seaweedfs/weed/filesys/page_writer/page_chunk_mem.go

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2022-01-22 13:59:07 +00:00
package page_writer
import (
"github.com/chrislusf/seaweedfs/weed/util"
"github.com/chrislusf/seaweedfs/weed/util/mem"
)
var (
_ = PageChunk(&MemChunk{})
)
type MemChunk struct {
buf []byte
usage *ChunkWrittenIntervalList
chunkSize int64
logicChunkIndex LogicChunkIndex
}
func NewMemChunk(logicChunkIndex LogicChunkIndex, chunkSize int64) *MemChunk {
return &MemChunk{
logicChunkIndex: logicChunkIndex,
chunkSize: chunkSize,
buf: mem.Allocate(int(chunkSize)),
usage: newChunkWrittenIntervalList(),
}
}
func (mc *MemChunk) FreeResource() {
mem.Free(mc.buf)
}
func (mc *MemChunk) WriteDataAt(src []byte, offset int64) (n int) {
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innerOffset := offset % mc.chunkSize
n = copy(mc.buf[innerOffset:], src)
mc.usage.MarkWritten(innerOffset, innerOffset+int64(n))
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return
}
func (mc *MemChunk) ReadDataAt(p []byte, off int64) (maxStop int64) {
memChunkBaseOffset := int64(mc.logicChunkIndex) * mc.chunkSize
for t := mc.usage.head.next; t != mc.usage.tail; t = t.next {
logicStart := max(off, int64(mc.logicChunkIndex)*mc.chunkSize+t.StartOffset)
logicStop := min(off+int64(len(p)), memChunkBaseOffset+t.stopOffset)
if logicStart < logicStop {
copy(p[logicStart-off:logicStop-off], mc.buf[logicStart-memChunkBaseOffset:logicStop-memChunkBaseOffset])
maxStop = max(maxStop, logicStop)
}
}
return
}
func (mc *MemChunk) IsComplete() bool {
return mc.usage.IsComplete(mc.chunkSize)
}
func (mc *MemChunk) SaveContent(saveFn SaveToStorageFunc) {
if saveFn == nil {
return
}
for t := mc.usage.head.next; t != mc.usage.tail; t = t.next {
reader := util.NewBytesReader(mc.buf[t.StartOffset:t.stopOffset])
saveFn(reader, int64(mc.logicChunkIndex)*mc.chunkSize+t.StartOffset, t.Size(), func() {
})
}
}