github.com/sagernet/sing@v0.4.0-beta.19.0.20240518125136-f67a0988a636/common/bufio/deadline/reader.go (about)

     1  package deadline
     2  
     3  import (
     4  	"io"
     5  	"os"
     6  	"time"
     7  
     8  	"github.com/sagernet/sing/common/atomic"
     9  	"github.com/sagernet/sing/common/buf"
    10  	"github.com/sagernet/sing/common/bufio"
    11  	N "github.com/sagernet/sing/common/network"
    12  )
    13  
    14  type TimeoutReader interface {
    15  	io.Reader
    16  	SetReadDeadline(t time.Time) error
    17  }
    18  
    19  type Reader interface {
    20  	N.ExtendedReader
    21  	TimeoutReader
    22  	N.WithUpstreamReader
    23  	N.ReaderWithUpstream
    24  }
    25  
    26  type reader struct {
    27  	N.ExtendedReader
    28  	timeoutReader TimeoutReader
    29  	deadline      atomic.TypedValue[time.Time]
    30  	pipeDeadline  pipeDeadline
    31  	result        chan *readResult
    32  	done          chan struct{}
    33  }
    34  
    35  type readResult struct {
    36  	buffer *buf.Buffer
    37  	err    error
    38  }
    39  
    40  func NewReader(timeoutReader TimeoutReader) Reader {
    41  	return &reader{
    42  		ExtendedReader: bufio.NewExtendedReader(timeoutReader),
    43  		timeoutReader:  timeoutReader,
    44  		pipeDeadline:   makePipeDeadline(),
    45  		result:         make(chan *readResult, 1),
    46  		done:           makeFilledChan(),
    47  	}
    48  }
    49  
    50  func (r *reader) Read(p []byte) (n int, err error) {
    51  	select {
    52  	case result := <-r.result:
    53  		return r.pipeReturn(result, p)
    54  	default:
    55  	}
    56  	select {
    57  	case result := <-r.result:
    58  		return r.pipeReturn(result, p)
    59  	case <-r.pipeDeadline.wait():
    60  		return 0, os.ErrDeadlineExceeded
    61  	case <-r.done:
    62  		go r.pipeRead(len(p))
    63  	}
    64  	select {
    65  	case result := <-r.result:
    66  		return r.pipeReturn(result, p)
    67  	case <-r.pipeDeadline.wait():
    68  		return 0, os.ErrDeadlineExceeded
    69  	}
    70  }
    71  
    72  func (r *reader) pipeReturn(result *readResult, p []byte) (n int, err error) {
    73  	n = copy(p, result.buffer.Bytes())
    74  	result.buffer.Advance(n)
    75  	if result.buffer.IsEmpty() {
    76  		result.buffer.Release()
    77  		err = result.err
    78  	} else {
    79  		r.result <- result
    80  	}
    81  	return
    82  }
    83  
    84  func (r *reader) pipeRead(pLen int) {
    85  	buffer := buf.NewSize(pLen)
    86  	_, err := buffer.ReadOnceFrom(r.ExtendedReader)
    87  	r.result <- &readResult{
    88  		buffer: buffer,
    89  		err:    err,
    90  	}
    91  	r.done <- struct{}{}
    92  }
    93  
    94  func (r *reader) ReadBuffer(buffer *buf.Buffer) error {
    95  	select {
    96  	case result := <-r.result:
    97  		return r.pipeReturnBuffer(result, buffer)
    98  	default:
    99  	}
   100  	select {
   101  	case result := <-r.result:
   102  		return r.pipeReturnBuffer(result, buffer)
   103  	case <-r.pipeDeadline.wait():
   104  		return os.ErrDeadlineExceeded
   105  	case <-r.done:
   106  		go r.pipeRead(buffer.FreeLen())
   107  	}
   108  	select {
   109  	case result := <-r.result:
   110  		return r.pipeReturnBuffer(result, buffer)
   111  	case <-r.pipeDeadline.wait():
   112  		return os.ErrDeadlineExceeded
   113  	}
   114  }
   115  
   116  func (r *reader) pipeReturnBuffer(result *readResult, buffer *buf.Buffer) error {
   117  	n, _ := buffer.Write(result.buffer.Bytes())
   118  	result.buffer.Advance(n)
   119  	if !result.buffer.IsEmpty() {
   120  		r.result <- result
   121  		return nil
   122  	} else {
   123  		result.buffer.Release()
   124  		return result.err
   125  	}
   126  }
   127  
   128  func (r *reader) SetReadDeadline(t time.Time) error {
   129  	r.deadline.Store(t)
   130  	r.pipeDeadline.set(t)
   131  	return nil
   132  }
   133  
   134  func (r *reader) ReaderReplaceable() bool {
   135  	select {
   136  	case <-r.done:
   137  		r.done <- struct{}{}
   138  	default:
   139  		return false
   140  	}
   141  	select {
   142  	case result := <-r.result:
   143  		r.result <- result
   144  		return false
   145  	default:
   146  	}
   147  	return r.deadline.Load().IsZero()
   148  }
   149  
   150  func (r *reader) UpstreamReader() any {
   151  	return r.ExtendedReader
   152  }