fix(mem): do not overwrite old data in some cases (fixes #286)

This commit is contained in:
tdakkota 2021-02-12 13:02:47 +03:00
parent 32b5faae5b
commit 7b47fea3fc
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GPG Key ID: F0EDAF0788F9CC04
2 changed files with 52 additions and 1 deletions

View File

@ -267,7 +267,7 @@ func (f *File) Write(b []byte) (n int, err error) {
tail = f.fileData.data[n+int(cur):] tail = f.fileData.data[n+int(cur):]
} }
if diff > 0 { if diff > 0 {
f.fileData.data = append(bytes.Repeat([]byte{00}, int(diff)), b...) f.fileData.data = append(f.fileData.data, append(bytes.Repeat([]byte{00}, int(diff)), b...)...)
f.fileData.data = append(f.fileData.data, tail...) f.fileData.data = append(f.fileData.data, tail...)
} else { } else {
f.fileData.data = append(f.fileData.data[:cur], b...) f.fileData.data = append(f.fileData.data[:cur], b...)

View File

@ -95,6 +95,57 @@ func TestFileDataModeRace(t *testing.T) {
} }
} }
// See https://github.com/spf13/afero/issues/286.
func TestFileWriteAt(t *testing.T) {
t.Parallel()
data := CreateFile("abc.txt")
f := NewFileHandle(data)
testData := []byte{1, 2, 3, 4, 5}
offset := len(testData)
// 5 zeros + testdata
_, err := f.WriteAt(testData, int64(offset))
if err != nil {
t.Fatal(err)
}
// 2 * testdata
_, err = f.WriteAt(testData, 0)
if err != nil {
t.Fatal(err)
}
// 3 * testdata
_, err = f.WriteAt(testData, int64(offset*2))
if err != nil {
t.Fatal(err)
}
// 3 * testdata + 5 zeros + testdata
_, err = f.WriteAt(testData, int64(offset*4))
if err != nil {
t.Fatal(err)
}
// 5 * testdata
_, err = f.WriteAt(testData, int64(offset*3))
if err != nil {
t.Fatal(err)
}
err = f.Close()
if err != nil {
t.Fatal(err)
}
expected := bytes.Repeat(testData, 5)
if !bytes.Equal(expected, data.data) {
t.Fatalf("expected: %v, got: %v", expected, data.data)
}
}
func TestFileDataIsDirRace(t *testing.T) { func TestFileDataIsDirRace(t *testing.T) {
t.Parallel() t.Parallel()