libgo: Update to weekly.2012-01-20.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@183540 138bc75d-0d04-0410-961f-82ee72b054a4

8 files changed, 2786 insertions, 0 deletions

diff --git a/libgo/go/database/sql/convert.go b/libgo/go/database/sql/convert.go
new file mode 100644
index 00000000000..9835e38de7e
--- /dev/null
+++ b/libgo/go/database/sql/convert.go
@@ -0,0 +1,133 @@
+// 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"
+)
+
+// subsetTypeArgs takes a slice of arguments from callers of the sql
+// package and converts them into a slice of the driver package's
+// "subset types".
+func subsetTypeArgs(args []interface{}) ([]interface{}, error) {
+	out := make([]interface{}, len(args))
+	for n, arg := range args {
+		var err error
+		out[n], err = driver.DefaultParameterConverter.ConvertValue(arg)
+		if err != nil {
+			return nil, fmt.Errorf("sql: converting argument #%d's type: %v", n+1, err)
+		}
+	}
+	return out, 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.  Fall through.
+	switch s := src.(type) {
+	case string:
+		switch d := dest.(type) {
+		case *string:
+			*d = s
+			return nil
+		}
+	case []byte:
+		switch d := dest.(type) {
+		case *string:
+			*d = string(s)
+			return nil
+		case *[]byte:
+			*d = s
+			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 = fmt.Sprintf("%v", src)
+			return nil
+		}
+	case *bool:
+		bv, err := driver.Bool.ConvertValue(src)
+		if err == nil {
+			*d = bv.(bool)
+		}
+		return err
+	}
+
+	if scanner, ok := dest.(ScannerInto); ok {
+		return scanner.ScanInto(src)
+	}
+
+	dpv := reflect.ValueOf(dest)
+	if dpv.Kind() != reflect.Ptr {
+		return errors.New("destination not a pointer")
+	}
+
+	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.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 asString(src interface{}) string {
+	switch v := src.(type) {
+	case string:
+		return v
+	case []byte:
+		return string(v)
+	}
+	return fmt.Sprintf("%v", src)
+}
diff --git a/libgo/go/database/sql/convert_test.go b/libgo/go/database/sql/convert_test.go
new file mode 100644
index 00000000000..b188864f623
--- /dev/null
+++ b/libgo/go/database/sql/convert_test.go
@@ -0,0 +1,206 @@
+// 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"
+	"testing"
+	"time"
+)
+
+var someTime = time.Unix(123, 0)
+
+type conversionTest struct {
+	s, d interface{} // source and destination
+
+	// following are used if they're non-zero
+	wantint  int64
+	wantuint uint64
+	wantstr  string
+	wantf32  float32
+	wantf64  float64
+	wanttime time.Time
+	wantbool bool // used if d is of type *bool
+	wanterr  string
+}
+
+// Target variables for scanning into.
+var (
+	scanstr    string
+	scanint    int
+	scanint8   int8
+	scanint16  int16
+	scanint32  int32
+	scanuint8  uint8
+	scanuint16 uint16
+	scanbool   bool
+	scanf32    float32
+	scanf64    float64
+	scantime   time.Time
+)
+
+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: []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"},
+
+	// 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)},
+}
+
+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))
+		}
+	}
+}
+
+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: %s(%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: %s(%T(%v)) = %v (%T); want %v (%T)",
+				i, tt.c, tt.in, tt.in, out, out, tt.out, tt.out)
+		}
+	}
+}
diff --git a/libgo/go/database/sql/driver/driver.go b/libgo/go/database/sql/driver/driver.go
new file mode 100644
index 00000000000..0cd2562d682
--- /dev/null
+++ b/libgo/go/database/sql/driver/driver.go
@@ -0,0 +1,207 @@
+// 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.
+//
+// Code simply using databases should use package sql.
+//
+// Drivers only need to be aware of a subset of Go's types.  The sql package
+// will convert all types into one of the following:
+//
+//   int64
+//   float64
+//   bool
+//   nil
+//   []byte
+//   string   [*] everywhere except from Rows.Next.
+//   time.Time
+//
+package driver
+
+import "errors"
+
+// 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")
+
+// Execer is an optional interface that may be implemented by a Conn.
+//
+// If a Conn does not implement Execer, the db package's DB.Exec will
+// first prepare a query, execute the statement, and then close the
+// statement.
+//
+// All arguments are of a subset type as defined in the package docs.
+//
+// Exec may return ErrSkip.
+type Execer interface {
+	Exec(query string, args []interface{}) (Result, 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.
+	//
+	// Closing a statement should not interrupt any outstanding
+	// query created from that statement. That is, the following
+	// order of operations is valid:
+	//
+	//  * create a driver statement
+	//  * call Query on statement, returning Rows
+	//  * close the statement
+	//  * read from Rows
+	//
+	// If closing a statement invalidates currently-running
+	// queries, the final step above will incorrectly fail.
+	//
+	// TODO(bradfitz): possibly remove the restriction above, if
+	// enough driver authors object and find it complicates their
+	// code too much. The sql package could be smarter about
+	// refcounting the statement and closing it at the appropriate
+	// time.
+	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.  The args are all of a subset
+	// type as defined above.
+	Exec(args []interface{}) (Result, error)
+
+	// Exec executes a query that may return rows, such as a
+	// SELECT.  The args of all of a subset type as defined above.
+	Query(args []interface{}) (Rows, error)
+}
+
+// ColumnConverter may be optionally implemented by Stmt if the
+// the statement is aware of its own columns' types and can
+// convert from any type to a driver subset type.
+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 with only with values
+	// of subset types defined above, but excluding string.
+	// All string values must be converted to []byte.
+	//
+	// Next should return io.EOF when there are no more rows.
+	Next(dest []interface{}) 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
+}
+
+// DDLSuccess is a pre-defined Result for drivers to return when a DDL
+// command succeeds.
+var DDLSuccess ddlSuccess
+
+type ddlSuccess struct{}
+
+var _ Result = ddlSuccess{}
+
+func (ddlSuccess) LastInsertId() (int64, error) {
+	return 0, errors.New("no LastInsertId available after DDL statement")
+}
+
+func (ddlSuccess) RowsAffected() (int64, error) {
+	return 0, errors.New("no RowsAffected available after DDL statement")
+}
diff --git a/libgo/go/database/sql/driver/types.go b/libgo/go/database/sql/driver/types.go
new file mode 100644
index 00000000000..f3838852311
--- /dev/null
+++ b/libgo/go/database/sql/driver/types.go
@@ -0,0 +1,265 @@
+// 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 subset 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
+//    subset types.
+//
+//  * by the sql package, for converting from a driver's subset type
+//    to a user's type in a scan.
+type ValueConverter interface {
+	// ConvertValue converts a value to a restricted subset type.
+	ConvertValue(v interface{}) (interface{}, error)
+}
+
+// SubsetValuer is the interface providing the SubsetValue method.
