From 408f6b050edd4d85035d6dce13232ce1ad2bd0bf Mon Sep 17 00:00:00 2001
From: AnnaShaleva <shaleva.ann@gmail.com>
Date: Mon, 21 Feb 2022 16:06:43 +0300
Subject: [PATCH] rpc: make RPC Client thread-safe

---
 pkg/rpc/client/client.go |  6 ++++++
 pkg/rpc/client/rpc.go    | 15 +++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/pkg/rpc/client/client.go b/pkg/rpc/client/client.go
index 4f41bd10b..4dfc40ef4 100644
--- a/pkg/rpc/client/client.go
+++ b/pkg/rpc/client/client.go
@@ -9,6 +9,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"sync"
 	"time"
 
 	"github.com/nspcc-dev/neo-go/pkg/config/netmode"
@@ -34,6 +35,7 @@ type Client struct {
 	opts     Options
 	requestF func(*request.Raw) (*response.Raw, error)
 
+	cacheLock sync.RWMutex
 	// cache stores RPC node related information client is bound to.
 	// cache is mostly filled in during Init(), but can also be updated
 	// during regular Client lifecycle.
@@ -123,6 +125,10 @@ func (c *Client) Init() error {
 	if err != nil {
 		return fmt.Errorf("failed to get network magic: %w", err)
 	}
+
+	c.cacheLock.Lock()
+	defer c.cacheLock.Unlock()
+
 	c.cache.network = version.Protocol.Network
 	c.cache.stateRootInHeader = version.Protocol.StateRootInHeader
 	if version.Protocol.MillisecondsPerBlock == 0 {
diff --git a/pkg/rpc/client/rpc.go b/pkg/rpc/client/rpc.go
index d00ede814..428cb30bb 100644
--- a/pkg/rpc/client/rpc.go
+++ b/pkg/rpc/client/rpc.go
@@ -924,18 +924,23 @@ func (c *Client) CalculateValidUntilBlock() (uint32, error) {
 		return result, fmt.Errorf("can't get block count: %w", err)
 	}
 
+	c.cacheLock.RLock()
 	if c.cache.calculateValidUntilBlock.expiresAt > blockCount {
 		validatorsCount = c.cache.calculateValidUntilBlock.validatorsCount
+		c.cacheLock.RUnlock()
 	} else {
+		c.cacheLock.RUnlock()
 		validators, err := c.GetNextBlockValidators()
 		if err != nil {
 			return result, fmt.Errorf("can't get validators: %w", err)
 		}
 		validatorsCount = uint32(len(validators))
+		c.cacheLock.Lock()
 		c.cache.calculateValidUntilBlock = calculateValidUntilBlockCache{
 			validatorsCount: validatorsCount,
 			expiresAt:       blockCount + cacheTimeout,
 		}
+		c.cacheLock.Unlock()
 	}
 	return blockCount + validatorsCount + 1, nil
 }
@@ -993,6 +998,9 @@ func (c *Client) AddNetworkFee(tx *transaction.Transaction, extraFee int64, accs
 
 // GetNetwork returns the network magic of the RPC node client connected to.
 func (c *Client) GetNetwork() (netmode.Magic, error) {
+	c.cacheLock.RLock()
+	defer c.cacheLock.RUnlock()
+
 	if !c.cache.initDone {
 		return 0, errNetworkNotInitialized
 	}
@@ -1002,6 +1010,9 @@ func (c *Client) GetNetwork() (netmode.Magic, error) {
 // StateRootInHeader returns true if state root is contained in block header.
 // You should initialize Client cache with Init() before calling StateRootInHeader.
 func (c *Client) StateRootInHeader() (bool, error) {
+	c.cacheLock.RLock()
+	defer c.cacheLock.RUnlock()
+
 	if !c.cache.initDone {
 		return false, errNetworkNotInitialized
 	}
@@ -1010,7 +1021,9 @@ func (c *Client) StateRootInHeader() (bool, error) {
 
 // GetNativeContractHash returns native contract hash by its name.
 func (c *Client) GetNativeContractHash(name string) (util.Uint160, error) {
+	c.cacheLock.RLock()
 	hash, ok := c.cache.nativeHashes[name]
+	c.cacheLock.RUnlock()
 	if ok {
 		return hash, nil
 	}
@@ -1018,6 +1031,8 @@ func (c *Client) GetNativeContractHash(name string) (util.Uint160, error) {
 	if err != nil {
 		return util.Uint160{}, err
 	}
+	c.cacheLock.Lock()
 	c.cache.nativeHashes[name] = cs.Hash
+	c.cacheLock.Unlock()
 	return cs.Hash, nil
 }