swarm: plan bee for content storage and distribution on web3

This change imports the Swarm protocol codebase. Compared to the 'swarm'
branch, a few mostly cosmetic changes had to be made:

* The various redundant log message prefixes are gone.
* All files now have LGPLv3 license headers.
* Minor code changes were needed to please go vet and make the tests
  pass on Windows.
* Further changes were required to adapt to the go-ethereum develop
  branch and its new Go APIs.

Some code has not (yet) been brought over:

* swarm/cmd/bzzhash: will reappear as cmd/bzzhash later
* swarm/cmd/bzzup.sh: will be reimplemented in cmd/bzzup
* swarm/cmd/makegenesis: will reappear somehow
* swarm/examples/album: will move to a separate repository
* swarm/examples/filemanager: ditto
* swarm/examples/files: will not be merged
* swarm/test/*: will not be merged
* swarm/services/swear: will reappear as contracts/swear when needed

1 files changed, 283 insertions, 0 deletions

diff --git a/swarm/services/swap/swap.go b/swarm/services/swap/swap.go
new file mode 100644
index 000000000..f72036d72
--- /dev/null
+++ b/swarm/services/swap/swap.go
@@ -0,0 +1,283 @@
+// 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/>.
+
+package swap
+
+import (
+	"crypto/ecdsa"
+	"fmt"
+	"math/big"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/accounts/abi/bind"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/contracts/chequebook"
+	"github.com/ethereum/go-ethereum/contracts/chequebook/contract"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
+	"github.com/ethereum/go-ethereum/swarm/services/swap/swap"
+	"golang.org/x/net/context"
+)
+
+// SwAP       Swarm Accounting Protocol with
+// SWAP^2     Strategies of Withholding Automatic Payments
+// SWAP^3     Accreditation: payment via credit SWAP
+// using chequebook pkg for delayed payments
+// default parameters
+
+var (
+	autoCashInterval     = 300 * time.Second           // default interval for autocash
+	autoCashThreshold    = big.NewInt(50000000000000)  // threshold that triggers autocash (wei)
+	autoDepositInterval  = 300 * time.Second           // default interval for autocash
+	autoDepositThreshold = big.NewInt(50000000000000)  // threshold that triggers autodeposit (wei)
+	autoDepositBuffer    = big.NewInt(100000000000000) // buffer that is surplus for fork protection etc (wei)
+	buyAt                = big.NewInt(20000000000)     // maximum chunk price host is willing to pay (wei)
+	sellAt               = big.NewInt(20000000000)     // minimum chunk price host requires (wei)
+	payAt                = 100                         // threshold that triggers payment {request} (units)
+	dropAt               = 10000                       // threshold that triggers disconnect (units)
+)
+
+const (
+	chequebookDeployRetries = 5
+	chequebookDeployDelay   = 1 * time.Second // delay between retries
+)
+
+type SwapParams struct {
+	*swap.Params
+	*PayProfile
+}
+
+type SwapProfile struct {
+	*swap.Profile
+	*PayProfile
+}
+
+type PayProfile struct {
+	PublicKey   string         // check against signature of promise
+	Contract    common.Address // address of chequebook contract
+	Beneficiary common.Address // recipient address for swarm sales revenue
+	privateKey  *ecdsa.PrivateKey
+	publicKey   *ecdsa.PublicKey
+	owner       common.Address
+	chbook      *chequebook.Chequebook
+	lock        sync.RWMutex
+}
+
+func DefaultSwapParams(contract common.Address, prvkey *ecdsa.PrivateKey) *SwapParams {
