241 lines
6.6 KiB
Go
241 lines
6.6 KiB
Go
// Package ante — 验证节点级合规交易拦截
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//
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// ComplianceAnteHandler 在验证节点打包交易前执行合规检查：
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// 1. OFAC 地址拦截 — 制裁名单地址的交易直接拒绝
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// 2. Structuring 检测 — 拆分交易规避 $3,000 Travel Rule 阈值
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// 3. Travel Rule 预检查 — ≥$3,000 转移必须携带身份哈希
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//
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// 参考: FinCEN Travel Rule, OFAC SDN List, FATF Recommendation 16
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package ante
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import (
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"fmt"
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"math/big"
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"sync"
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"time"
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)
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// ComplianceAnteHandler 验证节点级合规检查处理器
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type ComplianceAnteHandler struct {
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mu sync.RWMutex
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// OFAC 制裁名单（地址 → 是否制裁）
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ofacList map[string]bool
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// Travel Rule 记录（sender+receiver hash → 是否已记录）
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travelRuleRecords map[string]bool
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// Structuring 检测：地址 → 24h 内累计转移金额
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recentTransfers map[string]*TransferWindow
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// 配置
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travelRuleThreshold *big.Int // $3,000 USDC (3000 * 1e6)
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structuringWindow time.Duration
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}
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// TransferWindow 滑动窗口内的转移记录
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type TransferWindow struct {
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TotalAmount *big.Int
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Transfers []TransferRecord
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}
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// TransferRecord 单笔转移记录
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type TransferRecord struct {
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Amount *big.Int
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Timestamp time.Time
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}
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// ComplianceResult 合规检查结果
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type ComplianceResult struct {
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Allowed bool
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Reason string
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Suspicious bool // 标记为可疑但不拒绝
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SuspReason string // 可疑原因
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}
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// NewComplianceAnteHandler 创建合规检查处理器
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func NewComplianceAnteHandler() *ComplianceAnteHandler {
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threshold := new(big.Int).Mul(big.NewInt(3000), big.NewInt(1e6)) // $3,000 USDC
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return &ComplianceAnteHandler{
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ofacList: make(map[string]bool),
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travelRuleRecords: make(map[string]bool),
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recentTransfers: make(map[string]*TransferWindow),
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travelRuleThreshold: threshold,
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structuringWindow: 24 * time.Hour,
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}
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}
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// AnteHandle 执行合规检查（在交易打包前调用）
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//
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// 返回:
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// - ComplianceResult.Allowed = false: 交易被拒绝，不会被打包
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// - ComplianceResult.Suspicious = true: 标记为可疑，仍可打包但上报
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func (h *ComplianceAnteHandler) AnteHandle(from, to string, value *big.Int) ComplianceResult {
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h.mu.RLock()
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defer h.mu.RUnlock()
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// 1. OFAC 地址拦截（链级强制）
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if h.ofacList[from] {
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return ComplianceResult{
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Allowed: false,
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Reason: fmt.Sprintf("OFAC sanctioned address (sender: %s), transaction rejected at validator level", from),
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}
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}
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if h.ofacList[to] {
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return ComplianceResult{
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Allowed: false,
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Reason: fmt.Sprintf("OFAC sanctioned address (receiver: %s), transaction rejected at validator level", to),
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}
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}
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result := ComplianceResult{Allowed: true}
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// 2. Structuring 检测（拆分交易规避 $3,000 阈值）
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if h.isStructuringPattern(from, value) {
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result.Suspicious = true
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result.SuspReason = fmt.Sprintf(
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"Potential structuring detected for %s: cumulative transfers approaching Travel Rule threshold",
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from,
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)
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}
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// 3. Travel Rule 预打包检查（≥$3,000）
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if value.Cmp(h.travelRuleThreshold) >= 0 {
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recordKey := fmt.Sprintf("%s:%s", from, to)
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if !h.travelRuleRecords[recordKey] {
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return ComplianceResult{
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Allowed: false,
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Reason: fmt.Sprintf("Travel Rule: identity data required for transfers >= $3,000 (from: %s, to: %s)", from, to),
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}
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}
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}
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return result
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}
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// isStructuringPattern 检测是否存在拆分交易模式
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// 规则：24h 内同一地址的累计小额转移接近或超过 $3,000
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func (h *ComplianceAnteHandler) isStructuringPattern(from string, currentValue *big.Int) bool {
