Remove concat function and use snprintf wrapper.

1 files changed, 59 insertions, 85 deletions

diff --git a/main.c b/main.c
index 2b724c4..5202715 100644
--- a/main.c
+++ b/main.c
@@ -3,6 +3,7 @@
 #include <fcntl.h>
 #include <fnmatch.h>
 #include <ftw.h>
+#include <limits.h>
 #include <sha1.h>
 #include <stdarg.h>
 #include <stdio.h>
@@ -18,10 +19,10 @@
 
 #define EXCLUDE_PATHS  ".vcxignore" 
 
-#define BUF_LEN       8192
-#define MAX_DEPTH      256
-#define MAX_PATH_LEN  4096
-#define HASH_LEN      SHA1_DIGEST_STRING_LENGTH 
+#define MAX_DEPTH  256
+#define BUF_LEN    8192
+#define PATH_LEN   PATH_MAX
+#define HASH_LEN   SHA1_DIGEST_STRING_LENGTH 
 
 #define KIND_DEL  'D'
 #define KIND_MOD  'M'
@@ -44,15 +45,15 @@ static inline void print_status(const char *file, char kind, int islnk);
 static inline int scan_head(const char * path, const struct stat *st, int flag, struct FTW *ftwbuf);
 static inline int scan_tree(const char * path, const struct stat *st, int flag, struct FTW *ftwbuf);
 
-static inline void mkcopy(const char *path, char dst[HASH_LEN]);
-static inline void mklink(const char *src, const char obj[HASH_LEN]);
+static inline void mkcopy(const char *path, char *dst);
+static inline void mklink(const char *src, const char *obj);
 
 static inline void mkdirs(const char *path);
 static inline void copy_link(const char *src);
 static inline void copy_file(const char *src, const char *dst);
 
 static inline int lnklen(const char *lnk);
-static inline void concat(char *dst, size_t n, const char *arg1, ...);
+static inline char *format_path(const char *fmt, ...);
 
 static inline void *_xmalloc(size_t s, const char *file, int line);
 static inline void *_xrealloc(void *ptr, size_t s, const char *file, int line);
@@ -120,7 +121,7 @@ static inline void add(int argc, char *argv[])
 {
 	size_t i;
 	struct stat st;
-	char *wt_path;
+	char *wt_path, *hd_path;
 	
 	if (argc < 2)
 		errx(1, "Usage: %s [<files>]", argv[0]);
@@ -133,14 +134,8 @@ static inline void add(int argc, char *argv[])
 		if (lstat(wt_path, &st) == -1)
 			err(1, "%s", wt_path);
 
-		size_t hd_sz = strlen(HEAD) + strlen(wt_path) + 2;
-		char hd_path[hd_sz];
-		concat(hd_path, hd_sz, HEAD, "/", wt_path, NULL);
+		hd_path = format_path("%s/%s", HEAD, wt_path);
 
-		size_t tmp_sz = strlen(TMP_DIR) + strlen(wt_path) + 2;
-		char tmp_path[tmp_sz];
-		concat(tmp_path, tmp_sz, TMP_DIR, "/", wt_path, NULL);
-		
 		if (nftw(hd_path, scan_head, MAX_DEPTH, FTW_PHYS) == -1)
 			err(1, "Failed to scan head");	
 
@@ -152,14 +147,12 @@ static inline void add(int argc, char *argv[])
 int scan_head(const char * path, const struct stat *sb, int flag, 
 	struct FTW *ftwbuf)
 {
+	char *wt_path;
 	struct stat wt_stat;
 
 	if (flag == FTW_F) {
 		const char *filename = path + ftwbuf->base;
-
-		size_t wt_sz = strlen(filename) + 3;
-		char wt_path[wt_sz];
-		concat(wt_path, wt_sz, ".", "/", filename, NULL);
+		wt_path = format_path("./%s", filename);
 
 		if (lstat(wt_path, &wt_stat) == -1) {
 			if (errno == ENOENT) {
@@ -190,16 +183,14 @@ int scan_head(const char * path, const struct stat *sb, int flag,
 static inline int scan_tree(const char * path, const struct stat *st, 
 	int flag, struct FTW *ftwbuf)
 {
+	char *hd_path;
+
 	if (fnmatch("./.vcx/*", path, 0) == 0)
 		return 0;
 
 	if (flag == FTW_F) {
 		const char *filename = path + ftwbuf->base;
-
-		size_t hd_sz = strlen(HEAD) + strlen(filename) + 2;
-		char hd_path[hd_sz];
-		concat(hd_path, hd_sz, HEAD, "/", filename, NULL);
-
+		hd_path = format_path("%s/%s", HEAD, filename);
 		if (access(hd_path, F_OK) != 0)
 			scan_res_cb(path, KIND_NEW, S_ISLNK(st->st_mode) != 0);
 	}
@@ -304,36 +295,31 @@ static inline void stage_entry(const char *path, char kind, int islnk)
 	}
 }
 