+	pubkey := &prvkey.PublicKey
+	return &SwapParams{
+		PayProfile: &PayProfile{
+			PublicKey:   common.ToHex(crypto.FromECDSAPub(pubkey)),
+			Contract:    contract,
+			Beneficiary: crypto.PubkeyToAddress(*pubkey),
+			privateKey:  prvkey,
+			publicKey:   pubkey,
+			owner:       crypto.PubkeyToAddress(*pubkey),
+		},
+		Params: &swap.Params{
+			Profile: &swap.Profile{
+				BuyAt:  buyAt,
+				SellAt: sellAt,
+				PayAt:  uint(payAt),
+				DropAt: uint(dropAt),
+			},
+			Strategy: &swap.Strategy{
+				AutoCashInterval:     autoCashInterval,
+				AutoCashThreshold:    autoCashThreshold,
+				AutoDepositInterval:  autoDepositInterval,
+				AutoDepositThreshold: autoDepositThreshold,
+				AutoDepositBuffer:    autoDepositBuffer,
+			},
+		},
+	}
+}
+
+// swap constructor, parameters
+// * global chequebook, assume deployed service and
+// * the balance is at buffer.
+// swap.Add(n) called in netstore
+// n > 0 called when sending chunks = receiving retrieve requests
+//                 OR sending cheques.
+// n < 0  called when receiving chunks = receiving delivery responses
+//                 OR receiving cheques.
+
+func NewSwap(local *SwapParams, remote *SwapProfile, backend chequebook.Backend, proto swap.Protocol) (self *swap.Swap, err error) {
+	var (
+		ctx = context.TODO()
+		ok  bool
+		in  *chequebook.Inbox
+		out *chequebook.Outbox
+	)
+
+	// check if remote chequebook is valid
+	// insolvent chequebooks suicide so will signal as invalid
+	// TODO: monitoring a chequebooks events
+	ok, err = chequebook.ValidateCode(ctx, backend, remote.Contract)
+	if !ok {
+		glog.V(logger.Info).Infof("invalid contract %v for peer %v: %v)", remote.Contract.Hex()[:8], proto, err)
+	} else {
+		// remote contract valid, create inbox
+		in, err = chequebook.NewInbox(local.privateKey, remote.Contract, local.Beneficiary, crypto.ToECDSAPub(common.FromHex(remote.PublicKey)), backend)
+		if err != nil {
+			glog.V(logger.Warn).Infof("unable to set up inbox for chequebook contract %v for peer %v: %v)", remote.Contract.Hex()[:8], proto, err)
+		}
+	}
+
+	// check if local chequebook contract is valid
+	ok, err = chequebook.ValidateCode(ctx, backend, local.Contract)
+	if !ok {
+		glog.V(logger.Warn).Infof("unable to set up outbox for peer %v:  chequebook contract (owner: %v): %v)", proto, local.owner.Hex(), err)
+	} else {
+		out = chequebook.NewOutbox(local.Chequebook(), remote.Beneficiary)
+	}
+
+	pm := swap.Payment{
+		In:    in,
+		Out:   out,
+		Buys:  out != nil,
+		Sells: in != nil,
+	}
+	self, err = swap.New(local.Params, pm, proto)
+	if err != nil {
+		return
+	}
+	// remote profile given (first) in handshake
+	self.SetRemote(remote.Profile)
+	var buy, sell string
+	if self.Buys {
+		buy = "purchase from peer enabled at " + remote.SellAt.String() + " wei/chunk"
+	} else {
+		buy = "purchase from peer disabled"
+	}
+	if self.Sells {
+		sell = "selling to peer enabled at " + local.SellAt.String() + " wei/chunk"
+	} else {
+		sell = "selling to peer disabled"
+	}
+	glog.V(logger.Warn).Infof("SWAP arrangement with <%v>: %v; %v)", proto, buy, sell)
+
+	return
+}
+
+func (self *SwapParams) Chequebook() *chequebook.Chequebook {
+	defer self.lock.Unlock()
+	self.lock.Lock()
+	return self.chbook
+}
+
+func (self *SwapParams) PrivateKey() *ecdsa.PrivateKey {
+	return self.privateKey
+}
+
+// func (self *SwapParams) PublicKey() *ecdsa.PublicKey {
+// 	return self.publicKey
+// }
+
+func (self *SwapParams) SetKey(prvkey *ecdsa.PrivateKey) {
