Avoid escaping times (#256)

Author: ncruces

driver/driver.go

@@ -20,22 +20,45 @@
 //   - a [serializable] transaction is always "immediate";
 //   - a [read-only] transaction is always "deferred".
 //
+// # Datatypes In SQLite
+//
+// SQLite is dynamically typed.
+// Columns can mostly hold any value regardless of their declared type.
+// SQLite supports most [driver.Value] types out of the box,
+// but bool and [time.Time] require special care.
+//
+// Booleans can be stored on any column type and scanned back to a *bool.
+// However, if scanned to a *any, booleans may either become an
+// int64, string or bool, depending on the declared type of the column.
+// If you use BOOLEAN for your column type,
+// 1 and 0 will always scan as true and false.
+//
 // # Working with time
 //
+// Time values can similarly be stored on any column type.
 // The time encoding/decoding format can be specified using "_timefmt":
 //
 //	sql.Open("sqlite3", "file:demo.db?_timefmt=sqlite")
 //
-// Possible values are: "auto" (the default), "sqlite", "rfc3339";
+// Special values are: "auto" (the default), "sqlite", "rfc3339";
 //   - "auto" encodes as RFC 3339 and decodes any [format] supported by SQLite;
 //   - "sqlite" encodes as SQLite and decodes any [format] supported by SQLite;
 //   - "rfc3339" encodes and decodes RFC 3339 only.
 //
+// You can also set "_timefmt" to an arbitrary [sqlite3.TimeFormat] or [time.Layout].
+//
+// If you encode as RFC 3339 (the default),
+// consider using the TIME [collating sequence] to produce time-ordered sequences.
+//
 // If you encode as RFC 3339 (the default),
-// consider using the TIME [collating sequence] to produce a time-ordered sequence.
+// time values will scan back to a *time.Time unless your column type is TEXT.
+// Otherwise, if scanned to a *any, time values may either become an
+// int64, float64 or string, depending on the time format and declared type of the column.
+// If you use DATE, TIME, DATETIME, or TIMESTAMP for your column type,
+// "_timefmt" will be used to decode values.
 //
-// To scan values in other formats, [sqlite3.TimeFormat.Scanner] may be helpful.
-// To bind values in other formats, [sqlite3.TimeFormat.Encode] them before binding.
+// To scan values in custom formats, [sqlite3.TimeFormat.Scanner] may be helpful.
+// To bind values in custom formats, [sqlite3.TimeFormat.Encode] them before binding.
 //
 // When using a custom time struct, you'll have to implement
 // [database/sql/driver.Valuer] and [database/sql.Scanner].
@@ -48,7 +71,7 @@
 // The Scan method needs to take into account that the value it receives can be of differing types.
 // It can already be a [time.Time], if the driver decoded the value according to "_timefmt" rules.
 // Or it can be a: string, int64, float64, []byte, or nil,
-// depending on the column type and what whoever wrote the value.
+// depending on the column type and whoever wrote the value.
 // [sqlite3.TimeFormat.Decode] may help.
 //
 // # Setting PRAGMAs
@@ -595,6 +618,28 @@ const (
 	_TIME
 )
 
+func scanFromDecl(decl string) scantype {
+	// These types are only used before we have rows,
+	// and otherwise as type hints.
+	// The first few ensure STRICT tables are strictly typed.
+	// The other two are type hints for booleans and time.
+	switch decl {
+	case "INT", "INTEGER":
+		return _INT
+	case "REAL":
+		return _REAL
+	case "TEXT":
+		return _TEXT
+	case "BLOB":
+		return _BLOB
+	case "BOOLEAN":
+		return _BOOL
+	case "DATE", "TIME", "DATETIME", "TIMESTAMP":
+		return _TIME
+	}
+	return _ANY
+}
+
 var (
 	// Ensure these interfaces are implemented:
 	_ driver.RowsColumnTypeDatabaseTypeName = &rows{}
@@ -619,6 +664,18 @@ func (r *rows) Columns() []string {
 	return r.names
 }
 
