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Diffstat (limited to 'libgo/go/exp/sql/convert.go')
-rw-r--r-- | libgo/go/exp/sql/convert.go | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/libgo/go/exp/sql/convert.go b/libgo/go/exp/sql/convert.go new file mode 100644 index 00000000000..a35e0be9cbe --- /dev/null +++ b/libgo/go/exp/sql/convert.go @@ -0,0 +1,106 @@ +// 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 ( + "fmt" + "os" + "reflect" + "strconv" +) + +// 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{}) os.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 + } + } + + sv := reflect.ValueOf(src) + + switch d := dest.(type) { + case *string: + 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 + } + } + + if scanner, ok := dest.(ScannerInto); ok { + return scanner.ScanInto(src) + } + + dpv := reflect.ValueOf(dest) + if dpv.Kind() != reflect.Ptr { + return os.NewError("destination not a pointer") + } + + 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: + if s, ok := asString(src); ok { + i64, err := strconv.Atoi64(s) + if err != nil { + return fmt.Errorf("converting string %q to a %s: %v", s, dv.Kind(), err) + } + if dv.OverflowInt(i64) { + return fmt.Errorf("string %q overflows %s", s, dv.Kind()) + } + dv.SetInt(i64) + return nil + } + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64: + if s, ok := asString(src); ok { + u64, err := strconv.Atoui64(s) + if err != nil { + return fmt.Errorf("converting string %q to a %s: %v", s, dv.Kind(), err) + } + if dv.OverflowUint(u64) { + return fmt.Errorf("string %q overflows %s", s, dv.Kind()) + } + dv.SetUint(u64) + return nil + } + } + + return fmt.Errorf("unsupported driver -> Scan pair: %T -> %T", src, dest) +} + +func asString(src interface{}) (s string, ok bool) { + switch v := src.(type) { + case string: + return v, true + case []byte: + return string(v), true + } + return "", false +} |