搭建框架

vendor/github.com/cznic/fileutil/AUTHORS

@@ -0,0 +1,15 @@
+# This file lists authors for copyright purposes.  This file is distinct from
+# the CONTRIBUTORS files.  See the latter for an explanation.
+#
+# Names should be added to this file as:
+#     Name or Organization <email address>
+#
+# The email address is not required for organizations.
+#
+# Please keep the list sorted.
+
+CZ.NIC z.s.p.o. <kontakt@nic.cz>
+Jan Mercl <0xjnml@gmail.com>
+Linelane GmbH <info@linelane.com>
+Aaron Bieber <deftly@gmail.com>
+

vendor/github.com/cznic/fileutil/CONTRIBUTORS

@@ -0,0 +1,15 @@
+# This file lists people who contributed code to this repository.  The AUTHORS
+# file lists the copyright holders; this file lists people.
+#
+# Names should be added to this file like so:
+#     Name <email address>
+#
+# Please keep the list sorted.
+
+Andris Valums <info@linelane.com>
+Bill Thiede <xinu.tv>
+Gary Burd <gary@beagledreams.com>
+Jan Mercl <0xjnml@gmail.com>
+Nick Owens <mischief@offblast.org>
+Tamás Gulácsi <gt-dev@gthomas.eu>
+Aaron Bieber <deftly@gmail.com>

vendor/github.com/cznic/fileutil/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2014 The fileutil Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the names of the authors nor the names of the
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/cznic/fileutil/Makefile

@@ -0,0 +1,27 @@
+# Copyright (c) 2014 The fileutil authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+.PHONY: all clean editor todo
+
+all: editor
+	go vet
+	golint .
+	go install
+	make todo
+
+editor:
+	go fmt
+	go test -i
+	go test
+	go build
+
+todo:
+	@grep -n ^[[:space:]]*_[[:space:]]*=[[:space:]][[:alpha:]][[:alnum:]]* *.go || true
+	@grep -n TODO *.go || true
+	@grep -n BUG *.go || true
+	@grep -n println *.go || true
+
+clean:
+	@go clean
+	rm -f y.output

vendor/github.com/cznic/fileutil/README

@@ -0,0 +1,16 @@
+This is a goinstall-able mirror of modified code already published at:
+http://git.nic.cz/redmine/projects/gofileutil/repository
+
+Packages in this repository:
+
+Install: $go get github.com/cznic/fileutil
+Godocs: http://godoc.org/github.com/cznic/fileutil
+
+Install: $go get github.com/cznic/fileutil/storage
+Godocs: http://godoc.org/github.com/cznic/fileutil/storage
+
+Install: $go get github.com/cznic/fileutil/falloc
+Godocs: http://godoc.org/github.com/cznic/fileutil/falloc
+
+Install: $go get github.com/cznic/fileutil/hdb
+Godocs: http://godoc.org/github.com/cznic/fileutil/hdb

