build: move package sources from src/pkg to src

Preparation was in CL 134570043.
This CL contains only the effect of 'hg mv src/pkg/* src'.
For more about the move, see golang.org/s/go14nopkg.

src/database/sql/convert.go

@@ -0,0 +1,299 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Type conversions for Scan.
+
+package sql
+
+import (
+	"database/sql/driver"
+	"errors"
+	"fmt"
+	"reflect"
+	"strconv"
+)
+
+var errNilPtr = errors.New("destination pointer is nil") // embedded in descriptive error
+
+// driverArgs converts arguments from callers of Stmt.Exec and
+// Stmt.Query into driver Values.
+//
+// The statement ds may be nil, if no statement is available.
+func driverArgs(ds *driverStmt, args []interface{}) ([]driver.Value, error) {
+	dargs := make([]driver.Value, len(args))
+	var si driver.Stmt
+	if ds != nil {
+		si = ds.si
+	}
+	cc, ok := si.(driver.ColumnConverter)
+
+	// Normal path, for a driver.Stmt that is not a ColumnConverter.
+	if !ok {
+		for n, arg := range args {
+			var err error
+			dargs[n], err = driver.DefaultParameterConverter.ConvertValue(arg)
+			if err != nil {
+				return nil, fmt.Errorf("sql: converting Exec argument #%d's type: %v", n, err)
+			}
+		}
+		return dargs, nil
+	}
+
+	// Let the Stmt convert its own arguments.
+	for n, arg := range args {
+		// First, see if the value itself knows how to convert
+		// itself to a driver type.  For example, a NullString
+		// struct changing into a string or nil.
+		if svi, ok := arg.(driver.Valuer); ok {
+			sv, err := svi.Value()
+			if err != nil {
+				return nil, fmt.Errorf("sql: argument index %d from Value: %v", n, err)
+			}
+			if !driver.IsValue(sv) {
+				return nil, fmt.Errorf("sql: argument index %d: non-subset type %T returned from Value", n, sv)
+			}
+			arg = sv
+		}
+
+		// Second, ask the column to sanity check itself. For
+		// example, drivers might use this to make sure that
+		// an int64 values being inserted into a 16-bit
+		// integer field is in range (before getting
+		// truncated), or that a nil can't go into a NOT NULL
+		// column before going across the network to get the
+		// same error.
+		var err error
+		ds.Lock()
+		dargs[n], err = cc.ColumnConverter(n).ConvertValue(arg)
+		ds.Unlock()
+		if err != nil {
+			return nil, fmt.Errorf("sql: converting argument #%d's type: %v", n, err)
+		}
+		if !driver.IsValue(dargs[n]) {
+			return nil, fmt.Errorf("sql: driver ColumnConverter error converted %T to unsupported type %T",
+				arg, dargs[n])
+		}
+	}
+
+	return dargs, nil
+}
+
+// convertAssign copies to dest the value in src, converting it if possible.
+// An error is returned if the copy would result in loss of information.
+// dest should be a pointer type.
+func convertAssign(dest, src interface{}) error {
+	// Common cases, without reflect.
+	switch s := src.(type) {
+	case string:
+		switch d := dest.(type) {
+		case *string:
+			if d == nil {
+				return errNilPtr
+			}
+			*d = s
+			return nil
+		case *[]byte:
+			if d == nil {
+				return errNilPtr
+			}
+			*d = []byte(s)
+			return nil
+		}
+	case []byte:
+		switch d := dest.(type) {
+		case *string:
+			if d == nil {
+				return errNilPtr
+			}
+			*d = string(s)
+			return nil
+		case *interface{}:
+			if d == nil {
+				return errNilPtr
+			}
+			*d = cloneBytes(s)
+			return nil
+		case *[]byte:
+			if d == nil {
+				return errNilPtr
+			}
+			*d = cloneBytes(s)
+			return nil
+		case *RawBytes:
+			if d == nil {
+				return errNilPtr
+			}
+			*d = s
+			return nil
+		}
+	case nil:
+		switch d := dest.(type) {
+		case *interface{}:
+			if d == nil {
+				return errNilPtr
+			}
+			*d = nil
+			return nil
+		case *[]byte:
+			if d == nil {
+				return errNilPtr
+			}
+			*d = nil
+			return nil
+		case *RawBytes:
+			if d == nil {
+				return errNilPtr
+			}
+			*d = nil
+			return nil
+		}
+	}
+
+	var sv reflect.Value
+
+	switch d := dest.(type) {
+	case *string:
+		sv = reflect.ValueOf(src)
+		switch sv.Kind() {
+		case reflect.Bool,
+			reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
+			reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
+			reflect.Float32, reflect.Float64:
+			*d = asString(src)
+			return nil
+		}
+	case *[]byte:
+		sv = reflect.ValueOf(src)
+		if b, ok := asBytes(nil, sv); ok {
+			*d = b
+			return nil
+		}
+	case *RawBytes:
+		sv = reflect.ValueOf(src)
+		if b, ok := asBytes([]byte(*d)[:0], sv); ok {
+			*d = RawBytes(b)
+			return nil
+		}
+	case *bool:
+		bv, err := driver.Bool.ConvertValue(src)
+		if err == nil {
+			*d = bv.(bool)
+		}
+		return err
+	case *interface{}:
+		*d = src
+		return nil
+	}
+
+	if scanner, ok := dest.(Scanner); ok {
+		return scanner.Scan(src)
+	}
+
+	dpv := reflect.ValueOf(dest)
+	if dpv.Kind() != reflect.Ptr {
+		return errors.New("destination not a pointer")
+	}
+	if dpv.IsNil() {
+		return errNilPtr
+	}
+
+	if !sv.IsValid() {
+		sv = reflect.ValueOf(src)
+	}
+
+	dv := reflect.Indirect(dpv)
+	if dv.Kind() == sv.Kind() {
+		dv.Set(sv)
+		return nil
+	}
+
+	switch dv.Kind() {
+	case reflect.Ptr:
+		if src == nil {
+			dv.Set(reflect.Zero(dv.Type()))
+			return nil
+		} else {
+			dv.Set(reflect.New(dv.Type().Elem()))
+			return convertAssign(dv.Interface(), src)
+		}
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		s := asString(src)
+		i64, err := strconv.ParseInt(s, 10, dv.Type().Bits())
+		if err != nil {
+			return fmt.Errorf("converting string %q to a %s: %v", s, dv.Kind(), err)
+		}
+		dv.SetInt(i64)
+		return nil
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		s := asString(src)
+		u64, err := strconv.ParseUint(s, 10, dv.Type().Bits())
+		if err != nil {
+			return fmt.Errorf("converting string %q to a %s: %v", s, dv.Kind(), err)
+		}
+		dv.SetUint(u64)
+		return nil
+	case reflect.Float32, reflect.Float64:
+		s := asString(src)
+		f64, err := strconv.ParseFloat(s, dv.Type().Bits())
+		if err != nil {
+			return fmt.Errorf("converting string %q to a %s: %v", s, dv.Kind(), err)
+		}
+		dv.SetFloat(f64)
+		return nil
+	}
+
+	return fmt.Errorf("unsupported driver -> Scan pair: %T -> %T", src, dest)
+}
+
+func cloneBytes(b []byte) []byte {
+	if b == nil {
+		return nil
+	} else {
+		c := make([]byte, len(b))
+		copy(c, b)
+		return c
+	}
+}
+
+func asString(src interface{}) string {
+	switch v := src.(type) {
+	case string:
+		return v
+	case []byte:
+		return string(v)
+	}
+	rv := reflect.ValueOf(src)
+	switch rv.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return strconv.FormatInt(rv.Int(), 10)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return strconv.FormatUint(rv.Uint(), 10)
+	case reflect.Float64:
+		return strconv.FormatFloat(rv.Float(), 'g', -1, 64)
+	case reflect.Float32:
+		return strconv.FormatFloat(rv.Float(), 'g', -1, 32)
+	case reflect.Bool:
+		return strconv.FormatBool(rv.Bool())
+	}
+	return fmt.Sprintf("%v", src)
+}
+
+func asBytes(buf []byte, rv reflect.Value) (b []byte, ok bool) {
+	switch rv.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return strconv.AppendInt(buf, rv.Int(), 10), true
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return strconv.AppendUint(buf, rv.Uint(), 10), true
+	case reflect.Float32:
+		return strconv.AppendFloat(buf, rv.Float(), 'g', -1, 32), true
+	case reflect.Float64:
+		return strconv.AppendFloat(buf, rv.Float(), 'g', -1, 64), true
+	case reflect.Bool:
+		return strconv.AppendBool(buf, rv.Bool()), true
+	case reflect.String:
+		s := rv.String()
+		return append(buf, s...), true
+	}
+	return
+}

