-
Notifications
You must be signed in to change notification settings - Fork 496
/
asset.go
457 lines (396 loc) · 11.7 KB
/
asset.go
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
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
package xdr
import (
"crypto/sha256"
"errors"
"fmt"
"regexp"
"strings"
"github.com/stellar/go/strkey"
)
// This file contains helpers for working with xdr.Asset structs
// AssetTypeToString maps an xdr.AssetType to its string representation
var AssetTypeToString = map[AssetType]string{
AssetTypeAssetTypeNative: "native",
AssetTypeAssetTypeCreditAlphanum4: "credit_alphanum4",
AssetTypeAssetTypeCreditAlphanum12: "credit_alphanum12",
}
// StringToAssetType maps an strings to its xdr.AssetType representation
var StringToAssetType = map[string]AssetType{
"native": AssetTypeAssetTypeNative,
"credit_alphanum4": AssetTypeAssetTypeCreditAlphanum4,
"credit_alphanum12": AssetTypeAssetTypeCreditAlphanum12,
}
// MustNewNativeAsset returns a new native asset, panicking if it can't.
func MustNewNativeAsset() Asset {
a := Asset{}
err := a.SetNative()
if err != nil {
panic(err)
}
return a
}
// MustNewCreditAsset returns a new general asset, panicking if it can't.
func MustNewCreditAsset(code string, issuer string) Asset {
a, err := NewCreditAsset(code, issuer)
if err != nil {
panic(err)
}
return a
}
// NewAssetCodeFromString returns a new credit asset, erroring if it can't.
func NewAssetCodeFromString(code string) (AssetCode, error) {
a := AssetCode{}
length := len(code)
switch {
case length >= 1 && length <= 4:
var newCode AssetCode4
copy(newCode[:], []byte(code)[:length])
a.Type = AssetTypeAssetTypeCreditAlphanum4
a.AssetCode4 = &newCode
case length >= 5 && length <= 12:
var newCode AssetCode12
copy(newCode[:], []byte(code)[:length])
a.Type = AssetTypeAssetTypeCreditAlphanum12
a.AssetCode12 = &newCode
default:
return a, errors.New("Asset code length is invalid")
}
return a, nil
}
// MustNewAssetCodeFromString returns a new allow trust asset, panicking if it can't.
func MustNewAssetCodeFromString(code string) AssetCode {
a, err := NewAssetCodeFromString(code)
if err != nil {
panic(err)
}
return a
}
// NewCreditAsset returns a new general asset, returning an error if it can't.
func NewCreditAsset(code string, issuer string) (Asset, error) {
a := Asset{}
accountID := AccountId{}
if err := accountID.SetAddress(issuer); err != nil {
return Asset{}, err
}
if err := a.SetCredit(code, accountID); err != nil {
return Asset{}, err
}
return a, nil
}
// BuildAsset creates a new asset from a given `assetType`, `code`, and `issuer`.
//
// Valid assetTypes are:
// - `native`
// - `credit_alphanum4`
// - `credit_alphanum12`
func BuildAsset(assetType, issuer, code string) (Asset, error) {
t, ok := StringToAssetType[assetType]
if !ok {
return Asset{}, errors.New("invalid asset type: was not one of 'native', 'credit_alphanum4', 'credit_alphanum12'")
}
var asset Asset
switch t {
case AssetTypeAssetTypeNative:
if err := asset.SetNative(); err != nil {
return Asset{}, err
}
default:
issuerAccountID := AccountId{}
if err := issuerAccountID.SetAddress(issuer); err != nil {
return Asset{}, err
}
if err := asset.SetCredit(code, issuerAccountID); err != nil {
return Asset{}, err
}
}
return asset, nil
}
var ValidAssetCode = regexp.MustCompile("^[[:alnum:]]{1,12}$")
// BuildAssets parses a list of assets from a given string.
