mirror of
https://github.com/autc04/Retro68.git
synced 2024-09-08 05:54:40 +00:00
542 lines
14 KiB
Go
542 lines
14 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Type conversions for Scan.
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package sql
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import (
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"database/sql/driver"
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"errors"
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"fmt"
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"reflect"
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"strconv"
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"time"
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"unicode"
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"unicode/utf8"
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)
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var errNilPtr = errors.New("destination pointer is nil") // embedded in descriptive error
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func describeNamedValue(nv *driver.NamedValue) string {
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if len(nv.Name) == 0 {
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return fmt.Sprintf("$%d", nv.Ordinal)
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}
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return fmt.Sprintf("with name %q", nv.Name)
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}
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func validateNamedValueName(name string) error {
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if len(name) == 0 {
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return nil
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}
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r, _ := utf8.DecodeRuneInString(name)
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if unicode.IsLetter(r) {
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return nil
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}
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return fmt.Errorf("name %q does not begin with a letter", name)
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}
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// ccChecker wraps the driver.ColumnConverter and allows it to be used
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// as if it were a NamedValueChecker. If the driver ColumnConverter
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// is not present then the NamedValueChecker will return driver.ErrSkip.
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type ccChecker struct {
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cci driver.ColumnConverter
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want int
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}
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func (c ccChecker) CheckNamedValue(nv *driver.NamedValue) error {
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if c.cci == nil {
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return driver.ErrSkip
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}
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// The column converter shouldn't be called on any index
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// it isn't expecting. The final error will be thrown
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// in the argument converter loop.
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index := nv.Ordinal - 1
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if c.want <= index {
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return nil
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}
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// First, see if the value itself knows how to convert
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// itself to a driver type. For example, a NullString
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// struct changing into a string or nil.
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if vr, ok := nv.Value.(driver.Valuer); ok {
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sv, err := callValuerValue(vr)
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if err != nil {
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return err
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}
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if !driver.IsValue(sv) {
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return fmt.Errorf("non-subset type %T returned from Value", sv)
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}
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nv.Value = sv
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}
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// Second, ask the column to sanity check itself. For
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// example, drivers might use this to make sure that
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// an int64 values being inserted into a 16-bit
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// integer field is in range (before getting
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// truncated), or that a nil can't go into a NOT NULL
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// column before going across the network to get the
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// same error.
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var err error
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arg := nv.Value
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nv.Value, err = c.cci.ColumnConverter(index).ConvertValue(arg)
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if err != nil {
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return err
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}
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if !driver.IsValue(nv.Value) {
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return fmt.Errorf("driver ColumnConverter error converted %T to unsupported type %T", arg, nv.Value)
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}
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return nil
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}
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// defaultCheckNamedValue wraps the default ColumnConverter to have the same
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// function signature as the CheckNamedValue in the driver.NamedValueChecker
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// interface.
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func defaultCheckNamedValue(nv *driver.NamedValue) (err error) {
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nv.Value, err = driver.DefaultParameterConverter.ConvertValue(nv.Value)
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return err
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}
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// driverArgs converts arguments from callers of Stmt.Exec and
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// Stmt.Query into driver Values.
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//
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// The statement ds may be nil, if no statement is available.
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func driverArgsConnLocked(ci driver.Conn, ds *driverStmt, args []interface{}) ([]driver.NamedValue, error) {
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nvargs := make([]driver.NamedValue, len(args))
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// -1 means the driver doesn't know how to count the number of
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// placeholders, so we won't sanity check input here and instead let the
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// driver deal with errors.
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want := -1
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var si driver.Stmt
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var cc ccChecker
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if ds != nil {
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si = ds.si
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want = ds.si.NumInput()
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cc.want = want
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}
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// Check all types of interfaces from the start.
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// Drivers may opt to use the NamedValueChecker for special
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// argument types, then return driver.ErrSkip to pass it along
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// to the column converter.
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nvc, ok := si.(driver.NamedValueChecker)
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if !ok {
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nvc, ok = ci.(driver.NamedValueChecker)
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}
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cci, ok := si.(driver.ColumnConverter)
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if ok {
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cc.cci = cci
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}
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// Loop through all the arguments, checking each one.
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// If no error is returned simply increment the index
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// and continue. However if driver.ErrRemoveArgument
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// is returned the argument is not included in the query
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// argument list.
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var err error
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var n int
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for _, arg := range args {
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nv := &nvargs[n]
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if np, ok := arg.(NamedArg); ok {
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if err = validateNamedValueName(np.Name); err != nil {
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return nil, err
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}
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arg = np.Value
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nv.Name = np.Name
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}
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nv.Ordinal = n + 1
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nv.Value = arg
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// Checking sequence has four routes:
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// A: 1. Default
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// B: 1. NamedValueChecker 2. Column Converter 3. Default
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// C: 1. NamedValueChecker 3. Default
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// D: 1. Column Converter 2. Default
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//
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// The only time a Column Converter is called is first
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// or after NamedValueConverter. If first it is handled before
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// the nextCheck label. Thus for repeats tries only when the
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// NamedValueConverter is selected should the Column Converter
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// be used in the retry.
