Add pushover notifications, this should be a super basic MVP

vendor/github.com/dgraph-io/badger/dir_windows.go

@@ -0,0 +1,110 @@
+// +build windows
+
+/*
+ * Copyright 2017 Dgraph Labs, Inc. and Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package badger
+
+// OpenDir opens a directory in windows with write access for syncing.
+import (
+	"os"
+	"path/filepath"
+	"syscall"
+
+	"github.com/pkg/errors"
+)
+
+// FILE_ATTRIBUTE_TEMPORARY - A file that is being used for temporary storage.
+// FILE_FLAG_DELETE_ON_CLOSE - The file is to be deleted immediately after all of its handles are
+// closed, which includes the specified handle and any other open or duplicated handles.
+// See: https://docs.microsoft.com/en-us/windows/desktop/FileIO/file-attribute-constants
+// NOTE: Added here to avoid importing golang.org/x/sys/windows
+const (
+	FILE_ATTRIBUTE_TEMPORARY  = 0x00000100
+	FILE_FLAG_DELETE_ON_CLOSE = 0x04000000
+)
+
+func openDir(path string) (*os.File, error) {
+	fd, err := openDirWin(path)
+	if err != nil {
+		return nil, err
+	}
+	return os.NewFile(uintptr(fd), path), nil
+}
+
+func openDirWin(path string) (fd syscall.Handle, err error) {
+	if len(path) == 0 {
+		return syscall.InvalidHandle, syscall.ERROR_FILE_NOT_FOUND
+	}
+	pathp, err := syscall.UTF16PtrFromString(path)
+	if err != nil {
+		return syscall.InvalidHandle, err
+	}
+	access := uint32(syscall.GENERIC_READ | syscall.GENERIC_WRITE)
+	sharemode := uint32(syscall.FILE_SHARE_READ | syscall.FILE_SHARE_WRITE)
+	createmode := uint32(syscall.OPEN_EXISTING)
+	fl := uint32(syscall.FILE_FLAG_BACKUP_SEMANTICS)
+	return syscall.CreateFile(pathp, access, sharemode, nil, createmode, fl, 0)
+}
+
+// DirectoryLockGuard holds a lock on the directory.
+type directoryLockGuard struct {
+	h    syscall.Handle
+	path string
+}
+
+// AcquireDirectoryLock acquires exclusive access to a directory.
+func acquireDirectoryLock(dirPath string, pidFileName string, readOnly bool) (*directoryLockGuard, error) {
+	if readOnly {
+		return nil, ErrWindowsNotSupported
+	}
+
+	// Convert to absolute path so that Release still works even if we do an unbalanced
+	// chdir in the meantime.
+	absLockFilePath, err := filepath.Abs(filepath.Join(dirPath, pidFileName))
+	if err != nil {
+		return nil, errors.Wrap(err, "Cannot get absolute path for pid lock file")
+	}
+
+	// This call creates a file handler in memory that only one process can use at a time. When
+	// that process ends, the file is deleted by the system.
+	// FILE_ATTRIBUTE_TEMPORARY is used to tell Windows to try to create the handle in memory.
+	// FILE_FLAG_DELETE_ON_CLOSE is not specified in syscall_windows.go but tells Windows to delete
+	// the file when all processes holding the handler are closed.
+	// XXX: this works but it's a bit klunky. i'd prefer to use LockFileEx but it needs unsafe pkg.
+	h, err := syscall.CreateFile(
+		syscall.StringToUTF16Ptr(absLockFilePath), 0, 0, nil,
+		syscall.OPEN_ALWAYS,
+		uint32(FILE_ATTRIBUTE_TEMPORARY|FILE_FLAG_DELETE_ON_CLOSE),
+		0)
+	if err != nil {
+		return nil, errors.Wrapf(err,
+			"Cannot create lock file %q.  Another process is using this Badger database",
+			absLockFilePath)
+	}
+
+	return &directoryLockGuard{h: h, path: absLockFilePath}, nil
+}
+
+// Release removes the directory lock.
+func (g *directoryLockGuard) release() error {
+	g.path = ""
+	return syscall.CloseHandle(g.h)
+}
+
+// Windows doesn't support syncing directories to the file system. See
+// https://github.com/dgraph-io/badger/issues/699#issuecomment-504133587 for more details.
+func syncDir(dir string) error { return nil }