+func (r *rows) scanType(index int) scantype {
+	if r.scans == nil {
+		count := r.Stmt.ColumnCount()
+		scans := make([]scantype, count)
+		for i := range scans {
+			scans[i] = scanFromDecl(strings.ToUpper(r.Stmt.ColumnDeclType(i)))
+		}
+		r.scans = scans
+	}
+	return r.scans[index]
+}
+
 func (r *rows) loadColumnMetadata() {
 	if r.nulls == nil {
 		count := r.Stmt.ColumnCount()
@@ -632,24 +689,7 @@ func (r *rows) loadColumnMetadata() {
 					r.Stmt.ColumnTableName(i),
 					col)
 				types[i] = strings.ToUpper(types[i])
-				// These types are only used before we have rows,
-				// and otherwise as type hints.
-				// The first few ensure STRICT tables are strictly typed.
-				// The other two are type hints for booleans and time.
-				switch types[i] {
-				case "INT", "INTEGER":
-					scans[i] = _INT
-				case "REAL":
-					scans[i] = _REAL
-				case "TEXT":
-					scans[i] = _TEXT
-				case "BLOB":
-					scans[i] = _BLOB
-				case "BOOLEAN":
-					scans[i] = _BOOL
-				case "DATE", "TIME", "DATETIME", "TIMESTAMP":
-					scans[i] = _TIME
-				}
+				scans[i] = scanFromDecl(types[i])
 			}
 		}
 		r.nulls = nulls
@@ -658,27 +698,15 @@ func (r *rows) loadColumnMetadata() {
 	}
 }
 
-func (r *rows) declType(index int) string {
-	if r.types == nil {
-		count := r.Stmt.ColumnCount()
-		types := make([]string, count)
-		for i := range types {
-			types[i] = strings.ToUpper(r.Stmt.ColumnDeclType(i))
-		}
-		r.types = types
-	}
-	return r.types[index]
-}
-
 func (r *rows) ColumnTypeDatabaseTypeName(index int) string {
 	r.loadColumnMetadata()
-	decltype := r.types[index]
-	if len := len(decltype); len > 0 && decltype[len-1] == ')' {
-		if i := strings.LastIndexByte(decltype, '('); i >= 0 {
-			decltype = decltype[:i]
+	decl := r.types[index]
+	if len := len(decl); len > 0 && decl[len-1] == ')' {
+		if i := strings.LastIndexByte(decl, '('); i >= 0 {
+			decl = decl[:i]
 		}
 	}
-	return strings.TrimSpace(decltype)
+	return strings.TrimSpace(decl)
 }
 
 func (r *rows) ColumnTypeNullable(index int) (nullable, ok bool) {
@@ -745,36 +773,49 @@ func (r *rows) Next(dest []driver.Value) error {
 	}
 
 	data := unsafe.Slice((*any)(unsafe.SliceData(dest)), len(dest))
-	err := r.Stmt.Columns(data...)
-	for i := range dest {
-		if t, ok := r.decodeTime(i, dest[i]); ok {
-			dest[i] = t
-		}
+	if err := r.Stmt.ColumnsRaw(data...); err != nil {
+		return err
 	}
-	return err
-}
-
-func (r *rows) decodeTime(i int, v any) (_ time.Time, ok bool) {
-	switch v := v.(type) {
-	case int64, float64:
-		// could be a time value
-	case string:
-		if r.tmWrite != "" && r.tmWrite != time.RFC3339 && r.tmWrite != time.RFC3339Nano {
+	for i := range dest {
+		scan := r.scanType(i)
+		switch v := dest[i].(type) {
+		case int64:
+			if scan == _BOOL {
+				switch v {
+				case 1:
+					dest[i] = true
+				case 0:
+					dest[i] = false
+				}
+				continue
+			}
+		case []byte:
+			if len(v) == cap(v) { // a BLOB
+				continue
+			}
+			if scan != _TEXT {
+				switch r.tmWrite {
+				case "", time.RFC3339, time.RFC3339Nano:
+					t, ok := maybeTime(v)
+					if ok {
+						dest[i] = t
+						continue
+					}
+				}
+			}
+			dest[i] = string(v)
+		case float64:
 			break
+		default:
+			continue
 		}
-		t, ok := maybeTime(v)
-		if ok {
-			return t, true
+		if scan == _TIME {
+			t, err := r.tmRead.Decode(dest[i])
+			if err == nil {
+				dest[i] = t
+				continue
+			}
 		}
-	default:
-		return
 	}
-	switch r.declType(i) {
-	case "DATE", "TIME", "DATETIME", "TIMESTAMP":
-		// could be a time value
-	default:
-		return
-	}
-	t, err := r.tmRead.Decode(v)
-	return t, err == nil
+	return nil
 }