-static inline void mkcopy(const char *path, char dst[HASH_LEN])
+static inline void mkcopy(const char *path, char *dst)
 {
-	int len, obj_len;
-	char obj_name[HASH_LEN];
+	int len;
+	char *obj_path;
 
 	len = strlen(path);
-	obj_len = HASH_LEN - 1;
-	if (SHA1Data((const uint8_t *)path, len, obj_name) == NULL)
+
+	if (SHA1Data((const uint8_t *)path, len, dst) == NULL)
 		err(1, "Failed to compute hash for %s", path);
 
-	size_t obj_sz = strlen(OBJ_DIR) + obj_len + 6;
-	char obj_path[obj_sz];
-	concat(obj_path, obj_sz, OBJ_DIR, "/", obj_name, ".tmp", NULL);
+	obj_path = format_path("%s/%s.tmp", OBJ_DIR, dst);
 	copy_file(path, obj_path);
 }
 
-static inline void mklink(const char *src, const char obj[HASH_LEN])
+static inline void mklink(const char *src, const char *obj)
 {
-	// HASH_LEN includes null byte
-	size_t lnkt_sz = strlen("../obj/") + HASH_LEN + 4;
-	char lnk_target[lnkt_sz];
-	concat(lnk_target, lnkt_sz, "../obj/", obj, ".tmp", NULL);
-
-	size_t lnkp_sz = strlen(TMP_DIR) + strlen(src) + 2;
-	char lnk_path[lnkp_sz];
-	concat(lnk_path, lnkp_sz, TMP_DIR, "/", src, NULL);
-
-	mkdirs(lnk_path);
-	if (symlink(lnk_target, lnk_path) != 0)
-		err(1, "symlink error on %s", src);
+	char *lnk, *dst;
+
+	lnk = format_path("../obj/%s.tmp", obj);
+	dst = format_path("%s/%s", TMP_DIR, src);
+
+	mkdirs(dst);
+
+	if (symlink(lnk, dst) != 0)
+		err(1, "symlink %s", src);
 }
 
 static inline void print_status(const char *file, char kind, int islnk)
@@ -350,46 +336,12 @@ static inline int lnklen(const char *lnk)
 		err(1, "lstat %s", lnk);
 
 	len = st.st_size + 1;
-	if (MAX_PATH_LEN < len)
+	if (PATH_LEN < len)
 		errx(1, "Link too long: %s", lnk);
 	
 	return len;
 }
 
-static inline void concat(char *dst, size_t n, const char *arg1, ...)
-{
-	va_list ap;
-	const char *part;
-	int curlen, partlen;
-
-	if (!dst || n == 0)
-		return;
-
-	dst[0] = '\0';
-	curlen = 0;
-
-	if (!arg1)
-		return;
-
-	va_start(ap, arg1);
-	part = arg1;
-
-	while (part) {
-		partlen = strlen(part);
-		if (curlen + partlen + 1 > n) {
-			dst[curlen] = '\0'; 
-			va_end(ap);
-			errx(1, "Path too long: %s%s", dst, part);
-		}
-		memcpy(dst + curlen, part, partlen);
-		curlen += partlen;
-		part = va_arg(ap, const char *);
-	}
-
-	dst[curlen] = '\0';
-	va_end(ap);
-}
-
 static inline int diff(const char *file1, const char *file2)
 {
 	pid_t pid;
@@ -469,7 +421,9 @@ static inline void copy_link(const char *src)
 {
 	int len;
 	ssize_t n;
+	char *dst;
 
+	// todo: use path_buf
 	len = lnklen(src);
 	char target[len];
 	n = readlink(src, target, len);
@@ -478,9 +432,7 @@ static inline void copy_link(const char *src)
 
 	target[n] = '\0';
 
-	size_t dst_sz = strlen(TMP_DIR) + strlen(src) + 2;
-	char dst[dst_sz];
-	concat(dst, dst_sz, TMP_DIR, src, NULL);
+	dst = format_path("%s/%s", TMP_DIR, src);
 	mkdirs(dst);
 
 	if (symlink(target, dst) != 0)
@@ -492,10 +444,10 @@ static inline void mkdirs(const char *path)
 	char *p;
 	int pathlen;
 
-	static char buf[MAX_PATH_LEN];
+	static char buf[PATH_LEN];
 
 	pathlen = strlen(path);
-	if (MAX_PATH_LEN < pathlen + 1)
+	if (PATH_LEN < pathlen + 1)
 		errx(1, "Path too long: %s", path);
 
 	buf[0] = '\0';
@@ -513,6 +465,28 @@ static inline void mkdirs(const char *path)
 	}
 }
 
+static char *path_buf[2][PATH_LEN];
+
+static inline char *format_path(const char *fmt, ...)
+{
+	int rc;
+	va_list args;
+	static uint8_t i = 1;
+
+	i ^= 1;
+	va_start(args, fmt);
+	rc = vsnprintf((char *)path_buf[i], PATH_LEN, fmt, args);
+	va_end(args);
+
+	if (rc < 0)
+		err(1, "vsnprintf");
+	
+	if (rc >= PATH_LEN)
+		errx(1, "Path too long");
+
+	return (char *)path_buf[i];
+}
+
 static inline void *_xmalloc(size_t s, const char *file, int line)
 {
 	void *p;