1 files changed, 133 insertions, 67 deletions

diff --git a/abspath.c b/abspath.c
index b88122c..5edb4e7 100644
--- a/abspath.c
+++ b/abspath.c
@@ -14,104 +14,170 @@ int is_directory(const char *path)
 /* We allow "recursive" symbolic links. Only within reason, though. */
 #define MAXDEPTH 5
 
-const char *make_absolute_path(const char *path)
+/*
+ * Return the real path (i.e., absolute path, with symlinks resolved
+ * and extra slashes removed) equivalent to the specified path.  (If
+ * you want an absolute path but don't mind links, use
+ * absolute_path().)  The return value is a pointer to a static
+ * buffer.
+ *
+ * The input and all intermediate paths must be shorter than MAX_PATH.
+ * The directory part of path (i.e., everything up to the last
+ * dir_sep) must denote a valid, existing directory, but the last
+ * component need not exist.  If die_on_error is set, then die with an
+ * informative error message if there is a problem.  Otherwise, return
+ * NULL on errors (without generating any output).
+ *
+ * If path is our buffer, then return path, as it's already what the
+ * user wants.
+ */
+static const char *real_path_internal(const char *path, int die_on_error)
 {
-	static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1];
-	char cwd[1024] = "";
-	int buf_index = 1;
+	static struct strbuf sb = STRBUF_INIT;
+	char *retval = NULL;
+
+	/*
+	 * If we have to temporarily chdir(), store the original CWD
+	 * here so that we can chdir() back to it at the end of the
+	 * function:
+	 */
+	struct strbuf cwd = STRBUF_INIT;
 
 	int depth = MAXDEPTH;
 	char *last_elem = NULL;
 	struct stat st;
 
-	if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
-		die ("Too long path: %.*s", 60, path);
+	/* We've already done it */
+	if (path == sb.buf)
+		return path;
+
+	if (!*path) {
+		if (die_on_error)
+			die("The empty string is not a valid path");
+		else
+			goto error_out;
+	}
+
+	strbuf_reset(&sb);
+	strbuf_addstr(&sb, path);
 
 	while (depth--) {
-		if (!is_directory(buf)) {
-			char *last_slash = strrchr(buf, '/');
+		if (!is_directory(sb.buf)) {
+			char *last_slash = find_last_dir_sep(sb.buf);
 			if (last_slash) {
-				*last_slash = '\0';
 				last_elem = xstrdup(last_slash + 1);
+				strbuf_setlen(&sb, last_slash - sb.buf + 1);
 			} else {
-				last_elem = xstrdup(buf);
-				*buf = '\0';
+				last_elem = xmemdupz(sb.buf, sb.len);
+				strbuf_reset(&sb);
 			}
 		}
 
-		if (*buf) {
-			if (!*cwd && !getcwd(cwd, sizeof(cwd)))
-				die_errno ("Could not get current working directory");
+		if (sb.len) {
+			if (!cwd.len && strbuf_getcwd(&cwd)) {
+				if (die_on_error)
+					die_errno("Could not get current working directory");
+				else
+					goto error_out;
+			}
 
-			if (chdir(buf))
-				die_errno ("Could not switch to '%s'", buf);
+			if (chdir(sb.buf)) {
+				if (die_on_error)
+					die_errno("Could not switch to '%s'",
+						  sb.buf);
+				else
+					goto error_out;
+			}
+		}
+		if (strbuf_getcwd(&sb)) {
+			if (die_on_error)
+				die_errno("Could not get current working directory");
+			else
+				goto error_out;
 		}
-		if (!getcwd(buf, PATH_MAX))
-			die_errno ("Could not get current working directory");
 
 		if (last_elem) {
-			size_t len = strlen(buf);
-			if (len + strlen(last_elem) + 2 > PATH_MAX)
-				die ("Too long path name: '%s/%s'",
-						buf, last_elem);
-			buf[len] = '/';
-			strcpy(buf + len + 1, last_elem);
+			if (sb.len && !is_dir_sep(sb.buf[sb.len - 1]))
+				strbuf_addch(&sb, '/');
+			strbuf_addstr(&sb, last_elem);
 			free(last_elem);
 			last_elem = NULL;
 		}
 
