exp/winfsnotify: filesystem watcher for Windows

R=rsc, alex.brainman, bradfitz
CC=bsiegert, go.peter.90, golang-dev
https://golang.org/cl/4188047

src/pkg/exp/winfsnotify/Makefile

+# Copyright 2011 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+include ../../../Make.inc
+
+TARG=exp/winfsnotify
+GOFILES=\
+	winfsnotify.go\
+
+include ../../../Make.pkg

src/pkg/exp/winfsnotify/winfsnotify_test.go

+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package winfsnotify
+
+import (
+	"os"
+	"time"
+	"testing"
+)
+
+func expect(t *testing.T, eventstream <-chan *Event, name string, mask uint32) {
+	t.Logf(`expected: "%s": 0x%x`, name, mask)
+	select {
+	case event := <-eventstream:
+		if event == nil {
+			t.Fatal("nil event received")
+		}
+		t.Logf("received: %s", event)
+		if event.Name != name || event.Mask != mask {
+			t.Fatal("did not receive expected event")
+		}
+	case <-time.After(1e9):
+		t.Fatal("timed out waiting for event")
+	}
+}
+
+func TestNotifyEvents(t *testing.T) {
+	watcher, err := NewWatcher()
+	if err != nil {
+		t.Fatalf("NewWatcher() failed: %s", err)
+	}
+
+	testDir := "TestNotifyEvents.testdirectory"
+	testFile := testDir + "/TestNotifyEvents.testfile"
+	testFile2 := testFile + ".new"
+	const mask = FS_ALL_EVENTS & ^(FS_ATTRIB|FS_CLOSE) | FS_IGNORED
+
+	// Add a watch for testDir
+	os.RemoveAll(testDir)
+	if err = os.Mkdir(testDir, 0777); err != nil {
+		t.Fatalf("Failed to create test directory", err)
+	}
+	defer os.RemoveAll(testDir)
+	err = watcher.AddWatch(testDir, mask)
+	if err != nil {
+		t.Fatalf("Watcher.Watch() failed: %s", err)
+	}
+
+	// Receive errors on the error channel on a separate goroutine
+	go func() {
+		for err := range watcher.Error {
+			t.Fatalf("error received: %s", err)
+		}
+	}()
+
+	// Create a file
+	file, err := os.Create(testFile)
+	if err != nil {
+		t.Fatalf("creating test file failed: %s", err)
+	}
+	expect(t, watcher.Event, testFile, FS_CREATE)
+
+	err = watcher.AddWatch(testFile, mask)
+	if err != nil {
+		t.Fatalf("Watcher.Watch() failed: %s", err)
+	}
+
+	if _, err = file.WriteString("hello, world"); err != nil {
+		t.Fatalf("failed to write to test file: %s", err)
+	}
+	if err = file.Sync(); err != nil {
+		t.Fatalf("failed to sync test file: %s", err)
+	}
+	expect(t, watcher.Event, testFile, FS_MODIFY)
+	expect(t, watcher.Event, testFile, FS_MODIFY)
+
+	if err = file.Close(); err != nil {
+		t.Fatalf("failed to close test file: %s", err)
+	}
+
+	if err = os.Rename(testFile, testFile2); err != nil {
+		t.Fatalf("failed to rename test file: %s", err)
+	}
+	expect(t, watcher.Event, testFile, FS_MOVED_FROM)
+	expect(t, watcher.Event, testFile2, FS_MOVED_TO)
+	expect(t, watcher.Event, testFile, FS_MOVE_SELF)
+
+	if err = os.RemoveAll(testDir); err != nil {
+		t.Fatalf("failed to remove test directory: %s", err)
+	}
+	expect(t, watcher.Event, testFile2, FS_DELETE_SELF)
+	expect(t, watcher.Event, testFile2, FS_IGNORED)
+	expect(t, watcher.Event, testFile2, FS_DELETE)
+	expect(t, watcher.Event, testDir, FS_DELETE_SELF)
+	expect(t, watcher.Event, testDir, FS_IGNORED)
+
+	t.Log("calling Close()")
+	if err = watcher.Close(); err != nil {
+		t.Fatalf("failed to close watcher: %s", err)
+	}
+}
+
+func TestNotifyClose(t *testing.T) {
+	watcher, _ := NewWatcher()
+	watcher.Close()
+
+	done := false
+	go func() {
+		watcher.Close()
+		done = true
+	}()
+
+	time.Sleep(50e6) // 50 ms
+	if !done {
+		t.Fatal("double Close() test failed: second Close() call didn't return")
+	}
+
+	err := watcher.Watch("_test")
+	if err == nil {
+		t.Fatal("expected error on Watch() after Close(), got nil")
+	}
+}

