syscall: fix Stat(path) where path is directory with trailing '/' on windows

Fixes #1220.

R=rsc, r
CC=golang-dev
https://golang.org/cl/2728043

src/pkg/os/os_test.go

@@ -861,3 +861,27 @@ func TestAppend(t *testing.T) {
 		t.Fatalf("writeFile: have %q want %q", s, "new|append")
 	}
 }
+
+func TestStatDirWithTrailingSlash(t *testing.T) {
+	// Create new dir, in _obj so it will get
+	// cleaned up by make if not by us.
+	path := "_obj/_TestStatDirWithSlash_"
+	err := MkdirAll(path, 0777)
+	if err != nil {
+		t.Fatalf("MkdirAll %q: %s", path, err)
+	}
+
+	// Stat of path should succeed.
+	_, err = Stat(path)
+	if err != nil {
+		t.Fatal("stat failed:", err)
+	}
+
+	// Stat of path+"/" should succeed too.
+	_, err = Stat(path + "/")
+	if err != nil {
+		t.Fatal("stat failed:", err)
+	}
+
+	RemoveAll("_obj/_TestMkdirAll_")
+}

src/pkg/syscall/syscall_windows.go

@@ -144,6 +144,7 @@ func getSysProcAddr(m uint32, pname string) uintptr {
 //sys	GetEnvironmentVariable(name *uint16, buffer *uint16, size uint32) (n uint32, errno int) = kernel32.GetEnvironmentVariableW
 //sys	SetEnvironmentVariable(name *uint16, value *uint16) (ok bool, errno int) = kernel32.SetEnvironmentVariableW
 //sys	SetFileTime(handle int32, ctime *Filetime, atime *Filetime, wtime *Filetime) (ok bool, errno int)
+//sys	GetFileAttributes(name *uint16) (attrs uint32, errno int) [failretval=INVALID_FILE_ATTRIBUTES] = kernel32.GetFileAttributesW
 
 // syscall interface implementation for other packages
 
@@ -302,6 +303,21 @@ func getStdHandle(h int32) (fd int) {
 }
 
 func Stat(path string, stat *Stat_t) (errno int) {
+	// Remove trailing slash.
+	if path[len(path)-1] == '/' || path[len(path)-1] == '\\' {
+		// Check if we're given root directory ("\" or "c:\").
+		if len(path) == 1 || (len(path) == 3 && path[1] == ':') {
+			// TODO(brainman): Perhaps should fetch other fields, not just FileAttributes.
+			stat.Windata = Win32finddata{}
+			a, e := GetFileAttributes(StringToUTF16Ptr(path))
+			if e != 0 {
+				return e
+			}
+			stat.Windata.FileAttributes = a
+			return 0
+		}
+		path = path[:len(path)-1]
+	}
 	h, e := FindFirstFile(StringToUTF16Ptr(path), &stat.Windata)
 	if e != 0 {
 		return e

src/pkg/syscall/zsyscall_windows_386.go

@@ -60,6 +60,7 @@ var (
 	procGetEnvironmentVariableW    = getSysProcAddr(modkernel32, "GetEnvironmentVariableW")
 	procSetEnvironmentVariableW    = getSysProcAddr(modkernel32, "SetEnvironmentVariableW")
 	procSetFileTime                = getSysProcAddr(modkernel32, "SetFileTime")
+	procGetFileAttributesW         = getSysProcAddr(modkernel32, "GetFileAttributesW")
 	procWSAStartup                 = getSysProcAddr(modwsock32, "WSAStartup")
 	procWSACleanup                 = getSysProcAddr(modwsock32, "WSACleanup")
 	procsocket                     = getSysProcAddr(modwsock32, "socket")
@@ -683,7 +684,7 @@ func CryptGenRandom(provhandle uint32, buflen uint32, buf *byte) (ok bool, errno
 
 func OpenProcess(da uint32, b int, pid uint32) (handle uint32, errno int) {
 	r0, _, e1 := Syscall(procOpenProcess, uintptr(da), uintptr(b), uintptr(pid))
-	handle = (uint32)(r0)
+	handle = uint32(r0)
 	if handle == 0 {
 		if e1 != 0 {
 			errno = int(e1)
@@ -698,7 +699,7 @@ func OpenProcess(da uint32, b int, pid uint32) (handle uint32, errno int) {
 
 func GetExitCodeProcess(h uint32, c *uint32) (ok bool, errno int) {
 	r0, _, e1 := Syscall(procGetExitCodeProcess, uintptr(h), uintptr(unsafe.Pointer(c)), 0)
-	ok = (bool)(r0 != 0)
+	ok = bool(r0 != 0)
 	if !ok {
 		if e1 != 0 {
 			errno = int(e1)
@@ -786,6 +787,21 @@ func SetFileTime(handle int32, ctime *Filetime, atime *Filetime, wtime *Filetime
 	return
 }
 
+func GetFileAttributes(name *uint16) (attrs uint32, errno int) {
+	r0, _, e1 := Syscall(procGetFileAttributesW, uintptr(unsafe.Pointer(name)), 0, 0)
+	attrs = uint32(r0)
+	if attrs == INVALID_FILE_ATTRIBUTES {
+		if e1 != 0 {
+			errno = int(e1)
+		} else {
+			errno = EINVAL
+		}
+	} else {
+		errno = 0
+	}
+	return
+}
+
 func WSAStartup(verreq uint32, data *WSAData) (sockerrno int) {
 	r0, _, _ := Syscall(procWSAStartup, uintptr(verreq), uintptr(unsafe.Pointer(data)), 0)
 	sockerrno = int(r0)

src/pkg/syscall/ztypes_windows_386.go

@@ -66,6 +66,8 @@ const (
 	FILE_ATTRIBUTE_ARCHIVE   = 0x00000020
 	FILE_ATTRIBUTE_NORMAL    = 0x00000080
 
+	INVALID_FILE_ATTRIBUTES = 0xffffffff
+
 	CREATE_NEW        = 1
 	CREATE_ALWAYS     = 2
 	OPEN_EXISTING     = 3