src/database/sql/convert_test.go

@@ -0,0 +1,348 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sql
+
+import (
+	"database/sql/driver"
+	"fmt"
+	"reflect"
+	"runtime"
+	"testing"
+	"time"
+)
+
+var someTime = time.Unix(123, 0)
+var answer int64 = 42
+
+type conversionTest struct {
+	s, d interface{} // source and destination
+
+	// following are used if they're non-zero
+	wantint   int64
+	wantuint  uint64
+	wantstr   string
+	wantbytes []byte
+	wantraw   RawBytes
+	wantf32   float32
+	wantf64   float64
+	wanttime  time.Time
+	wantbool  bool // used if d is of type *bool
+	wanterr   string
+	wantiface interface{}
+	wantptr   *int64 // if non-nil, *d's pointed value must be equal to *wantptr
+	wantnil   bool   // if true, *d must be *int64(nil)
+}
+
+// Target variables for scanning into.
+var (
+	scanstr    string
+	scanbytes  []byte
+	scanraw    RawBytes
+	scanint    int
+	scanint8   int8
+	scanint16  int16
+	scanint32  int32
+	scanuint8  uint8
+	scanuint16 uint16
+	scanbool   bool
+	scanf32    float32
+	scanf64    float64
+	scantime   time.Time
+	scanptr    *int64
+	scaniface  interface{}
+)
+
+var conversionTests = []conversionTest{
+	// Exact conversions (destination pointer type matches source type)
+	{s: "foo", d: &scanstr, wantstr: "foo"},
+	{s: 123, d: &scanint, wantint: 123},
+	{s: someTime, d: &scantime, wanttime: someTime},
+
+	// To strings
+	{s: "string", d: &scanstr, wantstr: "string"},
+	{s: []byte("byteslice"), d: &scanstr, wantstr: "byteslice"},
+	{s: 123, d: &scanstr, wantstr: "123"},
+	{s: int8(123), d: &scanstr, wantstr: "123"},
+	{s: int64(123), d: &scanstr, wantstr: "123"},
+	{s: uint8(123), d: &scanstr, wantstr: "123"},
+	{s: uint16(123), d: &scanstr, wantstr: "123"},
+	{s: uint32(123), d: &scanstr, wantstr: "123"},
+	{s: uint64(123), d: &scanstr, wantstr: "123"},
+	{s: 1.5, d: &scanstr, wantstr: "1.5"},
+
+	// To []byte
+	{s: nil, d: &scanbytes, wantbytes: nil},
+	{s: "string", d: &scanbytes, wantbytes: []byte("string")},
+	{s: []byte("byteslice"), d: &scanbytes, wantbytes: []byte("byteslice")},
+	{s: 123, d: &scanbytes, wantbytes: []byte("123")},
+	{s: int8(123), d: &scanbytes, wantbytes: []byte("123")},
+	{s: int64(123), d: &scanbytes, wantbytes: []byte("123")},
+	{s: uint8(123), d: &scanbytes, wantbytes: []byte("123")},
+	{s: uint16(123), d: &scanbytes, wantbytes: []byte("123")},
+	{s: uint32(123), d: &scanbytes, wantbytes: []byte("123")},
+	{s: uint64(123), d: &scanbytes, wantbytes: []byte("123")},
+	{s: 1.5, d: &scanbytes, wantbytes: []byte("1.5")},
+
+	// To RawBytes
+	{s: nil, d: &scanraw, wantraw: nil},
+	{s: []byte("byteslice"), d: &scanraw, wantraw: RawBytes("byteslice")},
+	{s: 123, d: &scanraw, wantraw: RawBytes("123")},
+	{s: int8(123), d: &scanraw, wantraw: RawBytes("123")},
+	{s: int64(123), d: &scanraw, wantraw: RawBytes("123")},
+	{s: uint8(123), d: &scanraw, wantraw: RawBytes("123")},
+	{s: uint16(123), d: &scanraw, wantraw: RawBytes("123")},
+	{s: uint32(123), d: &scanraw, wantraw: RawBytes("123")},
+	{s: uint64(123), d: &scanraw, wantraw: RawBytes("123")},
+	{s: 1.5, d: &scanraw, wantraw: RawBytes("1.5")},
+
+	// Strings to integers
+	{s: "255", d: &scanuint8, wantuint: 255},
+	{s: "256", d: &scanuint8, wanterr: `converting string "256" to a uint8: strconv.ParseUint: parsing "256": value out of range`},
+	{s: "256", d: &scanuint16, wantuint: 256},
+	{s: "-1", d: &scanint, wantint: -1},
+	{s: "foo", d: &scanint, wanterr: `converting string "foo" to a int: strconv.ParseInt: parsing "foo": invalid syntax`},
+
+	// True bools
+	{s: true, d: &scanbool, wantbool: true},
+	{s: "True", d: &scanbool, wantbool: true},
+	{s: "TRUE", d: &scanbool, wantbool: true},
+	{s: "1", d: &scanbool, wantbool: true},
+	{s: 1, d: &scanbool, wantbool: true},
+	{s: int64(1), d: &scanbool, wantbool: true},
+	{s: uint16(1), d: &scanbool, wantbool: true},
+
+	// False bools
+	{s: false, d: &scanbool, wantbool: false},
+	{s: "false", d: &scanbool, wantbool: false},
+	{s: "FALSE", d: &scanbool, wantbool: false},
+	{s: "0", d: &scanbool, wantbool: false},
+	{s: 0, d: &scanbool, wantbool: false},
+	{s: int64(0), d: &scanbool, wantbool: false},
+	{s: uint16(0), d: &scanbool, wantbool: false},
+
+	// Not bools
+	{s: "yup", d: &scanbool, wanterr: `sql/driver: couldn't convert "yup" into type bool`},
+	{s: 2, d: &scanbool, wanterr: `sql/driver: couldn't convert 2 into type bool`},
+
+	// Floats
+	{s: float64(1.5), d: &scanf64, wantf64: float64(1.5)},
+	{s: int64(1), d: &scanf64, wantf64: float64(1)},
+	{s: float64(1.5), d: &scanf32, wantf32: float32(1.5)},
+	{s: "1.5", d: &scanf32, wantf32: float32(1.5)},
+	{s: "1.5", d: &scanf64, wantf64: float64(1.5)},
+
+	// Pointers
+	{s: interface{}(nil), d: &scanptr, wantnil: true},
+	{s: int64(42), d: &scanptr, wantptr: &answer},
+
+	// To interface{}
+	{s: float64(1.5), d: &scaniface, wantiface: float64(1.5)},
+	{s: int64(1), d: &scaniface, wantiface: int64(1)},
+	{s: "str", d: &scaniface, wantiface: "str"},
+	{s: []byte("byteslice"), d: &scaniface, wantiface: []byte("byteslice")},
+	{s: true, d: &scaniface, wantiface: true},
+	{s: nil, d: &scaniface},
+	{s: []byte(nil), d: &scaniface, wantiface: []byte(nil)},
+}
+
+func intPtrValue(intptr interface{}) interface{} {
+	return reflect.Indirect(reflect.Indirect(reflect.ValueOf(intptr))).Int()
+}
+
+func intValue(intptr interface{}) int64 {
+	return reflect.Indirect(reflect.ValueOf(intptr)).Int()
+}
+
+func uintValue(intptr interface{}) uint64 {
+	return reflect.Indirect(reflect.ValueOf(intptr)).Uint()
+}
+
+func float64Value(ptr interface{}) float64 {
+	return *(ptr.(*float64))
+}
+
+func float32Value(ptr interface{}) float32 {
+	return *(ptr.(*float32))
+}
+
+func timeValue(ptr interface{}) time.Time {
+	return *(ptr.(*time.Time))
+}
+
+func TestConversions(t *testing.T) {
+	for n, ct := range conversionTests {
+		err := convertAssign(ct.d, ct.s)
+		errstr := ""
+		if err != nil {
+			errstr = err.Error()
+		}
+		errf := func(format string, args ...interface{}) {
+			base := fmt.Sprintf("convertAssign #%d: for %v (%T) -> %T, ", n, ct.s, ct.s, ct.d)
+			t.Errorf(base+format, args...)
+		}
+		if errstr != ct.wanterr {
+			errf("got error %q, want error %q", errstr, ct.wanterr)
+		}
+		if ct.wantstr != "" && ct.wantstr != scanstr {
+			errf("want string %q, got %q", ct.wantstr, scanstr)
+		}
+		if ct.wantint != 0 && ct.wantint != intValue(ct.d) {
+			errf("want int %d, got %d", ct.wantint, intValue(ct.d))
+		}
+		if ct.wantuint != 0 && ct.wantuint != uintValue(ct.d) {
+			errf("want uint %d, got %d", ct.wantuint, uintValue(ct.d))
+		}
+		if ct.wantf32 != 0 && ct.wantf32 != float32Value(ct.d) {
+			errf("want float32 %v, got %v", ct.wantf32, float32Value(ct.d))
+		}
+		if ct.wantf64 != 0 && ct.wantf64 != float64Value(ct.d) {
+			errf("want float32 %v, got %v", ct.wantf64, float64Value(ct.d))
+		}
+		if bp, boolTest := ct.d.(*bool); boolTest && *bp != ct.wantbool && ct.wanterr == "" {
+			errf("want bool %v, got %v", ct.wantbool, *bp)
+		}
+		if !ct.wanttime.IsZero() && !ct.wanttime.Equal(timeValue(ct.d)) {
+			errf("want time %v, got %v", ct.wanttime, timeValue(ct.d))
+		}
+		if ct.wantnil && *ct.d.(**int64) != nil {
+			errf("want nil, got %v", intPtrValue(ct.d))
+		}
+		if ct.wantptr != nil {
+			if *ct.d.(**int64) == nil {
+				errf("want pointer to %v, got nil", *ct.wantptr)
+			} else if *ct.wantptr != intPtrValue(ct.d) {
+				errf("want pointer to %v, got %v", *ct.wantptr, intPtrValue(ct.d))
+			}
+		}
+		if ifptr, ok := ct.d.(*interface{}); ok {
+			if !reflect.DeepEqual(ct.wantiface, scaniface) {
+				errf("want interface %#v, got %#v", ct.wantiface, scaniface)
+				continue
+			}
+			if srcBytes, ok := ct.s.([]byte); ok {
+				dstBytes := (*ifptr).([]byte)
+				if len(srcBytes) > 0 && &dstBytes[0] == &srcBytes[0] {
+					errf("copy into interface{} didn't copy []byte data")
+				}
+			}
+		}
+	}
+}
+
+func TestNullString(t *testing.T) {
+	var ns NullString
+	convertAssign(&ns, []byte("foo"))
+	if !ns.Valid {
+		t.Errorf("expecting not null")
+	}
+	if ns.String != "foo" {
+		t.Errorf("expecting foo; got %q", ns.String)
+	}
+	convertAssign(&ns, nil)
+	if ns.Valid {
+		t.Errorf("expecting null on nil")
+	}
+	if ns.String != "" {
+		t.Errorf("expecting blank on nil; got %q", ns.String)
+	}
+}
+
+type valueConverterTest struct {
+	c       driver.ValueConverter
+	in, out interface{}
+	err     string
+}
+
+var valueConverterTests = []valueConverterTest{
+	{driver.DefaultParameterConverter, NullString{"hi", true}, "hi", ""},
+	{driver.DefaultParameterConverter, NullString{"", false}, nil, ""},
+}
+
+func TestValueConverters(t *testing.T) {
+	for i, tt := range valueConverterTests {
+		out, err := tt.c.ConvertValue(tt.in)
+		goterr := ""
+		if err != nil {
+			goterr = err.Error()
+		}
+		if goterr != tt.err {
+			t.Errorf("test %d: %T(%T(%v)) error = %q; want error = %q",
+				i, tt.c, tt.in, tt.in, goterr, tt.err)
+		}
+		if tt.err != "" {
+			continue
+		}
+		if !reflect.DeepEqual(out, tt.out) {
+			t.Errorf("test %d: %T(%T(%v)) = %v (%T); want %v (%T)",
+				i, tt.c, tt.in, tt.in, out, out, tt.out, tt.out)
+		}
+	}
+}
+
+// Tests that assigning to RawBytes doesn't allocate (and also works).
+func TestRawBytesAllocs(t *testing.T) {
+	var tests = []struct {
+		name string
+		in   interface{}
+		want string
+	}{
+		{"uint64", uint64(12345678), "12345678"},
+		{"uint32", uint32(1234), "1234"},
+		{"uint16", uint16(12), "12"},
+		{"uint8", uint8(1), "1"},
+		{"uint", uint(123), "123"},
+		{"int", int(123), "123"},
+		{"int8", int8(1), "1"},
+		{"int16", int16(12), "12"},
+		{"int32", int32(1234), "1234"},
+		{"int64", int64(12345678), "12345678"},
+		{"float32", float32(1.5), "1.5"},
+		{"float64", float64(64), "64"},
+		{"bool", false, "false"},
+	}
+
+	buf := make(RawBytes, 10)
+	test := func(name string, in interface{}, want string) {
+		if err := convertAssign(&buf, in); err != nil {
+			t.Fatalf("%s: convertAssign = %v", name, err)
+		}
+		match := len(buf) == len(want)
+		if match {
+			for i, b := range buf {
+				if want[i] != b {
+					match = false
+					break
+				}
+			}
+		}
+		if !match {
+			t.Fatalf("%s: got %q (len %d); want %q (len %d)", name, buf, len(buf), want, len(want))
+		}
+	}
+
+	n := testing.AllocsPerRun(100, func() {
+		for _, tt := range tests {
+			test(tt.name, tt.in, tt.want)
+		}
+	})
+
+	// The numbers below are only valid for 64-bit interface word sizes,
+	// and gc. With 32-bit words there are more convT2E allocs, and
+	// with gccgo, only pointers currently go in interface data.
+	// So only care on amd64 gc for now.
+	measureAllocs := runtime.GOARCH == "amd64" && runtime.Compiler == "gc"
+
+	if n > 0.5 && measureAllocs {
+		t.Fatalf("allocs = %v; want 0", n)
+	}
+
+	// This one involves a convT2E allocation, string -> interface{}
+	n = testing.AllocsPerRun(100, func() {
+		test("string", "foo", "foo")
+	})
+	if n > 1.5 && measureAllocs {
+		t.Fatalf("allocs = %v; want max 1", n)
+	}
+}

