ARGS_SIZE];
+};
+
+static struct Command commands[] = {
+	{
+		.name = "menu",
+		.monitor_arg_index = 2,
+		.args = {
+			"dmenu_run",
+			// monitor
+			"-m",
+			"0",
+			// font
+			"-fn",
+			"monospace:size=10",
+			// color: gray 1
+			"-nb",
+			"#222222",
+			// color: gray 3
+			"-nf",
+			"#bbbbbb",
+			// color: cyan
+			"-sb",
+			"#005577",
+			// color: gray 4
+			"-sf",
+			"#eeeeee",
+			NULL,
+		},
+	},
+	{
+		.name = "term",
+		.monitor_arg_index = -1,
+		.args = { "st", NULL },
+	},
+	{
+		.name = "firefox",
+		.monitor_arg_index = -1,
+		.args = { "firefox", NULL },
+	},
+};
+
+void spawn_command(
+	const char *const name,
+	void (*const callback)(),
+	const int monitor
+) {
+	if (name == NULL || monitor < 0 || monitor > 9) return;
+
+	for (
+		size_t command_index = 0;
+		command_index < sizeof(commands) / sizeof(struct Command);
+		++command_index
+	) {
+		const struct Command *const command = &commands[command_index];
+		if (strcmp(name, command->name) != 0) continue;
+
+		// We discard const modifier
+		// because we will only change newly allocated version.
+		char **args = (char**)command->args;
+
+		if (command->monitor_arg_index != -1) {
+			args = malloc(sizeof(char*) * ARGS_SIZE);
+			if (args == NULL) break;
+
+			for (size_t arg_index = 0;; ++arg_index) {
+				// We discard const modifier
+				// because we will only change newly allocated version.
+				args[arg_index] = (char*)command->args[arg_index];
+				if (args[arg_index] == NULL) break;
+			}
+
+			args[command->monitor_arg_index] =
+				malloc(sizeof(char) * MON_ARG_SIZE);
+			if (args[command->monitor_arg_index] == NULL) {
+				free(args);
+				break;
+			}
+
+			args[command->monitor_arg_index][0] = '0' + monitor;
+			args[command->monitor_arg_index][1] = '\0';
+		}
+
+		if (fork() == 0) {
+			// TODO: DRY (see the same code below)
+			if (command->monitor_arg_index != -1) {
+				free(args[command->monitor_arg_index]);
+				free(args);
+			}
+
+			callback();
+			setsid();
+			execvp(args[0], args);
+			fprintf(stderr, "polytreewm: execvp %s", args[0]);
+			perror(" failed");
+			exit(EXIT_SUCCESS);
+		}
+
+		if (command->monitor_arg_index != -1) {
+			free(args[command->monitor_arg_index]);
+			free(args);
+		}
+
+		break;
+	}
+}

spawn.h

@@ -0,0 +1,6 @@
+#ifndef _SPAWN_H
+#define _SPAWN_H
+
+void spawn_command(const char *name, void (*callback)(), int monitor);
+
+#endif // _SPAWN_H