add: 添加监听NFD发出的日志信息，并转发到区块链的功能

BlockChainLogger.cpp

@@ -0,0 +1,65 @@
+//
+// Created by sunny on 2020/9/9.
+//
+#include <utility>
+#include "BlockChainLogger.h"
+#include "utils/RingBuffer.h"
+
+
+BlockChainLogger::BlockChainLogger(std::string shareMemoryName,
+                                   std::string host, int port, std::string prefix) :
+    host(std::move(host)), port(port), prefix(std::move(prefix)), face(host, std::to_string(port)),
+    shareMemoryName(std::move(shareMemoryName)) {
+}
+
+void BlockChainLogger::run() {
+  RingBuffer ringBuffer;
+
+  if (!ringBuffer.connect(this->shareMemoryName)) {
+    // 打开共享内存失败，可能是NFD没有启动
+    std::cerr << "连接共享内存: " << shareMemoryName << " => 失败~" << std::endl;
+    exit(-1);
+  }
+  char buffer[4 * 1024 * 1024];
+  int expectedSize = 0;
+  int size = 0;
+  int offset = 0;
+
+  while (true) {
+    if (expectedSize <= 0) {       // 读取一个整型，表示后面跟着的json串的大小
+      size = ringBuffer.read(buffer, 4);
+      if (size <= 0) {    // 没有数据
+//        std::cout << "wait for data" << std::endl;
+        usleep(10000);
+        continue;
+      }
+      expectedSize = *((int *) buffer);
+      offset = 0;
+    }
+    size = ringBuffer.read(buffer + offset, expectedSize);
+    expectedSize -= size;
+    offset += size;
+    if (expectedSize == 0) {   // 读取到完整的一个json串
+      std::string logInfo(buffer, offset);
+      std::cout << logInfo << std::endl;
+
+      // 通过MIN的方式，将日志信息发给区块链
+      Interest interest((Name(prefix)));
+      interest.setMustBeFresh(true);
+      interest.setApplicationParameters((const uint8_t *) buffer, offset);
+      face.expressInterest(interest, [](const Interest &interest1, const Data &data) {
+        // onData
+        std::cout << "onData" << std::endl;
+      }, [](const Interest &interest1, const lp::Nack &nack) {
+        // onNack
+        std::cout << "onNack: " << nack.getReason() << std::endl;
+      }, [](const Interest &interest1) {
+        // onTimeout
+        std::cout << "onTimeout" << std::endl;
+      });
+      face.processEvents();
+    } else {
+//      std::cout << "数据接收不完整" << std::endl;
+    }
+  }
+}