aboutsummaryrefslogtreecommitdiffstats
path: root/accounts/abi/bind/base.go
blob: b88795aa86277b9dd55ae625517fe0f7eb0e59e3 (plain) (blame)
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
// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package bind

import (
    "context"
    "errors"
    "fmt"
    "math/big"

    "github.com/dexon-foundation/dexon"
    "github.com/dexon-foundation/dexon/accounts/abi"
    "github.com/dexon-foundation/dexon/common"
    "github.com/dexon-foundation/dexon/core/types"
    "github.com/dexon-foundation/dexon/crypto"
    "github.com/dexon-foundation/dexon/event"
)

// SignerFn is a signer function callback when a contract requires a method to
// sign the transaction before submission.
type SignerFn func(types.Signer, common.Address, *types.Transaction) (*types.Transaction, error)

// CallOpts is the collection of options to fine tune a contract call request.
type CallOpts struct {
    Pending     bool            // Whether to operate on the pending state or the last known one
    From        common.Address  // Optional the sender address, otherwise the first account is used
    BlockNumber *big.Int        // Optional the block number on which the call should be performed
    Context     context.Context // Network context to support cancellation and timeouts (nil = no timeout)
}

// TransactOpts is the collection of authorization data required to create a
// valid Ethereum transaction.
type TransactOpts struct {
    From   common.Address // Ethereum account to send the transaction from
    Nonce  *big.Int       // Nonce to use for the transaction execution (nil = use pending state)
    Signer SignerFn       // Method to use for signing the transaction (mandatory)

    Value    *big.Int // Funds to transfer along along the transaction (nil = 0 = no funds)
    GasPrice *big.Int // Gas price to use for the transaction execution (nil = gas price oracle)
    GasLimit uint64   // Gas limit to set for the transaction execution (0 = estimate)

    Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
}

// FilterOpts is the collection of options to fine tune filtering for events
// within a bound contract.
type FilterOpts struct {
    Start uint64  // Start of the queried range
    End   *uint64 // End of the range (nil = latest)

    Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
}

// WatchOpts is the collection of options to fine tune subscribing for events
// within a bound contract.
type WatchOpts struct {
    Start   *uint64         // Start of the queried range (nil = latest)
    Context context.Context // Network context to support cancellation and timeouts (nil = no timeout)
}

// BoundContract is the base wrapper object that reflects a contract on the
// Ethereum network. It contains a collection of methods that are used by the
// higher level contract bindings to operate.
type BoundContract struct {
    address    common.Address     // Deployment address of the contract on the Ethereum blockchain
    abi        abi.ABI            // Reflect based ABI to access the correct Ethereum methods
    caller     ContractCaller     // Read interface to interact with the blockchain
    transactor ContractTransactor // Write interface to interact with the blockchain
    filterer   ContractFilterer   // Event filtering to interact with the blockchain
}

// NewBoundContract creates a low level contract interface through which calls
// and transactions may be made through.
func NewBoundContract(address common.Address, abi abi.ABI, caller ContractCaller, transactor ContractTransactor, filterer ContractFilterer) *BoundContract {
    return &BoundContract{
        address:    address,
        abi:        abi,
        caller:     caller,
        transactor: transactor,
        filterer:   filterer,
    }
}

// DeployContract deploys a contract onto the Ethereum blockchain and binds the
// deployment address with a Go wrapper.
func DeployContract(opts *TransactOpts, abi abi.ABI, bytecode []byte, backend ContractBackend, params ...interface{}) (common.Address, *types.Transaction, *BoundContract, error) {
    // Otherwise try to deploy the contract
    c := NewBoundContract(common.Address{}, abi, backend, backend, backend)

    input, err := c.abi.Pack("", params...)
    if err != nil {
        return common.Address{}, nil, nil, err
    }
    tx, err := c.transact(opts, nil, append(bytecode, input...))
    if err != nil {
        return common.Address{}, nil, nil, err
    }
    c.address = crypto.CreateAddress(opts.From, tx.Nonce())
    return c.address, tx, c, nil
}

