/usr/share/gocode/src/google.golang.org/appengine/datastore/prop.go is in golang-google-appengine-dev 0.0~git20150606-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 | // Copyright 2011 Google Inc. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.
package datastore
import (
"fmt"
"reflect"
"strings"
"sync"
"unicode"
)
// Entities with more than this many indexed properties will not be saved.
const maxIndexedProperties = 20000
// []byte fields more than 1 megabyte long will not be loaded or saved.
const maxBlobLen = 1 << 20
// Property is a name/value pair plus some metadata. A datastore entity's
// contents are loaded and saved as a sequence of Properties. An entity can
// have multiple Properties with the same name, provided that p.Multiple is
// true on all of that entity's Properties with that name.
type Property struct {
// Name is the property name.
Name string
// Value is the property value. The valid types are:
// - int64
// - bool
// - string
// - float64
// - ByteString
// - *Key
// - time.Time
// - appengine.BlobKey
// - appengine.GeoPoint
// - []byte (up to 1 megabyte in length)
// This set is smaller than the set of valid struct field types that the
// datastore can load and save. A Property Value cannot be a slice (apart
// from []byte); use multiple Properties instead. Also, a Value's type
// must be explicitly on the list above; it is not sufficient for the
// underlying type to be on that list. For example, a Value of "type
// myInt64 int64" is invalid. Smaller-width integers and floats are also
// invalid. Again, this is more restrictive than the set of valid struct
// field types.
//
// A Value will have an opaque type when loading entities from an index,
// such as via a projection query. Load entities into a struct instead
// of a PropertyLoadSaver when using a projection query.
//
// A Value may also be the nil interface value; this is equivalent to
// Python's None but not directly representable by a Go struct. Loading
// a nil-valued property into a struct will set that field to the zero
// value.
Value interface{}
// NoIndex is whether the datastore cannot index this property.
NoIndex bool
// Multiple is whether the entity can have multiple properties with
// the same name. Even if a particular instance only has one property with
// a certain name, Multiple should be true if a struct would best represent
// it as a field of type []T instead of type T.
Multiple bool
}
// ByteString is a short byte slice (up to 1500 bytes) that can be indexed.
type ByteString []byte
// PropertyLoadSaver can be converted from and to a slice of Properties.
type PropertyLoadSaver interface {
Load([]Property) error
Save() ([]Property, error)
}
// PropertyList converts a []Property to implement PropertyLoadSaver.
type PropertyList []Property
var (
typeOfPropertyLoadSaver = reflect.TypeOf((*PropertyLoadSaver)(nil)).Elem()
typeOfPropertyList = reflect.TypeOf(PropertyList(nil))
)
// Load loads all of the provided properties into l.
// It does not first reset *l to an empty slice.
func (l *PropertyList) Load(p []Property) error {
*l = append(*l, p...)
return nil
}
// Save saves all of l's properties as a slice or Properties.
func (l *PropertyList) Save() ([]Property, error) {
return *l, nil
}
// validPropertyName returns whether name consists of one or more valid Go
// identifiers joined by ".".
func validPropertyName(name string) bool {
if name == "" {
return false
}
for _, s := range strings.Split(name, ".") {
if s == "" {
return false
}
first := true
for _, c := range s {
if first {
first = false
if c != '_' && !unicode.IsLetter(c) {
return false
}
} else {
if c != '_' && !unicode.IsLetter(c) && !unicode.IsDigit(c) {
return false
}
}
}
}
return true
}
// structTag is the parsed `datastore:"name,options"` tag of a struct field.
// If a field has no tag, or the tag has an empty name, then the structTag's
// name is just the field name. A "-" name means that the datastore ignores
// that field.
type structTag struct {
name string
noIndex bool
}
// structCodec describes how to convert a struct to and from a sequence of
// properties.
type structCodec struct {
// byIndex gives the structTag for the i'th field.
byIndex []structTag
// byName gives the field codec for the structTag with the given name.
byName map[string]fieldCodec
// hasSlice is whether a struct or any of its nested or embedded structs
// has a slice-typed field (other than []byte).
hasSlice bool
// complete is whether the structCodec is complete. An incomplete
// structCodec may be encountered when walking a recursive struct.