+//
+// Types implementing SubsetValuer interface are able to convert
+// themselves to one of the driver's allowed subset values.
+type SubsetValuer interface {
+	// SubsetValue returns a driver parameter subset value.
+	SubsetValue() (interface{}, 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{}) (interface{}, 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{}) (interface{}, 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{}) (interface{}, 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{}) (interface{}, 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{}) (interface{}, error) {
+	if v == nil {
+		return nil, fmt.Errorf("nil value not allowed")
+	}
+	return n.Converter.ConvertValue(v)
+}
+
+// IsParameterSubsetType reports whether v is of a valid type for a
+// parameter. These types are:
+//
+//   int64
+//   float64
+//   bool
+//   nil
+//   []byte
+//   time.Time
+//   string
+//
+// This is the same list as IsScanSubsetType, with the addition of
+// string.
+func IsParameterSubsetType(v interface{}) bool {
+	if IsScanSubsetType(v) {
+		return true
+	}
+	if _, ok := v.(string); ok {
+		return true
+	}
+	return false
+}
+
+// IsScanSubsetType reports whether v is of a valid type for a
+// value populated by Rows.Next. These types are:
+//
+//   int64
+//   float64
+//   bool
+//   nil
+//   []byte
+//   time.Time
+//
+// This is the same list as IsParameterSubsetType, without string.
+func IsScanSubsetType(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
+// IsSubsetType(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{}) (interface{}, error) {
+	if IsParameterSubsetType(v) {
+		return v, nil
+	}
+
+	if svi, ok := v.(SubsetValuer); ok {
+		sv, err := svi.SubsetValue()
+		if err != nil {
+			return nil, err
+		}
+		if !IsParameterSubsetType(sv) {
+			return nil, fmt.Errorf("non-subset type %T returned from SubsetValue", sv)
+		}
+		return sv, nil
+	}
+
+	rv := reflect.ValueOf(v)
+	switch rv.Kind() {
+	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())
+}
diff --git a/libgo/go/database/sql/driver/types_test.go b/libgo/go/database/sql/driver/types_test.go
new file mode 100644
index 00000000000..966bc6b4587
--- /dev/null
+++ b/libgo/go/database/sql/driver/types_test.go
@@ -0,0 +1,61 @@
+// 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 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, ""},
+}
+
+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: %s(%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: %s(%T(%v)) = %v (%T); want %v (%T)",
+				i, tt.c, tt.in, tt.in, out, out, tt.out, tt.out)
+		}
+	}
+}
diff --git a/libgo/go/database/sql/fakedb_test.go b/libgo/go/database/sql/fakedb_test.go
new file mode 100644
index 00000000000..b0d137cd715
--- /dev/null
+++ b/libgo/go/database/sql/fakedb_test.go
@@ -0,0 +1,598 @@
+// 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"
+	"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
+// syntantically 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 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
+	openCount int
+	dbs       map[string]*fakeDB
+}
+
+type fakeDB struct {
+	name string
+
+	mu     sync.Mutex
+	free   []*fakeConn
+	tables map[string]*table
+}
+
+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
+}
+
+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>  (no currently supported options)
+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()
+	return &fakeConn{db: db}, 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) Begin() (driver.Tx, error) {
+	if c.currTx != nil {
+		return nil, errors.New("already in a transaction")
+	}
+	c.currTx = &fakeTx{c: c}
+	return c.currTx, nil
+}
+
+func (c *fakeConn) Close() error {
+	if c.currTx != nil {
+		return errors.New("can't close; in a Transaction")
+	}
+	if c.db == nil {
+		return errors.New("can't close; already closed")
+	}
+	c.db = nil
+	return nil
+}
+
+func checkSubsetTypes(args []interface{}) 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 []interface{}) (driver.Result, error) {
+	// This is an optional interface, but it's implemented here
+	// just to check that all the args of 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 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 {
+		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 {
+			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 {
+			return nil, errf("SELECT on table %q references non-existent column %q", stmt.table, column)
+		}
+		if value != "?" {
+			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 {
+		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 {
+			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 {
+		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 {
+			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 {
+			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 {
+					return nil, errf("invalid conversion to int32 from %q", value)
+				}
+				subsetVal = int64(i) // int64 is a subset type, but not int32
+			default:
+				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
+}
+
+func (c *fakeConn) Prepare(query string) (driver.Stmt, error) {
+	if c.db == nil {
+		panic("nil c.db; conn = " + fmt.Sprintf("%#v", c))
+	}
+	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)
+	default:
+		return nil, errf("unsupported command type %q", cmd)
+	}
+	return stmt, nil
+}
+
+func (s *fakeStmt) ColumnConverter(idx int) driver.ValueConverter {
+	return s.placeholderConverter[idx]
+}
+
+func (s *fakeStmt) Close() error {
+	if !s.closed {
+		s.c.incrStat(&s.c.stmtsClosed)
+		s.closed = true
+	}
+	return nil
+}
+
+var errClosed = errors.New("fakedb: statement has been closed")
+
+func (s *fakeStmt) Exec(args []interface{}) (driver.Result, error) {
+	if s.closed {
+		return nil, errClosed
+	}
+	err := checkSubsetTypes(args)
+	if err != nil {
+		return nil, err
+	}
+
+	db := s.c.db
+	switch s.cmd {
+	case "WIPE":
+		db.wipe()
+		return driver.DDLSuccess, nil
+	case "CREATE":
+		if err := db.createTable(s.table, s.colName, s.colType); err != nil {
+			return nil, err
+		}
+		return driver.DDLSuccess, nil
+	case "INSERT":
+		return s.execInsert(args)
+	}
+	fmt.Printf("EXEC statement, cmd=%q: %#v\n", s.cmd, s)
+	return nil, fmt.Errorf("unimplemented statement Exec command type of %q", s.cmd)
+}
+
+func (s *fakeStmt) execInsert(args []interface{}) (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()
+
+	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]
+		}
+		cols[colidx] = val
+	}
+
+	t.rows = append(t.rows, &row{cols: cols})
+	return driver.RowsAffected(1), nil
+}
+
+func (s *fakeStmt) Query(args []interface{}) (driver.Rows, error) {
+	if s.closed {
+		return nil, errClosed
+	}
+	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)
+	}
+	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,
+	}
+	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
+
+	// 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
+}
+
+func (rc *rowsCursor) Next(dest []interface{}) error {
+	if rc.closed {
+		return errors.New("fakedb: cursor is closed")
+	}
+	rc.pos++
+	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
+}
+
+func converterForType(typ string) driver.ValueConverter {
+	switch typ {
+	case "bool":
+		return driver.Bool
+	case "int32":
+		return driver.Int32
+	case "string":
+		return driver.NotNull{driver.String}
+	case "nullstring":
+		return driver.Null{driver.String}
+	case "datetime":
+		return driver.DefaultParameterConverter
+	}
+	panic("invalid fakedb column type of " + typ)
+}
diff --git a/libgo/go/database/sql/sql.go b/libgo/go/database/sql/sql.go
new file mode 100644
index 00000000000..a8bf2a8b00c
--- /dev/null
+++ b/libgo/go/database/sql/sql.go
@@ -0,0 +1,912 @@
+// 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 provides a generic interface around SQL (or SQL-like)
+// databases.
