1 files changed, 269 insertions, 0 deletions
diff --git a/src/win32/path_w32.c b/src/win32/path_w32.c
new file mode 100644
index 000000000..f0eacaa63
--- /dev/null
+++ b/src/win32/path_w32.c
@@ -0,0 +1,269 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "common.h"
+#include "path.h"
+#include "path_w32.h"
+#include "utf-conv.h"
+
+#define PATH__NT_NAMESPACE     L"\\\\?\\"
+#define PATH__NT_NAMESPACE_LEN 4
+
+#define PATH__ABSOLUTE_LEN     3
+
+#define path__is_dirsep(p) ((p) == '/' || (p) == '\\')
+
+#define path__is_absolute(p) \
+	(git__isalpha((p)[0]) && (p)[1] == ':' && ((p)[2] == '\\' || (p)[2] == '/'))
+
+#define path__is_nt_namespace(p) \
+	(((p)[0] == '\\' && (p)[1] == '\\' && (p)[2] == '?' && (p)[3] == '\\') || \
+	 ((p)[0] == '/' && (p)[1] == '/' && (p)[2] == '?' && (p)[3] == '/'))
+
+#define path__is_unc(p) \
+	(((p)[0] == '\\' && (p)[1] == '\\') || ((p)[0] == '/' && (p)[1] == '/'))
+
+GIT_INLINE(int) path__cwd(wchar_t *path, int size)
+{
+	int len;
+
+	if ((len = GetCurrentDirectoryW(size, path)) == 0) {
+		errno = GetLastError() == ERROR_ACCESS_DENIED ? EACCES : ENOENT;
+		return -1;
+	} else if (len > size) {
+		errno = ENAMETOOLONG;
+		return -1;
+	}
+
+	/* The Win32 APIs may return "\\?\" once you've used it first.
+	 * But it may not.  What a gloriously predictible API!
+	 */
+	if (wcsncmp(path, PATH__NT_NAMESPACE, PATH__NT_NAMESPACE_LEN))
+		return len;
+
+	len -= PATH__NT_NAMESPACE_LEN;
+
+	memmove(path, path + PATH__NT_NAMESPACE_LEN, sizeof(wchar_t) * len);
+	return len;
+}
+
+static wchar_t *path__skip_server(wchar_t *path)
+{
+	wchar_t *c;
+
+	for (c = path; *c; c++) {
+		if (path__is_dirsep(*c))
+			return c + 1;
+	}
+
+	return c;
+}
+
+static wchar_t *path__skip_prefix(wchar_t *path)
+{
+	if (path__is_nt_namespace(path)) {
+		path += PATH__NT_NAMESPACE_LEN;
+
+		if (wcsncmp(path, L"UNC\\", 4) == 0)
+			path = path__skip_server(path + 4);
+		else if (path__is_absolute(path))
+			path += PATH__ABSOLUTE_LEN;
+	} else if (path__is_absolute(path)) {
+		path += PATH__ABSOLUTE_LEN;
+	} else if (path__is_unc(path)) {
+		path = path__skip_server(path + 2);
+	}
+
+	return path;
+}
+
+int git_win32_path_canonicalize(git_win32_path path)
+{
+	wchar_t *base, *from, *to, *next;
+	size_t len;
+
+	base = to = path__skip_prefix(path);
+
+	/* Unposixify if the prefix */
+	for (from = path; from < to; from++) {
+		if (*from == L'/')
+			*from = L'\\';
+	}
+
+	while (*from) {
+		for (next = from; *next; ++next) {
+			if (*next == L'/') {
+				*next = L'\\';
+				break;
+			}
+
+			if (*next == L'\\')
+				break;
+		}
+
+		len = next - from;
+
+		if (len == 1 && from[0] == L'.')