src/database/sql/doc.txt

@@ -0,0 +1,46 @@
+Goals of the sql and sql/driver packages:
+
+* Provide a generic database API for a variety of SQL or SQL-like
+  databases.  There currently exist Go libraries for SQLite, MySQL,
+  and Postgres, but all with a very different feel, and often
+  a non-Go-like feel.
+
+* Feel like Go.
+
+* Care mostly about the common cases. Common SQL should be portable.
+  SQL edge cases or db-specific extensions can be detected and
+  conditionally used by the application.  It is a non-goal to care
+  about every particular db's extension or quirk.
+
+* Separate out the basic implementation of a database driver
+  (implementing the sql/driver interfaces) vs the implementation
+  of all the user-level types and convenience methods.
+  In a nutshell:
+
+  User Code ---> sql package (concrete types) ---> sql/driver (interfaces)
+  Database Driver -> sql (to register) + sql/driver (implement interfaces)
+
+* Make type casting/conversions consistent between all drivers. To
+  achieve this, most of the conversions are done in the sql package,
+  not in each driver. The drivers then only have to deal with a
+  smaller set of types.
+
+* Be flexible with type conversions, but be paranoid about silent
+  truncation or other loss of precision.
+
+* Handle concurrency well.  Users shouldn't need to care about the
+  database's per-connection thread safety issues (or lack thereof),
+  and shouldn't have to maintain their own free pools of connections.
+  The 'db' package should deal with that bookkeeping as needed.  Given
+  an *sql.DB, it should be possible to share that instance between
+  multiple goroutines, without any extra synchronization.
+
+* Push complexity, where necessary, down into the sql+driver packages,
+  rather than exposing it to users. Said otherwise, the sql package
+  should expose an ideal database that's not finnicky about how it's
+  accessed, even if that's not true.
+
+* Provide optional interfaces in sql/driver for drivers to implement
+  for special cases or fastpaths.  But the only party that knows about
+  those is the sql package.  To user code, some stuff just might start
+  working or start working slightly faster.