vendor/github.com/cznic/fileutil/fileutil.go

@@ -0,0 +1,223 @@
+// Copyright (c) 2014 The fileutil 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 fileutil collects some file utility functions.
+package fileutil
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"sync"
+	"time"
+)
+
+// GoMFile is a concurrent access safe version of MFile.
+type GoMFile struct {
+	mfile *MFile
+	mutex sync.Mutex
+}
+
+// NewGoMFile return a newly created GoMFile.
+func NewGoMFile(fname string, flag int, perm os.FileMode, delta_ns int64) (m *GoMFile, err error) {
+	m = &GoMFile{}
+	if m.mfile, err = NewMFile(fname, flag, perm, delta_ns); err != nil {
+		m = nil
+	}
+	return
+}
+
+func (m *GoMFile) File() (file *os.File, err error) {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+	return m.mfile.File()
+}
+
+func (m *GoMFile) SetChanged() {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+	m.mfile.SetChanged()
+}
+
+func (m *GoMFile) SetHandler(h MFileHandler) {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+	m.mfile.SetHandler(h)
+}
+
+// MFileHandler resolves modifications of File.
+// Possible File context is expected to be a part of the handler's closure.
+type MFileHandler func(*os.File) error
+
+// MFile represents an os.File with a guard/handler on change/modification.
+// Example use case is an app with a configuration file which can be modified at any time
+// and have to be reloaded in such event prior to performing something configurable by that
+// file. The checks are made only on access to the MFile file by
+// File() and a time threshold/hysteresis value can be chosen on creating a new MFile.
+type MFile struct {
+	file    *os.File
+	handler MFileHandler
+	t0      int64
+	delta   int64
+	ctime   int64
+}
+
+// NewMFile returns a newly created MFile or Error if any.
+// The fname, flag and perm parameters have the same meaning as in os.Open.
+// For meaning of the delta_ns parameter please see the (m *MFile) File() docs.
+func NewMFile(fname string, flag int, perm os.FileMode, delta_ns int64) (m *MFile, err error) {
+	m = &MFile{}
+	m.t0 = time.Now().UnixNano()
+	if m.file, err = os.OpenFile(fname, flag, perm); err != nil {
+		return
+	}
+
+	var fi os.FileInfo
+	if fi, err = m.file.Stat(); err != nil {
+		return
+	}
+
+	m.ctime = fi.ModTime().UnixNano()
+	m.delta = delta_ns
+	runtime.SetFinalizer(m, func(m *MFile) {
+		m.file.Close()
+	})
+	return
+}
+
+// SetChanged forces next File() to unconditionally handle modification of the wrapped os.File.
+func (m *MFile) SetChanged() {
+	m.ctime = -1
+}
+
+// SetHandler sets a function to be invoked when modification of MFile is to be processed.
+func (m *MFile) SetHandler(h MFileHandler) {
+	m.handler = h
+}
+
+// File returns an os.File from MFile. If time elapsed between the last invocation of this function
+// and now is at least delta_ns ns (a parameter of NewMFile) then the file is checked for
+// change/modification. For delta_ns == 0 the modification is checked w/o getting os.Time().
+// If a change is detected a handler is invoked on the MFile file.
+// Any of these steps can produce an Error. If that happens the function returns nil, Error.
+func (m *MFile) File() (file *os.File, err error) {
+	var now int64
+
+	mustCheck := m.delta == 0
+	if !mustCheck {
+		now = time.Now().UnixNano()
+		mustCheck = now-m.t0 > m.delta
+	}
+
+	if mustCheck { // check interval reached
+		var fi os.FileInfo
+		if fi, err = m.file.Stat(); err != nil {
+			return
+		}
+
+		if fi.ModTime().UnixNano() != m.ctime { // modification detected
+			if m.handler == nil {
+				return nil, fmt.Errorf("no handler set for modified file %q", m.file.Name())
+			}
+			if err = m.handler(m.file); err != nil {
+				return
+			}
+
+			m.ctime = fi.ModTime().UnixNano()
+		}
+		m.t0 = now
+	}
+
+	return m.file, nil
+}
+
+// Read reads buf from r. It will either fill the full buf or fail.
+// It wraps the functionality of an io.Reader which may return less bytes than requested,
+// but may block if not all data are ready for the io.Reader.
+func Read(r io.Reader, buf []byte) (err error) {
+	have := 0
+	remain := len(buf)
+	got := 0
+	for remain > 0 {
+		if got, err = r.Read(buf[have:]); err != nil {
+			return
+		}
+
+		remain -= got
+		have += got
+	}
+	return
+}
+
+// "os" and/or "syscall" extensions
+
+// FadviseAdvice is used by Fadvise.
+type FadviseAdvice int
+
+// FAdviseAdvice values.
+const (
+	// $ grep FADV /usr/include/bits/fcntl.h
+	POSIX_FADV_NORMAL     FadviseAdvice = iota // No further special treatment.
+	POSIX_FADV_RANDOM                          // Expect random page references.
+	POSIX_FADV_SEQUENTIAL                      // Expect sequential page references.
+	POSIX_FADV_WILLNEED                        // Will need these pages.
+	POSIX_FADV_DONTNEED                        // Don't need these pages.
+	POSIX_FADV_NOREUSE                         // Data will be accessed once.
+)
+
+// TempFile creates a new temporary file in the directory dir with a name
+// ending with suffix, basename starting with prefix, opens the file for
+// reading and writing, and returns the resulting *os.File.  If dir is the
+// empty string, TempFile uses the default directory for temporary files (see
+// os.TempDir).  Multiple programs calling TempFile simultaneously will not
+// choose the same file.  The caller can use f.Name() to find the pathname of
+// the file.  It is the caller's responsibility to remove the file when no
+// longer needed.
+//
+// NOTE: This function differs from ioutil.TempFile.
+func TempFile(dir, prefix, suffix string) (f *os.File, err error) {
+	if dir == "" {
+		dir = os.TempDir()
+	}
+
+	nconflict := 0
+	for i := 0; i < 10000; i++ {
+		name := filepath.Join(dir, prefix+nextInfix()+suffix)
+		f, err = os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600)
+		if os.IsExist(err) {
+			if nconflict++; nconflict > 10 {
+				rand = reseed()
+			}
+			continue
+		}
+		break
+	}
+	return
+}
+
+// Random number state.
+// We generate random temporary file names so that there's a good
+// chance the file doesn't exist yet - keeps the number of tries in
+// TempFile to a minimum.
+var rand uint32
+var randmu sync.Mutex
+
+func reseed() uint32 {
+	return uint32(time.Now().UnixNano() + int64(os.Getpid()))
+}
+
+func nextInfix() string {
+	randmu.Lock()
+	r := rand
+	if r == 0 {
+		r = reseed()
+	}
+	r = r*1664525 + 1013904223 // constants from Numerical Recipes
+	rand = r
+	randmu.Unlock()
+	return strconv.Itoa(int(1e9 + r%1e9))[1:]
+}

