Improve wallet atomicity. (#339)

This is a step towards completing #315.

This changes the database access APIs and each of the "manager"
packages (waddrmgr/wtxmgr/wstakemgr) so that transactions are
opened (only) by the wallet package and the namespace buckets
that each manager expects to operate on are passed in as
parameters.

This helps improve the atomicity situation as it means that many
calls to these APIs can be grouped together into a single
database transaction.

This change does not attempt to completely fix
the "half-processed" block problem. Mined transactions are still
added to the wallet database under their own database transaction
as this is how they are notified by the consensus JSON-RPC
server (as loose transactions, without the rest of the block that
contains them). It will make updating to a fixed notification
model significantly easier, as the same "manager" APIs can still
be used, but grouped into a single atomic transaction.

chain/chain.go

@@ -33,11 +33,6 @@ type RPCClient struct {
 	dequeueVotingNotification chan interface{}
 	currentBlock              chan *waddrmgr.BlockStamp
 
-	// Information for reorganization handling.
-	reorganizingLock sync.Mutex
-	reorganizeToHash chainhash.Hash
-	reorganizing     bool
-
 	quit    chan struct{}
 	wg      sync.WaitGroup
 	started bool
@@ -68,8 +63,6 @@ func NewRPCClient(chainParams *chaincfg.Params, connect, user, pass string, cert
 			DisableConnectOnNew:  true,
 			DisableTLS:           disableTLS,
 		},
-		reorganizeToHash:          chainhash.Hash{},
-		reorganizing:              false,
 		chainParams:               chainParams,
 		reconnectAttempts:         reconnectAttempts,
 		enqueueNotification:       make(chan interface{}),
@@ -229,25 +222,6 @@ type (
 	}
 )
 
-// SetReorganizingState allows you to set the flag for blockchain
-// reorganization.
-func (c *RPCClient) SetReorganizingState(is bool, hash chainhash.Hash) {
-	c.reorganizingLock.Lock()
-	defer c.reorganizingLock.Unlock()
-
-	c.reorganizing = is
-	c.reorganizeToHash = hash
-}
-
-// GetReorganizing allows you to get the value of the flag for blockchain
-// reorganization.
-func (c *RPCClient) GetReorganizing() (bool, chainhash.Hash) {
-	c.reorganizingLock.Lock()
-	defer c.reorganizingLock.Unlock()
-
-	return c.reorganizing, c.reorganizeToHash
-}
-
 // Notifications returns a channel of parsed notifications sent by the remote
 // decred RPC server.  This channel must be continually read or the process
 // may abort for running out memory, as unread notifications are queued for

cmd/dropwtxmgr/main.go

@@ -104,7 +104,9 @@ func mainInt() int {
 	}
 	defer db.Close()
 	fmt.Println("Dropping wtxmgr namespace")
-	err = db.DeleteNamespace(wtxmgrNamespace)
+	err = walletdb.Update(db, func(tx walletdb.ReadWriteTx) error {
+		return tx.DeleteTopLevelBucket(wtxmgrNamespace)
+	})
 	if err != nil && err != walletdb.ErrBucketNotFound {
 		fmt.Println("Failed to drop namespace:", err)
 		return 1

goclean.sh

@@ -10,7 +10,7 @@ set -ex
 # Automatic checks
 test -z "$(go fmt $(glide novendor) | tee /dev/stderr)"
 # test -z "$(goimports -l -w . | tee /dev/stderr)"
-test -z "$(for package in $(glide novendor); do golint $package; done | grep -v 'ALL_CAPS\|OP_\|NewFieldVal\|RpcCommand\|RpcRawCommand\|RpcSend\|Dns\|api.pb.go\|StartConsensusRpc\|factory_test.go\|legacy' | tee /dev/stderr)"
+test -z "$(for package in $(glide novendor); do golint $package; done | grep -v 'ALL_CAPS\|OP_\|NewFieldVal\|RpcCommand\|RpcRawCommand\|RpcSend\|Dns\|api.pb.go\|StartConsensusRpc\|factory_test.go\|legacy\|UnstableAPI' | tee /dev/stderr)"
 test -z "$(go vet $(glide novendor) 2>&1 | grep -v '^exit status \|Example\|newestSha\| not a string in call to Errorf$' | tee /dev/stderr)"
 ############RE-ENABLE THIS WHEN TESTS ARE FIXED!!!!!!!!!!!###############
 #env GORACE="halt_on_error=1" go test -v -race $(glide novendor)