zmq: Pass lambda to zmq's ZMQPublishRawBlockNotifier

The lambda captures a reference to the chainman unique_ptr to retrieve
block data. An assert is added on the chainman to ensure that the lambda
is not used while the chainman is uninitialized.

This is done in preparation for the following commits where blockstorage
functions are made BlockManager methods.

6 files changed, 21 insertions, 9 deletions

diff --git a/src/init.cpp b/src/init.cpp
index 5c05b55f0d..2f3521a103 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1424,7 +1424,11 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     }
 
 #if ENABLE_ZMQ
-    g_zmq_notification_interface = CZMQNotificationInterface::Create();
+    g_zmq_notification_interface = CZMQNotificationInterface::Create(
+        [&chainman = node.chainman](CBlock& block, const CBlockIndex& index) {
+            assert(chainman);
+            return node::ReadBlockFromDisk(block, &index, chainman->GetConsensus());
+        });
 
     if (g_zmq_notification_interface) {
         RegisterValidationInterface(g_zmq_notification_interface.get());
diff --git a/src/zmq/zmqabstractnotifier.h b/src/zmq/zmqabstractnotifier.h
index cf0ee48f47..17fa7bbaa9 100644
--- a/src/zmq/zmqabstractnotifier.h
+++ b/src/zmq/zmqabstractnotifier.h
@@ -6,6 +6,7 @@
 #define BITCOIN_ZMQ_ZMQABSTRACTNOTIFIER_H
 
 #include <cstdint>
+#include <functional>
 #include <memory>
 #include <string>
 
@@ -13,7 +14,7 @@ class CBlockIndex;
 class CTransaction;
 class CZMQAbstractNotifier;
 
-using CZMQNotifierFactory = std::unique_ptr<CZMQAbstractNotifier> (*)();
+using CZMQNotifierFactory = std::function<std::unique_ptr<CZMQAbstractNotifier>()>;
 
 class CZMQAbstractNotifier
 {
diff --git a/src/zmq/zmqnotificationinterface.cpp b/src/zmq/zmqnotificationinterface.cpp
index 2ed0c93fc3..6755368249 100644
--- a/src/zmq/zmqnotificationinterface.cpp
+++ b/src/zmq/zmqnotificationinterface.cpp
@@ -39,12 +39,14 @@ std::list<const CZMQAbstractNotifier*> CZMQNotificationInterface::GetActiveNotif
     return result;
 }
 
-std::unique_ptr<CZMQNotificationInterface> CZMQNotificationInterface::Create()
+std::unique_ptr<CZMQNotificationInterface> CZMQNotificationInterface::Create(std::function<bool(CBlock&, const CBlockIndex&)> get_block_by_index)
 {
     std::map<std::string, CZMQNotifierFactory> factories;
     factories["pubhashblock"] = CZMQAbstractNotifier::Create<CZMQPublishHashBlockNotifier>;
     factories["pubhashtx"] = CZMQAbstractNotifier::Create<CZMQPublishHashTransactionNotifier>;
-    factories["pubrawblock"] = CZMQAbstractNotifier::Create<CZMQPublishRawBlockNotifier>;
+    factories["pubrawblock"] = [&get_block_by_index]() -> std::unique_ptr<CZMQAbstractNotifier> {
+        return std::make_unique<CZMQPublishRawBlockNotifier>(get_block_by_index);
+    };
     factories["pubrawtx"] = CZMQAbstractNotifier::Create<CZMQPublishRawTransactionNotifier>;
     factories["pubsequence"] = CZMQAbstractNotifier::Create<CZMQPublishSequenceNotifier>;
 
diff --git a/src/zmq/zmqnotificationinterface.h b/src/zmq/zmqnotificationinterface.h
index 4aef87c5a4..ce67633b30 100644
--- a/src/zmq/zmqnotificationinterface.h
+++ b/src/zmq/zmqnotificationinterface.h
@@ -9,6 +9,7 @@
 #include <validationinterface.h>
 
 #include <cstdint>
+#include <functional>
 #include <list>
 #include <memory>
 
@@ -23,7 +24,7 @@ public:
 
     std::list<const CZMQAbstractNotifier*> GetActiveNotifiers() const;
 
-    static std::unique_ptr<CZMQNotificationInterface> Create();
+    static std::unique_ptr<CZMQNotificationInterface> Create(std::function<bool(CBlock&, const CBlockIndex&)> get_block_by_index);
 
 protected:
     bool Initialize();
diff --git a/src/zmq/zmqpublishnotifier.cpp b/src/zmq/zmqpublishnotifier.cpp
index 55f3d4e934..21aa44c309 100644
--- a/src/zmq/zmqpublishnotifier.cpp
+++ b/src/zmq/zmqpublishnotifier.cpp
@@ -39,8 +39,6 @@ namespace Consensus {
 struct Params;
 }
 
-using node::ReadBlockFromDisk;
-
 static std::multimap<std::string, CZMQAbstractPublishNotifier*> mapPublishNotifiers;
 
 static const char *MSG_HASHBLOCK = "hashblock";
@@ -247,10 +245,9 @@ bool CZMQPublishRawBlockNotifier::NotifyBlock(const CBlockIndex *pindex)
 {
     LogPrint(BCLog::ZMQ, "Publish rawblock %s to %s\n", pindex->GetBlockHash().GetHex(), this->address);
 
-    const Consensus::Params& consensusParams = Params().GetConsensus();
     CDataStream ss(SER_NETWORK, PROTOCOL_VERSION | RPCSerializationFlags());
     CBlock block;
-    if (!ReadBlockFromDisk(block, pindex, consensusParams)) {
+    if (!m_get_block_by_index(block, *pindex)) {
         zmqError("Can't read block from disk");
         return false;
     }
diff --git a/src/zmq/zmqpublishnotifier.h b/src/zmq/zmqpublishnotifier.h
index 18336a5eb0..a5cd433761 100644
--- a/src/zmq/zmqpublishnotifier.h
+++ b/src/zmq/zmqpublishnotifier.h
@@ -9,7 +9,9 @@
 
 #include <cstddef>
 #include <cstdint>
+#include <functional>
 
+class CBlock;
 class CBlockIndex;
 class CTransaction;
 
@@ -46,7 +48,12 @@ public:
 
 class CZMQPublishRawBlockNotifier : public CZMQAbstractPublishNotifier
 {
+private:
+    const std::function<bool(CBlock&, const CBlockIndex&)> m_get_block_by_index;
+
 public:
+    CZMQPublishRawBlockNotifier(std::function<bool(CBlock&, const CBlockIndex&)> get_block_by_index)
+        : m_get_block_by_index{std::move(get_block_by_index)} {}
     bool NotifyBlock(const CBlockIndex *pindex) override;
 };