-		if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) {
-			ssize_t len = readlink(buf, next_buf, PATH_MAX);
-			if (len < 0)
-				die_errno ("Invalid symlink '%s'", buf);
-			if (PATH_MAX <= len)
-				die("symbolic link too long: %s", buf);
-			next_buf[len] = '\0';
-			buf = next_buf;
-			buf_index = 1 - buf_index;
-			next_buf = bufs[buf_index];
+		if (!lstat(sb.buf, &st) && S_ISLNK(st.st_mode)) {
+			struct strbuf next_sb = STRBUF_INIT;
+			ssize_t len = strbuf_readlink(&next_sb, sb.buf, 0);
+			if (len < 0) {
+				if (die_on_error)
+					die_errno("Invalid symlink '%s'",
+						  sb.buf);
+				else
+					goto error_out;
+			}
+			strbuf_swap(&sb, &next_sb);
+			strbuf_release(&next_sb);
 		} else
 			break;
 	}
 
-	if (*cwd && chdir(cwd))
-		die_errno ("Could not change back to '%s'", cwd);
+	retval = sb.buf;
+error_out:
+	free(last_elem);
+	if (cwd.len && chdir(cwd.buf))
+		die_errno("Could not change back to '%s'", cwd.buf);
+	strbuf_release(&cwd);
 
-	return buf;
+	return retval;
 }
 
-static const char *get_pwd_cwd(void)
+const char *real_path(const char *path)
 {
-	static char cwd[PATH_MAX + 1];
-	char *pwd;
-	struct stat cwd_stat, pwd_stat;
-	if (getcwd(cwd, PATH_MAX) == NULL)
-		return NULL;
-	pwd = getenv("PWD");
-	if (pwd && strcmp(pwd, cwd)) {
-		stat(cwd, &cwd_stat);
-		if (!stat(pwd, &pwd_stat) &&
-		    pwd_stat.st_dev == cwd_stat.st_dev &&
-		    pwd_stat.st_ino == cwd_stat.st_ino) {
-			strlcpy(cwd, pwd, PATH_MAX);
-		}
-	}
-	return cwd;
+	return real_path_internal(path, 1);
 }
 
-const char *make_nonrelative_path(const char *path)
+const char *real_path_if_valid(const char *path)
 {
-	static char buf[PATH_MAX + 1];
-
-	if (is_absolute_path(path)) {
-		if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
-			die("Too long path: %.*s", 60, path);
-	} else {
-		const char *cwd = get_pwd_cwd();
-		if (!cwd)
-			die_errno("Cannot determine the current working directory");
-		if (snprintf(buf, PATH_MAX, "%s/%s", cwd, path) >= PATH_MAX)
-			die("Too long path: %.*s", 60, path);
-	}
-	return buf;
+	return real_path_internal(path, 0);
+}
+
+/*
+ * Use this to get an absolute path from a relative one. If you want
+ * to resolve links, you should use real_path.
+ */
+const char *absolute_path(const char *path)
+{
+	static struct strbuf sb = STRBUF_INIT;
+	strbuf_reset(&sb);
+	strbuf_add_absolute_path(&sb, path);
+	return sb.buf;
+}
+
+/*
+ * Unlike prefix_path, this should be used if the named file does
+ * not have to interact with index entry; i.e. name of a random file
+ * on the filesystem.
+ */
+const char *prefix_filename(const char *pfx, int pfx_len, const char *arg)
+{
+	static struct strbuf path = STRBUF_INIT;
+#ifndef GIT_WINDOWS_NATIVE
+	if (!pfx_len || is_absolute_path(arg))
+		return arg;
+	strbuf_reset(&path);
+	strbuf_add(&path, pfx, pfx_len);
+	strbuf_addstr(&path, arg);
+#else
+	char *p;
+	/* don't add prefix to absolute paths, but still replace '\' by '/' */
+	strbuf_reset(&path);
+	if (is_absolute_path(arg))
+		pfx_len = 0;
+	else if (pfx_len)
+		strbuf_add(&path, pfx, pfx_len);
+	strbuf_addstr(&path, arg);
+	for (p = path.buf + pfx_len; *p; p++)
+		if (*p == '\\')
+			*p = '/';
+#endif
+	return path.buf;
 }