From 93ce586139da959a135293766c2ab33021982318 Mon Sep 17 00:00:00 2001
From: Nuno Cruces <ncruces@users.noreply.github.com>
Date: Tue, 18 Apr 2023 01:00:59 +0100
Subject: [PATCH] Optimize time.

---
 driver/driver.go    |  6 +++---
 driver/time.go      | 14 +++++++-------
 driver/time_test.go |  8 ++++----
 stmt.go             | 17 +++++++++++++++++
 4 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/driver/driver.go b/driver/driver.go
index 14acc8c..2a47af4 100644
--- a/driver/driver.go
+++ b/driver/driver.go
@@ -318,7 +318,7 @@ func (s stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (drive
 			case sqlite3.ZeroBlob:
 				err = s.stmt.BindZeroBlob(id, int64(a))
 			case time.Time:
-				err = s.stmt.BindText(id, a.Format(time.RFC3339Nano))
+				err = s.stmt.BindTime(id, a, sqlite3.TimeFormatDefault)
 			case nil:
 				err = s.stmt.BindNull(id)
 			default:
@@ -389,10 +389,10 @@ func (r rows) Next(dest []driver.Value) error {
 			dest[i] = r.stmt.ColumnInt64(i)
 		case sqlite3.FLOAT:
 			dest[i] = r.stmt.ColumnFloat(i)
-		case sqlite3.TEXT:
-			dest[i] = maybeTime(r.stmt.ColumnText(i))
 		case sqlite3.BLOB:
 			dest[i] = r.stmt.ColumnRawBlob(i)
+		case sqlite3.TEXT:
+			dest[i] = stringOrTime(r.stmt.ColumnRawText(i))
 		case sqlite3.NULL:
 			if buf, ok := dest[i].([]byte); ok {
 				dest[i] = buf[0:0]
diff --git a/driver/time.go b/driver/time.go
index 5c4f3d0..fa3247d 100644
--- a/driver/time.go
+++ b/driver/time.go
@@ -9,23 +9,23 @@ import (
 // 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) driver.Value {
+func stringOrTime(text []byte) driver.Value {
 	// Weed out (some) values that can't possibly be
 	// [time.RFC3339Nano] timestamps.
 	if len(text) < len("2006-01-02T15:04:05Z") {
-		return text
+		return string(text)
 	}
 	if len(text) > len(time.RFC3339Nano) {
-		return text
+		return string(text)
 	}
 	if text[4] != '-' || text[10] != 'T' || text[16] != ':' {
-		return text
+		return string(text)
 	}
 
 	// Slow path.
-	date, err := time.Parse(time.RFC3339Nano, text)
-	if err == nil && date.Format(time.RFC3339Nano) == text {
+	date, err := time.Parse(time.RFC3339Nano, string(text))
+	if err == nil && date.Format(time.RFC3339Nano) == string(text) {
 		return date
 	}
-	return text
+	return string(text)
 }
diff --git a/driver/time_test.go b/driver/time_test.go
index 2690159..e0306ff 100644
--- a/driver/time_test.go
+++ b/driver/time_test.go
@@ -6,7 +6,7 @@ import (
 )
 
 // This checks that any string can be recovered as the same string.
-func Fuzz_maybeTime_1(f *testing.F) {
+func Fuzz_stringOrTime_1(f *testing.F) {
 	f.Add("")
 	f.Add(" ")
 	f.Add("SQLite")
@@ -22,7 +22,7 @@ func Fuzz_maybeTime_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) {
-		value := maybeTime(str)
+		value := stringOrTime([]byte(str))
 
 		switch v := value.(type) {
 		case time.Time:
@@ -48,7 +48,7 @@ func Fuzz_maybeTime_1(f *testing.F) {
 
 // This checks that any [time.Time] can be recovered as a [time.Time],
 // with nanosecond accuracy, and preserving any timezone offset.
-func Fuzz_maybeTime_2(f *testing.F) {
+func Fuzz_stringOrTime_2(f *testing.F) {
 	f.Add(0, 0)
 	f.Add(0, 1)
 	f.Add(0, -1)
@@ -59,7 +59,7 @@ func Fuzz_maybeTime_2(f *testing.F) {
 	f.Add(-763421161058, 222_222_222) // twosday, year 22222BC
 
 	checkTime := func(t *testing.T, date time.Time) {
-		value := maybeTime(date.Format(time.RFC3339Nano))
+		value := stringOrTime([]byte(date.Format(time.RFC3339Nano)))
 
 		switch v := value.(type) {
 		case time.Time:
diff --git a/stmt.go b/stmt.go
index d64ddf1..9121d86 100644
--- a/stmt.go
+++ b/stmt.go
@@ -217,6 +217,9 @@ func (s *Stmt) BindNull(param int) error {
 //
 // https://www.sqlite.org/c3ref/bind_blob.html
 func (s *Stmt) BindTime(param int, value time.Time, format TimeFormat) error {
+	if format == TimeFormatDefault {
+		return s.bindRFC3339Nano(param, value)
+	}
 	switch v := format.Encode(value).(type) {
 	case string:
 		s.BindText(param, v)
@@ -230,6 +233,20 @@ func (s *Stmt) BindTime(param int, value time.Time, format TimeFormat) error {
 	return nil
 }
 
+func (s *Stmt) bindRFC3339Nano(param int, value time.Time) error {
+	const maxlen = uint64(len(time.RFC3339Nano))
+
+	ptr := s.c.new(maxlen)
+	buf := util.View(s.c.mod, ptr, maxlen)
+	buf = value.AppendFormat(buf[:0], time.RFC3339Nano)
+
+	r := s.c.call(s.c.api.bindText,
+		uint64(s.handle), uint64(param),
+		uint64(ptr), uint64(len(buf)),
+		uint64(s.c.api.destructor), _UTF8)
+	return s.c.error(r[0])
+}
+
 // ColumnCount returns the number of columns in a result set.
 //
 // https://www.sqlite.org/c3ref/column_count.html