Add ZeroMQ support. Notify blocks and transactions via ZeroMQ

Continues Johnathan Corgan's work.
Publishing multipart messages

Bugfix: Add missing zmq header includes

Bugfix: Adjust build system to link ZeroMQ code for Qt binaries

src/zmq/zmqpublishnotifier.cpp

@@ -0,0 +1,172 @@
+// Copyright (c) 2015 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "zmqpublishnotifier.h"
+#include "main.h"
+#include "util.h"
+
+static std::multimap<std::string, CZMQAbstractPublishNotifier*> mapPublishNotifiers;
+
+// Internal function to send multipart message
+static int zmq_send_multipart(void *sock, const void* data, size_t size, ...)
+{
+    va_list args;
+    va_start(args, size);
+
+    while (1)
+    {
+        zmq_msg_t msg;
+
+        int rc = zmq_msg_init_size(&msg, size);
+        if (rc != 0)
+        {
+            zmqError("Unable to initialize ZMQ msg");
+            return -1;
+        }
+
+        void *buf = zmq_msg_data(&msg);
+        memcpy(buf, data, size);
+
+        data = va_arg(args, const void*);
+
+        rc = zmq_msg_send(&msg, sock, data ? ZMQ_SNDMORE : 0);
+        if (rc == -1)
+        {
+            zmqError("Unable to send ZMQ msg");
+            zmq_msg_close(&msg);
+            return -1;
+        }
+
+        zmq_msg_close(&msg);
+
+        if (!data)
+            break;
+
+        size = va_arg(args, size_t);
+    }
+    return 0;
+}
+
+bool CZMQAbstractPublishNotifier::Initialize(void *pcontext)
+{
+    assert(!psocket);
+
+    // check if address is being used by other publish notifier
+    std::multimap<std::string, CZMQAbstractPublishNotifier*>::iterator i = mapPublishNotifiers.find(address);
+
+    if (i==mapPublishNotifiers.end())
+    {
+        psocket = zmq_socket(pcontext, ZMQ_PUB);
+        if (!psocket)
+        {
+            zmqError("Failed to create socket");
+            return false;
+        }
+
+        int rc = zmq_bind(psocket, address.c_str());
+        if (rc!=0)
+        {
+            zmqError("Failed to bind address");
+            return false;
+        }
+
+        // register this notifier for the address, so it can be reused for other publish notifier
+        mapPublishNotifiers.insert(std::make_pair(address, this));
+        return true;
+    }
+    else
+    {
+        LogPrint("zmq", "  Reuse socket for address %s\n", address);
+
+        psocket = i->second->psocket;
+        mapPublishNotifiers.insert(std::make_pair(address, this));
+
+        return true;
+    }
+}
+
+void CZMQAbstractPublishNotifier::Shutdown()
+{
+    assert(psocket);
+
+    int count = mapPublishNotifiers.count(address);
+
+    // remove this notifier from the list of publishers using this address
+    typedef std::multimap<std::string, CZMQAbstractPublishNotifier*>::iterator iterator;
+    std::pair<iterator, iterator> iterpair = mapPublishNotifiers.equal_range(address);
+
+    for (iterator it = iterpair.first; it != iterpair.second; ++it)
+    {
+        if (it->second==this)
+        {
+            mapPublishNotifiers.erase(it);
+            break;
+        }
+    }
+
+    if (count == 1)
+    {
+        LogPrint("zmq", "Close socket at address %s\n", address);
+        int linger = 0;
+        zmq_setsockopt(psocket, ZMQ_LINGER, &linger, sizeof(linger));
+        zmq_close(psocket);
+    }
+
+    psocket = 0;
+}
+
+bool CZMQPublishHashBlockNotifier::NotifyBlock(const uint256 &hash)
+{
+    LogPrint("zmq", "Publish hash block %s\n", hash.GetHex());
+    char data[32];
+    for (unsigned int i = 0; i < 32; i++)
+        data[31 - i] = hash.begin()[i];
+    int rc = zmq_send_multipart(psocket, "hashblock", 9, data, 32, 0);
+    return rc == 0;
+}
+
+bool CZMQPublishHashTransactionNotifier::NotifyTransaction(const CTransaction &transaction)
+{
+    uint256 hash = transaction.GetHash();
+    LogPrint("zmq", "Publish hash transaction %s\n", hash.GetHex());
+    char data[32];
+    for (unsigned int i = 0; i < 32; i++)
+        data[31 - i] = hash.begin()[i];
+    int rc = zmq_send_multipart(psocket, "hashtx", 6, data, 32, 0);
+    return rc == 0;
+}
+
+bool CZMQPublishRawBlockNotifier::NotifyBlock(const uint256 &hash)
+{
+    LogPrint("zmq", "Publish raw block %s\n", hash.GetHex());
+
+    CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
+    {
+        LOCK(cs_main);
+
+        CBlock block;
+        CBlockIndex* pblockindex = mapBlockIndex[hash];
+
+        if(!ReadBlockFromDisk(block, pblockindex))
+        {
+            zmqError("Can't read block from disk");
+            return false;
+        }
+
+        ss << block;
+    }
+
+    int rc = zmq_send_multipart(psocket, "rawblock", 8, &(*ss.begin()), ss.size(), 0);
+    return rc == 0;
+}
+
+bool CZMQPublishRawTransactionNotifier::NotifyTransaction(const CTransaction &transaction)
+{
+    uint256 hash = transaction.GetHash();
+    LogPrint("zmq", "Publish raw transaction %s\n", hash.GetHex());
+    CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
+    ss << transaction;
+    int rc = zmq_send_multipart(psocket, "rawtx", 5, &(*ss.begin()), ss.size(), 0);
+    return rc == 0;
+}