vendor/github.com/cznic/fileutil/fileutil_arm.go

@@ -0,0 +1,27 @@
+// Copyright (c) 2014 The fileutil 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 fileutil
+
+import (
+	"io"
+	"os"
+)
+
+const hasPunchHole = false
+
+// PunchHole deallocates space inside a file in the byte range starting at
+// offset and continuing for len bytes. Not supported on ARM.
+func PunchHole(f *os.File, off, len int64) error {
+	return nil
+}
+
+// Fadvise predeclares an access pattern for file data.  See also 'man 2
+// posix_fadvise'. Not supported on ARM.
+func Fadvise(f *os.File, off, len int64, advice FadviseAdvice) error {
+	return nil
+}
+
+// IsEOF reports whether err is an EOF condition.
+func IsEOF(err error) bool { return err == io.EOF }

vendor/github.com/cznic/fileutil/fileutil_darwin.go

@@ -0,0 +1,29 @@
+// Copyright (c) 2014 The fileutil Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !arm
+
+package fileutil
+
+import (
+	"io"
+	"os"
+)
+
+const hasPunchHole = false
+
+// PunchHole deallocates space inside a file in the byte range starting at
+// offset and continuing for len bytes. Not supported on OSX.
+func PunchHole(f *os.File, off, len int64) error {
+	return nil
+}
+
+// Fadvise predeclares an access pattern for file data.  See also 'man 2
+// posix_fadvise'. Not supported on OSX.
+func Fadvise(f *os.File, off, len int64, advice FadviseAdvice) error {
+	return nil
+}
+
+// IsEOF reports whether err is an EOF condition.
+func IsEOF(err error) bool { return err == io.EOF }