+package sql
+
+import (
+	"database/sql/driver"
+	"errors"
+	"fmt"
+	"io"
+	"sync"
+)
+
+var drivers = make(map[string]driver.Driver)
+
+// Register makes a database driver available by the provided name.
+// If Register is called twice with the same name or if driver is nil,
+// it panics.
+func Register(name string, driver driver.Driver) {
+	if driver == nil {
+		panic("sql: Register driver is nil")
+	}
+	if _, dup := drivers[name]; dup {
+		panic("sql: Register called twice for driver " + name)
+	}
+	drivers[name] = driver
+}
+
+// RawBytes is a byte slice that holds a reference to memory owned by
+// the database itself. After a Scan into a RawBytes, the slice is only
+// valid until the next call to Next, Scan, or Close.
+type RawBytes []byte
+
+// NullString represents a string that may be null.
+// NullString implements the ScannerInto interface so
+// it can be used as a scan destination:
+//
+//  var s NullString
+//  err := db.QueryRow("SELECT name FROM foo WHERE id=?", id).Scan(&s)
+//  ...
+//  if s.Valid {
+//     // use s.String
+//  } else {
+//     // NULL value
+//  }
+//
+// TODO(bradfitz): add other types.
+type NullString struct {
+	String string
+	Valid  bool // Valid is true if String is not NULL
+}
+
+// ScanInto implements the ScannerInto interface.
+func (ns *NullString) ScanInto(value interface{}) error {
+	if value == nil {
+		ns.String, ns.Valid = "", false
+		return nil
+	}
+	ns.Valid = true
+	return convertAssign(&ns.String, value)
+}
+
+// SubsetValue implements the driver SubsetValuer interface.
+func (ns NullString) SubsetValue() (interface{}, error) {
+	if !ns.Valid {
+		return nil, nil
+	}
+	return ns.String, nil
+}
+
+// ScannerInto is an interface used by Scan.
+type ScannerInto interface {
+	// ScanInto assigns a value from a database driver.
+	//
+	// The value will be of one of the following restricted
+	// set of types:
+	//
+	//    int64
+	//    float64
+	//    bool
+	//    []byte
+	//    nil - for NULL values
+	//
+	// An error should be returned if the value can not be stored
+	// without loss of information.
+	ScanInto(value interface{}) error
+}
+
+// ErrNoRows is returned by Scan when QueryRow doesn't return a
+// row. In such a case, QueryRow returns a placeholder *Row value that
+// defers this error until a Scan.
+var ErrNoRows = errors.New("sql: no rows in result set")
+
+// DB is a database handle. It's safe for concurrent use by multiple
+// goroutines.
+type DB struct {
+	driver driver.Driver
+	dsn    string
+
+	mu       sync.Mutex // protects freeConn and closed
+	freeConn []driver.Conn
+	closed   bool
+}
+
+// Open opens a database specified by its database driver name and a
+// driver-specific data source name, usually consisting of at least a
+// database name and connection information.
+//
+// Most users will open a database via a driver-specific connection
+// helper function that returns a *DB.
+func Open(driverName, dataSourceName string) (*DB, error) {
+	driver, ok := drivers[driverName]
+	if !ok {
+		return nil, fmt.Errorf("sql: unknown driver %q (forgotten import?)", driverName)
+	}
+	return &DB{driver: driver, dsn: dataSourceName}, nil
+}
+
+// Close closes the database, releasing any open resources.
+func (db *DB) Close() error {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+	var err error
+	for _, c := range db.freeConn {
+		err1 := c.Close()
+		if err1 != nil {
+			err = err1
+		}
+	}
+	db.freeConn = nil
+	db.closed = true
+	return err
+}
+
+func (db *DB) maxIdleConns() int {
+	const defaultMaxIdleConns = 2
+	// TODO(bradfitz): ask driver, if supported, for its default preference
+	// TODO(bradfitz): let users override?
+	return defaultMaxIdleConns
+}
+
+// conn returns a newly-opened or cached driver.Conn
+func (db *DB) conn() (driver.Conn, error) {
+	db.mu.Lock()
+	if db.closed {
+		db.mu.Unlock()
+		return nil, errors.New("sql: database is closed")
+	}
+	if n := len(db.freeConn); n > 0 {
+		conn := db.freeConn[n-1]
+		db.freeConn = db.freeConn[:n-1]
+		db.mu.Unlock()
+		return conn, nil
+	}
+	db.mu.Unlock()
+	return db.driver.Open(db.dsn)
+}
+
+func (db *DB) connIfFree(wanted driver.Conn) (conn driver.Conn, ok bool) {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+	for n, conn := range db.freeConn {
+		if conn == wanted {
+			db.freeConn[n] = db.freeConn[len(db.freeConn)-1]
+			db.freeConn = db.freeConn[:len(db.freeConn)-1]
+			return wanted, true
+		}
+	}
+	return nil, false
+}
+
+func (db *DB) putConn(c driver.Conn) {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+	if n := len(db.freeConn); !db.closed && n < db.maxIdleConns() {
+		db.freeConn = append(db.freeConn, c)
+		return
+	}
+	db.closeConn(c) // TODO(bradfitz): release lock before calling this?
+}
+
+func (db *DB) closeConn(c driver.Conn) {
+	// TODO: check to see if we need this Conn for any prepared statements
+	// that are active.
+	c.Close()
+}
+
+// Prepare creates a prepared statement for later execution.
+func (db *DB) Prepare(query string) (*Stmt, error) {
+	// TODO: check if db.driver supports an optional
+	// driver.Preparer interface and call that instead, if so,
+	// otherwise we make a prepared statement that's bound
+	// to a connection, and to execute this prepared statement
+	// we either need to use this connection (if it's free), else
+	// get a new connection + re-prepare + execute on that one.
+	ci, err := db.conn()
+	if err != nil {
+		return nil, err
+	}
+	defer db.putConn(ci)
+	si, err := ci.Prepare(query)
+	if err != nil {
+		return nil, err
+	}
+	stmt := &Stmt{
+		db:    db,
+		query: query,
+		css:   []connStmt{{ci, si}},
+	}
+	return stmt, nil
+}
+
+// Exec executes a query without returning any rows.
