nodegit · johnhaley81 · May 10, 2016 · Apr 29, 2016
diff --git a/generate/templates/manual/include/async_libgit2_queue_worker.h b/generate/templates/manual/include/async_libgit2_queue_worker.h
@@ -0,0 +1,33 @@
+#ifndef ASYNC_LIBGIT2_QUEUE_WORKER_H
+#define ASYNC_LIBGIT2_QUEUE_WORKER_H
+
+#include <nan.h>
+#include <uv.h>
+#include "../include/thread_pool.h"
+#include "../include/nodegit.h"
+
+
+// Runs WorkComplete of the scheduled AsyncWorker,
+// and destroys it.  This is run in the uv_default_loop event loop.
+NAN_INLINE void AsyncLibgit2Complete (void* data) {
+  Nan::AsyncWorker *worker = static_cast<Nan::AsyncWorker*>(data);
+  worker->WorkComplete();
+  worker->Destroy();
+}
+
+// Runs Execute of the scheduled AyncWorker on the dedicated libgit2 thread /
+// event loop, and schedules the WorkComplete callback to run on the
+// uv_default_loop event loop
+NAN_INLINE void AsyncLibgit2Execute (void *vworker) {
+  // execute the worker
+  Nan::AsyncWorker *worker = static_cast<Nan::AsyncWorker*>(vworker);
+  worker->Execute();
+}
+
+// Schedules the AsyncWorker to run on the dedicated libgit2 thread / event loop,
+// and on completion AsyncLibgit2Complete on the default loop
+NAN_INLINE void AsyncLibgit2QueueWorker (Nan::AsyncWorker* worker) {
+  libgit2ThreadPool.QueueWork(AsyncLibgit2Execute, AsyncLibgit2Complete, worker);
+}
+
+#endif
diff --git a/generate/templates/manual/include/nodegit.h b/generate/templates/manual/include/nodegit.h
@@ -0,0 +1,8 @@
+#ifndef NODEGIT_H
+#define NODEGIT_H
+
+#include "thread_pool.h"
+
+extern ThreadPool libgit2ThreadPool;
+
+#endif
diff --git a/generate/templates/manual/include/thread_pool.h b/generate/templates/manual/include/thread_pool.h
@@ -0,0 +1,45 @@
+#ifndef THREAD_POOL_H
+#define THREAD_POOL_H
+
+#include <uv.h>
+#include <queue>
+
+class ThreadPool {
+  typedef void (*Callback) (void *);
+  struct Work {
+    Callback workCallback;
+    Callback loopCallback;
+    void *data;
+
+    Work(Callback workCallback, Callback loopCallback, void *data)
+      : workCallback(workCallback), loopCallback(loopCallback), data(data) {
+    }
+  };
+
+  // work to be performed on the threadpool
+  std::queue<Work> workQueue;
+  uv_mutex_t workMutex;
+  uv_sem_t workSemaphore;
+  int workInProgressCount;
+
+  // completion callbacks to be performed on the loop
+  std::queue<Work> loopQueue;
+  uv_mutex_t loopMutex;
+  uv_async_t loopAsync;
+
+  static void RunEventQueue(void *threadPool);
+  void RunEventQueue();
+  static void RunLoopCallbacks(uv_async_t* handle);
+  void RunLoopCallbacks();
+public:
+  // Initializes thread pool and spins up the requested number of threads
+  // The provided loop will be used for completion callbacks, whenever
+  // queued work is completed
+  ThreadPool(int numberOfThreads, uv_loop_t *loop);
+  // Queues work on the thread pool, followed by completion call scheduled
+  // on the loop provided in the constructor.
+  // QueueWork should be called on the loop provided in the constructor.
+  void QueueWork(Callback workCallback, Callback loopCallback, void *data);
+};
+
+#endif
diff --git a/generate/templates/manual/src/thread_pool.cc b/generate/templates/manual/src/thread_pool.cc
@@ -0,0 +1,85 @@
+#include "../include/thread_pool.h"
+
+ThreadPool::ThreadPool(int numberOfThreads, uv_loop_t *loop) {
+  uv_mutex_init(&workMutex);
+  uv_sem_init(&workSemaphore, 0);
+
+  uv_async_init(loop, &loopAsync, RunLoopCallbacks);
+  loopAsync.data = this;
+  uv_unref((uv_handle_t *)&loopAsync);
+  uv_mutex_init(&loopMutex);
+
+  workInProgressCount = 0;
+
+  for(int i=0; i<numberOfThreads; i++) {
+    uv_thread_t thread;
+    uv_thread_create(&thread, RunEventQueue, this);
+  }
+}
+
+void ThreadPool::QueueWork(Callback workCallback, Callback loopCallback, void *data) {
+  uv_mutex_lock(&workMutex);
+  // there is work on the thread pool - reference the handle so
+  // node doesn't terminate
+  uv_ref((uv_handle_t *)&loopAsync);
+  workQueue.push(Work(workCallback, loopCallback, data));
+  workInProgressCount++;
+  uv_mutex_unlock(&workMutex);
+  uv_sem_post(&workSemaphore);
+}
+
+void ThreadPool::RunEventQueue(void *threadPool) {
+  static_cast<ThreadPool *>(threadPool)->RunEventQueue();
+}
+
+void ThreadPool::RunEventQueue() {
+  for ( ; ; ) {
+    // wait until there is work to do
+    uv_sem_wait(&workSemaphore);
+    uv_mutex_lock(&workMutex);
+    // the semaphore should guarantee that queue is not empty
+    Work work = workQueue.front();
+    workQueue.pop();
+    uv_mutex_unlock(&workMutex);
+
+    // perform the queued work
+    (*work.workCallback)(work.data);
+
+    // schedule the callback on the loop
+    uv_mutex_lock(&loopMutex);
+    loopQueue.push(work);
+    uv_mutex_unlock(&loopMutex);
+    uv_async_send(&loopAsync);
+  }
+}
+
+void ThreadPool::RunLoopCallbacks(uv_async_t* handle) {
+  static_cast<ThreadPool *>(handle->data)->RunLoopCallbacks();
+}
+
+void ThreadPool::RunLoopCallbacks() {
+  // uv_async_send can coalesce calls, so we are not guaranteed one
+  // RunLoopCallbacks per uv_async_send call
+  // so we always process the entire loopQueue
+  int callbacksCompleted = 0;
+  uv_mutex_lock(&loopMutex);
+  while(!loopQueue.empty()) {
+    Work work = loopQueue.front();
+    loopQueue.pop();
+    uv_mutex_unlock(&loopMutex);
+    // perform the queued loop callback
+    (*work.loopCallback)(work.data);
+    callbacksCompleted++;
+    uv_mutex_lock(&loopMutex);
+  }
+  uv_mutex_unlock(&loopMutex);
+
+  uv_mutex_lock(&workMutex);
+  // if there is no ongoing work / completion processing, node doesn't need
+  // to be prevented from terminating
+  workInProgressCount -= callbacksCompleted;
+  if(!workInProgressCount) {
+    uv_unref((uv_handle_t *)&loopAsync);
+  }
+  uv_mutex_unlock(&workMutex);
+}
diff --git a/generate/templates/partials/async_function.cc b/generate/templates/partials/async_function.cc
@@ -74,7 +74,7 @@ NAN_METHOD({{ cppClassName }}::{{ cppFunctionName }}) {
     {%endif%}
   {%endeach%}
 