vendor/github.com/cznic/fileutil/fileutil_freebsd.go

@@ -0,0 +1,29 @@
+// Copyright (c) 2014 The fileutil Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !arm
+
+package fileutil
+
+import (
+	"io"
+	"os"
+)
+
+const hasPunchHole = false
+
+// PunchHole deallocates space inside a file in the byte range starting at
+// offset and continuing for len bytes. Unimplemented on FreeBSD.
+func PunchHole(f *os.File, off, len int64) error {
+	return nil
+}
+
+// Fadvise predeclares an access pattern for file data.  See also 'man 2
+// posix_fadvise'. Unimplemented on FreeBSD.
+func Fadvise(f *os.File, off, len int64, advice FadviseAdvice) error {
+	return nil
+}
+
+// IsEOF reports whether err is an EOF condition.
+func IsEOF(err error) bool { return err == io.EOF }

vendor/github.com/cznic/fileutil/fileutil_linux.go

@@ -0,0 +1,98 @@
+// Copyright (c) 2014 The fileutil Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !arm
+
+package fileutil
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+	"os"
+	"strconv"
+	"syscall"
+)
+
+const hasPunchHole = true
+
+func n(s []byte) byte {
+	for i, c := range s {
+		if c < '0' || c > '9' {
+			s = s[:i]
+			break
+		}
+	}
+	v, _ := strconv.Atoi(string(s))
+	return byte(v)
+}
+
+func init() {
+	b, err := ioutil.ReadFile("/proc/sys/kernel/osrelease")
+	if err != nil {
+		panic(err)
+	}
+
+	tokens := bytes.Split(b, []byte("."))
+	if len(tokens) > 3 {
+		tokens = tokens[:3]
+	}
+	switch len(tokens) {
+	case 3:
+		// Supported since kernel 2.6.38
+		if bytes.Compare([]byte{n(tokens[0]), n(tokens[1]), n(tokens[2])}, []byte{2, 6, 38}) < 0 {
+			puncher = func(*os.File, int64, int64) error { return nil }
+		}
+	case 2:
+		if bytes.Compare([]byte{n(tokens[0]), n(tokens[1])}, []byte{2, 7}) < 0 {
+			puncher = func(*os.File, int64, int64) error { return nil }
+		}
+	default:
+		puncher = func(*os.File, int64, int64) error { return nil }
+	}
+}
+
+var puncher = func(f *os.File, off, len int64) error {
+	const (
+		/*
+			/usr/include/linux$ grep FL_ falloc.h
+		*/
+		_FALLOC_FL_KEEP_SIZE  = 0x01 // default is extend size
+		_FALLOC_FL_PUNCH_HOLE = 0x02 // de-allocates range
+	)
+
+	_, _, errno := syscall.Syscall6(
+		syscall.SYS_FALLOCATE,
+		uintptr(f.Fd()),
+		uintptr(_FALLOC_FL_KEEP_SIZE|_FALLOC_FL_PUNCH_HOLE),
+		uintptr(off),
+		uintptr(len),
+		0, 0)
+	if errno != 0 {
+		return os.NewSyscallError("SYS_FALLOCATE", errno)
+	}
+	return nil
+}
+
+// PunchHole deallocates space inside a file in the byte range starting at
+// offset and continuing for len bytes. No-op for kernels < 2.6.38 (or < 2.7).
+func PunchHole(f *os.File, off, len int64) error {
+	return puncher(f, off, len)
+}
+
+// Fadvise predeclares an access pattern for file data.  See also 'man 2
+// posix_fadvise'.
+func Fadvise(f *os.File, off, len int64, advice FadviseAdvice) error {
+	_, _, errno := syscall.Syscall6(
+		syscall.SYS_FADVISE64,
+		uintptr(f.Fd()),
+		uintptr(off),
+		uintptr(len),
+		uintptr(advice),
+		0, 0)
+	return os.NewSyscallError("SYS_FADVISE64", errno)
+}
+
+// IsEOF reports whether err is an EOF condition.
+func IsEOF(err error) bool { return err == io.EOF }

