From 22362568cf309a4ad3d7e48f9e8635f7cb67fba7 Mon Sep 17 00:00:00 2001
From: Jakub Konka <kubkon@jakubkonka.com>
Date: Wed, 15 Jul 2020 18:55:07 +0200
Subject: [PATCH] Refactor

---
 lib/std/os.zig         | 15 +++++++++----
 lib/std/os/windows.zig | 51 ++++++++++++++++++++++++------------------
 2 files changed, 40 insertions(+), 26 deletions(-)

diff --git a/lib/std/os.zig b/lib/std/os.zig
index e638e9f2e..8f86488c0 100644
--- a/lib/std/os.zig
+++ b/lib/std/os.zig
@@ -1524,8 +1524,8 @@ pub fn getcwd(out_buffer: []u8) GetCwdError![]u8 {
 /// or a directory. This value is ignored on all hosts except Windows where
 /// creating symlinks to different resource types, requires different flags.
 /// By default, symlink is assumed to point to a file.
-pub const SymlinkFlags = struct{
-    is_directory: bool = false, 
+pub const SymlinkFlags = struct {
+    is_directory: bool = false,
 };
 
 pub const SymLinkError = error{
@@ -2372,7 +2372,8 @@ pub const ReadLinkError = error{
     NotDir,
     InvalidUtf8,
     BadPathName,
-    /// Windows-only.
+    /// Windows-only. This error may occur if the opened reparse point is
+    /// of unsupported type.
     UnsupportedReparsePointType,
 } || UnexpectedError;
 
@@ -4075,7 +4076,13 @@ pub fn realpathZ(pathname: [*:0]const u8, out_buffer: *[MAX_PATH_BYTES]u8) RealP
         var procfs_buf: ["/proc/self/fd/-2147483648".len:0]u8 = undefined;
         const proc_path = std.fmt.bufPrint(procfs_buf[0..], "/proc/self/fd/{}\x00", .{fd}) catch unreachable;
 
-        return readlinkZ(@ptrCast([*:0]const u8, proc_path.ptr), out_buffer);
+        const target = readlinkZ(@ptrCast([*:0]const u8, proc_path.ptr), out_buffer) catch |err| {
+            switch (err) {
+                error.UnsupportedReparsePointType => unreachable, // Windows only,
+                else => |e| return e,
+            }
+        };
+        return target;
     }
     const result_path = std.c.realpath(pathname, out_buffer) orelse switch (std.c._errno().*) {
         EINVAL => unreachable,
diff --git a/lib/std/os/windows.zig b/lib/std/os/windows.zig
index ab8705048..82aea077c 100644
--- a/lib/std/os/windows.zig
+++ b/lib/std/os/windows.zig
@@ -1296,33 +1296,40 @@ pub fn cStrToWin32PrefixedFileW(s: [*:0]const u8) !PathSpace {
 /// it will get NT-style prefix `\??\` prepended automatically. For prepending
 /// Win32-style prefix, see `sliceToWin32PrefixedFileW` instead.
 pub fn sliceToPrefixedFileW(s: []const u8) !PathSpace {
-    // TODO https://github.com/ziglang/zig/issues/2765
-    var path_space: PathSpace = undefined;
-    const prefix_index: usize = if (mem.startsWith(u8, s, "\\??\\")) 4 else 0;
-    for (s[prefix_index..]) |byte| {
-        switch (byte) {
-            '*', '?', '"', '<', '>', '|' => return error.BadPathName,
-            else => {},
-        }
-    }
-    const start_index = if (prefix_index > 0 or !std.fs.path.isAbsolute(s)) 0 else blk: {
-        const prefix = [_]u16{ '\\', '?', '?', '\\' };
-        mem.copy(u16, path_space.data[0..], &prefix);
-        break :blk prefix.len;
-    };
-    path_space.len = start_index + try std.unicode.utf8ToUtf16Le(path_space.data[start_index..], s);
-    if (path_space.len > path_space.data.len) return error.NameTooLong;
-    path_space.ensureNtStyle();
-    return path_space;
+    return sliceToPrefixedFileWInternal(s, PathPrefix.Nt);
 }
 
 /// Converts the path `s` to WTF16, null-terminated. If the path is absolute,
 /// it will get Win32-style extended prefix `\\?\` prepended automatically. For prepending
 /// NT-style prefix, see `sliceToPrefixedFileW` instead.
 pub fn sliceToWin32PrefixedFileW(s: []const u8) !PathSpace {
+    return sliceToPrefixedFileWInternal(s, PathPrefix.Win32);
+}
+
+const PathPrefix = enum {
+    Win32,
+    Nt,
+
+    fn toUtf8(self: PathPrefix) []const u8 {
+        return switch (self) {
+            .Win32 => "\\\\?\\",
+            .Nt => "\\??\\",
+        };
+    }
+
+    fn toUtf16(self: PathPrefix) []const u16 {
+        return switch (self) {
+            .Win32 => &[_]u16{ '\\', '\\', '?', '\\' },
+            .Nt => &[_]u16{ '\\', '?', '?', '\\' },
+        };
+    }
+};
+
+fn sliceToPrefixedFileWInternal(s: []const u8, prefix: PathPrefix) !PathSpace {
     // TODO https://github.com/ziglang/zig/issues/2765
     var path_space: PathSpace = undefined;
-    const prefix_index: usize = if (mem.startsWith(u8, s, "\\\\?\\")) 4 else 0;
+    const prefix_utf8 = prefix.toUtf8();
+    const prefix_index: usize = if (mem.startsWith(u8, s, prefix_utf8)) prefix_utf8.len else 0;
     for (s[prefix_index..]) |byte| {
         switch (byte) {
             '*', '?', '"', '<', '>', '|' => return error.BadPathName,
@@ -1330,9 +1337,9 @@ pub fn sliceToWin32PrefixedFileW(s: []const u8) !PathSpace {
         }
     }
     const start_index = if (prefix_index > 0 or !std.fs.path.isAbsolute(s)) 0 else blk: {
-        const prefix = [_]u16{ '\\', '\\', '?', '\\' };
-        mem.copy(u16, path_space.data[0..], &prefix);
-        break :blk prefix.len;
+        const prefix_utf16 = prefix.toUtf16();
+        mem.copy(u16, path_space.data[0..], prefix_utf16);
+        break :blk prefix_utf16.len;
     };
     path_space.len = start_index + try std.unicode.utf8ToUtf16Le(path_space.data[start_index..], s);
     if (path_space.len > path_space.data.len) return error.NameTooLong;