+			/* do nothing with singleton dot */;
+
+		else if (len == 2 && from[0] == L'.' && from[1] == L'.') {
+			if (to == base) {
+				/* no more path segments to strip, eat the "../" */
+				if (*next == L'\\')
+					len++;
+
+				base = to;
+			} else {
+				/* back up a path segment */
+				while (to > base && to[-1] == L'\\') to--;
+				while (to > base && to[-1] != L'\\') to--;
+			}
+		} else {
+			if (*next == L'\\' && *from != L'\\')
+				len++;
+
+			if (to != from)
+				memmove(to, from, sizeof(wchar_t) * len);
+
+			to += len;
+		}
+
+		from += len;
+
+		while (*from == L'\\') from++;
+	}
+
+	/* Strip trailing backslashes */
+	while (to > base && to[-1] == L'\\') to--;
+
+	*to = L'\0';
+
+	return (to - path);
+}
+
+int git_win32_path__cwd(wchar_t *out, size_t len)
+{
+	int cwd_len;
+
+	if ((cwd_len = path__cwd(out, len)) < 0)
+		return -1;
+
+	/* UNC paths */
+	if (wcsncmp(L"\\\\", out, 2) == 0) {
+		/* Our buffer must be at least 5 characters larger than the
+		 * current working directory:  we swallow one of the leading
+		 * '\'s, but we we add a 'UNC' specifier to the path, plus
+		 * a trailing directory separator, plus a NUL.
+		 */
+		if (cwd_len > MAX_PATH - 4) {
+			errno = ENAMETOOLONG;
+			return -1;
+		}
+
+		memmove(out+2, out, sizeof(wchar_t) * cwd_len);
+		out[0] = L'U';
+		out[1] = L'N';
+		out[2] = L'C';
+
+		cwd_len += 2;
+	}
+
+	/* Our buffer must be at least 2 characters larger than the current
+	 * working directory.  (One character for the directory separator,
+	 * one for the null.
+	 */
+	else if (cwd_len > MAX_PATH - 2) {
+		errno = ENAMETOOLONG;
+		return -1;
+	}
+
+	return cwd_len;
+}
+
+int git_win32_path_from_utf8(git_win32_path out, const char *src)
+{
+	wchar_t *dest = out;
+
+	/* All win32 paths are in NT-prefixed format, beginning with "\\?\". */
+	memcpy(dest, PATH__NT_NAMESPACE, sizeof(wchar_t) * PATH__NT_NAMESPACE_LEN);
+	dest += PATH__NT_NAMESPACE_LEN;
+
+	/* See if this is an absolute path (beginning with a drive letter) */
+	if (path__is_absolute(src)) {
+		if (git__utf8_to_16(dest, MAX_PATH, src) < 0)
+			return -1;
+	}
+	/* File-prefixed NT-style paths beginning with \\?\ */
+	else if (path__is_nt_namespace(src)) {
+		/* Skip the NT prefix, the destination already contains it */
+		if (git__utf8_to_16(dest, MAX_PATH, src + PATH__NT_NAMESPACE_LEN) < 0)
+			return -1;
+	}
+	/* UNC paths */
+	else if (path__is_unc(src)) {
+		memcpy(dest, L"UNC\\", sizeof(wchar_t) * 4);
+		dest += 4;
+
+		/* Skip the leading "\\" */
+		if (git__utf8_to_16(dest, MAX_PATH - 2, src + 2) < 0)
+			return -1;
+	}
+	/* Absolute paths omitting the drive letter */
+	else if (src[0] == '\\' || src[0] == '/') {
+		if (path__cwd(dest, MAX_PATH) < 0)
+			return -1;
+
+		if (!path__is_absolute(dest)) {
+			errno = ENOENT;
+			return -1;
+		}
+
+		/* Skip the drive letter specification ("C:") */	
+		if (git__utf8_to_16(dest + 2, MAX_PATH - 2, src) < 0)
+			return -1;
+	}
+	/* Relative paths */
+	else {
+		int cwd_len;
+
+		if ((cwd_len = git_win32_path__cwd(dest, MAX_PATH)) < 0)
+			return -1;
+
+		dest[cwd_len++] = L'\\';
+
+		if (git__utf8_to_16(dest + cwd_len, MAX_PATH - cwd_len, src) < 0)
+			return -1;
+	}
+
+	return git_win32_path_canonicalize(out);
+}
+
+int git_win32_path_to_utf8(git_win32_utf8_path dest, const wchar_t *src)
+{
+	char *out = dest;
+	int len;
+
+	/* Strip NT namespacing "\\?\" */
+	if (path__is_nt_namespace(src)) {
+		src += 4;
+
+		/* "\\?\UNC\server\share" -> "\\server\share" */
+		if (wcsncmp(src, L"UNC\\", 4) == 0) {
+			src += 4;
+
+			memcpy(dest, "\\\\", 2);
+			out = dest + 2;
+		}
+	}
+
+	if ((len = git__utf16_to_8(out, GIT_WIN_PATH_UTF8, src)) < 0)
+		return len;
+
+	git_path_mkposix(dest);
+
+	return len;
+}