Add module "menu"

Makefile

@@ -3,7 +3,7 @@
 
 include config.mk
 
-SRC = atoms.c drw.c dwm.c helpers.c layouts.c settings.c spawn.c tags.c util.c
+SRC = atoms.c drw.c dwm.c helpers.c layouts.c menu.c settings.c spawn.c tags.c util.c
 OBJ = ${SRC:.c=.o}
 
 DWM_SRC = dwm/handlers.c dwm/layouts.c dwm/swallow.c dwm/systray.c
@@ -21,7 +21,7 @@ options:
 	${CC} -c $< -o $@ ${CFLAGS}
 
 dwm.o: ${DWM_SRC} ${DWM_HDR}
-${OBJ}: atoms.h drw.h config.def.h config.mk helpers.h layouts.h settings.h spawn.h tags.h util.h
+${OBJ}: atoms.h drw.h config.def.h config.mk helpers.h layouts.h menu.h settings.h spawn.h tags.h util.h
 
 polytreewm: ${OBJ}
 	${CC} -o $@ ${OBJ} ${LDFLAGS}

dwm.c

@@ -20,7 +20,6 @@
  *
  * To understand everything else, start reading main().
  */
-#include <errno.h>
 #include <locale.h>
 #include <signal.h>
 #include <stdarg.h>
@@ -50,6 +49,7 @@
 #include "drw.h"
 #include "helpers.h"
 #include "layouts.h"
+#include "menu.h"
 #include "settings.h"
 #include "spawn.h"
 #include "tags.h"
@@ -1243,25 +1243,11 @@ movemouse(const Arg *arg)
 // TODO: this function really needs to be refactored
 void
 nametag(const Arg *arg) {
-	char *p, name[TAGS_CUSTOM_NAME_SIZE];
-	FILE *f;
-	int i;
+	char name[TAGS_CUSTOM_NAME_SIZE];
 
-	errno = 0; // popen(3p) says on failure it "may" set errno
-	if(!(f = popen("rofi -dmenu -p \"Tag name\"", "r"))) {
-		fprintf(stderr, "polytreewm: popen 'rofi -dmenu -p \"Tag name\"' failed%s%s\n", errno ? ": " : "", errno ? strerror(errno) : "");
-		return;
-	}
-	if (!(p = fgets(name, TAGS_CUSTOM_NAME_SIZE, f)) && (i = errno) && ferror(f))
-		fprintf(stderr, "polytreewm: fgets failed: %s\n", strerror(i));
-	if (pclose(f) < 0)
-		fprintf(stderr, "polytreewm: pclose failed: %s\n", strerror(errno));
-	if(!p)
-		return;
-	if((p = strchr(name, '\n')))
-		*p = '\0';
+	if (!menu_run(name, TAGS_CUSTOM_NAME_SIZE, "Tag name")) return;
 
-	for (i = 0; i < TAGS_COUNT; ++i) {
+	for (int i = 0; i < TAGS_COUNT; ++i) {
 		if (selmon->tagset[selmon->seltags] & (1 << i)) {
 			tags_rename(i, name);
 		}

menu.c

@@ -0,0 +1,73 @@
+#include "menu.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define COMMAND_SIZE 256
+
+bool menu_run(
+	char *const buffer,
+	const size_t buffer_size,
+	const char *prompt
+) {
+	// TODO: maybe we should assert here
+	if (buffer == NULL || buffer_size < 2) return false;
+
+	if (prompt == NULL) {
+		prompt = "";
+	}
+
+	for (const char *s = prompt; *s; ++s) {
+		// Simple check to ensure that the prompt
+		// string doesn't need to be escaped.
+		// TODO: maybe we should assert here
+		if (*s == '"') return false;
+	}
+
+	char command[COMMAND_SIZE];
+	const int command_slen =
+		snprintf(command, COMMAND_SIZE, "rofi -dmenu -p \"%s\"", prompt);
+
+	// Simple check to ensure that the prompt string is not too long.
+	// TODO: maybe we should assert here
+	if (command_slen >= COMMAND_SIZE) return false;
+
+	errno = 0; // popen(3p) says on failure it "may" set errno
+	FILE *f = popen(command, "r");
+
+	if (!f) {
+		perror("polytreewm: menu: popen failed");
+		return false;
+	}
+
+	const char *const buffer_result = fgets(buffer, buffer_size, f);
+
+	// Just to ensure that string is null-terminated.
+	// The man page fgets(3) is not very clear about that.
+	buffer[buffer_size - 1] = '\0';
+
+	if (!buffer_result) {
+		perror("polytreewm: menu: fgets failed");
+		pclose(f);
+		return false;
+	}
+
+	// Fail on both pipe error and not successfull exit status.
+	if (pclose(f) != EXIT_SUCCESS) {
+		perror("polytreewm: menu: pclose failed");
+		return false;
+	}
+
+	for (char *s = buffer; *s; ++s) {
+		if (*s == '\n') {
+			if (*(s + 1) == '\0') {
+				*s = '\0';
+			} else {
+				*s = ' ';
+			}
+		}
+	}
+
+	return true;
+}

menu.h

@@ -0,0 +1,9 @@
+#ifndef _MENU_H
+#define _MENU_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+bool menu_run(char *buffer, size_t buffer_size, const char *prompt);
+
+#endif // _MENU_H