mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-11-22 11:46:40 +00:00
149 lines
3.1 KiB
Go
149 lines
3.1 KiB
Go
// Copyright 2015 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 bio implements common I/O abstractions used within the Go toolchain.
|
|
package bio
|
|
|
|
import (
|
|
"bufio"
|
|
"io"
|
|
"log"
|
|
"os"
|
|
)
|
|
|
|
// Reader implements a seekable buffered io.Reader.
|
|
type Reader struct {
|
|
f *os.File
|
|
*bufio.Reader
|
|
}
|
|
|
|
// Writer implements a seekable buffered io.Writer.
|
|
type Writer struct {
|
|
f *os.File
|
|
*bufio.Writer
|
|
}
|
|
|
|
// Create creates the file named name and returns a Writer
|
|
// for that file.
|
|
func Create(name string) (*Writer, error) {
|
|
f, err := os.Create(name)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return &Writer{f: f, Writer: bufio.NewWriter(f)}, nil
|
|
}
|
|
|
|
// Open returns a Reader for the file named name.
|
|
func Open(name string) (*Reader, error) {
|
|
f, err := os.Open(name)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return NewReader(f), nil
|
|
}
|
|
|
|
// NewReader returns a Reader from an open file.
|
|
func NewReader(f *os.File) *Reader {
|
|
return &Reader{f: f, Reader: bufio.NewReader(f)}
|
|
}
|
|
|
|
func (r *Reader) MustSeek(offset int64, whence int) int64 {
|
|
if whence == 1 {
|
|
offset -= int64(r.Buffered())
|
|
}
|
|
off, err := r.f.Seek(offset, whence)
|
|
if err != nil {
|
|
log.Fatalf("seeking in output: %v", err)
|
|
}
|
|
r.Reset(r.f)
|
|
return off
|
|
}
|
|
|
|
func (w *Writer) MustSeek(offset int64, whence int) int64 {
|
|
if err := w.Flush(); err != nil {
|
|
log.Fatalf("writing output: %v", err)
|
|
}
|
|
off, err := w.f.Seek(offset, whence)
|
|
if err != nil {
|
|
log.Fatalf("seeking in output: %v", err)
|
|
}
|
|
return off
|
|
}
|
|
|
|
func (r *Reader) Offset() int64 {
|
|
off, err := r.f.Seek(0, 1)
|
|
if err != nil {
|
|
log.Fatalf("seeking in output [0, 1]: %v", err)
|
|
}
|
|
off -= int64(r.Buffered())
|
|
return off
|
|
}
|
|
|
|
func (w *Writer) Offset() int64 {
|
|
if err := w.Flush(); err != nil {
|
|
log.Fatalf("writing output: %v", err)
|
|
}
|
|
off, err := w.f.Seek(0, 1)
|
|
if err != nil {
|
|
log.Fatalf("seeking in output [0, 1]: %v", err)
|
|
}
|
|
return off
|
|
}
|
|
|
|
func (r *Reader) Close() error {
|
|
return r.f.Close()
|
|
}
|
|
|
|
func (w *Writer) Close() error {
|
|
err := w.Flush()
|
|
err1 := w.f.Close()
|
|
if err == nil {
|
|
err = err1
|
|
}
|
|
return err
|
|
}
|
|
|
|
func (r *Reader) File() *os.File {
|
|
return r.f
|
|
}
|
|
|
|
func (w *Writer) File() *os.File {
|
|
return w.f
|
|
}
|
|
|
|
// Slice reads the next length bytes of r into a slice.
|
|
//
|
|
// This slice may be backed by mmap'ed memory. Currently, this memory
|
|
// will never be unmapped. The second result reports whether the
|
|
// backing memory is read-only.
|
|
func (r *Reader) Slice(length uint64) ([]byte, bool, error) {
|
|
if length == 0 {
|
|
return []byte{}, false, nil
|
|
}
|
|
|
|
data, ok := r.sliceOS(length)
|
|
if ok {
|
|
return data, true, nil
|
|
}
|
|
|
|
data = make([]byte, length)
|
|
_, err := io.ReadFull(r, data)
|
|
if err != nil {
|
|
return nil, false, err
|
|
}
|
|
return data, false, nil
|
|
}
|
|
|
|
// SliceRO returns a slice containing the next length bytes of r
|
|
// backed by a read-only mmap'd data. If the mmap cannot be
|
|
// established (limit exceeded, region too small, etc) a nil slice
|
|
// will be returned. If mmap succeeds, it will never be unmapped.
|
|
func (r *Reader) SliceRO(length uint64) []byte {
|
|
data, ok := r.sliceOS(length)
|
|
if ok {
|
|
return data
|
|
}
|
|
return nil
|
|
}
|