src/database/sql/driver/driver.go

@@ -0,0 +1,211 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package driver defines interfaces to be implemented by database
+// drivers as used by package sql.
+//
+// Most code should use package sql.
+package driver
+
+import "errors"
+
+// Value is a value that drivers must be able to handle.
+// It is either nil or an instance of one of these types:
+//
+//   int64
+//   float64
+//   bool
+//   []byte
+//   string   [*] everywhere except from Rows.Next.
+//   time.Time
+type Value interface{}
+
+// Driver is the interface that must be implemented by a database
+// driver.
+type Driver interface {
+	// Open returns a new connection to the database.
+	// The name is a string in a driver-specific format.
+	//
+	// Open may return a cached connection (one previously
+	// closed), but doing so is unnecessary; the sql package
+	// maintains a pool of idle connections for efficient re-use.
+	//
+	// The returned connection is only used by one goroutine at a
+	// time.
+	Open(name string) (Conn, error)
+}
+
+// ErrSkip may be returned by some optional interfaces' methods to
+// indicate at runtime that the fast path is unavailable and the sql
+// package should continue as if the optional interface was not
+// implemented. ErrSkip is only supported where explicitly
+// documented.
+var ErrSkip = errors.New("driver: skip fast-path; continue as if unimplemented")
+
+// ErrBadConn should be returned by a driver to signal to the sql
+// package that a driver.Conn is in a bad state (such as the server
+// having earlier closed the connection) and the sql package should
+// retry on a new connection.
+//
+// To prevent duplicate operations, ErrBadConn should NOT be returned
+// if there's a possibility that the database server might have
+// performed the operation. Even if the server sends back an error,
+// you shouldn't return ErrBadConn.
+var ErrBadConn = errors.New("driver: bad connection")
+
+// Execer is an optional interface that may be implemented by a Conn.
+//
+// If a Conn does not implement Execer, the sql package's DB.Exec will
+// first prepare a query, execute the statement, and then close the
+// statement.
+//
+// Exec may return ErrSkip.
+type Execer interface {
+	Exec(query string, args []Value) (Result, error)
+}
+
+// Queryer is an optional interface that may be implemented by a Conn.
+//
+// If a Conn does not implement Queryer, the sql package's DB.Query will
+// first prepare a query, execute the statement, and then close the
+// statement.
+//
+// Query may return ErrSkip.
+type Queryer interface {
+	Query(query string, args []Value) (Rows, error)
+}
+
+// Conn is a connection to a database. It is not used concurrently
+// by multiple goroutines.
+//
+// Conn is assumed to be stateful.
+type Conn interface {
+	// Prepare returns a prepared statement, bound to this connection.
+	Prepare(query string) (Stmt, error)
+
+	// Close invalidates and potentially stops any current
+	// prepared statements and transactions, marking this
+	// connection as no longer in use.
+	//
+	// Because the sql package maintains a free pool of
+	// connections and only calls Close when there's a surplus of
+	// idle connections, it shouldn't be necessary for drivers to
+	// do their own connection caching.
+	Close() error
+
+	// Begin starts and returns a new transaction.
+	Begin() (Tx, error)
+}
+
+// Result is the result of a query execution.
+type Result interface {
+	// LastInsertId returns the database's auto-generated ID
+	// after, for example, an INSERT into a table with primary
+	// key.
+	LastInsertId() (int64, error)
+
+	// RowsAffected returns the number of rows affected by the
+	// query.
+	RowsAffected() (int64, error)
+}
+
+// Stmt is a prepared statement. It is bound to a Conn and not
+// used by multiple goroutines concurrently.
+type Stmt interface {
+	// Close closes the statement.
+	//
+	// As of Go 1.1, a Stmt will not be closed if it's in use
+	// by any queries.
+	Close() error
+
+	// NumInput returns the number of placeholder parameters.
+	//
+	// If NumInput returns >= 0, the sql package will sanity check
+	// argument counts from callers and return errors to the caller
+	// before the statement's Exec or Query methods are called.
+	//
+	// NumInput may also return -1, if the driver doesn't know
+	// its number of placeholders. In that case, the sql package
+	// will not sanity check Exec or Query argument counts.
+	NumInput() int
+
+	// Exec executes a query that doesn't return rows, such
+	// as an INSERT or UPDATE.
+	Exec(args []Value) (Result, error)
+
+	// Query executes a query that may return rows, such as a
+	// SELECT.
+	Query(args []Value) (Rows, error)
+}
+
+// ColumnConverter may be optionally implemented by Stmt if the
+// statement is aware of its own columns' types and can convert from
+// any type to a driver Value.
+type ColumnConverter interface {
+	// ColumnConverter returns a ValueConverter for the provided
+	// column index.  If the type of a specific column isn't known
+	// or shouldn't be handled specially, DefaultValueConverter
+	// can be returned.
+	ColumnConverter(idx int) ValueConverter
+}
+
+// Rows is an iterator over an executed query's results.
+type Rows interface {
+	// Columns returns the names of the columns. The number of
+	// columns of the result is inferred from the length of the
+	// slice.  If a particular column name isn't known, an empty
+	// string should be returned for that entry.
+	Columns() []string
+
+	// Close closes the rows iterator.
+	Close() error
+
+	// Next is called to populate the next row of data into
+	// the provided slice. The provided slice will be the same
+	// size as the Columns() are wide.
+	//
+	// The dest slice may be populated only with
+	// a driver Value type, but excluding string.
+	// All string values must be converted to []byte.
+	//
+	// Next should return io.EOF when there are no more rows.
+	Next(dest []Value) error
+}
+
+// Tx is a transaction.
+type Tx interface {
+	Commit() error
+	Rollback() error
+}
+
+// RowsAffected implements Result for an INSERT or UPDATE operation
+// which mutates a number of rows.
+type RowsAffected int64
+
+var _ Result = RowsAffected(0)
+
+func (RowsAffected) LastInsertId() (int64, error) {
+	return 0, errors.New("no LastInsertId available")
+}
+
+func (v RowsAffected) RowsAffected() (int64, error) {
+	return int64(v), nil
+}
+
+// ResultNoRows is a pre-defined Result for drivers to return when a DDL
+// command (such as a CREATE TABLE) succeeds. It returns an error for both
+// LastInsertId and RowsAffected.
+var ResultNoRows noRows
+
+type noRows struct{}
+
+var _ Result = noRows{}
+
+func (noRows) LastInsertId() (int64, error) {
+	return 0, errors.New("no LastInsertId available after DDL statement")
+}
+
+func (noRows) RowsAffected() (int64, error) {
+	return 0, errors.New("no RowsAffected available after DDL statement")
+}

