forked from mongodb/mongo-tools-common
/
dbref.go
75 lines (66 loc) · 2.09 KB
/
dbref.go
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// Copyright (C) MongoDB, Inc. 2014-present.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
package json
import (
"fmt"
"reflect"
)
// Transition functions for recognizing DBRef and Dbref.
// Adapted from encoding/json/scanner.go.
// stateDB is the state after reading `DB`.
func stateDBR(s *scanner, c int) int {
if c == 'e' {
s.step = generateState("DBRef", []byte("f"), stateConstructor)
return scanContinue
}
return s.error(c, "in literal DBRef (expecting 'e')")
}
// stateDb is the state after reading `Db`.
func stateDb(s *scanner, c int) int {
if c == 'r' {
s.step = generateState("Dbref", []byte("ef"), stateConstructor)
return scanContinue
}
return s.error(c, "in literal Dbref (expecting 'r')")
}
// Decodes a DBRef literal stored in the underlying byte data into v.
func (d *decodeState) storeDBRef(v reflect.Value) {
op := d.scanWhile(scanSkipSpace)
if op != scanBeginCtor {
d.error(fmt.Errorf("expected beginning of constructor"))
}
args := d.ctorInterface()
if len(args) != 2 {
d.error(fmt.Errorf("expected 2 arguments to DBRef constructor, but %v received", len(args)))
}
switch kind := v.Kind(); kind {
case reflect.Interface:
arg0, ok := args[0].(string)
if !ok {
d.error(fmt.Errorf("expected first argument to DBRef to be of type string"))
}
arg1 := args[1]
v.Set(reflect.ValueOf(DBRef{arg0, arg1, ""}))
default:
d.error(fmt.Errorf("cannot store %v value into %v type", dbRefType, kind))
}
}
// Returns a DBRef literal from the underlying byte data.
func (d *decodeState) getDBRef() interface{} {
op := d.scanWhile(scanSkipSpace)
if op != scanBeginCtor {
d.error(fmt.Errorf("expected beginning of constructor"))
}
args := d.ctorInterface()
if err := ctorNumArgsMismatch("DBRef", 2, len(args)); err != nil {
d.error(err)
}
arg0, ok := args[0].(string)
if !ok {
d.error(fmt.Errorf("expected string for first argument of DBRef constructor"))
}
return DBRef{arg0, args[1], ""}
}