src/pkg/syscall/syscall_windows.go

@@ -114,6 +114,7 @@ func NewCallback(fn interface{}) uintptr
 //sys	GetTimeZoneInformation(tzi *Timezoneinformation) (rc uint32, errno int) [failretval==0xffffffff]
 //sys	CreateIoCompletionPort(filehandle Handle, cphandle Handle, key uint32, threadcnt uint32) (handle Handle, errno int)
 //sys	GetQueuedCompletionStatus(cphandle Handle, qty *uint32, key *uint32, overlapped **Overlapped, timeout uint32) (errno int)
+//sys	PostQueuedCompletionStatus(cphandle Handle, qty uint32, key uint32, overlapped *Overlapped) (errno int)
 //sys	CancelIo(s Handle) (errno int)
 //sys	CreateProcess(appName *uint16, commandLine *uint16, procSecurity *SecurityAttributes, threadSecurity *SecurityAttributes, inheritHandles bool, creationFlags uint32, env *uint16, currentDir *uint16, startupInfo *StartupInfo, outProcInfo *ProcessInformation) (errno int) = CreateProcessW
 //sys	OpenProcess(da uint32, inheritHandle bool, pid uint32) (handle Handle, errno int)
@@ -150,6 +151,7 @@ func NewCallback(fn interface{}) uintptr
 //sys	VirtualLock(addr uintptr, length uintptr) (errno int)
 //sys	VirtualUnlock(addr uintptr, length uintptr) (errno int)
 //sys	TransmitFile(s Handle, handle Handle, bytesToWrite uint32, bytsPerSend uint32, overlapped *Overlapped, transmitFileBuf *TransmitFileBuffers, flags uint32) (errno int) = mswsock.TransmitFile
+//sys	ReadDirectoryChanges(handle Handle, buf *byte, buflen uint32, watchSubTree bool, mask uint32, retlen *uint32, overlapped *Overlapped, completionRoutine uintptr) (errno int) = kernel32.ReadDirectoryChangesW
 //sys	CertOpenSystemStore(hprov Handle, name *uint16) (store Handle, errno int) = crypt32.CertOpenSystemStoreW
 //sys	CertEnumCertificatesInStore(store Handle, prevContext *CertContext) (context *CertContext) = crypt32.CertEnumCertificatesInStore
 //sys	CertCloseStore(store Handle, flags uint32) (errno int) = crypt32.CertCloseStore

src/pkg/syscall/zsyscall_windows_386.go

@@ -45,6 +45,7 @@ var (
 	procGetTimeZoneInformation      = modkernel32.NewProc("GetTimeZoneInformation")
 	procCreateIoCompletionPort      = modkernel32.NewProc("CreateIoCompletionPort")
 	procGetQueuedCompletionStatus   = modkernel32.NewProc("GetQueuedCompletionStatus")
+	procPostQueuedCompletionStatus  = modkernel32.NewProc("PostQueuedCompletionStatus")
 	procCancelIo                    = modkernel32.NewProc("CancelIo")
 	procCreateProcessW              = modkernel32.NewProc("CreateProcessW")
 	procOpenProcess                 = modkernel32.NewProc("OpenProcess")
@@ -81,6 +82,7 @@ var (
 	procVirtualLock                 = modkernel32.NewProc("VirtualLock")
 	procVirtualUnlock               = modkernel32.NewProc("VirtualUnlock")
 	procTransmitFile                = modmswsock.NewProc("TransmitFile")
+	procReadDirectoryChangesW       = modkernel32.NewProc("ReadDirectoryChangesW")
 	procCertOpenSystemStoreW        = modcrypt32.NewProc("CertOpenSystemStoreW")
 	procCertEnumCertificatesInStore = modcrypt32.NewProc("CertEnumCertificatesInStore")
 	procCertCloseStore              = modcrypt32.NewProc("CertCloseStore")
@@ -520,6 +522,20 @@ func GetQueuedCompletionStatus(cphandle Handle, qty *uint32, key *uint32, overla
 	return
 }
 