src/database/sql/driver/types.go

@@ -0,0 +1,252 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package driver
+
+import (
+	"fmt"
+	"reflect"
+	"strconv"
+	"time"
+)
+
+// ValueConverter is the interface providing the ConvertValue method.
+//
+// Various implementations of ValueConverter are provided by the
+// driver package to provide consistent implementations of conversions
+// between drivers.  The ValueConverters have several uses:
+//
+//  * converting from the Value types as provided by the sql package
+//    into a database table's specific column type and making sure it
+//    fits, such as making sure a particular int64 fits in a
+//    table's uint16 column.
+//
+//  * converting a value as given from the database into one of the
+//    driver Value types.
+//
+//  * by the sql package, for converting from a driver's Value type
+//    to a user's type in a scan.
+type ValueConverter interface {
+	// ConvertValue converts a value to a driver Value.
+	ConvertValue(v interface{}) (Value, error)
+}
+
+// Valuer is the interface providing the Value method.
+//
+// Types implementing Valuer interface are able to convert
+// themselves to a driver Value.
+type Valuer interface {
+	// Value returns a driver Value.
+	Value() (Value, error)
+}
+
+// Bool is a ValueConverter that converts input values to bools.
+//
+// The conversion rules are:
+//  - booleans are returned unchanged
+//  - for integer types,
+//       1 is true
+//       0 is false,
+//       other integers are an error
+//  - for strings and []byte, same rules as strconv.ParseBool
+//  - all other types are an error
+var Bool boolType
+
+type boolType struct{}
+
+var _ ValueConverter = boolType{}
+
+func (boolType) String() string { return "Bool" }
+
+func (boolType) ConvertValue(src interface{}) (Value, error) {
+	switch s := src.(type) {
+	case bool:
+		return s, nil
+	case string:
+		b, err := strconv.ParseBool(s)
+		if err != nil {
+			return nil, fmt.Errorf("sql/driver: couldn't convert %q into type bool", s)
+		}
+		return b, nil
+	case []byte:
+		b, err := strconv.ParseBool(string(s))
+		if err != nil {
+			return nil, fmt.Errorf("sql/driver: couldn't convert %q into type bool", s)
+		}
+		return b, nil
+	}
+
+	sv := reflect.ValueOf(src)
+	switch sv.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		iv := sv.Int()
+		if iv == 1 || iv == 0 {
+			return iv == 1, nil
+		}
+		return nil, fmt.Errorf("sql/driver: couldn't convert %d into type bool", iv)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		uv := sv.Uint()
+		if uv == 1 || uv == 0 {
+			return uv == 1, nil
+		}
+		return nil, fmt.Errorf("sql/driver: couldn't convert %d into type bool", uv)
+	}
+
+	return nil, fmt.Errorf("sql/driver: couldn't convert %v (%T) into type bool", src, src)
+}
+
+// Int32 is a ValueConverter that converts input values to int64,
+// respecting the limits of an int32 value.
+var Int32 int32Type
+
+type int32Type struct{}
+
+var _ ValueConverter = int32Type{}
+
+func (int32Type) ConvertValue(v interface{}) (Value, error) {
+	rv := reflect.ValueOf(v)
+	switch rv.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		i64 := rv.Int()
+		if i64 > (1<<31)-1 || i64 < -(1<<31) {
+			return nil, fmt.Errorf("sql/driver: value %d overflows int32", v)
+		}
+		return i64, nil
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		u64 := rv.Uint()
+		if u64 > (1<<31)-1 {
+			return nil, fmt.Errorf("sql/driver: value %d overflows int32", v)
+		}
+		return int64(u64), nil
+	case reflect.String:
+		i, err := strconv.Atoi(rv.String())
+		if err != nil {
+			return nil, fmt.Errorf("sql/driver: value %q can't be converted to int32", v)
+		}
+		return int64(i), nil
+	}
+	return nil, fmt.Errorf("sql/driver: unsupported value %v (type %T) converting to int32", v, v)
+}
+
+// String is a ValueConverter that converts its input to a string.
+// If the value is already a string or []byte, it's unchanged.
+// If the value is of another type, conversion to string is done
+// with fmt.Sprintf("%v", v).
+var String stringType
+
+type stringType struct{}
+
+func (stringType) ConvertValue(v interface{}) (Value, error) {
+	switch v.(type) {
+	case string, []byte:
+		return v, nil
+	}
+	return fmt.Sprintf("%v", v), nil
+}
+
+// Null is a type that implements ValueConverter by allowing nil
+// values but otherwise delegating to another ValueConverter.
+type Null struct {
+	Converter ValueConverter
+}
+
+func (n Null) ConvertValue(v interface{}) (Value, error) {
+	if v == nil {
+		return nil, nil
+	}
+	return n.Converter.ConvertValue(v)
+}
+
+// NotNull is a type that implements ValueConverter by disallowing nil
+// values but otherwise delegating to another ValueConverter.
+type NotNull struct {
+	Converter ValueConverter
+}
+
+func (n NotNull) ConvertValue(v interface{}) (Value, error) {
+	if v == nil {
+		return nil, fmt.Errorf("nil value not allowed")
+	}
+	return n.Converter.ConvertValue(v)
+}
+
+// IsValue reports whether v is a valid Value parameter type.
+// Unlike IsScanValue, IsValue permits the string type.
+func IsValue(v interface{}) bool {
+	if IsScanValue(v) {
+		return true
+	}
+	if _, ok := v.(string); ok {
+		return true
+	}
+	return false
+}
+
+// IsScanValue reports whether v is a valid Value scan type.
+// Unlike IsValue, IsScanValue does not permit the string type.
+func IsScanValue(v interface{}) bool {
+	if v == nil {
+		return true
+	}
+	switch v.(type) {
+	case int64, float64, []byte, bool, time.Time:
+		return true
+	}
+	return false
+}
+
+// DefaultParameterConverter is the default implementation of
+// ValueConverter that's used when a Stmt doesn't implement
+// ColumnConverter.
+//
+// DefaultParameterConverter returns the given value directly if
+// IsValue(value).  Otherwise integer type are converted to
+// int64, floats to float64, and strings to []byte.  Other types are
+// an error.
+var DefaultParameterConverter defaultConverter
+
+type defaultConverter struct{}
+
+var _ ValueConverter = defaultConverter{}
+
+func (defaultConverter) ConvertValue(v interface{}) (Value, error) {
+	if IsValue(v) {
+		return v, nil
+	}
+
+	if svi, ok := v.(Valuer); ok {
+		sv, err := svi.Value()
+		if err != nil {
+			return nil, err
+		}
+		if !IsValue(sv) {
+			return nil, fmt.Errorf("non-Value type %T returned from Value", sv)
+		}
+		return sv, nil
+	}
+
+	rv := reflect.ValueOf(v)
+	switch rv.Kind() {
+	case reflect.Ptr:
+		// indirect pointers
+		if rv.IsNil() {
+			return nil, nil
+		} else {
+			return defaultConverter{}.ConvertValue(rv.Elem().Interface())
+		}
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return rv.Int(), nil
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32:
+		return int64(rv.Uint()), nil
+	case reflect.Uint64:
+		u64 := rv.Uint()
+		if u64 >= 1<<63 {
+			return nil, fmt.Errorf("uint64 values with high bit set are not supported")
+		}
+		return int64(u64), nil
+	case reflect.Float32, reflect.Float64:
+		return rv.Float(), nil
+	}
+	return nil, fmt.Errorf("unsupported type %T, a %s", v, rv.Kind())
+}

src/database/sql/driver/types_test.go

@@ -0,0 +1,65 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package driver
+
+import (
+	"reflect"
+	"testing"
+	"time"
+)
+
+type valueConverterTest struct {
+	c   ValueConverter
+	in  interface{}
+	out interface{}
+	err string
+}
+
+var now = time.Now()
+var answer int64 = 42
+
+var valueConverterTests = []valueConverterTest{
+	{Bool, "true", true, ""},
+	{Bool, "True", true, ""},
+	{Bool, []byte("t"), true, ""},
+	{Bool, true, true, ""},
+	{Bool, "1", true, ""},
+	{Bool, 1, true, ""},
+	{Bool, int64(1), true, ""},
+	{Bool, uint16(1), true, ""},
+	{Bool, "false", false, ""},
+	{Bool, false, false, ""},
+	{Bool, "0", false, ""},
+	{Bool, 0, false, ""},
+	{Bool, int64(0), false, ""},
+	{Bool, uint16(0), false, ""},
+	{c: Bool, in: "foo", err: "sql/driver: couldn't convert \"foo\" into type bool"},
+	{c: Bool, in: 2, err: "sql/driver: couldn't convert 2 into type bool"},
+	{DefaultParameterConverter, now, now, ""},
+	{DefaultParameterConverter, (*int64)(nil), nil, ""},
+	{DefaultParameterConverter, &answer, answer, ""},
+	{DefaultParameterConverter, &now, now, ""},
+}
+
+func TestValueConverters(t *testing.T) {
+	for i, tt := range valueConverterTests {
+		out, err := tt.c.ConvertValue(tt.in)
+		goterr := ""
+		if err != nil {
+			goterr = err.Error()
+		}
+		if goterr != tt.err {
+			t.Errorf("test %d: %T(%T(%v)) error = %q; want error = %q",
+				i, tt.c, tt.in, tt.in, goterr, tt.err)
+		}
+		if tt.err != "" {
+			continue
+		}
+		if !reflect.DeepEqual(out, tt.out) {
+			t.Errorf("test %d: %T(%T(%v)) = %v (%T); want %v (%T)",
+				i, tt.c, tt.in, tt.in, out, out, tt.out, tt.out)
+		}
+	}
+}