// Call invokes the (constant) contract method with params as input values and
// sets the output to result. The result type might be a single field for simple
// returns, a slice of interfaces for anonymous returns and a struct for named
// returns.
func (c *BoundContract) Call(opts *CallOpts, result interface{}, method string, params ...interface{}) error {
    // Don't crash on a lazy user
    if opts == nil {
        opts = new(CallOpts)
    }
    // Pack the input, call and unpack the results
    input, err := c.abi.Pack(method, params...)
    if err != nil {
        return err
    }
    var (
        msg    = ethereum.CallMsg{From: opts.From, To: &c.address, Data: input}
        ctx    = ensureContext(opts.Context)
        code   []byte
        output []byte
    )
    if opts.Pending {
        pb, ok := c.caller.(PendingContractCaller)
        if !ok {
            return ErrNoPendingState
        }
        output, err = pb.PendingCallContract(ctx, msg)
        if err == nil && len(output) == 0 {
            // Make sure we have a contract to operate on, and bail out otherwise.
            if code, err = pb.PendingCodeAt(ctx, c.address); err != nil {
                return err
            } else if len(code) == 0 {
                return ErrNoCode
            }
        }
    } else {
        output, err = c.caller.CallContract(ctx, msg, opts.BlockNumber)
        if err == nil && len(output) == 0 {
            // Make sure we have a contract to operate on, and bail out otherwise.
            if code, err = c.caller.CodeAt(ctx, c.address, opts.BlockNumber); err != nil {
                return err
            } else if len(code) == 0 {
                return ErrNoCode
            }
        }
    }
    if err != nil {
        return err
    }
    return c.abi.Unpack(result, method, output)
}

// Transact invokes the (paid) contract method with params as input values.
func (c *BoundContract) Transact(opts *TransactOpts, method string, params ...interface{}) (*types.Transaction, error) {
    // Otherwise pack up the parameters and invoke the contract
    input, err := c.abi.Pack(method, params...)
    if err != nil {
        return nil, err
    }
    return c.transact(opts, &c.address, input)
}

// Transfer initiates a plain transaction to move funds to the contract, calling
// its default method if one is available.
func (c *BoundContract) Transfer(opts *TransactOpts) (*types.Transaction, error) {
    return c.transact(opts, &c.address, nil)
}

// transact executes an actual transaction invocation, first deriving any missing
// authorization fields, and then scheduling the transaction for execution.
func (c *BoundContract) transact(opts *TransactOpts, contract *common.Address, input []byte) (*types.Transaction, error) {
    var err error

    // Ensure a valid value field and resolve the account nonce
    value := opts.Value
    if value == nil {
        value = new(big.Int)
    }
    var nonce uint64
    if opts.Nonce == nil {
        nonce, err = c.transactor.PendingNonceAt(ensureContext(opts.Context), opts.From)
        if err != nil {
            return nil, fmt.Errorf("failed to retrieve account nonce: %v", err)
        }
    } else {
        nonce = opts.Nonce.Uint64()
    }
    // Figure out the gas allowance and gas price values
    gasPrice := opts.GasPrice
    if gasPrice == nil {
        gasPrice, err = c.transactor.SuggestGasPrice(ensureContext(opts.Context))
        if err != nil {
            return nil, fmt.Errorf("failed to suggest gas price: %v", err)
        }
    }
    gasLimit := opts.GasLimit
    if gasLimit == 0 {
        // Gas estimation cannot succeed without code for method invocations
        if contract != nil {
            if code, err := c.transactor.PendingCodeAt(ensureContext(opts.Context), c.address); err != nil {
                return nil, err
            } else if len(code) == 0 {
                return nil, ErrNoCode
            }
        }
        // If the contract surely has code (or code is not needed), estimate the transaction
        msg := ethereum.CallMsg{From: opts.From, To: contract, Value: value, Data: input}
        gasLimit, err = c.transactor.EstimateGas(ensureContext(opts.Context), msg)
        if err != nil {
            return nil, fmt.Errorf("failed to estimate gas needed: %v", err)
        }
    }
    // Create the transaction, sign it and schedule it for execution
    var rawTx *types.Transaction
    if contract == nil {
        rawTx = types.NewContractCreation(nonce, value, gasLimit, gasPrice, input)
    } else {
        rawTx = types.NewTransaction(nonce, c.address, value, gasLimit, gasPrice, input)
    }
    if opts.Signer == nil {
        return nil, errors.New("no signer to authorize the transaction with")
    }
    signedTx, err := opts.Signer(types.HomesteadSigner{}, opts.From, rawTx)
    if err != nil {
        return nil, err
    }
    if err := c.transactor.SendTransaction(ensureContext(opts.Context), signedTx); err != nil {
        return nil, err
    }
    return signedTx, nil
}

