func (wc *FileWriteCache) PReadThrough(offset int64, p []byte, r blobstore.PReader) error {
nr := int64(len(p))
remo := offset
remp := p
for _, patch := range wc.ps {
if nr <= 0 {
return nil
}
if remo > patch.Right() {
continue
}
if remo < patch.Left() {
fallbackLen := util.Int64Min(nr, patch.Left()-remo)
if err := r.PRead(remo, remp[:fallbackLen]); err != nil {
return err
}
remp = remp[fallbackLen:]
nr -= fallbackLen
remo += fallbackLen
}
if nr <= 0 {
return nil
}
applyOffset := remo - patch.Offset
applyLen := util.Int64Min(int64(len(patch.P))-applyOffset, nr)
copy(remp[:applyLen], patch.P[applyOffset:])
remp = remp[applyLen:]
nr -= applyLen
remo += applyLen
}
if err := r.PRead(remo, remp); err != nil {
return err
}
return nil
}
func (be *CachedBlobEntry) PRead(p []byte, offset int64) error {
// FIXME: may be we should allow stale reads w/o lock
be.mu.Lock()
defer be.mu.Unlock()
be.lastUsed = time.Now()
requiredlen := util.Int64Min(offset+int64(len(p)), be.bloblen)
for be.validlen < requiredlen {
logger.Infof(mylog, "Waiting for cache to be fulfilled: reqlen: %d, validlen: %d", requiredlen, be.validlen)
be.validlenExtended.Wait()
}
return be.cachebh.PRead(p, offset)
}
func (cfio *ChunkedFileIO) ReadAt(p []byte, offset int64) (int, error) {
remo := offset
remp := p
if offset < 0 {
return 0, fmt.Errorf("negative offset %d given", offset)
}
cs, err := cfio.caio.Read()
if err != nil {
return 0, fmt.Errorf("Failed to read cs array: %v", err)
}
if !fl.IsReadAllowed(cfio.bs.Flags()) {
return 0, EPERM
}
// fmt.Printf("cs: %v\n", cs)
for i := 0; i < len(cs) && len(remp) > 0; i++ {
c := cs[i]
if c.Left() > remo+int64(len(remp)) {
break
}
if c.Right() <= remo {
continue
}
coff := remo - c.Left()
if coff < 0 {
// Fill gap with zero
n := util.Int64Min(int64(len(remp)), -coff)
for j := int64(0); j < n; j++ {
remp[j] = 0
}
remo += n
coff = 0
if len(remp) == 0 {
return int(remo - offset), nil
}
}
bh, err := cfio.bs.Open(c.BlobPath, fl.O_RDONLY)
if err != nil {
return int(remo - offset), fmt.Errorf("Failed to open path \"%s\" for reading: %v", c.BlobPath, err)
}
defer func() {
if err := bh.Close(); err != nil {
logger.Criticalf(mylog, "blobhandle Close failed: %v", err)
}
}()
cio := cfio.newChunkIO(bh, cfio.c, c.Offset)
defer func() {
if err := cio.Close(); err != nil {
logger.Criticalf(mylog, "cio Close failed: %v", err)
}
}()
n := util.Int64Min(int64(len(p)), c.Length-coff)
if err := cio.PRead(remp[:n], coff); err != nil {
return int(remo - offset), err
}
remo += n
remp = remp[n:]
if len(remp) == 0 {
return int(remo - offset), nil
}
}
// logger.Debugf(mylog, "cs: %+v", cs)
return int(remo - offset), nil
}
func (wc *FileWriteCache) ReadAtThrough(p []byte, offset int64, r ReadAter) (int, error) {
nr := 0
remo := offset
remp := p
for _, patch := range wc.ps {
if len(remp) == 0 {
return nr, nil
}
if patch.IsSentinel() {
break
}
if remo > patch.Right() {
continue
}
if remo < patch.Left() {
fallbackLen64 := util.Int64Min(int64(len(remp)), patch.Left()-remo)
if fallbackLen64 > math.MaxInt32 {
panic("Logic error: fallbackLen should always be in int32 range")
}
fallbackLen := int(fallbackLen64)
n, err := r.ReadAt(remp[:fallbackLen], remo)
logger.Debugf(wclog, "BeforePatch: ReadAt issued offset %d, len %d bytes, read %d bytes", remo, fallbackLen, n)
if err != nil {
return nr + n, err
}
if n < fallbackLen {
zerofill(remp[n:fallbackLen])
}
nr += fallbackLen
remp = remp[fallbackLen:]
remo += int64(fallbackLen)
}
if len(remp) == 0 {
return nr, nil
}
applyOffset64 := remo - patch.Offset
if applyOffset64 > math.MaxInt32 {
panic("Logic error: applyOffset should always be in int32 range")
}
applyOffset := int(applyOffset64)
applyLen := util.IntMin(len(patch.P)-applyOffset, len(remp))
copy(remp[:applyLen], patch.P[applyOffset:])
nr += applyLen
remp = remp[applyLen:]
remo += int64(applyLen)
}
n, err := r.ReadAt(remp, remo)
logger.Debugf(wclog, "Last: ReadAt read %d bytes", n)
if err != nil {
return nr, err
}
nr += n
return nr, nil
}