+func (db *DB) Exec(query string, args ...interface{}) (Result, error) {
+	sargs, err := subsetTypeArgs(args)
+	if err != nil {
+		return nil, err
+	}
+
+	ci, err := db.conn()
+	if err != nil {
+		return nil, err
+	}
+	defer db.putConn(ci)
+
+	if execer, ok := ci.(driver.Execer); ok {
+		resi, err := execer.Exec(query, sargs)
+		if err != driver.ErrSkip {
+			if err != nil {
+				return nil, err
+			}
+			return result{resi}, nil
+		}
+	}
+
+	sti, err := ci.Prepare(query)
+	if err != nil {
+		return nil, err
+	}
+	defer sti.Close()
+
+	resi, err := sti.Exec(sargs)
+	if err != nil {
+		return nil, err
+	}
+	return result{resi}, nil
+}
+
+// Query executes a query that returns rows, typically a SELECT.
+func (db *DB) Query(query string, args ...interface{}) (*Rows, error) {
+	stmt, err := db.Prepare(query)
+	if err != nil {
+		return nil, err
+	}
+	rows, err := stmt.Query(args...)
+	if err != nil {
+		stmt.Close()
+		return nil, err
+	}
+	rows.closeStmt = stmt
+	return rows, nil
+}
+
+// QueryRow executes a query that is expected to return at most one row.
+// QueryRow always return a non-nil value. Errors are deferred until
+// Row's Scan method is called.
+func (db *DB) QueryRow(query string, args ...interface{}) *Row {
+	rows, err := db.Query(query, args...)
+	return &Row{rows: rows, err: err}
+}
+
+// Begin starts a transaction. The isolation level is dependent on
+// the driver.
+func (db *DB) Begin() (*Tx, error) {
+	ci, err := db.conn()
+	if err != nil {
+		return nil, err
+	}
+	txi, err := ci.Begin()
+	if err != nil {
+		db.putConn(ci)
+		return nil, fmt.Errorf("sql: failed to Begin transaction: %v", err)
+	}
+	return &Tx{
+		db:  db,
+		ci:  ci,
+		txi: txi,
+	}, nil
+}
+
+// DriverDatabase returns the database's underlying driver.
+func (db *DB) Driver() driver.Driver {
+	return db.driver
+}
+
+// Tx is an in-progress database transaction.
+//
+// A transaction must end with a call to Commit or Rollback.
+//
+// After a call to Commit or Rollback, all operations on the
+// transaction fail with ErrTransactionFinished.
+type Tx struct {
+	db *DB
+
+	// ci is owned exclusively until Commit or Rollback, at which point
+	// it's returned with putConn.
+	ci  driver.Conn
+	txi driver.Tx
+
+	// cimu is held while somebody is using ci (between grabConn
+	// and releaseConn)
+	cimu sync.Mutex
+
+	// done transitions from false to true exactly once, on Commit
+	// or Rollback. once done, all operations fail with
+	// ErrTransactionFinished.
+	done bool
+}
+
+var ErrTransactionFinished = errors.New("sql: Transaction has already been committed or rolled back")
+
+func (tx *Tx) close() {
+	if tx.done {
+		panic("double close") // internal error
+	}
+	tx.done = true
+	tx.db.putConn(tx.ci)
+	tx.ci = nil
+	tx.txi = nil
+}
+
+func (tx *Tx) grabConn() (driver.Conn, error) {
+	if tx.done {
+		return nil, ErrTransactionFinished
+	}
+	tx.cimu.Lock()
+	return tx.ci, nil
+}
+
+func (tx *Tx) releaseConn() {
+	tx.cimu.Unlock()
+}
+
+// Commit commits the transaction.
+func (tx *Tx) Commit() error {
+	if tx.done {
+		return ErrTransactionFinished
+	}
+	defer tx.close()
+	return tx.txi.Commit()
+}
+
+// Rollback aborts the transaction.
+func (tx *Tx) Rollback() error {
+	if tx.done {
+		return ErrTransactionFinished
+	}
+	defer tx.close()
+	return tx.txi.Rollback()
+}
+
+// Prepare creates a prepared statement for use within a transaction.
+//
+// The returned statement operates within the transaction and can no longer
+// be used once the transaction has been committed or rolled back.
+//
+// To use an existing prepared statement on this transaction, see Tx.Stmt.
+func (tx *Tx) Prepare(query string) (*Stmt, error) {
+	// TODO(bradfitz): We could be more efficient here and either
+	// provide a method to take an existing Stmt (created on
+	// perhaps a different Conn), and re-create it on this Conn if
+	// necessary. Or, better: keep a map in DB of query string to
+	// Stmts, and have Stmt.Execute do the right thing and
+	// re-prepare if the Conn in use doesn't have that prepared
+	// statement.  But we'll want to avoid caching the statement
+	// in the case where we only call conn.Prepare implicitly
+	// (such as in db.Exec or tx.Exec), but the caller package
+	// can't be holding a reference to the returned statement.
+	// Perhaps just looking at the reference count (by noting
+	// Stmt.Close) would be enough. We might also want a finalizer
+	// on Stmt to drop the reference count.
+	ci, err := tx.grabConn()
+	if err != nil {
+		return nil, err
+	}
+	defer tx.releaseConn()
+
+	si, err := ci.Prepare(query)
+	if err != nil {
+		return nil, err
+	}
+
+	stmt := &Stmt{
+		db:    tx.db,
+		tx:    tx,
+		txsi:  si,
+		query: query,
+	}
+	return stmt, nil
+}
+
+// Stmt returns a transaction-specific prepared statement from
+// an existing statement.
+//
+// Example:
+//  updateMoney, err := db.Prepare("UPDATE balance SET money=money+? WHERE id=?")
+//  ...
+//  tx, err := db.Begin()
+//  ...
+//  res, err := tx.Stmt(updateMoney).Exec(123.45, 98293203)
+func (tx *Tx) Stmt(stmt *Stmt) *Stmt {
+	// TODO(bradfitz): optimize this. Currently this re-prepares
+	// each time.  This is fine for now to illustrate the API but
+	// we should really cache already-prepared statements
+	// per-Conn. See also the big comment in Tx.Prepare.
+
+	if tx.db != stmt.db {
+		return &Stmt{stickyErr: errors.New("sql: Tx.Stmt: statement from different database used")}
+	}
+	ci, err := tx.grabConn()
+	if err != nil {
+		return &Stmt{stickyErr: err}
+	}
+	defer tx.releaseConn()
+	si, err := ci.Prepare(stmt.query)
+	return &Stmt{
+		db:        tx.db,
+		tx:        tx,
+		txsi:      si,
+		query:     stmt.query,
+		stickyErr: err,
+	}
+}
+
+// Exec executes a query that doesn't return rows.
+// For example: an INSERT and UPDATE.
