dmenu_path.c (shell is a bottleneck)

Makefile

@@ -3,7 +3,7 @@
 
 include config.mk
 
-all: options dmenu
+all: options dmenu dmenu_path
 
 options:
 	@echo dmenu build options:
@@ -11,22 +11,21 @@ options:
 	@echo "LDFLAGS  = ${LDFLAGS}"
 	@echo "CC       = ${CC}"
 
-dmenu.o: dmenu.c config.mk
-	@echo CC $<
-	@${CC} -c ${CFLAGS} $<
+dmenu: dmenu.c config.mk
+dmenu_path: dmenu_path.c
 
-dmenu: dmenu.o
+dmenu dmenu_path:
 	@echo CC -o $@
-	@${CC} -o $@ $+ ${LDFLAGS}
+	@${CC} -o $@ $< ${CFLAGS} ${LDFLAGS}
 
 clean:
 	@echo cleaning
-	@rm -f dmenu dmenu.o dmenu-${VERSION}.tar.gz
+	@rm -f dmenu dmenu_path dmenu-${VERSION}.tar.gz
 
 dist: clean
 	@echo creating dist tarball
 	@mkdir -p dmenu-${VERSION}
-	@cp LICENSE Makefile README config.mk dmenu.1 dmenu.c dmenu_path dmenu_run dmenu-${VERSION}
+	@cp LICENSE Makefile README config.mk dmenu.1 dmenu.c dmenu_path.c dmenu_run dmenu-${VERSION}
 	@tar -cf dmenu-${VERSION}.tar dmenu-${VERSION}
 	@gzip dmenu-${VERSION}.tar
 	@rm -rf dmenu-${VERSION}

dmenu_path

@@ -1,26 +0,0 @@
-#!/bin/sh
-CACHE=$HOME/.dmenu_cache
-IFS=:
-
-uptodate() {
-	test -f "$CACHE" &&
-	for dir in $PATH
-	do
-		test ! $dir -nt "$CACHE" || return 1
-	done
-}
-
-if ! uptodate
-then
-	for dir in $PATH
-	do
-		cd "$dir" &&
-		for file in *
-		do
-			test -x "$file" && echo "$file"
-		done
-	done | sort -u > "$CACHE".$$ &&
-	mv "$CACHE".$$ "$CACHE"
-fi
-
-cat "$CACHE"

dmenu_path.c

@@ -0,0 +1,101 @@
+/* See LICENSE file for copyright and license details. */
+#include <dirent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#define CACHE ".dmenu_cache"
+
+static int qstrcmp(const void *a, const void *b);
+static void die(const char *s);
+static void scan(void);
+static int uptodate(void);
+
+static char **items = NULL;
+static const char *Home, *Path;
+static size_t count = 0;
+
+int
+main(void) {
+	if(!(Home = getenv("HOME")))
+		die("no $HOME");
+	if(!(Path = getenv("PATH")))
+		die("no $PATH");
+	if(chdir(Home) < 0)
+		die("chdir failed");
+	if(uptodate()) {
+		execlp("cat", "cat", CACHE, NULL);
+		die("exec failed");
+	}
+	scan();
+	return EXIT_SUCCESS;
+}
+
+void
+die(const char *s) {
+	fprintf(stderr, "dmenu_path: %s\n", s);
+	exit(EXIT_FAILURE);
+}
+
+int
+qstrcmp(const void *a, const void *b) {
+	return strcmp(*(const char **)a, *(const char **)b);
+}
+
+void
+scan(void) {
+	char buf[PATH_MAX];
+	char *dir, *path;
+	size_t i;
+	struct dirent *ent;
+	DIR *dp;
+	FILE *cache;
+
+	if(!(path = strdup(Path)))
+		die("strdup failed");
+	for(dir = strtok(path, ":"); dir; dir = strtok(NULL, ":")) {
+		if(!(dp = opendir(dir)))
+			continue;
+		while((ent = readdir(dp))) {
+			snprintf(buf, sizeof buf, "%s/%s", dir, ent->d_name);
+			if(ent->d_name[0] == '.' || access(buf, X_OK) < 0)
+				continue;
+			if(!(items = realloc(items, ++count * sizeof *items)))
+				die("malloc failed");
+			if(!(items[count-1] = strdup(ent->d_name)))
+				die("strdup failed");
+		}
+		closedir(dp);
+	}
+	qsort(items, count, sizeof *items, qstrcmp);
+	if(!(cache = fopen(CACHE, "w")))
+		die("open failed");
+	for(i = 0; i < count; i++) {
+		if(i > 0 && !strcmp(items[i], items[i-1]))
+			continue;
+		fprintf(cache,  "%s\n", items[i]);
+		fprintf(stdout, "%s\n", items[i]);
+	}
+	fclose(cache);
+	free(path);
+}
+
+int
+uptodate(void) {
+	char *dir, *path;
+	time_t mtime;
+	struct stat st;
+
+	if(stat(CACHE, &st) < 0)
+		return 0;
+	mtime = st.st_mtime;
+	if(!(path = strdup(Path)))
+		die("strdup failed");
+	for(dir = strtok(path, ":"); dir; dir = strtok(NULL, ":"))
+		if(!stat(dir, &st) && st.st_mtime > mtime)
+			return 0;
+	free(path);
+	return 1;
+}