contracts/chequebook: add chequebook contract wrapper

The wrapper code is adapted from the swarm/services/chequebook package
with the following mostly cosmetic changes:

* The code now uses the new Go API interfaces to query balances. Some
  minor functional changes were required to make this work.
* The package no longer depends on swarm/services/swap/swap. References
  to swap.Promise are replaced by interface{}, the base type of Promise.
  This is temporary.
* The contract wrapper has been regenerated with latest abigen
  and solc v0.3.6.
* There is a new generator that creates the 'deployed code' variable.
* Documentation comments now follow the recommended godoc style.
* [CHEQUEBOOK] log prefixes are gone.
* LGPL license headers have been added to all files.

1 files changed, 73 insertions, 0 deletions

diff --git a/contracts/chequebook/gencode.go b/contracts/chequebook/gencode.go
new file mode 100644
index 000000000..f52c351e4
--- /dev/null
+++ b/contracts/chequebook/gencode.go
@@ -0,0 +1,73 @@
+// Copyright 2016 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/>.
+
+// +build none
+
+// This program generates contract/code.go, which contains the chequebook code
+// after deployment.
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/accounts/abi/bind"
+	"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
+	"github.com/ethereum/go-ethereum/contracts/chequebook/contract"
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+var (
+	testKey, _  = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
+	testAccount = core.GenesisAccount{
+		Address: crypto.PubkeyToAddress(testKey.PublicKey),
+		Balance: big.NewInt(500000000000),
+	}
+)
+
+func main() {
+	backend := backends.NewSimulatedBackend(testAccount)
+	auth := bind.NewKeyedTransactor(testKey)
+
+	// Deploy the contract, get the code.
+	addr, _, _, err := contract.DeployChequebook(auth, backend)
+	if err != nil {
+		panic(err)
+	}
+	backend.Commit()
+	code, err := backend.CodeAt(nil, addr, nil)
+	if err != nil {
+		panic(err)
+	}
+	if len(code) == 0 {
+		panic("empty code")
+	}
+
+	// Write the output file.
+	content := fmt.Sprintf(`// TODO: insert license header
+
+package contract
+
+// ContractDeployedCode is used to detect suicides. This constant needs to be
+// updated when the contract code is changed.
+const ContractDeployedCode = "%#x"
+`, code)
+	if err := ioutil.WriteFile("contract/code.go", []byte(content), 0644); err != nil {
+		panic(err)
+	}
+}