cleanup init functions (#977)

Author: serprex

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{}

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{})
 }
 

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

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
 	}
 }

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))
-	}
-}

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