From 93d8c2beba43af5c9d96db8d00252368a129e137 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zlatko=20=C4=8Calu=C5=A1i=C4=87?= <zcalusic@bitsync.net>
Date: Sat, 5 Nov 2016 17:33:34 +0100
Subject: [PATCH] Copy errors & fs packages from the restic repo and fix import
 paths

Tedious, but I see no better way...
---
 errors/doc.go          |   2 +
 errors/fatal.go        |  38 +++++++++++
 errors/wrap.go         |  20 ++++++
 fs/deviceid_unix.go    |  30 +++++++++
 fs/deviceid_windows.go |  15 +++++
 fs/doc.go              |   3 +
 fs/file.go             | 145 +++++++++++++++++++++++++++++++++++++++++
 fs/file_linux.go       |  58 +++++++++++++++++
 fs/file_nonlinux.go    |  15 +++++
 handlers.go            |   2 +-
 htpasswd.go            |   2 +-
 11 files changed, 328 insertions(+), 2 deletions(-)
 create mode 100644 errors/doc.go
 create mode 100644 errors/fatal.go
 create mode 100644 errors/wrap.go
 create mode 100644 fs/deviceid_unix.go
 create mode 100644 fs/deviceid_windows.go
 create mode 100644 fs/doc.go
 create mode 100644 fs/file.go
 create mode 100644 fs/file_linux.go
 create mode 100644 fs/file_nonlinux.go