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checker := defaultCheckNamedValue
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nextCC := false
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switch {
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case nvc != nil:
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nextCC = cci != nil
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checker = nvc.CheckNamedValue
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case cci != nil:
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checker = cc.CheckNamedValue
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}
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nextCheck:
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err = checker(nv)
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switch err {
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case nil:
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n++
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continue
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case driver.ErrRemoveArgument:
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nvargs = nvargs[:len(nvargs)-1]
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continue
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case driver.ErrSkip:
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if nextCC {
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nextCC = false
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checker = cc.CheckNamedValue
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} else {
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checker = defaultCheckNamedValue
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}
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goto nextCheck
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default:
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return nil, fmt.Errorf("sql: converting argument %s type: %v", describeNamedValue(nv), err)
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}
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}
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// Check the length of arguments after conversion to allow for omitted
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// arguments.
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if want != -1 && len(nvargs) != want {
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return nil, fmt.Errorf("sql: expected %d arguments, got %d", want, len(nvargs))
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}
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return nvargs, nil
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}
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// convertAssign is the same as convertAssignRows, but without the optional
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// rows argument.
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func convertAssign(dest, src interface{}) error {
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return convertAssignRows(dest, src, nil)
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}
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// convertAssignRows copies to dest the value in src, converting it if possible.
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// An error is returned if the copy would result in loss of information.
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// dest should be a pointer type. If rows is passed in, the rows will
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// be used as the parent for any cursor values converted from a
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// driver.Rows to a *Rows.
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func convertAssignRows(dest, src interface{}, rows *Rows) error {
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// Common cases, without reflect.
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switch s := src.(type) {
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case string:
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switch d := dest.(type) {
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case *string:
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if d == nil {
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return errNilPtr
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}
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*d = s
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return nil
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case *[]byte:
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if d == nil {
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return errNilPtr
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}
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*d = []byte(s)
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return nil
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case *RawBytes:
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if d == nil {
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return errNilPtr
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}
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*d = append((*d)[:0], s...)
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return nil
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}
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case []byte:
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switch d := dest.(type) {
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case *string:
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if d == nil {
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return errNilPtr
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}
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*d = string(s)
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return nil
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case *interface{}:
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if d == nil {
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return errNilPtr
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}
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*d = cloneBytes(s)
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return nil
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case *[]byte:
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if d == nil {
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return errNilPtr
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}
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*d = cloneBytes(s)
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return nil
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case *RawBytes:
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if d == nil {
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return errNilPtr
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}
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*d = s
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return nil
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}
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case time.Time:
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switch d := dest.(type) {
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case *time.Time:
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*d = s
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return nil
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case *string:
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*d = s.Format(time.RFC3339Nano)
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return nil
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case *[]byte:
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if d == nil {
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return errNilPtr
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}
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*d = []byte(s.Format(time.RFC3339Nano))
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return nil
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case *RawBytes:
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if d == nil {
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return errNilPtr
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}
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*d = s.AppendFormat((*d)[:0], time.RFC3339Nano)
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return nil
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}
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case nil:
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switch d := dest.(type) {
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case *interface{}:
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if d == nil {
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return errNilPtr
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}
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*d = nil
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return nil
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case *[]byte:
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if d == nil {
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return errNilPtr
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}
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*d = nil
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return nil
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case *RawBytes:
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if d == nil {
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return errNilPtr
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}
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*d = nil
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return nil
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}
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// The driver is returning a cursor the client may iterate over.
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case driver.Rows:
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switch d := dest.(type) {
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case *Rows:
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if d == nil {
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return errNilPtr
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}
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if rows == nil {
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return errors.New("invalid context to convert cursor rows, missing parent *Rows")
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}
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rows.closemu.Lock()
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*d = Rows{
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dc: rows.dc,
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releaseConn: func(error) {},
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rowsi: s,
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}
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// Chain the cancel function.
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parentCancel := rows.cancel
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rows.cancel = func() {
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// When Rows.cancel is called, the closemu will be locked as well.
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// So we can access rs.lasterr.
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d.close(rows.lasterr)
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if parentCancel != nil {
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parentCancel()
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}
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}
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rows.closemu.Unlock()
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return nil
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}
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}
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var sv reflect.Value
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switch d := dest.(type) {
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case *string:
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sv = reflect.ValueOf(src)
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switch sv.Kind() {
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case reflect.Bool,
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reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
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reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
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reflect.Float32, reflect.Float64:
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*d = asString(src)
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return nil
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}
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case *[]byte:
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sv = reflect.ValueOf(src)
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if b, ok := asBytes(nil, sv); ok {
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*d = b
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return nil
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}
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case *RawBytes:
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sv = reflect.ValueOf(src)
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if b, ok := asBytes([]byte(*d)[:0], sv); ok {
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*d = RawBytes(b)
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return nil
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}
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case *bool:
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bv, err := driver.Bool.ConvertValue(src)
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if err == nil {
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*d = bv.(bool)
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}
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return err
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case *interface{}:
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*d = src
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return nil
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}
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if scanner, ok := dest.(Scanner); ok {
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return scanner.Scan(src)
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}
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dpv := reflect.ValueOf(dest)
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if dpv.Kind() != reflect.Ptr {
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return errors.New("destination not a pointer")
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}
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if dpv.IsNil() {
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return errNilPtr
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}
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if !sv.IsValid() {
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sv = reflect.ValueOf(src)
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}
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dv := reflect.Indirect(dpv)
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if sv.IsValid() && sv.Type().AssignableTo(dv.Type()) {
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switch b := src.(type) {
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case []byte:
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dv.Set(reflect.ValueOf(cloneBytes(b)))
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default:
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dv.Set(sv)
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}
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return nil
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}
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if dv.Kind() == sv.Kind() && sv.Type().ConvertibleTo(dv.Type()) {
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dv.Set(sv.Convert(dv.Type()))
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return nil
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}
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// The following conversions use a string value as an intermediate representation
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// to convert between various numeric types.