+func (tx *Tx) Exec(query string, args ...interface{}) (Result, error) {
+	ci, err := tx.grabConn()
+	if err != nil {
+		return nil, err
+	}
+	defer tx.releaseConn()
+
+	if execer, ok := ci.(driver.Execer); ok {
+		resi, err := execer.Exec(query, args)
+		if err != nil {
+			return nil, err
+		}
+		return result{resi}, nil
+	}
+
+	sti, err := ci.Prepare(query)
+	if err != nil {
+		return nil, err
+	}
+	defer sti.Close()
+
+	sargs, err := subsetTypeArgs(args)
+	if err != nil {
+		return nil, err
+	}
+
+	resi, err := sti.Exec(sargs)
+	if err != nil {
+		return nil, err
+	}
+	return result{resi}, nil
+}
+
+// Query executes a query that returns rows, typically a SELECT.
+func (tx *Tx) Query(query string, args ...interface{}) (*Rows, error) {
+	if tx.done {
+		return nil, ErrTransactionFinished
+	}
+	stmt, err := tx.Prepare(query)
+	if err != nil {
+		return nil, err
+	}
+	defer stmt.Close()
+	return stmt.Query(args...)
+}
+
+// QueryRow executes a query that is expected to return at most one row.
+// QueryRow always return a non-nil value. Errors are deferred until
+// Row's Scan method is called.
+func (tx *Tx) QueryRow(query string, args ...interface{}) *Row {
+	rows, err := tx.Query(query, args...)
+	return &Row{rows: rows, err: err}
+}
+
+// connStmt is a prepared statement on a particular connection.
+type connStmt struct {
+	ci driver.Conn
+	si driver.Stmt
+}
+
+// Stmt is a prepared statement. Stmt is safe for concurrent use by multiple goroutines.
+type Stmt struct {
+	// Immutable:
+	db        *DB    // where we came from
+	query     string // that created the Stmt
+	stickyErr error  // if non-nil, this error is returned for all operations
+
+	// If in a transaction, else both nil:
+	tx   *Tx
+	txsi driver.Stmt
+
+	mu     sync.Mutex // protects the rest of the fields
+	closed bool
+
+	// css is a list of underlying driver statement interfaces
+	// that are valid on particular connections.  This is only
+	// used if tx == nil and one is found that has idle
+	// connections.  If tx != nil, txsi is always used.
+	css []connStmt
+}
+
+// Exec executes a prepared statement with the given arguments and
+// returns a Result summarizing the effect of the statement.
+func (s *Stmt) Exec(args ...interface{}) (Result, error) {
+	_, releaseConn, si, err := s.connStmt()
+	if err != nil {
+		return nil, err
+	}
+	defer releaseConn()
+
+	// -1 means the driver doesn't know how to count the number of
+	// placeholders, so we won't sanity check input here and instead let the
+	// driver deal with errors.
+	if want := si.NumInput(); want != -1 && len(args) != want {
+		return nil, fmt.Errorf("sql: expected %d arguments, got %d", want, len(args))
+	}
+
+	// Convert args to subset types.
+	if cc, ok := si.(driver.ColumnConverter); ok {
+		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.SubsetValuer); ok {
+				sv, err := svi.SubsetValue()
+				if err != nil {
+					return nil, fmt.Errorf("sql: argument index %d from SubsetValue: %v", n, err)
+				}
+				if !driver.IsParameterSubsetType(sv) {
+					return nil, fmt.Errorf("sql: argument index %d: non-subset type %T returned from SubsetValue", 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.
+			args[n], err = cc.ColumnConverter(n).ConvertValue(arg)
+			if err != nil {
+				return nil, fmt.Errorf("sql: converting Exec argument #%d's type: %v", n, err)
+			}
+			if !driver.IsParameterSubsetType(args[n]) {
+				return nil, fmt.Errorf("sql: driver ColumnConverter error converted %T to unsupported type %T",
+					arg, args[n])
+			}
+		}
+	} else {
+		for n, arg := range args {
+			args[n], err = driver.DefaultParameterConverter.ConvertValue(arg)
+			if err != nil {
+				return nil, fmt.Errorf("sql: converting Exec argument #%d's type: %v", n, err)
+			}
+		}
+	}
+
+	resi, err := si.Exec(args)
+	if err != nil {
+		return nil, err
+	}
+	return result{resi}, nil
+}
+
+// connStmt returns a free driver connection on which to execute the
+// statement, a function to call to release the connection, and a
+// statement bound to that connection.
+func (s *Stmt) connStmt() (ci driver.Conn, releaseConn func(), si driver.Stmt, err error) {
+	if err = s.stickyErr; err != nil {
+		return
+	}
+	s.mu.Lock()
+	if s.closed {
+		s.mu.Unlock()
+		err = errors.New("sql: statement is closed")
+		return
+	}
+
+	// In a transaction, we always use the connection that the
+	// transaction was created on.
+	if s.tx != nil {
+		s.mu.Unlock()
+		ci, err = s.tx.grabConn() // blocks, waiting for the connection.
+		if err != nil {
+			return
+		}
+		releaseConn = func() { s.tx.releaseConn() }
+		return ci, releaseConn, s.txsi, nil
+	}
+
+	var cs connStmt
+	match := false
+	for _, v := range s.css {
+		// TODO(bradfitz): lazily clean up entries in this
+		// list with dead conns while enumerating
+		if _, match = s.db.connIfFree(cs.ci); match {
+			cs = v
+			break
+		}
+	}
+	s.mu.Unlock()
+
+	// Make a new conn if all are busy.
+	// TODO(bradfitz): or wait for one? make configurable later?
+	if !match {
+		ci, err := s.db.conn()
+		if err != nil {
+			return nil, nil, nil, err
+		}
+		si, err := ci.Prepare(s.query)
+		if err != nil {
+			return nil, nil, nil, err
+		}
+		s.mu.Lock()
+		cs = connStmt{ci, si}
+		s.css = append(s.css, cs)
+		s.mu.Unlock()
+	}
+
+	conn := cs.ci
+	releaseConn = func() { s.db.putConn(conn) }
+	return conn, releaseConn, cs.si, nil
+}
+
+// Query executes a prepared query statement with the given arguments
+// and returns the query results as a *Rows.
+func (s *Stmt) Query(args ...interface{}) (*Rows, error) {
+	ci, releaseConn, si, err := s.connStmt()
+	if err != nil {
+		return nil, err
+	}
+
+	// -1 means the driver doesn't know how to count the number of
+	// placeholders, so we won't sanity check input here and instead let the
+	// driver deal with errors.
+	if want := si.NumInput(); want != -1 && len(args) != want {
+		return nil, fmt.Errorf("sql: statement expects %d inputs; got %d", si.NumInput(), len(args))
+	}
+	sargs, err := subsetTypeArgs(args)
+	if err != nil {
+		return nil, err
+	}
+	rowsi, err := si.Query(sargs)
+	if err != nil {
+		s.db.putConn(ci)
+		return nil, err
+	}
+	// Note: ownership of ci passes to the *Rows, to be freed
+	// with releaseConn.
+	rows := &Rows{
+		db:          s.db,
+		ci:          ci,
+		releaseConn: releaseConn,
+		rowsi:       rowsi,
+	}
+	return rows, nil
+}
+
+// QueryRow executes a prepared query statement with the given arguments.