diff --git a/errors/doc.go b/errors/doc.go
new file mode 100644
index 0000000..9f63cf9
--- /dev/null
+++ b/errors/doc.go
@@ -0,0 +1,2 @@
+// Package errors provides custom error types used within restic.
+package errors
diff --git a/errors/fatal.go b/errors/fatal.go
new file mode 100644
index 0000000..b61822c
--- /dev/null
+++ b/errors/fatal.go
@@ -0,0 +1,38 @@
+package errors
+
+import "fmt"
+
+// fatalError is an error that should be printed to the user, then the program
+// should exit with an error code.
+type fatalError string
+
+func (e fatalError) Error() string {
+	return string(e)
+}
+
+func (e fatalError) Fatal() bool {
+	return true
+}
+
+// Fataler is an error which should be printed to the user directly.
+// Afterwards, the program should exit with an error.
+type Fataler interface {
+	Fatal() bool
+}
+
+// IsFatal returns true if err is a fatal message that should be printed to the
+// user. Then, the program should exit.
+func IsFatal(err error) bool {
+	e, ok := err.(Fataler)
+	return ok && e.Fatal()
+}
+
+// Fatal returns a wrapped error which implements the Fataler interface.
+func Fatal(s string) error {
+	return Wrap(fatalError(s), "Fatal")
+}
+
+// Fatalf returns an error which implements the Fataler interface.
+func Fatalf(s string, data ...interface{}) error {
+	return fatalError(fmt.Sprintf(s, data...))
+}
diff --git a/errors/wrap.go b/errors/wrap.go
new file mode 100644
index 0000000..5906bd6
--- /dev/null
+++ b/errors/wrap.go
@@ -0,0 +1,20 @@
+package errors
+
+import "github.com/pkg/errors"
+
+// Cause returns the cause of an error.
+func Cause(err error) error {
+	return errors.Cause(err)
+}
+
+// New creates a new error based on message. Wrapped so that this package does
+// not appear in the stack trace.
+var New = errors.New
+
+// Errorf creates an error based on a format string and values. Wrapped so that
+// this package does not appear in the stack trace.
+var Errorf = errors.Errorf
+
+// Wrap wraps an error retrieved from outside of restic. Wrapped so that this
+// package does not appear in the stack trace.
+var Wrap = errors.Wrap
diff --git a/fs/deviceid_unix.go b/fs/deviceid_unix.go
new file mode 100644
index 0000000..a872a4f
--- /dev/null
+++ b/fs/deviceid_unix.go
@@ -0,0 +1,30 @@
+// +build !windows
+
+package fs
+
+import (
+	"os"
+	"syscall"
+
+	"github.com/zcalusic/restic-server/errors"
+)
+
+// DeviceID extracts the device ID from an os.FileInfo object by casting it
+// to syscall.Stat_t
+func DeviceID(fi os.FileInfo) (deviceID uint64, err error) {
+	if fi == nil {
+		return 0, errors.New("unable to determine device: fi is nil")
+	}
+
+	if fi.Sys() == nil {
+		return 0, errors.New("unable to determine device: fi.Sys() is nil")
+	}
+
+	if st, ok := fi.Sys().(*syscall.Stat_t); ok {
+		// st.Dev is uint32 on Darwin and uint64 on Linux. Just cast
+		// everything to uint64.
+		return uint64(st.Dev), nil
+	}
+
+	return 0, errors.New("Could not cast to syscall.Stat_t")
+}
diff --git a/fs/deviceid_windows.go b/fs/deviceid_windows.go
new file mode 100644
index 0000000..e4590aa
--- /dev/null
+++ b/fs/deviceid_windows.go
@@ -0,0 +1,15 @@
+// +build windows
+
+package fs
+
+import (
+	"os"
+
+	"github.com/zcalusic/restic-server/errors"
+)
+
+// DeviceID extracts the device ID from an os.FileInfo object by casting it
+// to syscall.Stat_t
+func DeviceID(fi os.FileInfo) (deviceID uint64, err error) {
+	return 0, errors.New("Device IDs are not supported on Windows")
+}
diff --git a/fs/doc.go b/fs/doc.go
new file mode 100644
index 0000000..29bfa66
--- /dev/null
+++ b/fs/doc.go
@@ -0,0 +1,3 @@
+// Package fs implements an OS independend abstraction of a file system
+// suitable for backup purposes.
+package fs
diff --git a/fs/file.go b/fs/file.go
new file mode 100644
index 0000000..2f6c500
--- /dev/null
+++ b/fs/file.go
@@ -0,0 +1,145 @@
+package fs
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+// File is an open file on a file system.
+type File interface {
+	io.Reader
+	io.Writer
+	io.Closer
+
+	Fd() uintptr
+	Readdirnames(n int) ([]string, error)
+	Readdir(int) ([]os.FileInfo, error)
+	Seek(int64, int) (int64, error)
+	Stat() (os.FileInfo, error)
+}
+
+// fixpath returns an absolute path on windows, so restic can open long file
+// names.
+func fixpath(name string) string {
+	if runtime.GOOS == "windows" {
+		abspath, err := filepath.Abs(name)
+		if err == nil {
+			// Check if \\?\UNC\ already exist
+			if strings.HasPrefix(abspath, `\\?\UNC\`) {
+				return abspath
+			}
+			// Check if \\?\ already exist
+			if strings.HasPrefix(abspath, `\\?\`) {
+				return abspath
+			}
+			// Check if path starts with \\
+			if strings.HasPrefix(abspath, `\\`) {
+				return strings.Replace(abspath, `\\`, `\\?\UNC\`, 1)
+			}
+			// Normal path
+			return `\\?\` + abspath
+		}
+	}
+	return name
+}
+
+// Chmod changes the mode of the named file to mode.
+func Chmod(name string, mode os.FileMode) error {
+	return os.Chmod(fixpath(name), mode)
+}
+
+// Mkdir creates a new directory with the specified name and permission bits.
+// If there is an error, it will be of type *PathError.
+func Mkdir(name string, perm os.FileMode) error {
+	return os.Mkdir(fixpath(name), perm)
+}
+
+// MkdirAll creates a directory named path,
+// along with any necessary parents, and returns nil,
+// or else returns an error.
+// The permission bits perm are used for all
+// directories that MkdirAll creates.
+// If path is already a directory, MkdirAll does nothing
+// and returns nil.
+func MkdirAll(path string, perm os.FileMode) error {
