From b96abb7627bf6d6339e5d5ef0bdd3f466aea8b8e Mon Sep 17 00:00:00 2001
From: Dave Collins <davec@conformal.com>
Date: Wed, 13 Sep 2023 23:40:40 -0500
Subject: [PATCH] pool: Gen extra nonce before initialize.

This modifies the new client logic to create the extra nonce before to
creating the client and using it during initialization.  Constructors
should generally handle everything that can error prior to creating the
object since it is wasteful to create an object only to immediately
throw it away when there is an error.
---
 pool/client.go | 45 ++++++++++++++++++---------------------------
 1 file changed, 18 insertions(+), 27 deletions(-)

diff --git a/pool/client.go b/pool/client.go
index 40110192..334fcdfd 100644
--- a/pool/client.go
+++ b/pool/client.go
@@ -150,39 +150,30 @@ type Client struct {
 	wg          sync.WaitGroup
 }
 
-// generateExtraNonce1 generates a random 4-byte extraNonce1
-// for the client.
-func (c *Client) generateExtraNonce1() error {
-	id := make([]byte, 4)
-	_, err := rand.Read(id)
-	if err != nil {
-		return err
-	}
-	c.extraNonce1 = hex.EncodeToString(id)
-	return nil
-}
-
 // NewClient creates client connection instance.
 func NewClient(ctx context.Context, conn net.Conn, addr *net.TCPAddr, cCfg *ClientConfig) (*Client, error) {
-	ctx, cancel := context.WithCancel(ctx)
-	c := &Client{
-		addr:     addr,
-		cfg:      cCfg,
-		conn:     conn,
-		ctx:      ctx,
-		cancel:   cancel,
-		ch:       make(chan Message),
-		readCh:   make(chan readPayload),
-		encoder:  json.NewEncoder(conn),
-		reader:   bufio.NewReaderSize(conn, maxMessageSize),
-		hashRate: ZeroRat,
-	}
-	err := c.generateExtraNonce1()
+	// Generate a random 4-byte value to use as extraNonce1 for the client.
+	var extraNonce1 [4]byte
+	_, err := rand.Read(extraNonce1[:])
 	if err != nil {
 		return nil, err
 	}
 
-	return c, nil
+	ctx, cancel := context.WithCancel(ctx)
+	c := Client{
+		addr:        addr,
+		cfg:         cCfg,
+		conn:        conn,
+		ctx:         ctx,
+		cancel:      cancel,
+		ch:          make(chan Message),
+		extraNonce1: hex.EncodeToString(extraNonce1[:]),
+		readCh:      make(chan readPayload),
+		encoder:     json.NewEncoder(conn),
+		reader:      bufio.NewReaderSize(conn, maxMessageSize),
+		hashRate:    ZeroRat,
+	}
+	return &c, nil
 }
 
 // shutdown terminates all client processes and established connections.