// The string is expected to be a comma separated list of assets
// encoded in the format (Code:Issuer or "native") defined by SEP-0011
// https://github.com/stellar/stellar-protocol/pull/313
// If the string is empty, BuildAssets will return an empty list of assets
func BuildAssets(s string) ([]Asset, error) {
var assets []Asset
if s == "" {
return assets, nil
}
assetStrings := strings.Split(s, ",")
for _, assetString := range assetStrings {
var asset Asset
// Technically https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0011.md allows
// any string up to 12 characters not containing an unescaped colon to represent XLM
// however, this function only accepts the string "native" to represent XLM
if strings.ToLower(assetString) == "native" {
if err := asset.SetNative(); err != nil {
return nil, err
}
} else {
parts := strings.Split(assetString, ":")
if len(parts) != 2 {
return nil, fmt.Errorf("%s is not a valid asset", assetString)
}
code := parts[0]
if !ValidAssetCode.MatchString(code) {
return nil, fmt.Errorf(
"%s is not a valid asset, it contains an invalid asset code",
assetString,
)
}
issuer, err := AddressToAccountId(parts[1])
if err != nil {
return nil, fmt.Errorf(
"%s is not a valid asset, it contains an invalid issuer",
assetString,
)
}
if err := asset.SetCredit(code, issuer); err != nil {
return nil, fmt.Errorf("%s is not a valid asset", assetString)
}
}
assets = append(assets, asset)
}
return assets, nil
}
// SetCredit overwrites `a` with a credit asset using `code` and `issuer`. The
// asset type (CreditAlphanum4 or CreditAlphanum12) is chosen automatically
// based upon the length of `code`.
func (a *Asset) SetCredit(code string, issuer AccountId) error {
length := len(code)
var typ AssetType
var body interface{}
switch {
case length >= 1 && length <= 4:
newbody := AlphaNum4{Issuer: issuer}
copy(newbody.AssetCode[:], []byte(code)[:length])
typ = AssetTypeAssetTypeCreditAlphanum4
body = newbody
case length >= 5 && length <= 12:
newbody := AlphaNum12{Issuer: issuer}
copy(newbody.AssetCode[:], []byte(code)[:length])
typ = AssetTypeAssetTypeCreditAlphanum12
body = newbody
default:
return errors.New("Asset code length is invalid")
}
newa, err := NewAsset(typ, body)
if err != nil {
return err
}
*a = newa
return nil
}
// SetNative overwrites `a` with the native asset type
func (a *Asset) SetNative() error {
newa, err := NewAsset(AssetTypeAssetTypeNative, nil)
if err != nil {
return err
}
*a = newa
return nil
}
// ToAssetCode for Asset converts the Asset to a corresponding XDR
// "allow trust" asset, used by the XDR allow trust operation.
func (a *Asset) ToAssetCode(code string) (AssetCode, error) {
length := len(code)
switch {
case length >= 1 && length <= 4:
var bytecode AssetCode4
byteArray := []byte(code)
copy(bytecode[:], byteArray[0:length])
return NewAssetCode(AssetTypeAssetTypeCreditAlphanum4, bytecode)
case length >= 5 && length <= 12:
var bytecode AssetCode12
byteArray := []byte(code)
copy(bytecode[:], byteArray[0:length])
return NewAssetCode(AssetTypeAssetTypeCreditAlphanum12, bytecode)
default:
return AssetCode{}, errors.New("Asset code length is invalid")
}
}
// String returns a display friendly form of the asset
func (a Asset) String() string {
var t, c, i string
a.MustExtract(&t, &c, &i)
if a.Type == AssetTypeAssetTypeNative {
return t
}
return t + "/" + c + "/" + i
}
// StringCanonical returns a display friendly form of the asset following its
// canonical representation
func (a Asset) StringCanonical() string {
var t, c, i string
a.MustExtract(&t, &c, &i)
if a.Type == AssetTypeAssetTypeNative {
return t
}
return c + ":" + i
}
// Equals returns true if `other` is equivalent to `a`
func (a Asset) Equals(other Asset) bool {
if a.Type != other.Type {
return false
}
switch a.Type {
case AssetTypeAssetTypeNative:
return true
case AssetTypeAssetTypeCreditAlphanum4:
l := a.MustAlphaNum4()
r := other.MustAlphaNum4()
return l.AssetCode == r.AssetCode && l.Issuer.Equals(r.Issuer)
case AssetTypeAssetTypeCreditAlphanum12:
l := a.MustAlphaNum12()
r := other.MustAlphaNum12()
return l.AssetCode == r.AssetCode && l.Issuer.Equals(r.Issuer)
default:
panic(fmt.Errorf("Unknown asset type: %v", a.Type))
}
}
// Extract is a helper function to extract information from an xdr.Asset
// structure. It extracts the asset's type to the `typ` input parameter (which
// must be either a *string or *xdr.AssetType). It also extracts the asset's
// code and issuer to `code` and `issuer` respectively if they are of type
// *string and the asset is non-native
func (a Asset) Extract(typ interface{}, code interface{}, issuer interface{}) error {
switch typ := typ.(type) {
case *AssetType:
*typ = a.Type
case *string:
*typ = AssetTypeToString[a.Type]
default:
return errors.New("can't extract type")
}
if code != nil {
switch code := code.(type) {
case *string:
switch a.Type {
case AssetTypeAssetTypeCreditAlphanum4:
an := a.MustAlphaNum4()
*code = string(trimRightZeros(an.AssetCode[:]))
case AssetTypeAssetTypeCreditAlphanum12:
an := a.MustAlphaNum12()
*code = string(trimRightZeros(an.AssetCode[:]))
}
default:
return errors.New("can't extract code")
}
}
if issuer != nil {
switch issuer := issuer.(type) {
case *string:
switch a.Type {
case AssetTypeAssetTypeCreditAlphanum4:
an := a.MustAlphaNum4()
raw := an.Issuer.MustEd25519()
*issuer = strkey.MustEncode(strkey.VersionByteAccountID, raw[:])
case AssetTypeAssetTypeCreditAlphanum12:
an := a.MustAlphaNum12()
raw := an.Issuer.MustEd25519()
*issuer = strkey.MustEncode(strkey.VersionByteAccountID, raw[:])
}
default:
return errors.New("can't extract issuer")
}
}
return nil
}
// MustExtract behaves as Extract, but panics if an error occurs.