+	return os.MkdirAll(fixpath(path), perm)
+}
+
+// Readlink returns the destination of the named symbolic link.
+// If there is an error, it will be of type *PathError.
+func Readlink(name string) (string, error) {
+	return os.Readlink(fixpath(name))
+}
+
+// Remove removes the named file or directory.
+// If there is an error, it will be of type *PathError.
+func Remove(name string) error {
+	return os.Remove(fixpath(name))
+}
+
+// RemoveAll removes path and any children it contains.
+// It removes everything it can but returns the first error
+// it encounters.  If the path does not exist, RemoveAll
+// returns nil (no error).
+func RemoveAll(path string) error {
+	return os.RemoveAll(fixpath(path))
+}
+
+// Rename renames (moves) oldpath to newpath.
+// If newpath already exists, Rename replaces it.
+// OS-specific restrictions may apply when oldpath and newpath are in different directories.
+// If there is an error, it will be of type *LinkError.
+func Rename(oldpath, newpath string) error {
+	return os.Rename(fixpath(oldpath), fixpath(newpath))
+}
+
+// Symlink creates newname as a symbolic link to oldname.
+// If there is an error, it will be of type *LinkError.
+func Symlink(oldname, newname string) error {
+	return os.Symlink(fixpath(oldname), fixpath(newname))
+}
+
+// Stat returns a FileInfo structure describing the named file.
+// If there is an error, it will be of type *PathError.
+func Stat(name string) (os.FileInfo, error) {
+	return os.Stat(fixpath(name))
+}
+
+// Lstat returns the FileInfo structure describing the named file.
+// If the file is a symbolic link, the returned FileInfo
+// describes the symbolic link.  Lstat makes no attempt to follow the link.
+// If there is an error, it will be of type *PathError.
+func Lstat(name string) (os.FileInfo, error) {
+	return os.Lstat(fixpath(name))
+}
+
+// Create creates the named file with mode 0666 (before umask), truncating
+// it if it already exists. If successful, methods on the returned
+// File can be used for I/O; the associated file descriptor has mode
+// O_RDWR.
+// If there is an error, it will be of type *PathError.
+func Create(name string) (*os.File, error) {
+	return os.Create(fixpath(name))
+}
+
+// OpenFile is the generalized open call; most users will use Open
+// or Create instead.  It opens the named file with specified flag
+// (O_RDONLY etc.) and perm, (0666 etc.) if applicable.  If successful,
+// methods on the returned File can be used for I/O.
+// If there is an error, it will be of type *PathError.
+func OpenFile(name string, flag int, perm os.FileMode) (*os.File, error) {
+	return os.OpenFile(fixpath(name), flag, perm)
+}
+
+// Walk walks the file tree rooted at root, calling walkFn for each file or
+// directory in the tree, including root. All errors that arise visiting files
+// and directories are filtered by walkFn. The files are walked in lexical
+// order, which makes the output deterministic but means that for very
+// large directories Walk can be inefficient.
+// Walk does not follow symbolic links.
+func Walk(root string, walkFn filepath.WalkFunc) error {
+	return filepath.Walk(fixpath(root), walkFn)
+}
diff --git a/fs/file_linux.go b/fs/file_linux.go
new file mode 100644
index 0000000..95b2e64
--- /dev/null
+++ b/fs/file_linux.go
@@ -0,0 +1,58 @@
+// +build linux,go1.4
+
+package fs
+
+import (
+	"os"
+	"syscall"
+
+	"github.com/zcalusic/restic-server/errors"
+	"golang.org/x/sys/unix"
+)
+
+// Open opens a file for reading, without updating the atime and without caching data on read.
+func Open(name string) (File, error) {
+	file, err := os.OpenFile(name, os.O_RDONLY|syscall.O_NOATIME, 0)
+	if os.IsPermission(errors.Cause(err)) {
+		file, err = os.OpenFile(name, os.O_RDONLY, 0)
+	}
+	return &nonCachingFile{File: file}, err
+}
+
+// nonCachingFile wraps an *os.File and calls fadvise() to instantly forget
+// data that has been read or written.
+type nonCachingFile struct {
+	*os.File
+	readOffset int64
+}
+
+func (f *nonCachingFile) Read(p []byte) (int, error) {
+	n, err := f.File.Read(p)
+
+	if n > 0 {
+		ferr := unix.Fadvise(int(f.File.Fd()), f.readOffset, int64(n), unix.FADV_DONTNEED)
+
+		f.readOffset += int64(n)
+
+		if err == nil {
+			err = ferr
+		}
+	}
+
+	return n, err
+}
+
+// ClearCache syncs and then removes the file's content from the OS cache.
+func ClearCache(file File) error {
+	f, ok := file.(*os.File)
+	if !ok {
+		panic("ClearCache called for file not *os.File")
+	}
+
+	err := f.Sync()
+	if err != nil {
+		return err
+	}
+
+	return unix.Fadvise(int(f.Fd()), 0, 0, unix.FADV_DONTNEED)
+}
diff --git a/fs/file_nonlinux.go b/fs/file_nonlinux.go
new file mode 100644
index 0000000..6723480
--- /dev/null
+++ b/fs/file_nonlinux.go
@@ -0,0 +1,15 @@
+// +build !linux !go1.4
+
+package fs
+
+import "os"
+
+// Open opens a file for reading.
+func Open(name string) (File, error) {
+	return os.OpenFile(fixpath(name), os.O_RDONLY, 0)
+}
+
+// ClearCache syncs and then removes the file's content from the OS cache.
+func ClearCache(f File) error {
+	return nil
+}
diff --git a/handlers.go b/handlers.go
index 3351fdc..f53d5c4 100644
--- a/handlers.go
+++ b/handlers.go
@@ -13,7 +13,7 @@ import (
 	"strings"
 	"time"
 
-	"restic/fs"
+	"github.com/zcalusic/restic-server/fs"
 )
 
 // Context contains repository meta-data.
diff --git a/htpasswd.go b/htpasswd.go
index 6ec6704..b0a60c0 100644
--- a/htpasswd.go
+++ b/htpasswd.go
@@ -33,7 +33,7 @@ import (
 	"io"
 	"log"
 
-	"restic/fs"
+	"github.com/zcalusic/restic-server/fs"
 )
 
 // lookup passwords in a htpasswd file