blockchain: make subscriptions arguments read only

There is no need to accept rw channel. Strengthening the type to read-only will allow the caller to ensure control of reading from the provided channel. Closes #2885 Signed-off-by: Ekaterina Pavlova <[email protected]>
nspcc-dev · Dec 28, 2023 · df365e6 · df365e6
1 parent 3176f72
commit df365e6
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Showing 7 changed files with 27 additions and 26 deletions.
diff --git a/internal/fakechain/fakechain.go b/internal/fakechain/fakechain.go
@@ -24,7 +24,7 @@ import (
 type FakeChain struct {
 	config.Blockchain
 	*mempool.Pool
-	blocksCh                 []chan *block.Block
+	blocksCh                 []chan<- *block.Block
 	Blockheight              atomic.Uint32
 	PoolTxF                  func(*transaction.Transaction) error
 	poolTxWithData           func(*transaction.Transaction, any, *mempool.Pool) error
@@ -346,7 +346,7 @@ func (chain *FakeChain) PoolTx(tx *transaction.Transaction, _ ...*mempool.Pool)
 }
 
 // SubscribeForBlocks implements the Blockchainer interface.
-func (chain *FakeChain) SubscribeForBlocks(ch chan *block.Block) {
+func (chain *FakeChain) SubscribeForBlocks(ch chan<- *block.Block) {
 	chain.blocksCh = append(chain.blocksCh, ch)
 }
 

diff --git a/pkg/consensus/consensus.go b/pkg/consensus/consensus.go
@@ -50,7 +50,7 @@ type Ledger interface {
 	GetTransaction(util.Uint256) (*transaction.Transaction, uint32, error)
 	ComputeNextBlockValidators() []*keys.PublicKey
 	PoolTx(t *transaction.Transaction, pools ...*mempool.Pool) error
-	SubscribeForBlocks(ch chan *coreb.Block)
+	SubscribeForBlocks(ch chan<- *coreb.Block)
 	UnsubscribeFromBlocks(ch chan *coreb.Block)
 	GetBaseExecFee() int64
 	CalculateAttributesFee(tx *transaction.Transaction) int64

diff --git a/pkg/core/blockchain.go b/pkg/core/blockchain.go
@@ -1327,27 +1327,27 @@ func (bc *Blockchain) notificationDispatcher() {
 		// These are just sets of subscribers, though modelled as maps
 		// for ease of management (not a lot of subscriptions is really
 		// expected, but maps are convenient for adding/deleting elements).
-		blockFeed        = make(map[chan *block.Block]bool)
-		headerFeed       = make(map[chan *block.Header]bool)
-		txFeed           = make(map[chan *transaction.Transaction]bool)
-		notificationFeed = make(map[chan *state.ContainedNotificationEvent]bool)
-		executionFeed    = make(map[chan *state.AppExecResult]bool)
+		blockFeed        = make(map[chan<- *block.Block]bool)
+		headerFeed       = make(map[chan<- *block.Header]bool)
+		txFeed           = make(map[chan<- *transaction.Transaction]bool)
+		notificationFeed = make(map[chan<- *state.ContainedNotificationEvent]bool)
+		executionFeed    = make(map[chan<- *state.AppExecResult]bool)
 	)
 	for {
 		select {
 		case <-bc.stopCh:
 			return
 		case sub := <-bc.subCh:
 			switch ch := sub.(type) {
-			case chan *block.Header:
+			case chan<- *block.Header:
 				headerFeed[ch] = true
-			case chan *block.Block:
+			case chan<- *block.Block:
 				blockFeed[ch] = true
-			case chan *transaction.Transaction:
+			case chan<- *transaction.Transaction:
 				txFeed[ch] = true
-			case chan *state.ContainedNotificationEvent:
+			case chan<- *state.ContainedNotificationEvent:
 				notificationFeed[ch] = true
-			case chan *state.AppExecResult:
+			case chan<- *state.AppExecResult:
 				executionFeed[ch] = true
 			default:
 				panic(fmt.Sprintf("bad subscription: %T", sub))
@@ -1377,6 +1377,7 @@ func (bc *Blockchain) notificationDispatcher() {
 				}
 				for ch := range executionFeed {
 					ch <- aer
+					//aer := <- ch
 				}
 				for i := range aer.Events {
 					for ch := range notificationFeed {
@@ -2285,7 +2286,7 @@ func (bc *Blockchain) GetConfig() config.Blockchain {
 // Make sure it's read from regularly as not reading these events might affect
 // other Blockchain functions. Make sure you're not changing the received blocks,
 // as it may affect the functionality of Blockchain and other subscribers.
-func (bc *Blockchain) SubscribeForBlocks(ch chan *block.Block) {
+func (bc *Blockchain) SubscribeForBlocks(ch chan<- *block.Block) {
 	bc.subCh <- ch
 }
 
@@ -2295,7 +2296,7 @@ func (bc *Blockchain) SubscribeForBlocks(ch chan *block.Block) {
 // affect other Blockchain functions. Make sure you're not changing the received
 // headers, as it may affect the functionality of Blockchain and other
 // subscribers.
-func (bc *Blockchain) SubscribeForHeadersOfAddedBlocks(ch chan *block.Header) {
+func (bc *Blockchain) SubscribeForHeadersOfAddedBlocks(ch chan<- *block.Header) {
 	bc.subCh <- ch
 }
 