vendor/github.com/cznic/fileutil/fileutil_netbsd.go

@@ -0,0 +1,29 @@
+// Copyright (c) 2014 The fileutil Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !arm
+
+package fileutil
+
+import (
+	"io"
+	"os"
+)
+
+const hasPunchHole = false
+
+// PunchHole deallocates space inside a file in the byte range starting at
+// offset and continuing for len bytes. Similar to FreeBSD, this is
+// unimplemented.
+func PunchHole(f *os.File, off, len int64) error {
+	return nil
+}
+
+// Unimplemented on NetBSD.
+func Fadvise(f *os.File, off, len int64, advice FadviseAdvice) error {
+	return nil
+}
+
+// IsEOF reports whether err is an EOF condition.
+func IsEOF(err error) bool { return err == io.EOF }

vendor/github.com/cznic/fileutil/fileutil_openbsd.go

@@ -0,0 +1,27 @@
+// Copyright (c) 2014 The fileutil 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 fileutil
+
+import (
+	"io"
+	"os"
+)
+
+const hasPunchHole = false
+
+// PunchHole deallocates space inside a file in the byte range starting at
+// offset and continuing for len bytes. Similar to FreeBSD, this is
+// unimplemented.
+func PunchHole(f *os.File, off, len int64) error {
+	return nil
+}
+
+// Unimplemented on OpenBSD.
+func Fadvise(f *os.File, off, len int64, advice FadviseAdvice) error {
+	return nil
+}
+
+// IsEOF reports whether err is an EOF condition.
+func IsEOF(err error) bool { return err == io.EOF }

vendor/github.com/cznic/fileutil/fileutil_plan9.go

@@ -0,0 +1,27 @@
+// Copyright (c) 2014 The fileutil 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 fileutil
+
+import (
+	"io"
+	"os"
+)
+
+const hasPunchHole = false
+
+// PunchHole deallocates space inside a file in the byte range starting at
+// offset and continuing for len bytes. Unimplemented on Plan 9.
+func PunchHole(f *os.File, off, len int64) error {
+	return nil
+}
+
+// Fadvise predeclares an access pattern for file data.  See also 'man 2
+// posix_fadvise'. Unimplemented on Plan 9.
+func Fadvise(f *os.File, off, len int64, advice FadviseAdvice) error {
+	return nil
+}
+
+// IsEOF reports whether err is an EOF condition.
+func IsEOF(err error) bool { return err == io.EOF }

vendor/github.com/cznic/fileutil/fileutil_solaris.go

@@ -0,0 +1,29 @@
+// Copyright (c) 2013 jnml. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.3
+
+package fileutil
+
+import (
+	"io"
+	"os"
+)
+
+const hasPunchHole = false
+
+// PunchHole deallocates space inside a file in the byte range starting at
+// offset and continuing for len bytes. Not supported on Solaris.
+func PunchHole(f *os.File, off, len int64) error {
+	return nil
+}
+
+// Fadvise predeclares an access pattern for file data.  See also 'man 2
+// posix_fadvise'. Not supported on Solaris.
+func Fadvise(f *os.File, off, len int64, advice FadviseAdvice) error {
+	return nil
+}
+
+// IsEOF reports whether err is an EOF condition.
+func IsEOF(err error) bool { return err == io.EOF }

