1 files changed, 131 insertions, 0 deletions

diff --git a/src/win32/path_w32.c b/src/win32/path_w32.c
index 0e6aff748..d9fc8292b 100644
--- a/src/win32/path_w32.c
+++ b/src/win32/path_w32.c
@@ -151,6 +151,137 @@ int git_win32_path_canonicalize(git_win32_path path)
 	return (int)(to - path);
 }
 
+static int git_win32_path_join(
+	git_win32_path dest,
+	const wchar_t *one,
+	size_t one_len,
+	const wchar_t *two,
+	size_t two_len)
+{
+	size_t backslash = 0;
+
+	if (one_len && two_len && one[one_len - 1] != L'\\')
+		backslash = 1;
+
+	if (one_len + two_len + backslash > MAX_PATH) {
+		git_error_set(GIT_ERROR_INVALID, "path too long");
+		return -1;
+	}
+
+	memmove(dest, one, one_len * sizeof(wchar_t));
+
+	if (backslash)
+		dest[one_len] = L'\\';
+
+	memcpy(dest + one_len + backslash, two, two_len * sizeof(wchar_t));
+	dest[one_len + backslash + two_len] = L'\0';
+
+	return 0;
+}
+
+struct win32_path_iter {
+	wchar_t *env;
+	const wchar_t *current_dir;
+};
+
+static int win32_path_iter_init(struct win32_path_iter *iter)
+{
+	DWORD len = GetEnvironmentVariableW(L"PATH", NULL, 0);
+
+	if (!len && GetLastError() == ERROR_ENVVAR_NOT_FOUND) {
+		iter->env = NULL;
+		iter->current_dir = NULL;
+		return 0;
+	} else if (!len) {
+		git_error_set(GIT_ERROR_OS, "could not load PATH");
+		return -1;
+	}
+
+	iter->env = git__malloc(len * sizeof(wchar_t));
+	GIT_ERROR_CHECK_ALLOC(iter->env);
+
+	len = GetEnvironmentVariableW(L"PATH", iter->env, len);
+
+	if (len == 0) {
+		git_error_set(GIT_ERROR_OS, "could not load PATH");
+		return -1;
+	}
+
+	iter->current_dir = iter->env;
+	return 0;
+}
+
+static int win32_path_iter_next(
+	const wchar_t **out,
+	size_t *out_len,
+	struct win32_path_iter *iter)
+{
+	const wchar_t *start;
+	wchar_t term;
+	size_t len = 0;
+
+	if (!iter->current_dir || !*iter->current_dir)
+		return GIT_ITEROVER;
+
+	term = (*iter->current_dir == L'"') ? *iter->current_dir++ : L';';
+	start = iter->current_dir;
+
+	while (*iter->current_dir && *iter->current_dir != term) {
+		iter->current_dir++;
+		len++;
+	}
+
+	*out = start;
+	*out_len = len;
+
+	if (term == L'"' && *iter->current_dir)
+		iter->current_dir++;
+
+	while (*iter->current_dir == L';')
+		iter->current_dir++;
+
+	return 0;
+}
+
+static void win32_path_iter_dispose(struct win32_path_iter *iter)
+{
+	if (!iter)
+		return;
+
+	git__free(iter->env);
+	iter->env = NULL;
+	iter->current_dir = NULL;
+}
+
+int git_win32_path_find_executable(git_win32_path fullpath, wchar_t *exe)
+{
+	struct win32_path_iter path_iter;
+	const wchar_t *dir;
+	size_t dir_len, exe_len = wcslen(exe);
+	bool found = false;
+
+	if (win32_path_iter_init(&path_iter) < 0)
+		return -1;
+
+	while (win32_path_iter_next(&dir, &dir_len, &path_iter) != GIT_ITEROVER) {
+		if (git_win32_path_join(fullpath, dir, dir_len, exe, exe_len) < 0)
+			continue;
+
+		if (_waccess(fullpath, 0) == 0) {
+			found = true;
+			break;
+		}
+	}
+
+	win32_path_iter_dispose(&path_iter);
+
+	if (found)
+		return 0;
+
+	fullpath[0] = L'\0';
+	return GIT_ENOTFOUND;
+}
+
 static int win32_path_cwd(wchar_t *out, size_t len)
 {
 	int cwd_len;