From 5c9f1dc4efa27b9f6e4238f2317336b86c1780b9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Philip=20Dub=C3=A9?= <philip@peerdb.io>
Date: Wed, 29 Jan 2025 13:54:39 +0000
Subject: [PATCH] cleanup init functions

---
 compress/zlib.go    | 10 ++--------
 driver/driver.go    | 12 ++++++------
 dump/parser.go      | 12 ++++--------
 mysql/util.go       |  6 ++----
 replication/time.go | 20 +++++++++-----------
 server/stmt.go      | 14 ++++----------
 6 files changed, 27 insertions(+), 47 deletions(-)

diff --git a/compress/zlib.go b/compress/zlib.go
index 17bad746d..07e8186c7 100644
--- a/compress/zlib.go
+++ b/compress/zlib.go
@@ -11,17 +11,11 @@ import (
 const DefaultCompressionLevel = 6
 
 var (
-	zlibReaderPool *sync.Pool
-	zlibWriterPool sync.Pool
-)
-
-func init() {
-	zlibReaderPool = &sync.Pool{
+	zlibReaderPool = sync.Pool{
 		New: func() interface{} {
 			return nil
 		},
 	}
-
 	zlibWriterPool = sync.Pool{
 		New: func() interface{} {
 			w, err := zlib.NewWriterLevel(new(bytes.Buffer), DefaultCompressionLevel)
@@ -31,7 +25,7 @@ func init() {
 			return w
 		},
 	}
-}
+)
 
 var _ io.WriteCloser = zlibWriter{}
 var _ io.ReadCloser = zlibReader{}
diff --git a/driver/driver.go b/driver/driver.go
index eb72f2ca3..094ac0cbd 100644
--- a/driver/driver.go
+++ b/driver/driver.go
@@ -27,7 +27,12 @@ var customTLSMutex sync.Mutex
 var (
 	dsnRegex           = regexp.MustCompile("@[^@]+/[^@/]+")
 	customTLSConfigMap = make(map[string]*tls.Config)
-	options            = make(map[string]DriverOption)
+	options            = map[string]DriverOption{
+		"compress":     CompressOption,
+		"collation":    CollationOption,
+		"readTimeout":  ReadTimeoutOption,
+		"writeTimeout": WriteTimeoutOption,
+	}
 
 	// can be provided by clients to allow more control in handling Go and database
 	// types beyond the default Value types allowed
@@ -392,11 +397,6 @@ func (r *rows) Next(dest []sqldriver.Value) error {
 var driverName = "mysql"
 
 func init() {
-	options["compress"] = CompressOption
-	options["collation"] = CollationOption
-	options["readTimeout"] = ReadTimeoutOption
-	options["writeTimeout"] = WriteTimeoutOption
-
 	sql.Register(driverName, driver{})
 }
 
diff --git a/dump/parser.go b/dump/parser.go
index 529e78bd9..f3c699b7b 100644
--- a/dump/parser.go
+++ b/dump/parser.go
@@ -23,20 +23,16 @@ type ParseHandler interface {
 	Data(schema string, table string, values []string) error
 }
 
-var binlogExp *regexp.Regexp
-var useExp *regexp.Regexp
-var valuesExp *regexp.Regexp
-var gtidExp *regexp.Regexp
-
-func init() {
+var (
 	binlogExp = regexp.MustCompile(`^CHANGE (MASTER|REPLICATION SOURCE) TO (MASTER_LOG_FILE|SOURCE_LOG_FILE)='(.+)', (MASTER_LOG_POS|SOURCE_LOG_POS)=(\d+);`)
-	useExp = regexp.MustCompile("^USE `(.+)`;")
+	useExp    = regexp.MustCompile("^USE `(.+)`;")
 	valuesExp = regexp.MustCompile("^INSERT INTO `(.+?)` VALUES \\((.+)\\);$")
+
 	// The pattern will only match MySQL GTID, as you know SET GLOBAL gtid_slave_pos='0-1-4' is used for MariaDB.
 	// SET @@GLOBAL.GTID_PURGED='1638041a-0457-11e9-bb9f-00505690b730:1-429405150';
 	// https://dev.mysql.com/doc/refman/5.7/en/replication-gtids-concepts.html
 	gtidExp = regexp.MustCompile(`(\w{8}(-\w{4}){3}-\w{12}(:\d+(-\d+)?)+)`)
-}
+)
 
 // Parse the dump data with Dumper generate.
 // It can not parse all the data formats with mysqldump outputs
diff --git a/mysql/util.go b/mysql/util.go
index c0c9f5452..5bde1fdb8 100644
--- a/mysql/util.go
+++ b/mysql/util.go
@@ -443,9 +443,7 @@ func init() {
 	for i := range EncodeMap {
 		EncodeMap[i] = DONTESCAPE
 	}
-	for i := range EncodeMap {
-		if to, ok := encodeRef[byte(i)]; ok {
-			EncodeMap[byte(i)] = to
-		}
+	for k, v := range encodeRef {
+		EncodeMap[k] = v
 	}
 }
diff --git a/replication/time.go b/replication/time.go
index 2adc832f4..4134f8ac0 100644
--- a/replication/time.go
+++ b/replication/time.go
@@ -2,12 +2,19 @@ package replication
 
 import (
 	"fmt"
-	"strings"
 	"time"
 )
 
 var (
-	fracTimeFormat []string
+	fracTimeFormat = [7]string{
+		"2006-01-02 15:04:05",
+		"2006-01-02 15:04:05.0",
+		"2006-01-02 15:04:05.00",
+		"2006-01-02 15:04:05.000",
+		"2006-01-02 15:04:05.0000",
+		"2006-01-02 15:04:05.00000",
+		"2006-01-02 15:04:05.000000",
+	}
 )
 
 // fracTime is a help structure wrapping Golang Time.
@@ -56,12 +63,3 @@ func microSecTimestampToTime(ts uint64) time.Time {
 	}
 	return time.Unix(int64(ts/1000000), int64(ts%1000000)*1000)
 }
-
-func init() {
-	fracTimeFormat = make([]string, 7)
-	fracTimeFormat[0] = "2006-01-02 15:04:05"
-
-	for i := 1; i <= 6; i++ {
-		fracTimeFormat[i] = fmt.Sprintf("2006-01-02 15:04:05.%s", strings.Repeat("0", i))
-	}
-}
diff --git a/server/stmt.go b/server/stmt.go
index cdccb3d42..bc7902e19 100644
--- a/server/stmt.go
+++ b/server/stmt.go
@@ -10,16 +10,10 @@ import (
 	"github.com/pingcap/errors"
 )
 
-var paramFieldData []byte
-var columnFieldData []byte
-
-func init() {
-	var p = &Field{Name: []byte("?")}
-	var c = &Field{}
-
-	paramFieldData = p.Dump()
-	columnFieldData = c.Dump()
-}
+var (
+	paramFieldData  = (&Field{Name: []byte("?")}).Dump()
+	columnFieldData = (&Field{}).Dump()
+)
 
 type Stmt struct {
 	ID    uint32