vendor/github.com/cznic/fileutil/fileutil_windows.go

@@ -0,0 +1,185 @@
+// Copyright (c) 2014 The fileutil 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 fileutil
+
+import (
+	"io"
+	"os"
+	"sync"
+	"syscall"
+	"unsafe"
+)
+
+const hasPunchHole = true
+
+// PunchHole deallocates space inside a file in the byte range starting at
+// offset and continuing for len bytes. Not supported on Windows.
+func PunchHole(f *os.File, off, len int64) error {
+	return puncher(f, off, len)
+}
+
+// Fadvise predeclares an access pattern for file data.  See also 'man 2
+// posix_fadvise'. Not supported on Windows.
+func Fadvise(f *os.File, off, len int64, advice FadviseAdvice) error {
+	return nil
+}
+
+// IsEOF reports whether err is an EOF condition.
+func IsEOF(err error) bool {
+	if err == io.EOF {
+		return true
+	}
+
+	// http://social.technet.microsoft.com/Forums/windowsserver/en-US/1a16311b-c625-46cf-830b-6a26af488435/how-to-solve-error-38-0x26-errorhandleeof-using-fsctlgetretrievalpointers
+	x, ok := err.(*os.PathError)
+	return ok && x.Op == "read" && x.Err.(syscall.Errno) == 0x26
+}
+
+var (
+	modkernel32 = syscall.NewLazyDLL("kernel32.dll")
+
+	procDeviceIOControl = modkernel32.NewProc("DeviceIoControl")
+
+	sparseFilesMu sync.Mutex
+	sparseFiles   map[uintptr]struct{}
+)
+
+func init() {
+	// sparseFiles is an fd set for already "sparsed" files - according to
+	// msdn.microsoft.com/en-us/library/windows/desktop/aa364225(v=vs.85).aspx
+	// the file handles are unique per process.
+	sparseFiles = make(map[uintptr]struct{})
+}
+
+// puncHoleWindows punches a hole into the given file starting at offset,
+// measuring "size" bytes
+// (http://msdn.microsoft.com/en-us/library/windows/desktop/aa364597%28v=vs.85%29.aspx)
+func puncher(file *os.File, offset, size int64) error {
+	if err := ensureFileSparse(file); err != nil {
+		return err
+	}
+
+	// http://msdn.microsoft.com/en-us/library/windows/desktop/aa364411%28v=vs.85%29.aspx
+	// typedef struct _FILE_ZERO_DATA_INFORMATION {
+	//  LARGE_INTEGER FileOffset;
+	//  LARGE_INTEGER BeyondFinalZero;
+	//} FILE_ZERO_DATA_INFORMATION, *PFILE_ZERO_DATA_INFORMATION;
+	type fileZeroDataInformation struct {
+		FileOffset, BeyondFinalZero int64
+	}
+
+	lpInBuffer := fileZeroDataInformation{
+		FileOffset:      offset,
+		BeyondFinalZero: offset + size}
+	return deviceIOControl(false, file.Fd(), uintptr(unsafe.Pointer(&lpInBuffer)), 16)
+}
+
+// // http://msdn.microsoft.com/en-us/library/windows/desktop/cc948908%28v=vs.85%29.aspx
+// type fileSetSparseBuffer struct {
+//	 SetSparse bool
+// }
+
+func ensureFileSparse(file *os.File) (err error) {
+	fd := file.Fd()
+	sparseFilesMu.Lock()
+	if _, ok := sparseFiles[fd]; ok {
+		sparseFilesMu.Unlock()
+		return nil
+	}
+
+	if err = deviceIOControl(true, fd, 0, 0); err == nil {
+		sparseFiles[fd] = struct{}{}
+	}
+	sparseFilesMu.Unlock()
+	return err
+}
+
+func deviceIOControl(setSparse bool, fd, inBuf, inBufLen uintptr) (err error) {
+	const (
+		//http://source.winehq.org/source/include/winnt.h#L4605
+		file_read_data  = 1
+		file_write_data = 2
+
+		// METHOD_BUFFERED	0
+		method_buffered = 0
+		// FILE_ANY_ACCESS   0
+		file_any_access = 0
+		// FILE_DEVICE_FILE_SYSTEM   0x00000009
+		file_device_file_system = 0x00000009
+		// FILE_SPECIAL_ACCESS   (FILE_ANY_ACCESS)
+		file_special_access = file_any_access
+		file_read_access    = file_read_data
+		file_write_access   = file_write_data
