125 lines
2.2 KiB
Go
125 lines
2.2 KiB
Go
package protocol
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import (
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"io"
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"github.com/calmh/syncthing/buffers"
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)
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func pad(l int) int {
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d := l % 4
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if d == 0 {
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return 0
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}
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return 4 - d
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}
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var padBytes = []byte{0, 0, 0}
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type marshalWriter struct {
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w io.Writer
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tot int
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err error
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}
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func (w *marshalWriter) writeString(s string) {
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w.writeBytes([]byte(s))
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}
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func (w *marshalWriter) writeBytes(bs []byte) {
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if w.err != nil {
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return
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}
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w.writeUint32(uint32(len(bs)))
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if w.err != nil {
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return
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}
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_, w.err = w.w.Write(bs)
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if p := pad(len(bs)); p > 0 {
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w.w.Write(padBytes[:p])
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}
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w.tot += len(bs) + pad(len(bs))
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}
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func (w *marshalWriter) writeUint32(v uint32) {
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if w.err != nil {
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return
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}
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var b [4]byte
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b[0] = byte(v >> 24)
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b[1] = byte(v >> 16)
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b[2] = byte(v >> 8)
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b[3] = byte(v)
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_, w.err = w.w.Write(b[:])
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w.tot += 4
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}
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func (w *marshalWriter) writeUint64(v uint64) {
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if w.err != nil {
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return
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}
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var b [8]byte
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b[0] = byte(v >> 56)
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b[1] = byte(v >> 48)
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b[2] = byte(v >> 40)
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b[3] = byte(v >> 32)
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b[4] = byte(v >> 24)
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b[5] = byte(v >> 16)
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b[6] = byte(v >> 8)
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b[7] = byte(v)
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_, w.err = w.w.Write(b[:])
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w.tot += 8
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}
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type marshalReader struct {
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r io.Reader
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tot int
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err error
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}
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func (r *marshalReader) readString() string {
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bs := r.readBytes()
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defer buffers.Put(bs)
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return string(bs)
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}
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func (r *marshalReader) readBytes() []byte {
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if r.err != nil {
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return nil
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}
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l := int(r.readUint32())
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if r.err != nil {
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return nil
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}
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if l > 10*1<<20 {
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// Individual blobs in BEP are not significantly larger than BlockSize.
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// BlockSize is not larger than 1MB.
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panic("too large read - protocol error or out of sync")
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}
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b := buffers.Get(l + pad(l))
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_, r.err = io.ReadFull(r.r, b)
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r.tot += int(l + pad(l))
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return b[:l]
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}
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func (r *marshalReader) readUint32() uint32 {
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if r.err != nil {
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return 0
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}
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var b [4]byte
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_, r.err = io.ReadFull(r.r, b[:])
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r.tot += 4
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return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
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}
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func (r *marshalReader) readUint64() uint64 {
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if r.err != nil {
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return 0
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}
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var b [8]byte
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_, r.err = io.ReadFull(r.r, b[:])
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r.tot += 8
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return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
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uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
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}
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