// FilterLogs filters contract logs for past blocks, returning the necessary
// channels to construct a strongly typed bound iterator on top of them.
func (c *BoundContract) FilterLogs(opts *FilterOpts, name string, query ...[]interface{}) (chan types.Log, event.Subscription, error) {
    // Don't crash on a lazy user
    if opts == nil {
        opts = new(FilterOpts)
    }
    // Append the event selector to the query parameters and construct the topic set
    query = append([][]interface{}{{c.abi.Events[name].Id()}}, query...)

    topics, err := makeTopics(query...)
    if err != nil {
        return nil, nil, err
    }
    // Start the background filtering
    logs := make(chan types.Log, 128)

    config := ethereum.FilterQuery{
        Addresses: []common.Address{c.address},
        Topics:    topics,
        FromBlock: new(big.Int).SetUint64(opts.Start),
    }
    if opts.End != nil {
        config.ToBlock = new(big.Int).SetUint64(*opts.End)
    }
    /* TODO(karalabe): Replace the rest of the method below with this when supported
    sub, err := c.filterer.SubscribeFilterLogs(ensureContext(opts.Context), config, logs)
    */
    buff, err := c.filterer.FilterLogs(ensureContext(opts.Context), config)
    if err != nil {
        return nil, nil, err
    }
    sub, err := event.NewSubscription(func(quit <-chan struct{}) error {
        for _, log := range buff {
            select {
            case logs <- log:
            case <-quit:
                return nil
            }
        }
        return nil
    }), nil

    if err != nil {
        return nil, nil, err
    }
    return logs, sub, nil
}

// WatchLogs filters subscribes to contract logs for future blocks, returning a
// subscription object that can be used to tear down the watcher.
func (c *BoundContract) WatchLogs(opts *WatchOpts, name string, query ...[]interface{}) (chan types.Log, event.Subscription, error) {
    // Don't crash on a lazy user
    if opts == nil {
        opts = new(WatchOpts)
    }
    // Append the event selector to the query parameters and construct the topic set
    query = append([][]interface{}{{c.abi.Events[name].Id()}}, query...)

    topics, err := makeTopics(query...)
    if err != nil {
        return nil, nil, err
    }
    // Start the background filtering
    logs := make(chan types.Log, 128)

    config := ethereum.FilterQuery{
        Addresses: []common.Address{c.address},
        Topics:    topics,
    }
    if opts.Start != nil {
        config.FromBlock = new(big.Int).SetUint64(*opts.Start)
    }
    sub, err := c.filterer.SubscribeFilterLogs(ensureContext(opts.Context), config, logs)
    if err != nil {
        return nil, nil, err
    }
    return logs, sub, nil
}

// UnpackLog unpacks a retrieved log into the provided output structure.
func (c *BoundContract) UnpackLog(out interface{}, event string, log types.Log) error {
    if len(log.Data) > 0 {
        if err := c.abi.Unpack(out, event, log.Data); err != nil {
            return err
        }
    }
    var indexed abi.Arguments
    for _, arg := range c.abi.Events[event].Inputs {
        if arg.Indexed {
            indexed = append(indexed, arg)
        }
    }
    return parseTopics(out, indexed, log.Topics[1:])
}

// ensureContext is a helper method to ensure a context is not nil, even if the
// user specified it as such.
func ensureContext(ctx context.Context) context.Context {
    if ctx == nil {
        return context.TODO()
    }
    return ctx
}