+
+		// http://source.winehq.org/source/include/winioctl.h
+		// #define CTL_CODE 	(  	DeviceType,
+		//		Function,
+		//		Method,
+		//		Access  		 )
+		//    ((DeviceType) << 16) | ((Access) << 14) | ((Function) << 2) | (Method)
+
+		// FSCTL_SET_COMPRESSION   CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 16, METHOD_BUFFERED, FILE_READ_DATA | FILE_WRITE_DATA)
+		fsctl_set_compression = (file_device_file_system << 16) | ((file_read_access | file_write_access) << 14) | (16 << 2) | method_buffered
+		// FSCTL_SET_SPARSE   CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 49, METHOD_BUFFERED, FILE_SPECIAL_ACCESS)
+		fsctl_set_sparse = (file_device_file_system << 16) | (file_special_access << 14) | (49 << 2) | method_buffered
+		// FSCTL_SET_ZERO_DATA   CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 50, METHOD_BUFFERED, FILE_WRITE_DATA)
+		fsctl_set_zero_data = (file_device_file_system << 16) | (file_write_data << 14) | (50 << 2) | method_buffered
+	)
+	retPtr := uintptr(unsafe.Pointer(&(make([]byte, 8)[0])))
+	var r1 uintptr
+	var e1 syscall.Errno
+	if setSparse {
+		// BOOL
+		// WINAPI
+		// DeviceIoControl( (HANDLE) hDevice,                      // handle to a file
+		//                  FSCTL_SET_SPARSE,                      // dwIoControlCode
+		//                  (PFILE_SET_SPARSE_BUFFER) lpInBuffer,  // input buffer
+		//                  (DWORD) nInBufferSize,                 // size of input buffer
+		//                  NULL,                                  // lpOutBuffer
+		//                  0,                                     // nOutBufferSize
+		//                  (LPDWORD) lpBytesReturned,             // number of bytes returned
+		//                  (LPOVERLAPPED) lpOverlapped );         // OVERLAPPED structure
+		r1, _, e1 = syscall.Syscall9(procDeviceIOControl.Addr(), 8,
+			fd,
+			uintptr(fsctl_set_sparse),
+			// If the lpInBuffer parameter is NULL, the operation will behave the same as if the SetSparse member of the FILE_SET_SPARSE_BUFFER structure were TRUE. In other words, the operation sets the file to a sparse file.
+			0, // uintptr(unsafe.Pointer(&lpInBuffer)),
+			0, // 1,
+			0,
+			0,
+			retPtr,
+			0,
+			0)
+	} else {
+		// BOOL
+		// WINAPI
+		// DeviceIoControl( (HANDLE) hDevice,              // handle to a file
+		//                  FSCTL_SET_ZERO_DATA,           // dwIoControlCode
+		//                  (LPVOID) lpInBuffer,           // input buffer
+		//                  (DWORD) nInBufferSize,         // size of input buffer
+		//                  NULL,                          // lpOutBuffer
+		//                  0,                             // nOutBufferSize
+		//                  (LPDWORD) lpBytesReturned,     // number of bytes returned
+		//                  (LPOVERLAPPED) lpOverlapped ); // OVERLAPPED structure
+		r1, _, e1 = syscall.Syscall9(procDeviceIOControl.Addr(), 8,
+			fd,
+			uintptr(fsctl_set_zero_data),
+			inBuf,
+			inBufLen,
+			0,
+			0,
+			retPtr,
+			0,
+			0)
+	}
+	if r1 == 0 {
+		if e1 != 0 {
+			err = error(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return err
+}

vendor/github.com/cznic/fileutil/test_deps.go

@@ -0,0 +1,13 @@
+// Copyright (c) 2014 The fileutil Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// blame: jnml, labs.nic.cz
+
+package fileutil
+
+// Pull test dependencies too.
+// Enables easy 'go test X' after 'go get X'
+import (
+// nothing yet
+)