+	self.privateKey = prvkey
+	self.publicKey = &prvkey.PublicKey
+}
+
+// setChequebook(path, backend) wraps the
+// chequebook initialiser and sets up autoDeposit to cover spending.
+func (self *SwapParams) SetChequebook(ctx context.Context, backend chequebook.Backend, path string) error {
+	self.lock.Lock()
+	contract := self.Contract
+	self.lock.Unlock()
+
+	valid, err := chequebook.ValidateCode(ctx, backend, contract)
+	if err != nil {
+		return err
+	} else if valid {
+		return self.newChequebookFromContract(path, backend)
+	}
+	return self.deployChequebook(ctx, backend, path)
+}
+
+func (self *SwapParams) deployChequebook(ctx context.Context, backend chequebook.Backend, path string) error {
+	opts := bind.NewKeyedTransactor(self.privateKey)
+	opts.Value = self.AutoDepositBuffer
+	opts.Context = ctx
+
+	glog.V(logger.Info).Infof("Deploying new chequebook (owner: %v)", opts.From.Hex())
+	contract, err := deployChequebookLoop(opts, backend)
+	if err != nil {
+		glog.V(logger.Error).Infof("unable to deploy new chequebook: %v", err)
+		return err
+	}
+	glog.V(logger.Info).Infof("new chequebook deployed at %v (owner: %v)", contract.Hex(), opts.From.Hex())
+
+	// need to save config at this point
+	self.lock.Lock()
+	self.Contract = contract
+	err = self.newChequebookFromContract(path, backend)
+	self.lock.Unlock()
+	if err != nil {
+		glog.V(logger.Warn).Infof("error initialising cheque book (owner: %v): %v", opts.From.Hex(), err)
+	}
+	return err
+}
+
+// repeatedly tries to deploy a chequebook.
+func deployChequebookLoop(opts *bind.TransactOpts, backend chequebook.Backend) (addr common.Address, err error) {
+	var tx *types.Transaction
+	for try := 0; try < chequebookDeployRetries; try++ {
+		if try > 0 {
+			time.Sleep(chequebookDeployDelay)
+		}
+		if _, tx, _, err = contract.DeployChequebook(opts, backend); err != nil {
+			glog.V(logger.Warn).Infof("can't send chequebook deploy tx (try %d): %v", try, err)
+			continue
+		}
+		if addr, err = bind.WaitDeployed(opts.Context, backend, tx); err != nil {
+			glog.V(logger.Warn).Infof("chequebook deploy error (try %d): %v", try, err)
+			continue
+		}
+		return addr, nil
+	}
+	return addr, err
+}
+
+// initialise the chequebook from a persisted json file or create a new one
+// caller holds the lock
+func (self *SwapParams) newChequebookFromContract(path string, backend chequebook.Backend) error {
+	hexkey := common.Bytes2Hex(self.Contract.Bytes())
+	err := os.MkdirAll(filepath.Join(path, "chequebooks"), os.ModePerm)
+	if err != nil {
+		return fmt.Errorf("unable to create directory for chequebooks: %v", err)
+	}
+
+	chbookpath := filepath.Join(path, "chequebooks", hexkey+".json")
+	self.chbook, err = chequebook.LoadChequebook(chbookpath, self.privateKey, backend, true)
+
+	if err != nil {
+		self.chbook, err = chequebook.NewChequebook(chbookpath, self.Contract, self.privateKey, backend)
+		if err != nil {
+			glog.V(logger.Warn).Infof("unable to initialise chequebook (owner: %v): %v", self.owner.Hex(), err)
+			return fmt.Errorf("unable to initialise chequebook (owner: %v): %v", self.owner.Hex(), err)
+		}
+	}
+
+	self.chbook.AutoDeposit(self.AutoDepositInterval, self.AutoDepositThreshold, self.AutoDepositBuffer)
+	glog.V(logger.Info).Infof("auto deposit ON for %v -> %v: interval = %v, threshold = %v, buffer = %v)", crypto.PubkeyToAddress(*(self.publicKey)).Hex()[:8], self.Contract.Hex()[:8], self.AutoDepositInterval, self.AutoDepositThreshold, self.AutoDepositBuffer)
+
+	return nil
+}