From 784e5d4ad86b3ab5c1b24c0bf3eb4d324eeb7390 Mon Sep 17 00:00:00 2001
From: HuangYi <huang@crypto.com>
Date: Fri, 28 Oct 2022 11:30:45 +0800
Subject: [PATCH] more efficient ParseChainID implementation

---
 types/benchmark_test.go | 60 +++++++++++++++++++++++++++++++++++++----
 types/chain_id.go       | 47 +++++++++++---------------------
 2 files changed, 71 insertions(+), 36 deletions(-)

diff --git a/types/benchmark_test.go b/types/benchmark_test.go
index 23d7790a95..c1fdd38537 100644
--- a/types/benchmark_test.go
+++ b/types/benchmark_test.go
@@ -1,16 +1,66 @@
 package types
 
 import (
-	"fmt"
+	fmt "fmt"
+	"math/big"
+	"regexp"
+	"strings"
 	"testing"
+
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+)
+
+var (
+	regexChainID         = `[a-z]{1,}`
+	regexEIP155Separator = `_{1}`
+	regexEIP155          = `[1-9][0-9]*`
+	regexEpochSeparator  = `-{1}`
+	regexEpoch           = `[1-9][0-9]*`
+	ethermintChainID     = regexp.MustCompile(fmt.Sprintf(`^(%s)%s(%s)%s(%s)$`,
+		regexChainID,
+		regexEIP155Separator,
+		regexEIP155,
+		regexEpochSeparator,
+		regexEpoch))
 )
 
+// ParseChainID parses a string chain identifier's epoch to an Ethereum-compatible
+// chain-id in *big.Int format. The function returns an error if the chain-id has an invalid format
+func ParseChainIDLegacy(chainID string) (*big.Int, error) {
+	chainID = strings.TrimSpace(chainID)
+	if len(chainID) > 48 {
+		return nil, sdkerrors.Wrapf(ErrInvalidChainID, "chain-id '%s' cannot exceed 48 chars", chainID)
+	}
+
+	matches := ethermintChainID.FindStringSubmatch(chainID)
+	if matches == nil || len(matches) != 4 || matches[1] == "" {
+		return nil, sdkerrors.Wrapf(ErrInvalidChainID, "%s: %v", chainID, matches)
+	}
+
+	// verify that the chain-id entered is a base 10 integer
+	chainIDInt, ok := new(big.Int).SetString(matches[2], 10)
+	if !ok {
+		return nil, sdkerrors.Wrapf(ErrInvalidChainID, "epoch %s must be base-10 integer format", matches[2])
+	}
+
+	return chainIDInt, nil
+}
+
 func BenchmarkParseChainID(b *testing.B) {
 	b.ReportAllocs()
-	// Start at 1, for valid EIP155, see regexEIP155 variable.
-	for i := 1; i < b.N; i++ {
-		chainID := fmt.Sprintf("ethermint_1-%d", i)
-		if _, err := ParseChainID(chainID); err != nil {
+	// Parsing a typical ethermint chain id
+	for i := 0; i < b.N; i++ {
+		if _, err := ParseChainID("ethermint_9000-1"); err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func BenchmarkParseChainIDLegacy(b *testing.B) {
+	b.ReportAllocs()
+	// Parsing a typical ethermint chain id
+	for i := 0; i < b.N; i++ {
+		if _, err := ParseChainIDLegacy("ethermint_9000-1"); err != nil {
 			b.Fatal(err)
 		}
 	}
diff --git a/types/chain_id.go b/types/chain_id.go
index 0688423c9f..b5834dac69 100644
--- a/types/chain_id.go
+++ b/types/chain_id.go
@@ -1,55 +1,40 @@
 package types
 
 import (
-	"fmt"
 	"math/big"
-	"regexp"
+	"strconv"
 	"strings"
 
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 )
 
-var (
-	regexChainID         = `[a-z]{1,}`
-	regexEIP155Separator = `_{1}`
-	regexEIP155          = `[1-9][0-9]*`
-	regexEpochSeparator  = `-{1}`
-	regexEpoch           = `[1-9][0-9]*`
-	ethermintChainID     = regexp.MustCompile(fmt.Sprintf(`^(%s)%s(%s)%s(%s)$`,
-		regexChainID,
-		regexEIP155Separator,
-		regexEIP155,
-		regexEpochSeparator,
-		regexEpoch))
-)
-
 // IsValidChainID returns false if the given chain identifier is incorrectly formatted.
 func IsValidChainID(chainID string) bool {
-	if len(chainID) > 48 {
-		return false
-	}
-
-	return ethermintChainID.MatchString(chainID)
+	_, err := ParseChainID(chainID)
+	return err != nil
 }
 
 // ParseChainID parses a string chain identifier's epoch to an Ethereum-compatible
 // chain-id in *big.Int format. The function returns an error if the chain-id has an invalid format
 func ParseChainID(chainID string) (*big.Int, error) {
 	chainID = strings.TrimSpace(chainID)
-	if len(chainID) > 48 {
-		return nil, sdkerrors.Wrapf(ErrInvalidChainID, "chain-id '%s' cannot exceed 48 chars", chainID)
+	if len(chainID) == 0 {
+		return nil, sdkerrors.Wrapf(ErrInvalidChainID, "empty chain id")
 	}
 
-	matches := ethermintChainID.FindStringSubmatch(chainID)
-	if matches == nil || len(matches) != 4 || matches[1] == "" {
-		return nil, sdkerrors.Wrapf(ErrInvalidChainID, "%s: %v", chainID, matches)
+	idx := strings.LastIndexByte(chainID, '-')
+	if idx < 0 {
+		return nil, sdkerrors.Wrapf(ErrInvalidChainID, "expect at least 1 epoch seperator, got 0")
+	}
+	idx2 := strings.LastIndexByte(chainID[:idx], '_')
+	if idx2 < 0 {
+		return nil, sdkerrors.Wrapf(ErrInvalidChainID, "expect at least 1 eip155 chain-id seperator, got 0")
 	}
 
 	// verify that the chain-id entered is a base 10 integer
-	chainIDInt, ok := new(big.Int).SetString(matches[2], 10)
-	if !ok {
-		return nil, sdkerrors.Wrapf(ErrInvalidChainID, "epoch %s must be base-10 integer format", matches[2])
+	n, err := strconv.ParseInt(chainID[idx2+1:idx], 10, 64)
+	if err != nil {
+		return nil, sdkerrors.Wrapf(ErrInvalidChainID, "eip155 chain-id %s must be base-10 64bit integer format", chainID[idx2+1:idx])
 	}
-
-	return chainIDInt, nil
+	return big.NewInt(n), nil
 }