src/database/sql/example_test.go

@@ -0,0 +1,46 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sql_test
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+)
+
+var db *sql.DB
+
+func ExampleDB_Query() {
+	age := 27
+	rows, err := db.Query("SELECT name FROM users WHERE age=?", age)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var name string
+		if err := rows.Scan(&name); err != nil {
+			log.Fatal(err)
+		}
+		fmt.Printf("%s is %d\n", name, age)
+	}
+	if err := rows.Err(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func ExampleDB_QueryRow() {
+	id := 123
+	var username string
+	err := db.QueryRow("SELECT username FROM users WHERE id=?", id).Scan(&username)
+	switch {
+	case err == sql.ErrNoRows:
+		log.Printf("No user with that ID.")
+	case err != nil:
+		log.Fatal(err)
+	default:
+		fmt.Printf("Username is %s\n", username)
+	}
+}

src/database/sql/fakedb_test.go

@@ -0,0 +1,805 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sql
+
+import (
+	"database/sql/driver"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"strconv"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+)
+
+var _ = log.Printf
+
+// fakeDriver is a fake database that implements Go's driver.Driver
+// interface, just for testing.
+//
+// It speaks a query language that's semantically similar to but
+// syntactically different and simpler than SQL.  The syntax is as
+// follows:
+//
+//   WIPE
+//   CREATE|<tablename>|<col>=<type>,<col>=<type>,...
+//     where types are: "string", [u]int{8,16,32,64}, "bool"
+//   INSERT|<tablename>|col=val,col2=val2,col3=?
+//   SELECT|<tablename>|projectcol1,projectcol2|filtercol=?,filtercol2=?
+//
+// When opening a fakeDriver's database, it starts empty with no
+// tables.  All tables and data are stored in memory only.
+type fakeDriver struct {
+	mu         sync.Mutex // guards 3 following fields
+	openCount  int        // conn opens
+	closeCount int        // conn closes
+	waitCh     chan struct{}
+	waitingCh  chan struct{}
+	dbs        map[string]*fakeDB
+}
+
+type fakeDB struct {
+	name string
+
+	mu      sync.Mutex
+	free    []*fakeConn
+	tables  map[string]*table
+	badConn bool
+}
+
+type table struct {
+	mu      sync.Mutex
+	colname []string
+	coltype []string
+	rows    []*row
+}
+
+func (t *table) columnIndex(name string) int {
+	for n, nname := range t.colname {
+		if name == nname {
+			return n
+		}
+	}
+	return -1
+}
+
+type row struct {
+	cols []interface{} // must be same size as its table colname + coltype
+}
+
+func (r *row) clone() *row {
+	nrow := &row{cols: make([]interface{}, len(r.cols))}
+	copy(nrow.cols, r.cols)
+	return nrow
+}
+
+type fakeConn struct {
+	db *fakeDB // where to return ourselves to
+
+	currTx *fakeTx
+
+	// Stats for tests:
+	mu          sync.Mutex
+	stmtsMade   int
+	stmtsClosed int
+	numPrepare  int
+	bad         bool
+}
+
+func (c *fakeConn) incrStat(v *int) {
+	c.mu.Lock()
+	*v++
+	c.mu.Unlock()
+}
+
+type fakeTx struct {
+	c *fakeConn
+}
+
+type fakeStmt struct {
+	c *fakeConn
+	q string // just for debugging
+
+	cmd   string
+	table string
+
+	closed bool
+
+	colName      []string      // used by CREATE, INSERT, SELECT (selected columns)
+	colType      []string      // used by CREATE
+	colValue     []interface{} // used by INSERT (mix of strings and "?" for bound params)
+	placeholders int           // used by INSERT/SELECT: number of ? params
+
+	whereCol []string // used by SELECT (all placeholders)
+
+	placeholderConverter []driver.ValueConverter // used by INSERT
+}
+
+var fdriver driver.Driver = &fakeDriver{}
+
+func init() {
+	Register("test", fdriver)
+}
+
+// Supports dsn forms:
+//    <dbname>
+//    <dbname>;<opts>  (only currently supported option is `badConn`,
+//                      which causes driver.ErrBadConn to be returned on
+//                      every other conn.Begin())
+func (d *fakeDriver) Open(dsn string) (driver.Conn, error) {
+	parts := strings.Split(dsn, ";")
+	if len(parts) < 1 {
+		return nil, errors.New("fakedb: no database name")
+	}
+	name := parts[0]
+
+	db := d.getDB(name)
+
+	d.mu.Lock()
+	d.openCount++
+	d.mu.Unlock()
+	conn := &fakeConn{db: db}
+
+	if len(parts) >= 2 && parts[1] == "badConn" {
+		conn.bad = true
+	}
+	if d.waitCh != nil {
+		d.waitingCh <- struct{}{}
+		<-d.waitCh
+		d.waitCh = nil
+		d.waitingCh = nil
+	}
+	return conn, nil
+}
+
+func (d *fakeDriver) getDB(name string) *fakeDB {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if d.dbs == nil {
+		d.dbs = make(map[string]*fakeDB)
+	}
+	db, ok := d.dbs[name]
+	if !ok {
+		db = &fakeDB{name: name}
+		d.dbs[name] = db
+	}
+	return db
+}
+
+func (db *fakeDB) wipe() {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+	db.tables = nil
+}
+
+func (db *fakeDB) createTable(name string, columnNames, columnTypes []string) error {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+	if db.tables == nil {
+		db.tables = make(map[string]*table)
+	}
+	if _, exist := db.tables[name]; exist {
+		return fmt.Errorf("table %q already exists", name)
+	}
+	if len(columnNames) != len(columnTypes) {
+		return fmt.Errorf("create table of %q len(names) != len(types): %d vs %d",
+			name, len(columnNames), len(columnTypes))
+	}
+	db.tables[name] = &table{colname: columnNames, coltype: columnTypes}
+	return nil
+}
+
+// must be called with db.mu lock held
+func (db *fakeDB) table(table string) (*table, bool) {
+	if db.tables == nil {
+		return nil, false
+	}
+	t, ok := db.tables[table]
+	return t, ok
+}
+
+func (db *fakeDB) columnType(table, column string) (typ string, ok bool) {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+	t, ok := db.table(table)
+	if !ok {
+		return
+	}
+	for n, cname := range t.colname {
+		if cname == column {
+			return t.coltype[n], true
+		}
+	}
+	return "", false
+}
+
+func (c *fakeConn) isBad() bool {
+	// if not simulating bad conn, do nothing
+	if !c.bad {
+		return false
+	}
+	// alternate between bad conn and not bad conn
+	c.db.badConn = !c.db.badConn
+	return c.db.badConn
+}
+
+func (c *fakeConn) Begin() (driver.Tx, error) {
+	if c.isBad() {
+		return nil, driver.ErrBadConn
+	}
+	if c.currTx != nil {
+		return nil, errors.New("already in a transaction")
+	}
+	c.currTx = &fakeTx{c: c}
+	return c.currTx, nil
+}
+
+var hookPostCloseConn struct {
+	sync.Mutex
+	fn func(*fakeConn, error)
+}
+
+func setHookpostCloseConn(fn func(*fakeConn, error)) {
+	hookPostCloseConn.Lock()
+	defer hookPostCloseConn.Unlock()
+	hookPostCloseConn.fn = fn
+}
+
+var testStrictClose *testing.T
+
+// setStrictFakeConnClose sets the t to Errorf on when fakeConn.Close
+// fails to close. If nil, the check is disabled.
+func setStrictFakeConnClose(t *testing.T) {
+	testStrictClose = t
+}
+
+func (c *fakeConn) Close() (err error) {
+	drv := fdriver.(*fakeDriver)
+	defer func() {
+		if err != nil && testStrictClose != nil {
+			testStrictClose.Errorf("failed to close a test fakeConn: %v", err)
+		}
+		hookPostCloseConn.Lock()
+		fn := hookPostCloseConn.fn
+		hookPostCloseConn.Unlock()
+		if fn != nil {
+			fn(c, err)
+		}
+		if err == nil {
+			drv.mu.Lock()
+			drv.closeCount++
+			drv.mu.Unlock()
+		}
+	}()
+	if c.currTx != nil {
+		return errors.New("can't close fakeConn; in a Transaction")
+	}