+// If an error occurs during the execution of the statement, that error will
+// be returned by a call to Scan on the returned *Row, which is always non-nil.
+// If the query selects no rows, the *Row's Scan will return ErrNoRows.
+// Otherwise, the *Row's Scan scans the first selected row and discards
+// the rest.
+//
+// Example usage:
+//
+//  var name string
+//  err := nameByUseridStmt.QueryRow(id).Scan(&s)
+func (s *Stmt) QueryRow(args ...interface{}) *Row {
+	rows, err := s.Query(args...)
+	if err != nil {
+		return &Row{err: err}
+	}
+	return &Row{rows: rows}
+}
+
+// Close closes the statement.
+func (s *Stmt) Close() error {
+	if s.stickyErr != nil {
+		return s.stickyErr
+	}
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.closed {
+		return nil
+	}
+	s.closed = true
+
+	if s.tx != nil {
+		s.txsi.Close()
+	} else {
+		for _, v := range s.css {
+			if ci, match := s.db.connIfFree(v.ci); match {
+				v.si.Close()
+				s.db.putConn(ci)
+			} else {
+				// TODO(bradfitz): care that we can't close
+				// this statement because the statement's
+				// connection is in use?
+			}
+		}
+	}
+	return nil
+}
+
+// Rows is the result of a query. Its cursor starts before the first row
+// of the result set. Use Next to advance through the rows:
+//
+//     rows, err := db.Query("SELECT ...")
+//     ...
+//     for rows.Next() {
+//         var id int
+//         var name string
+//         err = rows.Scan(&id, &name)
+//         ...
+//     }
+//     err = rows.Err() // get any error encountered during iteration
+//     ...
+type Rows struct {
+	db          *DB
+	ci          driver.Conn // owned; must call putconn when closed to release
+	releaseConn func()
+	rowsi       driver.Rows
+
+	closed    bool
+	lastcols  []interface{}
+	lasterr   error
+	closeStmt *Stmt // if non-nil, statement to Close on close
+}
+
+// Next prepares the next result row for reading with the Scan method.
+// It returns true on success, false if there is no next result row.
+// Every call to Scan, even the first one, must be preceded by a call
+// to Next.
+func (rs *Rows) Next() bool {
+	if rs.closed {
+		return false
+	}
+	if rs.lasterr != nil {
+		return false
+	}
+	if rs.lastcols == nil {
+		rs.lastcols = make([]interface{}, len(rs.rowsi.Columns()))
+	}
+	rs.lasterr = rs.rowsi.Next(rs.lastcols)
+	if rs.lasterr == io.EOF {
+		rs.Close()
+	}
+	return rs.lasterr == nil
+}
+
+// Err returns the error, if any, that was encountered during iteration.
+func (rs *Rows) Err() error {
+	if rs.lasterr == io.EOF {
+		return nil
+	}
+	return rs.lasterr
+}
+
+// Columns returns the column names.
+// Columns returns an error if the rows are closed, or if the rows
+// are from QueryRow and there was a deferred error.
+func (rs *Rows) Columns() ([]string, error) {
+	if rs.closed {
+		return nil, errors.New("sql: Rows are closed")
+	}
+	if rs.rowsi == nil {
+		return nil, errors.New("sql: no Rows available")
+	}
+	return rs.rowsi.Columns(), nil
+}
+
+// Scan copies the columns in the current row into the values pointed
+// at by dest.
+//
+// If an argument has type *[]byte, Scan saves in that argument a copy
+// of the corresponding data. The copy is owned by the caller and can
+// be modified and held indefinitely. The copy can be avoided by using
+// an argument of type *RawBytes instead; see the documentation for
+// RawBytes for restrictions on its use.
+func (rs *Rows) Scan(dest ...interface{}) error {
+	if rs.closed {
+		return errors.New("sql: Rows closed")
+	}
+	if rs.lasterr != nil {
+		return rs.lasterr
+	}
+	if rs.lastcols == nil {
+		return errors.New("sql: Scan called without calling Next")
+	}
+	if len(dest) != len(rs.lastcols) {
+		return fmt.Errorf("sql: expected %d destination arguments in Scan, not %d", len(rs.lastcols), len(dest))
+	}
+	for i, sv := range rs.lastcols {
+		err := convertAssign(dest[i], sv)
+		if err != nil {
+			return fmt.Errorf("sql: Scan error on column index %d: %v", i, err)
+		}
+	}
+	for _, dp := range dest {
+		b, ok := dp.(*[]byte)
+		if !ok {
+			continue
+		}
+		if _, ok = dp.(*RawBytes); ok {
+			continue
+		}
+		clone := make([]byte, len(*b))
+		copy(clone, *b)
+		*b = clone
+	}
+	return nil
+}
+
+// Close closes the Rows, preventing further enumeration. If the
+// end is encountered, the Rows are closed automatically. Close
+// is idempotent.
+func (rs *Rows) Close() error {
+	if rs.closed {
+		return nil
+	}
+	rs.closed = true
+	err := rs.rowsi.Close()
+	rs.releaseConn()
+	if rs.closeStmt != nil {
+		rs.closeStmt.Close()
+	}
+	return err
+}
+
+// Row is the result of calling QueryRow to select a single row.
+type Row struct {
+	// One of these two will be non-nil:
+	err  error // deferred error for easy chaining
+	rows *Rows
+}
+
+// Scan copies the columns from the matched row into the values
+// pointed at by dest.  If more than one row matches the query,
+// Scan uses the first row and discards the rest.  If no row matches
+// the query, Scan returns ErrNoRows.
+func (r *Row) Scan(dest ...interface{}) error {
+	if r.err != nil {
+		return r.err
+	}
+	defer r.rows.Close()
+	if !r.rows.Next() {
+		return ErrNoRows
+	}
+	err := r.rows.Scan(dest...)
+	if err != nil {
+		return err
+	}
+
+	// TODO(bradfitz): for now we need to defensively clone all
+	// []byte that the driver returned, since we're about to close
+	// the Rows in our defer, when we return from this function.
+	// the contract with the driver.Next(...) interface is that it
+	// can return slices into read-only temporary memory that's
+	// only valid until the next Scan/Close.  But the TODO is that
+	// for a lot of drivers, this copy will be unnecessary.  We
+	// should provide an optional interface for drivers to
+	// implement to say, "don't worry, the []bytes that I return
+	// from Next will not be modified again." (for instance, if
+	// they were obtained from the network anyway) But for now we
+	// don't care.
+	for _, dp := range dest {
+		if _, ok := dp.(*RawBytes); ok {
+			return errors.New("sql: RawBytes isn't allowed on Row.Scan")
+		}
+		b, ok := dp.(*[]byte)
+		if !ok {
+			continue
+		}
+		clone := make([]byte, len(*b))
+		copy(clone, *b)
+		*b = clone
+	}
+	return nil
+}
+
+// A Result summarizes an executed SQL command.