complete bool
}
// fieldCodec is a struct field's index and, if that struct field's type is
// itself a struct, that substruct's structCodec.
type fieldCodec struct {
index int
substructCodec *structCodec
}
// structCodecs collects the structCodecs that have already been calculated.
var (
structCodecsMutex sync.Mutex
structCodecs = make(map[reflect.Type]*structCodec)
)
// getStructCodec returns the structCodec for the given struct type.
func getStructCodec(t reflect.Type) (*structCodec, error) {
structCodecsMutex.Lock()
defer structCodecsMutex.Unlock()
return getStructCodecLocked(t)
}
// getStructCodecLocked implements getStructCodec. The structCodecsMutex must
// be held when calling this function.
func getStructCodecLocked(t reflect.Type) (ret *structCodec, retErr error) {
c, ok := structCodecs[t]
if ok {
return c, nil
}
c = &structCodec{
byIndex: make([]structTag, t.NumField()),
byName: make(map[string]fieldCodec),
}
// Add c to the structCodecs map before we are sure it is good. If t is
// a recursive type, it needs to find the incomplete entry for itself in
// the map.
structCodecs[t] = c
defer func() {
if retErr != nil {
delete(structCodecs, t)
}
}()
for i := range c.byIndex {
f := t.Field(i)
name, opts := f.Tag.Get("datastore"), ""
if i := strings.Index(name, ","); i != -1 {
name, opts = name[:i], name[i+1:]
}
if name == "" {
if !f.Anonymous {
name = f.Name
}
} else if name == "-" {
c.byIndex[i] = structTag{name: name}
continue
} else if !validPropertyName(name) {
return nil, fmt.Errorf("datastore: struct tag has invalid property name: %q", name)
}
substructType, fIsSlice := reflect.Type(nil), false
switch f.Type.Kind() {
case reflect.Struct:
substructType = f.Type
case reflect.Slice:
if f.Type.Elem().Kind() == reflect.Struct {
substructType = f.Type.Elem()
}
fIsSlice = f.Type != typeOfByteSlice
c.hasSlice = c.hasSlice || fIsSlice
}
if substructType != nil && substructType != typeOfTime && substructType != typeOfGeoPoint {
if name != "" {
name = name + "."
}
sub, err := getStructCodecLocked(substructType)
if err != nil {
return nil, err
}
if !sub.complete {
return nil, fmt.Errorf("datastore: recursive struct: field %q", f.Name)
}
if fIsSlice && sub.hasSlice {
return nil, fmt.Errorf(
"datastore: flattening nested structs leads to a slice of slices: field %q", f.Name)
}
c.hasSlice = c.hasSlice || sub.hasSlice
for relName := range sub.byName {
absName := name + relName
if _, ok := c.byName[absName]; ok {
return nil, fmt.Errorf("datastore: struct tag has repeated property name: %q", absName)
}
c.byName[absName] = fieldCodec{index: i, substructCodec: sub}
}
} else {
if _, ok := c.byName[name]; ok {
return nil, fmt.Errorf("datastore: struct tag has repeated property name: %q", name)
}
c.byName[name] = fieldCodec{index: i}
}
c.byIndex[i] = structTag{
name: name,
noIndex: opts == "noindex",
}
}
c.complete = true
return c, nil
}
// structPLS adapts a struct to be a PropertyLoadSaver.
type structPLS struct {
v reflect.Value
codec *structCodec
}
// newStructPLS returns a PropertyLoadSaver for the struct pointer p.
func newStructPLS(p interface{}) (PropertyLoadSaver, error) {
v := reflect.ValueOf(p)
if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
return nil, ErrInvalidEntityType
}
v = v.Elem()
codec, err := getStructCodec(v.Type())
if err != nil {
return nil, err
}
return structPLS{v, codec}, nil
}
// LoadStruct loads the properties from p to dst.
// dst must be a struct pointer.
func LoadStruct(dst interface{}, p []Property) error {
x, err := newStructPLS(dst)
if err != nil {
return err
}
return x.Load(p)
}
// SaveStruct returns the properties from src as a slice of Properties.
// src must be a struct pointer.
func SaveStruct(src interface{}) ([]Property, error) {
x, err := newStructPLS(src)
if err != nil {
return nil, err
}
return x.Save()
}
|