-  Nan::AsyncQueueWorker(worker);
+  AsyncLibgit2QueueWorker(worker);
   return;
 }
 

diff --git a/generate/templates/templates/binding.gyp b/generate/templates/templates/binding.gyp
@@ -22,6 +22,7 @@
         "src/convenient_patch.cc",
         "src/convenient_hunk.cc",
         "src/str_array_converter.cc",
+        "src/thread_pool.cc",
         {% each %}
           {% if type != "enum" %}
             "src/{{ name }}.cc",

diff --git a/generate/templates/templates/class_content.cc b/generate/templates/templates/class_content.cc
@@ -12,6 +12,7 @@ extern "C" {
 #include "../include/functions/copy.h"
 #include "../include/{{ filename }}.h"
 #include "nodegit_wrapper.cc"
+#include "../include/async_libgit2_queue_worker.h"
 
 {% each dependencies as dependency %}
   #include "{{ dependency }}"

diff --git a/generate/templates/templates/nodegit.cc b/generate/templates/templates/nodegit.cc
@@ -10,6 +10,7 @@
 
 #include "../include/init_ssh2.h"
 #include "../include/lock_master.h"
+#include "../include/nodegit.h"
 #include "../include/wrapper.h"
 #include "../include/promise_completion.h"
 #include "../include/functions/copy.h"
@@ -80,6 +81,8 @@ void OpenSSL_ThreadSetup() {
   CRYPTO_set_id_callback(OpenSSL_IDCallback);
 }
 
+ThreadPool libgit2ThreadPool(10, uv_default_loop());
+
 extern "C" void init(Local<v8::Object> target) {
   // Initialize thread safety in openssl and libssh2
   OpenSSL_ThreadSetup();