+	if c.db == nil {
+		return errors.New("can't close fakeConn; already closed")
+	}
+	if c.stmtsMade > c.stmtsClosed {
+		return errors.New("can't close; dangling statement(s)")
+	}
+	c.db = nil
+	return nil
+}
+
+func checkSubsetTypes(args []driver.Value) error {
+	for n, arg := range args {
+		switch arg.(type) {
+		case int64, float64, bool, nil, []byte, string, time.Time:
+		default:
+			return fmt.Errorf("fakedb_test: invalid argument #%d: %v, type %T", n+1, arg, arg)
+		}
+	}
+	return nil
+}
+
+func (c *fakeConn) Exec(query string, args []driver.Value) (driver.Result, error) {
+	// This is an optional interface, but it's implemented here
+	// just to check that all the args are of the proper types.
+	// ErrSkip is returned so the caller acts as if we didn't
+	// implement this at all.
+	err := checkSubsetTypes(args)
+	if err != nil {
+		return nil, err
+	}
+	return nil, driver.ErrSkip
+}
+
+func (c *fakeConn) Query(query string, args []driver.Value) (driver.Rows, error) {
+	// This is an optional interface, but it's implemented here
+	// just to check that all the args are of the proper types.
+	// ErrSkip is returned so the caller acts as if we didn't
+	// implement this at all.
+	err := checkSubsetTypes(args)
+	if err != nil {
+		return nil, err
+	}
+	return nil, driver.ErrSkip
+}
+
+func errf(msg string, args ...interface{}) error {
+	return errors.New("fakedb: " + fmt.Sprintf(msg, args...))
+}
+
+// parts are table|selectCol1,selectCol2|whereCol=?,whereCol2=?
+// (note that where columns must always contain ? marks,
+//  just a limitation for fakedb)
+func (c *fakeConn) prepareSelect(stmt *fakeStmt, parts []string) (driver.Stmt, error) {
+	if len(parts) != 3 {
+		stmt.Close()
+		return nil, errf("invalid SELECT syntax with %d parts; want 3", len(parts))
+	}
+	stmt.table = parts[0]
+	stmt.colName = strings.Split(parts[1], ",")
+	for n, colspec := range strings.Split(parts[2], ",") {
+		if colspec == "" {
+			continue
+		}
+		nameVal := strings.Split(colspec, "=")
+		if len(nameVal) != 2 {
+			stmt.Close()
+			return nil, errf("SELECT on table %q has invalid column spec of %q (index %d)", stmt.table, colspec, n)
+		}
+		column, value := nameVal[0], nameVal[1]
+		_, ok := c.db.columnType(stmt.table, column)
+		if !ok {
+			stmt.Close()
+			return nil, errf("SELECT on table %q references non-existent column %q", stmt.table, column)
+		}
+		if value != "?" {
+			stmt.Close()
+			return nil, errf("SELECT on table %q has pre-bound value for where column %q; need a question mark",
+				stmt.table, column)
+		}
+		stmt.whereCol = append(stmt.whereCol, column)
+		stmt.placeholders++
+	}
+	return stmt, nil
+}
+
+// parts are table|col=type,col2=type2
+func (c *fakeConn) prepareCreate(stmt *fakeStmt, parts []string) (driver.Stmt, error) {
+	if len(parts) != 2 {
+		stmt.Close()
+		return nil, errf("invalid CREATE syntax with %d parts; want 2", len(parts))
+	}
+	stmt.table = parts[0]
+	for n, colspec := range strings.Split(parts[1], ",") {
+		nameType := strings.Split(colspec, "=")
+		if len(nameType) != 2 {
+			stmt.Close()
+			return nil, errf("CREATE table %q has invalid column spec of %q (index %d)", stmt.table, colspec, n)
+		}
+		stmt.colName = append(stmt.colName, nameType[0])
+		stmt.colType = append(stmt.colType, nameType[1])
+	}
+	return stmt, nil
+}
+
+// parts are table|col=?,col2=val
+func (c *fakeConn) prepareInsert(stmt *fakeStmt, parts []string) (driver.Stmt, error) {
+	if len(parts) != 2 {
+		stmt.Close()
+		return nil, errf("invalid INSERT syntax with %d parts; want 2", len(parts))
+	}
+	stmt.table = parts[0]
+	for n, colspec := range strings.Split(parts[1], ",") {
+		nameVal := strings.Split(colspec, "=")
+		if len(nameVal) != 2 {
+			stmt.Close()
+			return nil, errf("INSERT table %q has invalid column spec of %q (index %d)", stmt.table, colspec, n)
+		}
+		column, value := nameVal[0], nameVal[1]
+		ctype, ok := c.db.columnType(stmt.table, column)
+		if !ok {
+			stmt.Close()
+			return nil, errf("INSERT table %q references non-existent column %q", stmt.table, column)
+		}
+		stmt.colName = append(stmt.colName, column)
+
+		if value != "?" {
+			var subsetVal interface{}
+			// Convert to driver subset type
+			switch ctype {
+			case "string":
+				subsetVal = []byte(value)
+			case "blob":
+				subsetVal = []byte(value)
+			case "int32":
+				i, err := strconv.Atoi(value)
+				if err != nil {
+					stmt.Close()
+					return nil, errf("invalid conversion to int32 from %q", value)
+				}
+				subsetVal = int64(i) // int64 is a subset type, but not int32
+			default:
+				stmt.Close()
+				return nil, errf("unsupported conversion for pre-bound parameter %q to type %q", value, ctype)
+			}
+			stmt.colValue = append(stmt.colValue, subsetVal)
+		} else {
+			stmt.placeholders++
+			stmt.placeholderConverter = append(stmt.placeholderConverter, converterForType(ctype))
+			stmt.colValue = append(stmt.colValue, "?")
+		}
+	}
+	return stmt, nil
+}
+
+// hook to simulate broken connections
+var hookPrepareBadConn func() bool
+
+func (c *fakeConn) Prepare(query string) (driver.Stmt, error) {
+	c.numPrepare++
+	if c.db == nil {
+		panic("nil c.db; conn = " + fmt.Sprintf("%#v", c))
+	}
+
+	if hookPrepareBadConn != nil && hookPrepareBadConn() {
+		return nil, driver.ErrBadConn
+	}
+
+	parts := strings.Split(query, "|")
+	if len(parts) < 1 {
+		return nil, errf("empty query")
+	}
+	cmd := parts[0]
+	parts = parts[1:]
+	stmt := &fakeStmt{q: query, c: c, cmd: cmd}
+	c.incrStat(&c.stmtsMade)
+	switch cmd {
+	case "WIPE":
+		// Nothing
+	case "SELECT":
+		return c.prepareSelect(stmt, parts)
+	case "CREATE":
+		return c.prepareCreate(stmt, parts)
+	case "INSERT":
+		return c.prepareInsert(stmt, parts)
+	case "NOSERT":
+		// Do all the prep-work like for an INSERT but don't actually insert the row.
+		// Used for some of the concurrent tests.
+		return c.prepareInsert(stmt, parts)
+	default:
+		stmt.Close()
+		return nil, errf("unsupported command type %q", cmd)
+	}
+	return stmt, nil
+}
+
+func (s *fakeStmt) ColumnConverter(idx int) driver.ValueConverter {
+	if len(s.placeholderConverter) == 0 {
+		return driver.DefaultParameterConverter
+	}
+	return s.placeholderConverter[idx]
+}
+
+func (s *fakeStmt) Close() error {
+	if s.c == nil {
+		panic("nil conn in fakeStmt.Close")
+	}
+	if s.c.db == nil {
+		panic("in fakeStmt.Close, conn's db is nil (already closed)")
+	}
+	if !s.closed {
+		s.c.incrStat(&s.c.stmtsClosed)
+		s.closed = true
+	}
+	return nil
+}
+
+var errClosed = errors.New("fakedb: statement has been closed")
+
+// hook to simulate broken connections
+var hookExecBadConn func() bool
+
+func (s *fakeStmt) Exec(args []driver.Value) (driver.Result, error) {
+	if s.closed {
+		return nil, errClosed
+	}
+
+	if hookExecBadConn != nil && hookExecBadConn() {
+		return nil, driver.ErrBadConn
+	}
+
+	err := checkSubsetTypes(args)
+	if err != nil {
+		return nil, err
+	}
+
+	db := s.c.db
+	switch s.cmd {
+	case "WIPE":
+		db.wipe()
+		return driver.ResultNoRows, nil
+	case "CREATE":
+		if err := db.createTable(s.table, s.colName, s.colType); err != nil {
+			return nil, err
+		}
+		return driver.ResultNoRows, nil
+	case "INSERT":
+		return s.execInsert(args, true)
+	case "NOSERT":
