136 lines
4.2 KiB
Go
136 lines
4.2 KiB
Go
// Copyright (c) 2014-2015 The btcsuite developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package wire
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import (
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"fmt"
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"io"
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)
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// BloomUpdateType specifies how the filter is updated when a match is found
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type BloomUpdateType uint8
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const (
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// BloomUpdateNone indicates the filter is not adjusted when a match is
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// found.
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BloomUpdateNone BloomUpdateType = 0
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// BloomUpdateAll indicates if the filter matches any data element in a
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// public key script, the outpoint is serialized and inserted into the
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// filter.
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BloomUpdateAll BloomUpdateType = 1
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// BloomUpdateP2PubkeyOnly indicates if the filter matches a data
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// element in a public key script and the script is of the standard
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// pay-to-pubkey or multisig, the outpoint is serialized and inserted
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// into the filter.
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BloomUpdateP2PubkeyOnly BloomUpdateType = 2
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)
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const (
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// MaxFilterLoadHashFuncs is the maximum number of hash functions to
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// load into the Bloom filter.
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MaxFilterLoadHashFuncs = 50
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// MaxFilterLoadFilterSize is the maximum size in bytes a filter may be.
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MaxFilterLoadFilterSize = 36000
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)
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// MsgFilterLoad implements the Message interface and represents a bitcoin
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// filterload message which is used to reset a Bloom filter.
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//
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// This message was not added until protocol version BIP0037Version.
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type MsgFilterLoad struct {
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Filter []byte
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HashFuncs uint32
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Tweak uint32
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Flags BloomUpdateType
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}
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// BtcDecode decodes r using the bitcoin protocol encoding into the receiver.
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// This is part of the Message interface implementation.
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func (msg *MsgFilterLoad) BtcDecode(r io.Reader, pver uint32) error {
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if pver < BIP0037Version {
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str := fmt.Sprintf("filterload message invalid for protocol "+
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"version %d", pver)
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return messageError("MsgFilterLoad.BtcDecode", str)
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}
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var err error
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msg.Filter, err = ReadVarBytes(r, pver, MaxFilterLoadFilterSize,
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"filterload filter size")
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if err != nil {
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return err
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}
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err = readElements(r, &msg.HashFuncs, &msg.Tweak, &msg.Flags)
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if err != nil {
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return err
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}
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if msg.HashFuncs > MaxFilterLoadHashFuncs {
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str := fmt.Sprintf("too many filter hash functions for message "+
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"[count %v, max %v]", msg.HashFuncs, MaxFilterLoadHashFuncs)
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return messageError("MsgFilterLoad.BtcDecode", str)
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}
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return nil
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}
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// BtcEncode encodes the receiver to w using the bitcoin protocol encoding.
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// This is part of the Message interface implementation.
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func (msg *MsgFilterLoad) BtcEncode(w io.Writer, pver uint32) error {
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if pver < BIP0037Version {
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str := fmt.Sprintf("filterload message invalid for protocol "+
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"version %d", pver)
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return messageError("MsgFilterLoad.BtcEncode", str)
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}
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size := len(msg.Filter)
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if size > MaxFilterLoadFilterSize {
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str := fmt.Sprintf("filterload filter size too large for message "+
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"[size %v, max %v]", size, MaxFilterLoadFilterSize)
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return messageError("MsgFilterLoad.BtcEncode", str)
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}
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if msg.HashFuncs > MaxFilterLoadHashFuncs {
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str := fmt.Sprintf("too many filter hash functions for message "+
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"[count %v, max %v]", msg.HashFuncs, MaxFilterLoadHashFuncs)
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return messageError("MsgFilterLoad.BtcEncode", str)
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}
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err := WriteVarBytes(w, pver, msg.Filter)
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if err != nil {
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return err
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}
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return writeElements(w, msg.HashFuncs, msg.Tweak, msg.Flags)
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}
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// Command returns the protocol command string for the message. This is part
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// of the Message interface implementation.
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func (msg *MsgFilterLoad) Command() string {
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return CmdFilterLoad
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}
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// MaxPayloadLength returns the maximum length the payload can be for the
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// receiver. This is part of the Message interface implementation.
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func (msg *MsgFilterLoad) MaxPayloadLength(pver uint32) uint32 {
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// Num filter bytes (varInt) + filter + 4 bytes hash funcs +
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// 4 bytes tweak + 1 byte flags.
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return uint32(VarIntSerializeSize(MaxFilterLoadFilterSize)) +
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MaxFilterLoadFilterSize + 9
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}
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// NewMsgFilterLoad returns a new bitcoin filterload message that conforms to
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// the Message interface. See MsgFilterLoad for details.
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func NewMsgFilterLoad(filter []byte, hashFuncs uint32, tweak uint32, flags BloomUpdateType) *MsgFilterLoad {
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return &MsgFilterLoad{
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Filter: filter,
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HashFuncs: hashFuncs,
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Tweak: tweak,
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Flags: flags,
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}
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}
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