+func PostQueuedCompletionStatus(cphandle Handle, qty uint32, key uint32, overlapped *Overlapped) (errno int) {
+	r1, _, e1 := Syscall6(procPostQueuedCompletionStatus.Addr(), 4, uintptr(cphandle), uintptr(qty), uintptr(key), uintptr(unsafe.Pointer(overlapped)), 0, 0)
+	if int(r1) == 0 {
+		if e1 != 0 {
+			errno = int(e1)
+		} else {
+			errno = EINVAL
+		}
+	} else {
+		errno = 0
+	}
+	return
+}
+
 func CancelIo(s Handle) (errno int) {
 	r1, _, e1 := Syscall(procCancelIo.Addr(), 1, uintptr(s), 0, 0)
 	if int(r1) == 0 {
@@ -1047,6 +1063,26 @@ func TransmitFile(s Handle, handle Handle, bytesToWrite uint32, bytsPerSend uint
 	return
 }
 
+func ReadDirectoryChanges(handle Handle, buf *byte, buflen uint32, watchSubTree bool, mask uint32, retlen *uint32, overlapped *Overlapped, completionRoutine uintptr) (errno int) {
+	var _p0 uint32
+	if watchSubTree {
+		_p0 = 1
+	} else {
+		_p0 = 0
+	}
+	r1, _, e1 := Syscall9(procReadDirectoryChangesW.Addr(), 8, uintptr(handle), uintptr(unsafe.Pointer(buf)), uintptr(buflen), uintptr(_p0), uintptr(mask), uintptr(unsafe.Pointer(retlen)), uintptr(unsafe.Pointer(overlapped)), uintptr(completionRoutine), 0)
+	if int(r1) == 0 {
+		if e1 != 0 {
+			errno = int(e1)
+		} else {
+			errno = EINVAL
+		}
+	} else {
+		errno = 0
+	}
+	return
+}
+
 func CertOpenSystemStore(hprov Handle, name *uint16) (store Handle, errno int) {
 	r0, _, e1 := Syscall(procCertOpenSystemStoreW.Addr(), 2, uintptr(hprov), uintptr(unsafe.Pointer(name)), 0)
 	store = Handle(r0)

src/pkg/syscall/zsyscall_windows_amd64.go

@@ -45,6 +45,7 @@ var (
 	procGetTimeZoneInformation      = modkernel32.NewProc("GetTimeZoneInformation")
 	procCreateIoCompletionPort      = modkernel32.NewProc("CreateIoCompletionPort")
 	procGetQueuedCompletionStatus   = modkernel32.NewProc("GetQueuedCompletionStatus")
+	procPostQueuedCompletionStatus  = modkernel32.NewProc("PostQueuedCompletionStatus")
 	procCancelIo                    = modkernel32.NewProc("CancelIo")
 	procCreateProcessW              = modkernel32.NewProc("CreateProcessW")
 	procOpenProcess                 = modkernel32.NewProc("OpenProcess")
@@ -81,6 +82,7 @@ var (
 	procVirtualLock                 = modkernel32.NewProc("VirtualLock")
 	procVirtualUnlock               = modkernel32.NewProc("VirtualUnlock")
 	procTransmitFile                = modmswsock.NewProc("TransmitFile")
+	procReadDirectoryChangesW       = modkernel32.NewProc("ReadDirectoryChangesW")
 	procCertOpenSystemStoreW        = modcrypt32.NewProc("CertOpenSystemStoreW")
 	procCertEnumCertificatesInStore = modcrypt32.NewProc("CertEnumCertificatesInStore")
 	procCertCloseStore              = modcrypt32.NewProc("CertCloseStore")
@@ -520,6 +522,20 @@ func GetQueuedCompletionStatus(cphandle Handle, qty *uint32, key *uint32, overla
 	return
 }
 
+func PostQueuedCompletionStatus(cphandle Handle, qty uint32, key uint32, overlapped *Overlapped) (errno int) {
+	r1, _, e1 := Syscall6(procPostQueuedCompletionStatus.Addr(), 4, uintptr(cphandle), uintptr(qty), uintptr(key), uintptr(unsafe.Pointer(overlapped)), 0, 0)
+	if int(r1) == 0 {
+		if e1 != 0 {
+			errno = int(e1)
+		} else {
+			errno = EINVAL
+		}
+	} else {
+		errno = 0
+	}
+	return
+}
+
 func CancelIo(s Handle) (errno int) {
 	r1, _, e1 := Syscall(procCancelIo.Addr(), 1, uintptr(s), 0, 0)
 	if int(r1) == 0 {
@@ -1047,6 +1063,26 @@ func TransmitFile(s Handle, handle Handle, bytesToWrite uint32, bytsPerSend uint
 	return
 }
 