+type Result interface {
+	LastInsertId() (int64, error)
+	RowsAffected() (int64, error)
+}
+
+type result struct {
+	driver.Result
+}
diff --git a/libgo/go/database/sql/sql_test.go b/libgo/go/database/sql/sql_test.go
new file mode 100644
index 00000000000..3fe93986faa
--- /dev/null
+++ b/libgo/go/database/sql/sql_test.go
@@ -0,0 +1,404 @@
+// 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 (
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+)
+
+const fakeDBName = "foo"
+
+var chrisBirthday = time.Unix(123456789, 0)
+
+func newTestDB(t *testing.T, name string) *DB {
+	db, err := Open("test", fakeDBName)
+	if err != nil {
+		t.Fatalf("Open: %v", err)
+	}
+	if _, err := db.Exec("WIPE"); err != nil {
+		t.Fatalf("exec wipe: %v", err)
+	}
+	if name == "people" {
+		exec(t, db, "CREATE|people|name=string,age=int32,photo=blob,dead=bool,bdate=datetime")
+		exec(t, db, "INSERT|people|name=Alice,age=?,photo=APHOTO", 1)
+		exec(t, db, "INSERT|people|name=Bob,age=?,photo=BPHOTO", 2)
+		exec(t, db, "INSERT|people|name=Chris,age=?,photo=CPHOTO,bdate=?", 3, chrisBirthday)
+	}
+	return db
+}
+
+func exec(t *testing.T, db *DB, query string, args ...interface{}) {
+	_, err := db.Exec(query, args...)
+	if err != nil {
+		t.Fatalf("Exec of %q: %v", query, err)
+	}
+}
+
+func closeDB(t *testing.T, db *DB) {
+	err := db.Close()
+	if err != nil {
+		t.Fatalf("error closing DB: %v", err)
+	}
+}
+
+func TestQuery(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	rows, err := db.Query("SELECT|people|age,name|")
+	if err != nil {
+		t.Fatalf("Query: %v", err)
+	}
+	type row struct {
+		age  int
+		name string
+	}
+	got := []row{}
+	for rows.Next() {
+		var r row
+		err = rows.Scan(&r.age, &r.name)
+		if err != nil {
+			t.Fatalf("Scan: %v", err)
+		}
+		got = append(got, r)
+	}
+	err = rows.Err()
+	if err != nil {
+		t.Fatalf("Err: %v", err)
+	}
+	want := []row{
+		{age: 1, name: "Alice"},
+		{age: 2, name: "Bob"},
+		{age: 3, name: "Chris"},
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got, want)
+	}
+
+	// And verify that the final rows.Next() call, which hit EOF,
+	// also closed the rows connection.
+	if n := len(db.freeConn); n != 1 {
+		t.Errorf("free conns after query hitting EOF = %d; want 1", n)
+	}
+}
+
+func TestByteOwnership(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	rows, err := db.Query("SELECT|people|name,photo|")
+	if err != nil {
+		t.Fatalf("Query: %v", err)
+	}
+	type row struct {
+		name  []byte
+		photo RawBytes
+	}
+	got := []row{}
+	for rows.Next() {
+		var r row
+		err = rows.Scan(&r.name, &r.photo)
+		if err != nil {
+			t.Fatalf("Scan: %v", err)
+		}
+		got = append(got, r)
+	}
+	corruptMemory := []byte("\xffPHOTO")
+	want := []row{
+		{name: []byte("Alice"), photo: corruptMemory},
+		{name: []byte("Bob"), photo: corruptMemory},
+		{name: []byte("Chris"), photo: corruptMemory},
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got, want)
+	}
+
+	var photo RawBytes
+	err = db.QueryRow("SELECT|people|photo|name=?", "Alice").Scan(&photo)
+	if err == nil {
+		t.Error("want error scanning into RawBytes from QueryRow")
+	}
+}
+
+func TestRowsColumns(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	rows, err := db.Query("SELECT|people|age,name|")
+	if err != nil {
+		t.Fatalf("Query: %v", err)
+	}
+	cols, err := rows.Columns()
+	if err != nil {
+		t.Fatalf("Columns: %v", err)
+	}
+	want := []string{"age", "name"}
+	if !reflect.DeepEqual(cols, want) {
+		t.Errorf("got %#v; want %#v", cols, want)
+	}
+}
+
+func TestQueryRow(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	var name string
+	var age int
+	var birthday time.Time
+
+	err := db.QueryRow("SELECT|people|age,name|age=?", 3).Scan(&age)
+	if err == nil || !strings.Contains(err.Error(), "expected 2 destination arguments") {
+		t.Errorf("expected error from wrong number of arguments; actually got: %v", err)
+	}
+
+	err = db.QueryRow("SELECT|people|bdate|age=?", 3).Scan(&birthday)
+	if err != nil || !birthday.Equal(chrisBirthday) {
+		t.Errorf("chris birthday = %v, err = %v; want %v", birthday, err, chrisBirthday)
+	}
+
+	err = db.QueryRow("SELECT|people|age,name|age=?", 2).Scan(&age, &name)
+	if err != nil {
+		t.Fatalf("age QueryRow+Scan: %v", err)
+	}
+	if name != "Bob" {
+		t.Errorf("expected name Bob, got %q", name)
+	}
+	if age != 2 {
+		t.Errorf("expected age 2, got %d", age)
+	}
+
+	err = db.QueryRow("SELECT|people|age,name|name=?", "Alice").Scan(&age, &name)
+	if err != nil {
+		t.Fatalf("name QueryRow+Scan: %v", err)
+	}
+	if name != "Alice" {
+		t.Errorf("expected name Alice, got %q", name)
+	}
+	if age != 1 {
+		t.Errorf("expected age 1, got %d", age)
+	}
+
+	var photo []byte
+	err = db.QueryRow("SELECT|people|photo|name=?", "Alice").Scan(&photo)
+	if err != nil {
+		t.Fatalf("photo QueryRow+Scan: %v", err)
+	}
+	want := []byte("APHOTO")
+	if !reflect.DeepEqual(photo, want) {
+		t.Errorf("photo = %q; want %q", photo, want)
+	}
+}
+
+func TestStatementErrorAfterClose(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	stmt, err := db.Prepare("SELECT|people|age|name=?")
+	if err != nil {
+		t.Fatalf("Prepare: %v", err)
+	}
+	err = stmt.Close()
+	if err != nil {
+		t.Fatalf("Close: %v", err)
+	}
+	var name string
+	err = stmt.QueryRow("foo").Scan(&name)
+	if err == nil {
+		t.Errorf("expected error from QueryRow.Scan after Stmt.Close")
+	}
+}
+
+func TestStatementQueryRow(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	stmt, err := db.Prepare("SELECT|people|age|name=?")
