Skip to content

Commit

Permalink
Merge pull request #263 from yerden/fix-mmap-fs-seeker
Browse files Browse the repository at this point in the history
mem: fix incorrect offset in Write
  • Loading branch information
0xmichalis authored Sep 2, 2020
2 parents 6400260 + 84f9c83 commit 215b26b
Show file tree
Hide file tree
Showing 2 changed files with 45 additions and 5 deletions.
10 changes: 5 additions & 5 deletions mem/file.go
Original file line number Diff line number Diff line change
Expand Up @@ -225,11 +225,11 @@ func (f *File) Seek(offset int64, whence int) (int64, error) {
return 0, ErrFileClosed
}
switch whence {
case 0:
case io.SeekStart:
atomic.StoreInt64(&f.at, offset)
case 1:
atomic.AddInt64(&f.at, int64(offset))
case 2:
case io.SeekCurrent:
atomic.AddInt64(&f.at, offset)
case io.SeekEnd:
atomic.StoreInt64(&f.at, int64(len(f.fileData.data))+offset)
}
return f.at, nil
Expand Down Expand Up @@ -260,7 +260,7 @@ func (f *File) Write(b []byte) (n int, err error) {
}
setModTime(f.fileData, time.Now())

atomic.StoreInt64(&f.at, int64(len(f.fileData.data)))
atomic.AddInt64(&f.at, int64(n))
return
}

Expand Down
40 changes: 40 additions & 0 deletions mem/file_test.go
Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
package mem

import (
"bytes"
"io"
"testing"
"time"
Expand Down Expand Up @@ -205,3 +206,42 @@ func TestFileReadAtSeekOffset(t *testing.T) {
t.Fatal(err)
}
}

func TestFileWriteAndSeek(t *testing.T) {
fd := CreateFile("foo")
f := NewFileHandle(fd)

assert := func(expected bool, v ...interface{}) {
if !expected {
t.Helper()
t.Fatal(v...)
}
}

data4 := []byte{0, 1, 2, 3}
data20 := bytes.Repeat(data4, 5)
var off int64

for i := 0; i < 100; i++ {
// write 20 bytes
n, err := f.Write(data20)
assert(err == nil, err)
off += int64(n)
assert(n == len(data20), n)
assert(off == int64((i+1)*len(data20)), off)

// rewind to start and write 4 bytes there
cur, err := f.Seek(-off, io.SeekCurrent)
assert(err == nil, err)
assert(cur == 0, cur)

n, err = f.Write(data4)
assert(err == nil, err)
assert(n == len(data4), n)

// back at the end
cur, err = f.Seek(off-int64(n), io.SeekCurrent)
assert(err == nil, err)
assert(cur == off, cur, off)
}
}

0 comments on commit 215b26b

Please sign in to comment.