driver/example2_test.go

@@ -1,9 +1,5 @@
-//go:build linux || darwin || windows || freebsd || openbsd || netbsd || dragonfly || illumos || sqlite3_flock || sqlite3_dotlk
-
 package driver_test
 
-// Adapted from: https://go.dev/doc/tutorial/database-access
-
 import (
 	"database/sql"
 	"database/sql/driver"
@@ -27,7 +23,7 @@ func Example_customTime() {
 	_, err = db.Exec(`
 		CREATE TABLE data (
 			id INTEGER PRIMARY KEY,
-			date_time TEXT
+			date_time ANY
 		) STRICT;
 	`)
 	if err != nil {

driver/time.go

@@ -1,12 +1,15 @@
 package driver
 
-import "time"
+import (
+	"bytes"
+	"time"
+)
 
 // Convert a string in [time.RFC3339Nano] format into a [time.Time]
 // if it roundtrips back to the same string.
 // This way times can be persisted to, and recovered from, the database,
 // but if a string is needed, [database/sql] will recover the same string.
-func maybeTime(text string) (_ time.Time, _ bool) {
+func maybeTime(text []byte) (_ time.Time, _ bool) {
 	// Weed out (some) values that can't possibly be
 	// [time.RFC3339Nano] timestamps.
 	if len(text) < len("2006-01-02T15:04:05Z") {
@@ -21,8 +24,8 @@ func maybeTime(text string) (_ time.Time, _ bool) {
 
 	// Slow path.
 	var buf [len(time.RFC3339Nano)]byte
-	date, err := time.Parse(time.RFC3339Nano, text)
-	if err == nil && text == string(date.AppendFormat(buf[:0], time.RFC3339Nano)) {
+	date, err := time.Parse(time.RFC3339Nano, string(text))
+	if err == nil && bytes.Equal(text, date.AppendFormat(buf[:0], time.RFC3339Nano)) {
 		return date, true
 	}
 	return

driver/time_test.go

@@ -22,7 +22,7 @@ func Fuzz_stringOrTime_1(f *testing.F) {
 	f.Add("Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.")
 
 	f.Fuzz(func(t *testing.T, str string) {
-		v, ok := maybeTime(str)
+		v, ok := maybeTime([]byte(str))
 		if ok {
 			// Make sure times round-trip to the same string:
 			// https://pkg.go.dev/database/sql#Rows.Scan
@@ -51,7 +51,7 @@ func Fuzz_stringOrTime_2(f *testing.F) {
 	f.Add(int64(-763421161058), int64(222_222_222)) // twosday, year 22222BC
 
 	checkTime := func(t testing.TB, date time.Time) {
-		v, ok := maybeTime(date.Format(time.RFC3339Nano))
+		v, ok := maybeTime(date.AppendFormat(nil, time.RFC3339Nano))
 		if ok {
 			// Make sure times round-trip to the same time:
 			if !v.Equal(date) {