+	if err != nil {
+		t.Fatalf("Prepare: %v", err)
+	}
+	var age int
+	for n, tt := range []struct {
+		name string
+		want int
+	}{
+		{"Alice", 1},
+		{"Bob", 2},
+		{"Chris", 3},
+	} {
+		if err := stmt.QueryRow(tt.name).Scan(&age); err != nil {
+			t.Errorf("%d: on %q, QueryRow/Scan: %v", n, tt.name, err)
+		} else if age != tt.want {
+			t.Errorf("%d: age=%d, want %d", n, age, tt.want)
+		}
+	}
+
+}
+
+// just a test of fakedb itself
+func TestBogusPreboundParameters(t *testing.T) {
+	db := newTestDB(t, "foo")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
+	_, err := db.Prepare("INSERT|t1|name=?,age=bogusconversion")
+	if err == nil {
+		t.Fatalf("expected error")
+	}
+	if err.Error() != `fakedb: invalid conversion to int32 from "bogusconversion"` {
+		t.Errorf("unexpected error: %v", err)
+	}
+}
+
+func TestExec(t *testing.T) {
+	db := newTestDB(t, "foo")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
+	stmt, err := db.Prepare("INSERT|t1|name=?,age=?")
+	if err != nil {
+		t.Errorf("Stmt, err = %v, %v", stmt, err)
+	}
+
+	type execTest struct {
+		args    []interface{}
+		wantErr string
+	}
+	execTests := []execTest{
+		// Okay:
+		{[]interface{}{"Brad", 31}, ""},
+		{[]interface{}{"Brad", int64(31)}, ""},
+		{[]interface{}{"Bob", "32"}, ""},
+		{[]interface{}{7, 9}, ""},
+
+		// Invalid conversions:
+		{[]interface{}{"Brad", int64(0xFFFFFFFF)}, "sql: converting Exec argument #1's type: sql/driver: value 4294967295 overflows int32"},
+		{[]interface{}{"Brad", "strconv fail"}, "sql: converting Exec argument #1's type: sql/driver: value \"strconv fail\" can't be converted to int32"},
+
+		// Wrong number of args:
+		{[]interface{}{}, "sql: expected 2 arguments, got 0"},
+		{[]interface{}{1, 2, 3}, "sql: expected 2 arguments, got 3"},
+	}
+	for n, et := range execTests {
+		_, err := stmt.Exec(et.args...)
+		errStr := ""
+		if err != nil {
+			errStr = err.Error()
+		}
+		if errStr != et.wantErr {
+			t.Errorf("stmt.Execute #%d: for %v, got error %q, want error %q",
+				n, et.args, errStr, et.wantErr)
+		}
+	}
+}
+
+func TestTxStmt(t *testing.T) {
+	db := newTestDB(t, "")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
+	stmt, err := db.Prepare("INSERT|t1|name=?,age=?")
+	if err != nil {
+		t.Fatalf("Stmt, err = %v, %v", stmt, err)
+	}
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatalf("Begin = %v", err)
+	}
+	_, err = tx.Stmt(stmt).Exec("Bobby", 7)
+	if err != nil {
+		t.Fatalf("Exec = %v", err)
+	}
+	err = tx.Commit()
+	if err != nil {
+		t.Fatalf("Commit = %v", err)
+	}
+}
+
+// Tests fix for issue 2542, that we release a lock when querying on
+// a closed connection.
+func TestIssue2542Deadlock(t *testing.T) {
+	db := newTestDB(t, "people")
+	closeDB(t, db)
+	for i := 0; i < 2; i++ {
+		_, err := db.Query("SELECT|people|age,name|")
+		if err == nil {
+			t.Fatalf("expected error")
+		}
+	}
+}
+
+func TestQueryRowClosingStmt(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	var name string
+	var age int
+	err := db.QueryRow("SELECT|people|age,name|age=?", 3).Scan(&age, &name)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(db.freeConn) != 1 {
+		t.Fatalf("expected 1 free conn")
+	}
+	fakeConn := db.freeConn[0].(*fakeConn)
+	if made, closed := fakeConn.stmtsMade, fakeConn.stmtsClosed; made != closed {
+		t.Errorf("statement close mismatch: made %d, closed %d", made, closed)
+	}
+}
+
+func TestNullStringParam(t *testing.T) {
+	db := newTestDB(t, "")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t|id=int32,name=string,favcolor=nullstring")
+
+	// Inserts with db.Exec:
+	exec(t, db, "INSERT|t|id=?,name=?,favcolor=?", 1, "alice", NullString{"aqua", true})
+	exec(t, db, "INSERT|t|id=?,name=?,favcolor=?", 2, "bob", NullString{"brown", false})
+
+	_, err := db.Exec("INSERT|t|id=?,name=?,favcolor=?", 999, nil, nil)
+	if err == nil {
+		// TODO: this test fails, but it's just because
+		// fakeConn implements the optional Execer interface,
+		// so arguably this is the correct behavior.  But
+		// maybe I should flesh out the fakeConn.Exec
+		// implementation so this properly fails.
+		// t.Errorf("expected error inserting nil name with Exec")
+	}
+
+	// Inserts with a prepared statement:
+	stmt, err := db.Prepare("INSERT|t|id=?,name=?,favcolor=?")
+	if err != nil {
+		t.Fatalf("prepare: %v", err)
+	}
+	if _, err := stmt.Exec(3, "chris", "chartreuse"); err != nil {
+		t.Errorf("exec insert chris: %v", err)
+	}
+	if _, err := stmt.Exec(4, "dave", NullString{"darkred", true}); err != nil {
+		t.Errorf("exec insert dave: %v", err)
+	}
+	if _, err := stmt.Exec(5, "eleanor", NullString{"eel", false}); err != nil {
+		t.Errorf("exec insert dave: %v", err)
+	}
+
+	// Can't put null name into non-nullstring column,
+	if _, err := stmt.Exec(5, NullString{"", false}, nil); err == nil {
+		t.Errorf("expected error inserting nil name with prepared statement Exec")
+	}
+
+	type nameColor struct {
+		name     string
+		favColor NullString
+	}
+
+	wantMap := map[int]nameColor{
+		1: nameColor{"alice", NullString{"aqua", true}},
+		2: nameColor{"bob", NullString{"", false}},
+		3: nameColor{"chris", NullString{"chartreuse", true}},
+		4: nameColor{"dave", NullString{"darkred", true}},
+		5: nameColor{"eleanor", NullString{"", false}},
+	}
+	for id, want := range wantMap {
+		var got nameColor
+		if err := db.QueryRow("SELECT|t|name,favcolor|id=?", id).Scan(&got.name, &got.favColor); err != nil {
+			t.Errorf("id=%d Scan: %v", id, err)
+		}
+		if got != want {
+			t.Errorf("id=%d got %#v, want %#v", id, got, want)
+		}
+	}
+}