@@ -2305,7 +2306,7 @@ func (bc *Blockchain) SubscribeForHeadersOfAddedBlocks(ch chan *block.Header) {
 // as not reading these events might affect other Blockchain functions. Make sure
 // you're not changing the received transactions, as it may affect the
 // functionality of Blockchain and other subscribers.
-func (bc *Blockchain) SubscribeForTransactions(ch chan *transaction.Transaction) {
+func (bc *Blockchain) SubscribeForTransactions(ch chan<- *transaction.Transaction) {
 	bc.subCh <- ch
 }
 
@@ -2317,7 +2318,7 @@ func (bc *Blockchain) SubscribeForTransactions(ch chan *transaction.Transaction)
 // read from regularly as not reading these events might affect other Blockchain
 // functions. Make sure you're not changing the received notification events, as
 // it may affect the functionality of Blockchain and other subscribers.
-func (bc *Blockchain) SubscribeForNotifications(ch chan *state.ContainedNotificationEvent) {
+func (bc *Blockchain) SubscribeForNotifications(ch chan<- *state.ContainedNotificationEvent) {
 	bc.subCh <- ch
 }
 
@@ -2327,7 +2328,7 @@ func (bc *Blockchain) SubscribeForNotifications(ch chan *state.ContainedNotifica
 // reading these events might affect other Blockchain functions. Make sure you're
 // not changing the received execution results, as it may affect the
 // functionality of Blockchain and other subscribers.
-func (bc *Blockchain) SubscribeForExecutions(ch chan *state.AppExecResult) {
+func (bc *Blockchain) SubscribeForExecutions(ch chan<- *state.AppExecResult) {
 	bc.subCh <- ch
 }
 

diff --git a/pkg/network/server.go b/pkg/network/server.go
@@ -74,7 +74,7 @@ type (
 		PoolTx(t *transaction.Transaction, pools ...*mempool.Pool) error
 		PoolTxWithData(t *transaction.Transaction, data any, mp *mempool.Pool, feer mempool.Feer, verificationFunction func(t *transaction.Transaction, data any) error) error
 		RegisterPostBlock(f func(func(*transaction.Transaction, *mempool.Pool, bool) bool, *mempool.Pool, *block.Block))
-		SubscribeForBlocks(ch chan *block.Block)
+		SubscribeForBlocks(ch chan<- *block.Block)
 		UnsubscribeFromBlocks(ch chan *block.Block)
 	}
 

diff --git a/pkg/services/notary/notary.go b/pkg/services/notary/notary.go
@@ -33,7 +33,7 @@ type (
 		BlockHeight() uint32
 		GetMaxVerificationGAS() int64
 		GetNotaryContractScriptHash() util.Uint160
-		SubscribeForBlocks(ch chan *block.Block)
+		SubscribeForBlocks(ch chan<- *block.Block)
 		UnsubscribeFromBlocks(ch chan *block.Block)
 		VerifyWitness(util.Uint160, hash.Hashable, *transaction.Witness, int64) (int64, error)
 	}

diff --git a/pkg/services/rpcsrv/server.go b/pkg/services/rpcsrv/server.go
@@ -99,11 +99,11 @@ type (
 		HeaderHeight() uint32
 		InitVerificationContext(ic *interop.Context, hash util.Uint160, witness *transaction.Witness) error
 		P2PSigExtensionsEnabled() bool
-		SubscribeForBlocks(ch chan *block.Block)
-		SubscribeForHeadersOfAddedBlocks(ch chan *block.Header)
-		SubscribeForExecutions(ch chan *state.AppExecResult)
-		SubscribeForNotifications(ch chan *state.ContainedNotificationEvent)
-		SubscribeForTransactions(ch chan *transaction.Transaction)
+		SubscribeForBlocks(ch chan<- *block.Block)
+		SubscribeForHeadersOfAddedBlocks(ch chan<- *block.Header)
+		SubscribeForExecutions(ch chan<- *state.AppExecResult)
+		SubscribeForNotifications(ch chan<- *state.ContainedNotificationEvent)
+		SubscribeForTransactions(ch chan<- *transaction.Transaction)
 		UnsubscribeFromBlocks(ch chan *block.Block)
 		UnsubscribeFromHeadersOfAddedBlocks(ch chan *block.Header)
 		UnsubscribeFromExecutions(ch chan *state.AppExecResult)

diff --git a/pkg/services/stateroot/service.go b/pkg/services/stateroot/service.go
@@ -26,7 +26,7 @@ type (
 		GetConfig() config.Blockchain
 		GetDesignatedByRole(role noderoles.Role) (keys.PublicKeys, uint32, error)
 		HeaderHeight() uint32
-		SubscribeForBlocks(ch chan *block.Block)
+		SubscribeForBlocks(ch chan<- *block.Block)
 		UnsubscribeFromBlocks(ch chan *block.Block)
 	}