+		// Do all the prep-work like for an INSERT but don't actually insert the row.
+		// Used for some of the concurrent tests.
+		return s.execInsert(args, false)
+	}
+	fmt.Printf("EXEC statement, cmd=%q: %#v\n", s.cmd, s)
+	return nil, fmt.Errorf("unimplemented statement Exec command type of %q", s.cmd)
+}
+
+// When doInsert is true, add the row to the table.
+// When doInsert is false do prep-work and error checking, but don't
+// actually add the row to the table.
+func (s *fakeStmt) execInsert(args []driver.Value, doInsert bool) (driver.Result, error) {
+	db := s.c.db
+	if len(args) != s.placeholders {
+		panic("error in pkg db; should only get here if size is correct")
+	}
+	db.mu.Lock()
+	t, ok := db.table(s.table)
+	db.mu.Unlock()
+	if !ok {
+		return nil, fmt.Errorf("fakedb: table %q doesn't exist", s.table)
+	}
+
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	var cols []interface{}
+	if doInsert {
+		cols = make([]interface{}, len(t.colname))
+	}
+	argPos := 0
+	for n, colname := range s.colName {
+		colidx := t.columnIndex(colname)
+		if colidx == -1 {
+			return nil, fmt.Errorf("fakedb: column %q doesn't exist or dropped since prepared statement was created", colname)
+		}
+		var val interface{}
+		if strvalue, ok := s.colValue[n].(string); ok && strvalue == "?" {
+			val = args[argPos]
+			argPos++
+		} else {
+			val = s.colValue[n]
+		}
+		if doInsert {
+			cols[colidx] = val
+		}
+	}
+
+	if doInsert {
+		t.rows = append(t.rows, &row{cols: cols})
+	}
+	return driver.RowsAffected(1), nil
+}
+
+// hook to simulate broken connections
+var hookQueryBadConn func() bool
+
+func (s *fakeStmt) Query(args []driver.Value) (driver.Rows, error) {
+	if s.closed {
+		return nil, errClosed
+	}
+
+	if hookQueryBadConn != nil && hookQueryBadConn() {
+		return nil, driver.ErrBadConn
+	}
+
+	err := checkSubsetTypes(args)
+	if err != nil {
+		return nil, err
+	}
+
+	db := s.c.db
+	if len(args) != s.placeholders {
+		panic("error in pkg db; should only get here if size is correct")
+	}
+
+	db.mu.Lock()
+	t, ok := db.table(s.table)
+	db.mu.Unlock()
+	if !ok {
+		return nil, fmt.Errorf("fakedb: table %q doesn't exist", s.table)
+	}
+
+	if s.table == "magicquery" {
+		if len(s.whereCol) == 2 && s.whereCol[0] == "op" && s.whereCol[1] == "millis" {
+			if args[0] == "sleep" {
+				time.Sleep(time.Duration(args[1].(int64)) * time.Millisecond)
+			}
+		}
+	}
+
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	colIdx := make(map[string]int) // select column name -> column index in table
+	for _, name := range s.colName {
+		idx := t.columnIndex(name)
+		if idx == -1 {
+			return nil, fmt.Errorf("fakedb: unknown column name %q", name)
+		}
+		colIdx[name] = idx
+	}
+
+	mrows := []*row{}
+rows:
+	for _, trow := range t.rows {
+		// Process the where clause, skipping non-match rows. This is lazy
+		// and just uses fmt.Sprintf("%v") to test equality.  Good enough
+		// for test code.
+		for widx, wcol := range s.whereCol {
+			idx := t.columnIndex(wcol)
+			if idx == -1 {
+				return nil, fmt.Errorf("db: invalid where clause column %q", wcol)
+			}
+			tcol := trow.cols[idx]
+			if bs, ok := tcol.([]byte); ok {
+				// lazy hack to avoid sprintf %v on a []byte
+				tcol = string(bs)
+			}
+			if fmt.Sprintf("%v", tcol) != fmt.Sprintf("%v", args[widx]) {
+				continue rows
+			}
+		}
+		mrow := &row{cols: make([]interface{}, len(s.colName))}
+		for seli, name := range s.colName {
+			mrow.cols[seli] = trow.cols[colIdx[name]]
+		}
+		mrows = append(mrows, mrow)
+	}
+
+	cursor := &rowsCursor{
+		pos:    -1,
+		rows:   mrows,
+		cols:   s.colName,
+		errPos: -1,
+	}
+	return cursor, nil
+}
+
+func (s *fakeStmt) NumInput() int {
+	return s.placeholders
+}
+
+func (tx *fakeTx) Commit() error {
+	tx.c.currTx = nil
+	return nil
+}
+
+func (tx *fakeTx) Rollback() error {
+	tx.c.currTx = nil
+	return nil
+}
+
+type rowsCursor struct {
+	cols   []string
+	pos    int
+	rows   []*row
+	closed bool
+
+	// errPos and err are for making Next return early with error.
+	errPos int
+	err    error
+
+	// a clone of slices to give out to clients, indexed by the
+	// the original slice's first byte address.  we clone them
+	// just so we're able to corrupt them on close.
+	bytesClone map[*byte][]byte
+}
+
+func (rc *rowsCursor) Close() error {
+	if !rc.closed {
+		for _, bs := range rc.bytesClone {
+			bs[0] = 255 // first byte corrupted
+		}
+	}
+	rc.closed = true
+	return nil
+}
+
+func (rc *rowsCursor) Columns() []string {
+	return rc.cols
+}
+
+var rowsCursorNextHook func(dest []driver.Value) error
+
+func (rc *rowsCursor) Next(dest []driver.Value) error {
+	if rowsCursorNextHook != nil {
+		return rowsCursorNextHook(dest)
+	}
+
+	if rc.closed {
+		return errors.New("fakedb: cursor is closed")
+	}
+	rc.pos++
+	if rc.pos == rc.errPos {
+		return rc.err
+	}
+	if rc.pos >= len(rc.rows) {
+		return io.EOF // per interface spec
+	}
+	for i, v := range rc.rows[rc.pos].cols {
+		// TODO(bradfitz): convert to subset types? naah, I
+		// think the subset types should only be input to
+		// driver, but the sql package should be able to handle
+		// a wider range of types coming out of drivers. all
+		// for ease of drivers, and to prevent drivers from
+		// messing up conversions or doing them differently.
+		dest[i] = v
+
+		if bs, ok := v.([]byte); ok {
+			if rc.bytesClone == nil {
+				rc.bytesClone = make(map[*byte][]byte)
+			}
+			clone, ok := rc.bytesClone[&bs[0]]
+			if !ok {
+				clone = make([]byte, len(bs))
+				copy(clone, bs)
+				rc.bytesClone[&bs[0]] = clone
+			}
+			dest[i] = clone
+		}
+	}
+	return nil
+}
+
+// fakeDriverString is like driver.String, but indirects pointers like
+// DefaultValueConverter.
+//
+// This could be surprising behavior to retroactively apply to
+// driver.String now that Go1 is out, but this is convenient for
+// our TestPointerParamsAndScans.
+//
+type fakeDriverString struct{}
+
+func (fakeDriverString) ConvertValue(v interface{}) (driver.Value, error) {
+	switch c := v.(type) {
+	case string, []byte:
+		return v, nil
+	case *string:
+		if c == nil {
+			return nil, nil
+		}
+		return *c, nil
+	}
+	return fmt.Sprintf("%v", v), nil
+}
+
+func converterForType(typ string) driver.ValueConverter {
+	switch typ {
+	case "bool":
+		return driver.Bool
+	case "nullbool":
+		return driver.Null{Converter: driver.Bool}
+	case "int32":
+		return driver.Int32
+	case "string":
+		return driver.NotNull{Converter: fakeDriverString{}}
+	case "nullstring":
+		return driver.Null{Converter: fakeDriverString{}}
+	case "int64":
+		// TODO(coopernurse): add type-specific converter
+		return driver.NotNull{Converter: driver.DefaultParameterConverter}
+	case "nullint64":
+		// TODO(coopernurse): add type-specific converter
+		return driver.Null{Converter: driver.DefaultParameterConverter}
+	case "float64":
+		// TODO(coopernurse): add type-specific converter
+		return driver.NotNull{Converter: driver.DefaultParameterConverter}
+	case "nullfloat64":
+		// TODO(coopernurse): add type-specific converter
+		return driver.Null{Converter: driver.DefaultParameterConverter}
+	case "datetime":
+		return driver.DefaultParameterConverter
+	}
+	panic("invalid fakedb column type of " + typ)
+}