perf: sync dispatch hot path optimizations

internal/mtprotoedge/seq_validate_test.go

@@ -0,0 +1,74 @@
+package mtprotoedge
+
+import (
+	"math/rand"
+	"testing"
+)
+
+// referenceValidateSeq 是 validateSeq 的旧全扫描语义（无高水位快路径），
+// 作为随机对拍的行为基准：快路径只允许接受「全扫描也必然接受」的子集。
+func referenceValidateSeq(cs *connState, msgID int64, seqNo int32, content bool) int {
+	if !content {
+		return 0
+	}
+	for seenMsgID, record := range cs.seen {
+		if !record.content {
+			continue
+		}
+		if seenMsgID < msgID && record.seqNo >= seqNo {
+			return badMsgSeqTooLow
+		}
+		if seenMsgID > msgID && record.seqNo <= seqNo {
+			return badMsgSeqTooHigh
+		}
+	}
+	return 0
+}
+
+func TestValidateSeqFastPathMatchesFullScan(t *testing.T) {
+	rng := rand.New(rand.NewSource(20260705))
+	for round := 0; round < 32; round++ {
+		fast := newConnState()
+		ref := newConnState()
+		for i := 0; i < 2000; i++ {
+			// 小值域制造乱序、重复 seq 与 too_low/too_high 反转；大 i 也覆盖淘汰窗口。
+			msgID := int64(rng.Intn(3000) + 1)
+			seqNo := int32(rng.Intn(600))
+			content := rng.Intn(4) != 0
+			if _, ok := fast.seen[msgID]; ok {
+				continue // 真实调用链在 seenRecord 命中时不会走 validateSeq
+			}
+			got := fast.validateSeq(msgID, seqNo, content)
+			want := referenceValidateSeq(ref, msgID, seqNo, content)
+			if got != want {
+				t.Fatalf("round %d step %d: validateSeq(msg_id=%d seq=%d content=%v) = %d, want %d",
+					round, i, msgID, seqNo, content, got, want)
+			}
+			if got == 0 {
+				fast.track(msgID, seqNo, content, msgStateReceived)
+				ref.track(msgID, seqNo, content, msgStateReceived)
+			}
+		}
+	}
+}
+
+func TestValidateSeqOrderedFastPath(t *testing.T) {
+	cs := newConnState()
+	// 正常客户端：msg_id 与 content seq_no 严格递增，应全部通过。
+	for i := 0; i < 1000; i++ {
+		msgID := int64(1000 + i*4)
+		seqNo := int32(i*2 + 1)
+		if code := cs.validateSeq(msgID, seqNo, true); code != 0 {
+			t.Fatalf("ordered message %d rejected with code %d", i, code)
+		}
+		cs.track(msgID, seqNo, true, msgStateReceived)
+	}
+	// seq 回退必须仍被拒绝（快路径不放行）。
+	if code := cs.validateSeq(1000+1000*4, 3, true); code != badMsgSeqTooLow {
+		t.Fatalf("seq regression code = %d, want badMsgSeqTooLow", code)
+	}
+	// 旧 msg_id 配新 seq 也必须仍被拒绝。
+	if code := cs.validateSeq(500, 5000, true); code != badMsgSeqTooHigh {
+		t.Fatalf("old msg_id with high seq code = %d, want badMsgSeqTooHigh", code)
+	}
+}