func (a Asset) MustExtract(typ interface{}, code interface{}, issuer interface{}) {
err := a.Extract(typ, code, issuer)
if err != nil {
panic(err)
}
}
// ToChangeTrustAsset converts Asset to ChangeTrustAsset.
func (a Asset) ToChangeTrustAsset() ChangeTrustAsset {
var cta ChangeTrustAsset
cta.Type = a.Type
switch a.Type {
case AssetTypeAssetTypeNative:
// Empty branch
case AssetTypeAssetTypeCreditAlphanum4:
assetCode4 := *a.AlphaNum4
cta.AlphaNum4 = &assetCode4
case AssetTypeAssetTypeCreditAlphanum12:
assetCode12 := *a.AlphaNum12
cta.AlphaNum12 = &assetCode12
default:
panic(fmt.Errorf("Cannot transform type %v to Asset", a.Type))
}
return cta
}
// ToTrustLineAsset converts Asset to TrustLineAsset.
func (a Asset) ToTrustLineAsset() TrustLineAsset {
var tla TrustLineAsset
tla.Type = a.Type
switch a.Type {
case AssetTypeAssetTypeNative:
// Empty branch
case AssetTypeAssetTypeCreditAlphanum4:
assetCode4 := *a.AlphaNum4
tla.AlphaNum4 = &assetCode4
case AssetTypeAssetTypeCreditAlphanum12:
assetCode12 := *a.AlphaNum12
tla.AlphaNum12 = &assetCode12
default:
panic(fmt.Errorf("Cannot transform type %v to Asset", a.Type))
}
return tla
}
func (a *Asset) GetCode() string {
switch a.Type {
case AssetTypeAssetTypeNative:
return ""
case AssetTypeAssetTypeCreditAlphanum4:
return string((*a.AlphaNum4).AssetCode[:])
case AssetTypeAssetTypeCreditAlphanum12:
return string((*a.AlphaNum12).AssetCode[:])
default:
return ""
}
}
func (a *Asset) GetIssuer() string {
switch a.Type {
case AssetTypeAssetTypeNative:
return ""
case AssetTypeAssetTypeCreditAlphanum4:
addr, _ := (*a.AlphaNum4).Issuer.GetAddress()
return addr
case AssetTypeAssetTypeCreditAlphanum12:
addr, _ := (*a.AlphaNum12).Issuer.GetAddress()
return addr
default:
return ""
}
}
func (a *Asset) LessThan(b Asset) bool {
if a.Type != b.Type {
return int32(a.Type) < int32(b.Type)
}
if a.GetCode() != b.GetCode() {
return a.GetCode() < b.GetCode()
}
return a.GetIssuer() < b.GetIssuer()
}
// ContractID returns the expected Stellar Asset Contract id for the given
// asset and network.
func (a Asset) ContractID(passphrase string) ([32]byte, error) {
networkId := Hash(sha256.Sum256([]byte(passphrase)))
preImage := HashIdPreimage{
Type: EnvelopeTypeEnvelopeTypeContractId,
ContractId: &HashIdPreimageContractId{
NetworkId: networkId,
ContractIdPreimage: ContractIdPreimage{
Type: ContractIdPreimageTypeContractIdPreimageFromAsset,
FromAsset: &a,
},
},
}
xdrPreImageBytes, err := preImage.MarshalBinary()
if err != nil {
return [32]byte{}, err
}
return sha256.Sum256(xdrPreImageBytes), nil
}