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//
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// This also allows scanning into user defined types such as "type Int int64".
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// For symmetry, also check for string destination types.
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switch dv.Kind() {
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case reflect.Ptr:
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if src == nil {
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dv.Set(reflect.Zero(dv.Type()))
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return nil
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}
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dv.Set(reflect.New(dv.Type().Elem()))
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return convertAssignRows(dv.Interface(), src, rows)
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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s := asString(src)
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i64, err := strconv.ParseInt(s, 10, dv.Type().Bits())
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if err != nil {
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err = strconvErr(err)
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return fmt.Errorf("converting driver.Value type %T (%q) to a %s: %v", src, s, dv.Kind(), err)
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}
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dv.SetInt(i64)
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return nil
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
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s := asString(src)
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u64, err := strconv.ParseUint(s, 10, dv.Type().Bits())
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if err != nil {
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err = strconvErr(err)
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return fmt.Errorf("converting driver.Value type %T (%q) to a %s: %v", src, s, dv.Kind(), err)
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}
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dv.SetUint(u64)
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return nil
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case reflect.Float32, reflect.Float64:
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s := asString(src)
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f64, err := strconv.ParseFloat(s, dv.Type().Bits())
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if err != nil {
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err = strconvErr(err)
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return fmt.Errorf("converting driver.Value type %T (%q) to a %s: %v", src, s, dv.Kind(), err)
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}
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dv.SetFloat(f64)
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return nil
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case reflect.String:
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switch v := src.(type) {
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case string:
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dv.SetString(v)
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return nil
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case []byte:
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dv.SetString(string(v))
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return nil
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}
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}
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return fmt.Errorf("unsupported Scan, storing driver.Value type %T into type %T", src, dest)
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}
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func strconvErr(err error) error {
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if ne, ok := err.(*strconv.NumError); ok {
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return ne.Err
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}
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return err
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}
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func cloneBytes(b []byte) []byte {
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if b == nil {
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return nil
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}
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c := make([]byte, len(b))
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copy(c, b)
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return c
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}
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func asString(src interface{}) string {
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switch v := src.(type) {
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case string:
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return v
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case []byte:
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return string(v)
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}
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rv := reflect.ValueOf(src)
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switch rv.Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return strconv.FormatInt(rv.Int(), 10)
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
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return strconv.FormatUint(rv.Uint(), 10)
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case reflect.Float64:
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return strconv.FormatFloat(rv.Float(), 'g', -1, 64)
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case reflect.Float32:
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return strconv.FormatFloat(rv.Float(), 'g', -1, 32)
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case reflect.Bool:
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return strconv.FormatBool(rv.Bool())
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}
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return fmt.Sprintf("%v", src)
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}
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func asBytes(buf []byte, rv reflect.Value) (b []byte, ok bool) {
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switch rv.Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return strconv.AppendInt(buf, rv.Int(), 10), true
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
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return strconv.AppendUint(buf, rv.Uint(), 10), true
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case reflect.Float32:
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return strconv.AppendFloat(buf, rv.Float(), 'g', -1, 32), true
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case reflect.Float64:
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return strconv.AppendFloat(buf, rv.Float(), 'g', -1, 64), true
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case reflect.Bool:
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return strconv.AppendBool(buf, rv.Bool()), true
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case reflect.String:
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s := rv.String()
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return append(buf, s...), true
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}
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return
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}
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var valuerReflectType = reflect.TypeOf((*driver.Valuer)(nil)).Elem()
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|
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// callValuerValue returns vr.Value(), with one exception:
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// If vr.Value is an auto-generated method on a pointer type and the
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// pointer is nil, it would panic at runtime in the panicwrap
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// method. Treat it like nil instead.
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// Issue 8415.
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//
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// This is so people can implement driver.Value on value types and
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// still use nil pointers to those types to mean nil/NULL, just like
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// string/*string.
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//
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// This function is mirrored in the database/sql/driver package.
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func callValuerValue(vr driver.Valuer) (v driver.Value, err error) {
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if rv := reflect.ValueOf(vr); rv.Kind() == reflect.Ptr &&
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rv.IsNil() &&
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rv.Type().Elem().Implements(valuerReflectType) {
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return nil, nil
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}
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return vr.Value()
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}
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