+func ReadDirectoryChanges(handle Handle, buf *byte, buflen uint32, watchSubTree bool, mask uint32, retlen *uint32, overlapped *Overlapped, completionRoutine uintptr) (errno int) {
+	var _p0 uint32
+	if watchSubTree {
+		_p0 = 1
+	} else {
+		_p0 = 0
+	}
+	r1, _, e1 := Syscall9(procReadDirectoryChangesW.Addr(), 8, uintptr(handle), uintptr(unsafe.Pointer(buf)), uintptr(buflen), uintptr(_p0), uintptr(mask), uintptr(unsafe.Pointer(retlen)), uintptr(unsafe.Pointer(overlapped)), uintptr(completionRoutine), 0)
+	if int(r1) == 0 {
+		if e1 != 0 {
+			errno = int(e1)
+		} else {
+			errno = EINVAL
+		}
+	} else {
+		errno = 0
+	}
+	return
+}
+
 func CertOpenSystemStore(hprov Handle, name *uint16) (store Handle, errno int) {
 	r0, _, e1 := Syscall(procCertOpenSystemStoreW.Addr(), 2, uintptr(hprov), uintptr(unsafe.Pointer(name)), 0)
 	store = Handle(r0)

src/pkg/syscall/ztypes_windows.go

@@ -4,6 +4,7 @@ const (
 	// Windows errors.
 	ERROR_FILE_NOT_FOUND      = 2
 	ERROR_PATH_NOT_FOUND      = 3
+	ERROR_ACCESS_DENIED       = 5
 	ERROR_NO_MORE_FILES       = 18
 	ERROR_BROKEN_PIPE         = 109
 	ERROR_BUFFER_OVERFLOW     = 111
@@ -54,6 +55,7 @@ const (
 	GENERIC_EXECUTE = 0x20000000
 	GENERIC_ALL     = 0x10000000
 
+	FILE_LIST_DIRECTORY   = 0x00000001
 	FILE_APPEND_DATA      = 0x00000004
 	FILE_WRITE_ATTRIBUTES = 0x00000100
 
@@ -75,6 +77,9 @@ const (
 	OPEN_ALWAYS       = 4
 	TRUNCATE_EXISTING = 5
 
+	FILE_FLAG_BACKUP_SEMANTICS = 0x02000000
+	FILE_FLAG_OVERLAPPED       = 0x40000000
+
 	HANDLE_FLAG_INHERIT    = 0x00000001
 	STARTF_USESTDHANDLES   = 0x00000100
 	STARTF_USESHOWWINDOW   = 0x00000001
@@ -133,6 +138,24 @@ const (
 	FILE_MAP_EXECUTE = 0x20
 )
 
+const (
+	FILE_NOTIFY_CHANGE_FILE_NAME = 1 << iota
+	FILE_NOTIFY_CHANGE_DIR_NAME
+	FILE_NOTIFY_CHANGE_ATTRIBUTES
+	FILE_NOTIFY_CHANGE_SIZE
+	FILE_NOTIFY_CHANGE_LAST_WRITE
+	FILE_NOTIFY_CHANGE_LAST_ACCESS
+	FILE_NOTIFY_CHANGE_CREATION
+)
+
+const (
+	FILE_ACTION_ADDED = iota + 1
+	FILE_ACTION_REMOVED
+	FILE_ACTION_MODIFIED
+	FILE_ACTION_RENAMED_OLD_NAME
+	FILE_ACTION_RENAMED_NEW_NAME
+)
+
 const (
 	// wincrypt.h
 	PROV_RSA_FULL                    = 1
@@ -191,6 +214,13 @@ type Overlapped struct {
 	HEvent       Handle
 }
 
+type FileNotifyInformation struct {
+	NextEntryOffset uint32
+	Action          uint32
+	FileNameLength  uint32
+	FileName        uint16
+}
+
 type Filetime struct {
 	LowDateTime  uint32
 	HighDateTime uint32