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window, exists := h.recentTransfers[from]
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if !exists {
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return false
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}
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// 清理过期记录
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now := time.Now()
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var validTransfers []TransferRecord
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totalAmount := new(big.Int)
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for _, t := range window.Transfers {
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if now.Sub(t.Timestamp) <= h.structuringWindow {
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validTransfers = append(validTransfers, t)
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totalAmount.Add(totalAmount, t.Amount)
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}
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}
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// 加上当前交易
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totalAmount.Add(totalAmount, currentValue)
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// 如果每笔都低于阈值，但累计超过阈值 → 可疑
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allBelowThreshold := true
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for _, t := range validTransfers {
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if t.Amount.Cmp(h.travelRuleThreshold) >= 0 {
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allBelowThreshold = false
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break
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}
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}
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if currentValue.Cmp(h.travelRuleThreshold) >= 0 {
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allBelowThreshold = false
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}
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return allBelowThreshold && totalAmount.Cmp(h.travelRuleThreshold) >= 0
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}
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// ========================
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// OFAC 名单管理
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// ========================
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// UpdateOFACList 更新 OFAC 制裁名单（由链下服务定期调用）
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func (h *ComplianceAnteHandler) UpdateOFACList(addresses []string) {
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h.mu.Lock()
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defer h.mu.Unlock()
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h.ofacList = make(map[string]bool, len(addresses))
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for _, addr := range addresses {
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h.ofacList[addr] = true
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}
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}
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// AddToOFACList 添加地址到 OFAC 名单
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func (h *ComplianceAnteHandler) AddToOFACList(address string) {
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h.mu.Lock()
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defer h.mu.Unlock()
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h.ofacList[address] = true
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}
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// RemoveFromOFACList 从 OFAC 名单移除
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func (h *ComplianceAnteHandler) RemoveFromOFACList(address string) {
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h.mu.Lock()
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defer h.mu.Unlock()
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delete(h.ofacList, address)
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}
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// IsOFACSanctioned 查询地址是否在 OFAC 名单中
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func (h *ComplianceAnteHandler) IsOFACSanctioned(address string) bool {
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h.mu.RLock()
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defer h.mu.RUnlock()
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return h.ofacList[address]
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}
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// ========================
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// Travel Rule 管理
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// ========================
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// RecordTravelRule 记录 Travel Rule 数据
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func (h *ComplianceAnteHandler) RecordTravelRule(from, to string) {
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h.mu.Lock()
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defer h.mu.Unlock()
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key := fmt.Sprintf("%s:%s", from, to)
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h.travelRuleRecords[key] = true
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}
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// HasTravelRuleRecord 查询是否已记录 Travel Rule
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func (h *ComplianceAnteHandler) HasTravelRuleRecord(from, to string) bool {
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h.mu.RLock()
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defer h.mu.RUnlock()
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key := fmt.Sprintf("%s:%s", from, to)
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return h.travelRuleRecords[key]
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}
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// ========================
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// 转移记录（Structuring 检测用）
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// ========================
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// RecordTransfer 记录一笔转移（用于 Structuring 检测）
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func (h *ComplianceAnteHandler) RecordTransfer(from string, amount *big.Int) {
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h.mu.Lock()
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defer h.mu.Unlock()
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window, exists := h.recentTransfers[from]
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if !exists {
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window = &TransferWindow{
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TotalAmount: new(big.Int),
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Transfers: make([]TransferRecord, 0),
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}
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h.recentTransfers[from] = window
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}
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window.Transfers = append(window.Transfers, TransferRecord{
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Amount: new(big.Int).Set(amount),
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Timestamp: time.Now(),
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})
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window.TotalAmount.Add(window.TotalAmount, amount)
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}
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// GetOFACListSize 获取当前 OFAC 名单大小
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func (h *ComplianceAnteHandler) GetOFACListSize() int {
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h.mu.RLock()
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defer h.mu.RUnlock()
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return len(h.ofacList)
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}
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