Make TimeTruncate functional option

connection.go

@@ -251,7 +251,7 @@ func (mc *mysqlConn) interpolateParams(query string, args []driver.Value) (strin
  buf = append(buf, "'0000-00-00'"...)
  } else{
  buf = append(buf, '\'')
- buf, err = appendDateTime(buf, v.In(mc.cfg.Loc), mc.cfg.TimeTruncate)
+ buf, err = appendDateTime(buf, v.In(mc.cfg.Loc), mc.cfg.timeTruncate)
  if err != nil{
  return "", err
  }

dsn.go

@@ -34,6 +34,8 @@ var (
 // If a new Config is created instead of being parsed from a DSN string,
 // the NewConfig function should be used, which sets default values.
 type Config struct{
+ // non boolean fields
+
  User string // Username
  Passwd string // Password (requires User)
  Net string // Network (e.g. "tcp", "tcp6", "unix". default: "tcp")
@@ -45,15 +47,15 @@ type Config struct{
  Loc *time.Location // Location for time.Time values
  MaxAllowedPacket int // Max packet size allowed
  ServerPubKey string // Server public key name
- pubKey *rsa.PublicKey // Server public key
  TLSConfig string // TLS configuration name
  TLS *tls.Config // TLS configuration, its priority is higher than TLSConfig
- TimeTruncate time.Duration // Truncate time.Time values to the specified duration
  Timeout time.Duration // Dial timeout
  ReadTimeout time.Duration // I/O read timeout
  WriteTimeout time.Duration // I/O write timeout
  Logger Logger // Logger
 
+ // boolean fields
+
  AllowAllFiles bool // Allow all files to be used with LOAD DATA LOCAL INFILE
  AllowCleartextPasswords bool // Allows the cleartext client side plugin
  AllowFallbackToPlaintext bool // Allows fallback to unencrypted connection if server does not support TLS
@@ -66,17 +68,48 @@ type Config struct{
  MultiStatements bool // Allow multiple statements in one query
  ParseTime bool // Parse time values to time.Time
  RejectReadOnly bool // Reject read-only connections
+
+ // unexported fields. new options should be come here
+
+ pubKey *rsa.PublicKey // Server public key
+ timeTruncate time.Duration // Truncate time.Time values to the specified duration
 }
 
+// Functional Options Pattern
+// https://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis
+type Option func(*Config) error
+
 // NewConfig creates a new Config and sets default values.
 func NewConfig() *Config{
-return &Config{
+cfg := &Config{
  Loc: time.UTC,
  MaxAllowedPacket: defaultMaxAllowedPacket,
  Logger: defaultLogger,
  AllowNativePasswords: true,
  CheckConnLiveness: true,
  }
+
+ return cfg
+}
+
+// Apply applies the given options to the Config object.
+func (c *Config) Apply(opts ...Option) error{
+ for _, opt := range opts{
+ err := opt(c)
+ if err != nil{
+ return err
+ }
+ }
+ return nil
+}
+
+// TimeTruncate sets the time duration to truncate time.Time values in
+// query parameters.
+func TimeTruncate(d time.Duration) Option{
+ return func(cfg *Config) error{
+ cfg.timeTruncate = d
+ return nil
+ }
 }
 
 func (cfg *Config) Clone() *Config{
@@ -263,8 +296,8 @@ func (cfg *Config) FormatDSN() string{
  writeDSNParam(&buf, &hasParam, "parseTime", "true")
  }
 
- if cfg.TimeTruncate > 0{
- writeDSNParam(&buf, &hasParam, "timeTruncate", cfg.TimeTruncate.String())
+ if cfg.timeTruncate > 0{
+ writeDSNParam(&buf, &hasParam, "timeTruncate", cfg.timeTruncate.String())
  }
 
  if cfg.ReadTimeout > 0{
@@ -509,9 +542,9 @@ func parseDSNParams(cfg *Config, params string) (err error){
 
  // time.Time truncation
  case "timeTruncate":
- cfg.TimeTruncate, err = time.ParseDuration(value)
+ cfg.timeTruncate, err = time.ParseDuration(value)
  if err != nil{
- return
+ return fmt.Errorf("invalid timeTruncate value: %v, error: %w", value, err)
  }
 
  // I/O read Timeout

dsn_test.go

@@ -76,7 +76,7 @@ var testDSNs = []struct{
  &Config{Net: "tcp", Addr: "[de:ad:be:ef::ca:fe]:3306", DBName: "dbname", Loc: time.UTC, MaxAllowedPacket: defaultMaxAllowedPacket, Logger: defaultLogger, AllowNativePasswords: true, CheckConnLiveness: true},
 },{
  "user:password@/dbname?loc=UTC&timeout=30s&parseTime=true&timeTruncate=1h",
- &Config{User: "user", Passwd: "password", Net: "tcp", Addr: "127.0.0.1:3306", DBName: "dbname", Loc: time.UTC, Timeout: 30 * time.Second, ParseTime: true, MaxAllowedPacket: defaultMaxAllowedPacket, Logger: defaultLogger, AllowNativePasswords: true, CheckConnLiveness: true, TimeTruncate: time.Hour},
+ &Config{User: "user", Passwd: "password", Net: "tcp", Addr: "127.0.0.1:3306", DBName: "dbname", Loc: time.UTC, Timeout: 30 * time.Second, ParseTime: true, MaxAllowedPacket: defaultMaxAllowedPacket, Logger: defaultLogger, AllowNativePasswords: true, CheckConnLiveness: true, timeTruncate: time.Hour},
 },
 }
 

packets.go

@@ -1172,7 +1172,7 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error{
  if v.IsZero(){
  b = append(b, "0000-00-00"...)
  } else{
- b, err = appendDateTime(b, v.In(mc.cfg.Loc), mc.cfg.TimeTruncate)
+ b, err = appendDateTime(b, v.In(mc.cfg.Loc), mc.cfg.timeTruncate)
  if err != nil{
  return err
  }

result.go

@@ -15,9 +15,8 @@ import "database/sql/driver"
 // This is accessible by executing statements using sql.Conn.Raw() and
 // downcasting the returned result:
 //
-// res, err := rawConn.Exec(...)
-// res.(mysql.Result).AllRowsAffected()
-//
+// res, err := rawConn.Exec(...)
+// res.(mysql.Result).AllRowsAffected()
 type Result interface{
  driver.Result
  // AllRowsAffected returns a slice containing the affected rows for each