storj/cmd/uplinkng/ulfs/handle_std.go

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// Copyright (C) 2021 Storj Labs, Inc.
// See LICENSE for copying information.
package ulfs
import (
"context"
"io"
"sync"
"github.com/zeebo/errs"
"storj.io/common/sync2"
)
//
// read handles
//
// stdMultiReadHandle implements MultiReadHandle for stdin.
type stdMultiReadHandle struct {
stdin io.Reader
mu sync.Mutex
curr *stdReadHandle
done bool
}
func newStdMultiReadHandle(stdin io.Reader) *stdMultiReadHandle {
return &stdMultiReadHandle{
stdin: stdin,
}
}
func (o *stdMultiReadHandle) Close() error {
o.mu.Lock()
defer o.mu.Unlock()
o.done = true
return nil
}
func (o *stdMultiReadHandle) SetOffset(offset int64) error {
return errs.New("cannot set offset on stdin read handle")
}
func (o *stdMultiReadHandle) NextPart(ctx context.Context, length int64) (ReadHandle, error) {
o.mu.Lock()
defer o.mu.Unlock()
if o.done {
return nil, errs.New("already closed")
}
if o.curr != nil {
if !o.curr.done.Wait(ctx) {
return nil, ctx.Err()
}
o.curr.mu.Lock()
defer o.curr.mu.Unlock()
if o.curr.err != nil {
return nil, o.curr.err
}
}
o.curr = &stdReadHandle{
stdin: o.stdin,
len: length,
}
return o.curr, nil
}
func (o *stdMultiReadHandle) Info(ctx context.Context) (*ObjectInfo, error) {
return &ObjectInfo{ContentLength: -1}, nil
}
// stdReadHandle implements ReadHandle for stdin.
type stdReadHandle struct {
stdin io.Reader
mu sync.Mutex
done sync2.Fence
err error
len int64
closed bool
}
func (o *stdReadHandle) Info() ObjectInfo { return ObjectInfo{ContentLength: -1} }
func (o *stdReadHandle) Close() error {
o.mu.Lock()
defer o.mu.Unlock()
o.closed = true
o.done.Release()
return nil
}
func (o *stdReadHandle) Read(p []byte) (int, error) {
o.mu.Lock()
defer o.mu.Unlock()
if o.err != nil {
return 0, o.err
} else if o.closed {
return 0, io.EOF
}
if o.len < int64(len(p)) {
p = p[:o.len]
}
n, err := o.stdin.Read(p)
o.len -= int64(n)
if err != nil && o.err == nil {
o.err = err
o.done.Release()
}
if o.len <= 0 {
o.closed = true
o.done.Release()
}
return n, err
}
//
// write handles
//
// stdMultiWriteHandle implements MultiWriteHandle for stdouts.
type stdMultiWriteHandle struct {
stdout io.Writer
mu sync.Mutex
next *sync.Mutex
tail bool
done bool
}
func newStdMultiWriteHandle(stdout io.Writer) *stdMultiWriteHandle {
return &stdMultiWriteHandle{
stdout: stdout,
next: new(sync.Mutex),
}
}
func (s *stdMultiWriteHandle) NextPart(ctx context.Context, length int64) (WriteHandle, error) {
s.mu.Lock()
defer s.mu.Unlock()
if s.done {
return nil, errs.New("already closed")
} else if s.tail {
return nil, errs.New("unable to make part after tail part")
}
next := new(sync.Mutex)
next.Lock()
w := &stdWriteHandle{
stdout: s.stdout,
mu: s.next,
next: next,
tail: length < 0,
len: length,
}
s.tail = w.tail
s.next = next
return w, nil
}
func (s *stdMultiWriteHandle) Commit(ctx context.Context) error {
s.mu.Lock()
defer s.mu.Unlock()
s.done = true
return nil
}
func (s *stdMultiWriteHandle) Abort(ctx context.Context) error {
s.mu.Lock()
defer s.mu.Unlock()
s.done = true
return nil
}
// stdWriteHandle implements WriteHandle for stdouts.
type stdWriteHandle struct {
stdout io.Writer
mu *sync.Mutex
next *sync.Mutex
tail bool
len int64
}
func (s *stdWriteHandle) unlockNext() {
if s.next != nil {
s.next.Unlock()
s.next = nil
}
}
func (s *stdWriteHandle) Write(p []byte) (int, error) {
s.mu.Lock()
defer s.mu.Unlock()
if !s.tail {
if s.len <= 0 {
return 0, errs.New("write past maximum length")
} else if s.len < int64(len(p)) {
p = p[:s.len]
}
}
n, err := s.stdout.Write(p)
if !s.tail {
s.len -= int64(n)
if s.len == 0 {
s.unlockNext()
}
}
return n, err
}
func (s *stdWriteHandle) Commit() error {
s.mu.Lock()
defer s.mu.Unlock()
s.len = 0
s.unlockNext()
return nil
}
func (s *stdWriteHandle) Abort() error {
s.mu.Lock()
defer s.mu.Unlock()
s.len = 0
s.unlockNext()
return nil
}