Async file

linux-perf-listener.cc

@@ -1,17 +1,39 @@
 #include <sstream>
+#include <thread>
+#include <array>
+#include <string>
+#include <chrono>
+#include <fstream>
+#include <iostream>
 
 #include "linux-perf.h"
 
 namespace node {
 
+void write_to_file(LinuxPerfHandler* handler) {
+
+  while(handler->IsAlive()) {
+    std::vector<std::string> arr = handler->GetBufferElements(100);
+    if (arr.size() > 0 ) {
+      for(uint i = 0; i < arr.size(); i++) {
+        *(handler->GetFile()) << arr[i];
+      }
+    }
+    std::chrono::milliseconds(1000);
+  }
+}
+
 LinuxPerfHandler::LinuxPerfHandler(v8::Isolate* isolate) : v8::CodeEventHandler(isolate) {
   // TODO(mmarchini):: ideally this should be handled in another thread.
   auto pid = static_cast<int>(uv_os_getpid());
 
   mapFile.open("/tmp/perf-" + std::to_string(pid) + ".map");
+  t = std::thread(write_to_file, this);
 }
 
 LinuxPerfHandler::~LinuxPerfHandler() {
+  alive = false;
+  t.join();
   mapFile.close();
 }
 
@@ -36,10 +58,16 @@ std::string LinuxPerfHandler::FormatName(v8::CodeEvent* code_event) {
 }
 
 void LinuxPerfHandler::Handle(v8::CodeEvent* code_event) {
-  mapFile << std::hex << code_event->GetCodeStartAddress() << " "
+  // std::cout << "Handling event" << std::endl;
+  codeEventStream << std::hex << code_event->GetCodeStartAddress() << " "
           << std::hex << code_event->GetCodeSize() << " "
           << v8::CodeEvent::GetCodeEventTypeName(code_event->GetCodeType())
           << ":" << FormatName(code_event) << std::endl;
+
+  std::lock_guard<std::mutex> lock(mutex_);
+  buffer.push(codeEventStream.str());
+  codeEventStream.str("");
 }
 
+
 }

linux-perf.h

@@ -5,7 +5,12 @@
 #include <nan.h>
 #include <node_object_wrap.h>
 #include <fstream>
-
+#include <queue>
+#include <vector>
+#include <string>
+#include <sstream>
+#include <thread>
+#include <mutex>
 
 namespace node {
 
@@ -14,11 +19,36 @@ class LinuxPerfHandler : public v8::CodeEventHandler {
   explicit LinuxPerfHandler(v8::Isolate* isolate);
   ~LinuxPerfHandler() override;
 
-
   void Handle(v8::CodeEvent* code_event) override;
+
+  std::vector<std::string> GetBufferElements(int n) {
+    int count = 0;
+    std::vector<std::string> values;
+    std::lock_guard<std::mutex> lock(mutex_);
+    while(count < n && !buffer.empty()) {
+      values.push_back(buffer.front());
+      buffer.pop();
+      count++;
+    }
+    return values;
+  }
+
+  bool IsAlive() {
+    return alive;
+  }
+
+  std::ofstream* GetFile() {
+    return &mapFile;
+  }
+
  private:
+  bool alive = true;
+  std::thread t;
   std::ofstream mapFile;
+  std::queue<std::string> buffer;
+  std::stringstream codeEventStream;
   std::string FormatName(v8::CodeEvent* code_event);
+  std::mutex mutex_;
 };
 
 class LinuxPerf : public Nan::ObjectWrap {