// NewReader returns a new table reader for the file. Closing the reader will
// close the file.
func NewReader(f db.File, o *db.Options) *Reader {
r := &Reader{
file: f,
comparer: o.GetComparer(),
verifyChecksums: o.GetVerifyChecksums(),
}
if f == nil {
r.err = errors.New("leveldb/table: nil file")
return r
}
stat, err := f.Stat()
if err != nil {
r.err = fmt.Errorf("leveldb/table: invalid table (could not stat file): %v", err)
return r
}
var footer [footerLen]byte
if stat.Size() < int64(len(footer)) {
r.err = errors.New("leveldb/table: invalid table (file size is too small)")
return r
}
_, err = f.ReadAt(footer[:], stat.Size()-int64(len(footer)))
if err != nil && err != io.EOF {
r.err = fmt.Errorf("leveldb/table: invalid table (could not read footer): %v", err)
return r
}
if string(footer[footerLen-len(magic):footerLen]) != magic {
r.err = errors.New("leveldb/table: invalid table (bad magic number)")
return r
}
// Ignore the metaindex.
_, n := decodeBlockHandle(footer[:])
if n == 0 {
r.err = errors.New("leveldb/table: invalid table (bad metaindex block handle)")
return r
}
// Read the index into memory.
indexBH, n := decodeBlockHandle(footer[n:])
if n == 0 {
r.err = errors.New("leveldb/table: invalid table (bad index block handle)")
return r
}
r.index, r.err = r.readBlock(indexBH)
return r
}
func TestBasics(t *testing.T) {
fs := New()
testCases := []string{
// Create a top-level file.
"1a: create /foo",
// Create a child of that file. It should fail, since /foo is not a directory.
"2a: create /foo/x fails",
// Create a third-level file. It should fail, since /bar has not been created.
// Similarly, opening that file should fail.
"3a: create /bar/baz/y fails",
"3b: open /bar/baz/y fails",
// Make the /bar/baz directory; create a third-level file. Creation should now succeed.
"4a: mkdirall /bar/baz",
"4b: f = create /bar/baz/y",
"4c: f.stat.name == y",
// Write some data; read it back.
"5a: f.write abcde",
"5b: f.close",
"5c: f = open /bar/baz/y",
"5d: f.read 5 == abcde",
"5e: f.readat 2 1 == bc",
"5f: f.close",
// Remove the file twice. The first should succeed, the second should fail.
"6a: remove /bar/baz/y",
"6b: remove /bar/baz/y fails",
"6c: open /bar/baz/y fails",
// Rename /foo to /goo. Trying to open /foo should succeed before the rename and
// fail afterwards, and vice versa for /goo.
"7a: open /foo",
"7b: open /goo fails",
"7c: rename /foo /goo",
"7d: open /foo fails",
"7e: open /goo",
// Create /bar/baz/z and rename /bar/baz to /bar/caz.
"8a: create /bar/baz/z",
"8b: open /bar/baz/z",
"8c: open /bar/caz/z fails",
"8d: rename /bar/baz /bar/caz",
"8e: open /bar/baz/z fails",
"8f: open /bar/caz/z",
}
var f db.File
for _, tc := range testCases {
s := strings.Split(tc, " ")[1:]
saveF := s[0] == "f" && s[1] == "="
if saveF {
s = s[2:]
}
fails := s[len(s)-1] == "fails"
if fails {
s = s[:len(s)-1]
}
var (
fi os.FileInfo
g db.File
err error
)
switch s[0] {
case "create":
g, err = fs.Create(normalize(s[1]))
case "open":
g, err = fs.Open(normalize(s[1]))
case "mkdirall":
err = fs.MkdirAll(normalize(s[1]), 0755)
case "remove":
err = fs.Remove(normalize(s[1]))
case "rename":
err = fs.Rename(normalize(s[1]), normalize(s[2]))
case "f.write":
_, err = f.Write([]byte(s[1]))
case "f.read":
n, _ := strconv.Atoi(s[1])
buf := make([]byte, n)
_, err = io.ReadFull(f, buf)
if err != nil {
break
}
if got, want := string(buf), s[3]; got != want {
t.Fatalf("%q: got %q, want %q", tc, got, want)
}
case "f.readat":
n, _ := strconv.Atoi(s[1])
off, _ := strconv.Atoi(s[2])
buf := make([]byte, n)
_, err = f.ReadAt(buf, int64(off))
if err != nil {
break
}
if got, want := string(buf), s[4]; got != want {
t.Fatalf("%q: got %q, want %q", tc, got, want)
}
case "f.close":
f, err = nil, f.Close()
case "f.stat.name":
fi, err = f.Stat()
if err != nil {
break
}
if got, want := fi.Name(), s[2]; got != want {
t.Fatalf("%q: got %q, want %q", tc, got, want)
}
default:
t.Fatalf("bad test case: %q", tc)
}
if saveF {
f, g = g, nil
} else if g != nil {
g.Close()
}
if fails {
if err == nil {
t.Fatalf("%q: got nil error, want non-nil", tc)
}
} else {
if err != nil {
t.Fatalf("%q: %v", tc, err)
}
}
}
}