1 files changed, 0 insertions, 153 deletions
diff --git a/common/copy.go b/common/copy.go
deleted file mode 100644
index 02e33a5..0000000
--- a/common/copy.go
+++ /dev/null
@@ -1,153 +0,0 @@
-package common
-
-/*
-Copied from https://ixday.github.io/post/golang-cancel-copy/
-*/
-
-import (
-	"context"
-	"fmt"
-	"io"
-	"os"
-	"sync"
-)
-
-// CopyToFileWithBuffer copies data from io.Reader to os.File with given buffer and read chunk size.
-// The reader and writer may not be synchronized if any error occurs.
-// A block contains one or more chunks.
-// Every syscall reads at most one chunk.
-// Every disk-write writes at most one block.
-// The buffer is a ring contains one or more blocks.
-// The reader and file won't be closed.
-// If syncFile is set, the file will be synced after every read.
-// ringSize: how many blocks are in the buffer ring.
-func CopyToFileWithBuffer(
-	ctx context.Context,
-	out *os.File,
-	in io.Reader,
-	buffer []byte,
-	syncFile bool,
-	ringSize uint,
-) (written int64, err error) {
-	var blkSize uint
-	bufSize := uint(len(buffer))
-	if bufSize%ringSize != 0 {
-		err = fmt.Errorf("len(buffer) %% ringSize != 0")
-	} else {
-		blkSize = bufSize / ringSize
-	}
-
-	chWriteQue := make(chan uint, ringSize) // buffer write task queue
-	chReadQue := make(chan uint, ringSize)  // buffer read task queue
-
-	// when reader and writer are stopped, this channel must have 2 elements
-	chResult := make(chan error, 2)
-
-	type task struct {
-		Offset uint
-		Length uint
-	}
-
-	chLastWrite := make(chan task, 1)
-
-	rwCtx, cancelReadWrite := context.WithCancel(ctx)
-
-	// wait reader and writer to finish
-	wg := sync.WaitGroup{}
-
-	// buffer reader
-	// buffer -> file
-	go func() {
-		var err error
-		wg.Add(1)
-		defer wg.Done()
-		defer func() {
-			chResult <- err
-		}()
-		for {
-			select {
-			case <-rwCtx.Done():
-				return
-			default:
-				// get the next available block to read from
-				// this block is fully written in the buffer
-				off := <-chReadQue
-
-				// read the entire block to file
-				n, err2 := out.Write(buffer[off : off+blkSize])
-				if err2 != nil {
-					// failed to write to the file
-					// we can do nothing more than stop reading and writing
-					err = fmt.Errorf("write error (%v byte written in this call): %w", n, err2)
-					cancelReadWrite()
-					return
-				}
-			}
-		}
-	}()
-
-	// buffer writer
-	// reader -> buffer
-	go func() {
-		var err error
-		wg.Add(1)
-		defer wg.Done()
-		defer func() {
-			chResult <- err
-		}()
-		for {
-			select {
-			case <-rwCtx.Done():
-				chLastWrite <- task{
-					Offset: 0,
-					Length: 0,
-				}
-				return
-			default:
-				// get the next free block for writing
-				off := <-chWriteQue // byte offset
-
-				// fully fill the block
-				nWritten := uint(0) // bytes written in this block currently
-				for nWritten < blkSize {
-					n, err := in.Read(buffer[off+nWritten : off+blkSize])
-					nWritten += uint(n)
-					if err != nil {
-						// if we can't fully fill current block (e.g. EOF or IO error),
-						// set nLeft to make the main goroutine handle that
-						cancelReadWrite()
-						err = fmt.Errorf("reader failed: %w", err)
-						chLastWrite <- task{
-							Offset: off,
-							Length: nWritten, // bytes of valid data in the last incomplete block
-						}
-						return
-					}
-				}
-			}
-		}
-	}()
-
-	// init write tasks, all buffer blocks are available for writing initially
-	for i := uint(0); i < bufSize; i += blkSize {
-		chWriteQue <- i
-	}
-
-	wg.Wait()
-
-	for i := 0; i < 2; i++ {
-		if err2 := <-chResult; err2 != nil {
-			err = err2
-			return
-		}
-	}
-
-	// write the remaining data
-	last := <-chLastWrite
-	if last.Length > 0 {
-		var n int
-		n, err = out.Write(buffer[last.Offset : last.Offset+last.Length])
-		written += int64(n)
-	}
-	return
-}