1 files changed, 202 insertions, 0 deletions
diff --git a/src/node/ext/completion_queue_threadpool.cc b/src/node/ext/completion_queue_threadpool.cc
new file mode 100644
index 0000000000..6302e7a103
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+++ b/src/node/ext/completion_queue_threadpool.cc
@@ -0,0 +1,202 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+/* I don't like using #ifndef, but I don't see a better way to do this */
+#ifndef GRPC_UV
+
+#include <node.h>
+#include <nan.h>
+
+#include "grpc/grpc.h"
+#include "grpc/support/log.h"
+#include "grpc/support/time.h"
+#include "completion_queue.h"
+#include "call.h"
+
+namespace grpc {
+namespace node {
+
+namespace {
+
+/* A worker that asynchronously calls completion_queue_next, and queues onto the
+   node event loop a call to the function stored in the event's tag. */
+class CompletionQueueAsyncWorker : public Nan::AsyncWorker {
+ public:
+  CompletionQueueAsyncWorker();
+
+  ~CompletionQueueAsyncWorker();
+  /* Calls completion_queue_next with the provided deadline, and stores the
+     event if there was one or sets an error message if there was not */
+  void Execute();
+
+  /* Returns the completion queue attached to this class */
+  static grpc_completion_queue *GetQueue();
+
+  /* Convenience function to create a worker with the given arguments and queue
+     it to run asynchronously */
+  static void Next();
+
+  /* Initialize the CompletionQueueAsyncWorker class */
+  static void Init(v8::Local<v8::Object> exports);
+
+ protected:
+  /* Called when Execute has succeeded (completed without setting an error
+     message). Calls the saved callback with the event that came from
+     completion_queue_next */
+  void HandleOKCallback();
+
+  void HandleErrorCallback();
+
+ private:
+  grpc_event result;
+
+  static grpc_completion_queue *queue;
+
+  // Number of grpc_completion_queue_next calls in the thread pool
+  static int current_threads;
+  // Number of grpc_completion_queue_next calls waiting to enter the thread pool
+  static int waiting_next_calls;
+};
+
+const int max_queue_threads = 2;
+
+using v8::Function;
+using v8::Local;
+using v8::Object;
+using v8::Value;
+
+grpc_completion_queue *CompletionQueueAsyncWorker::queue;
+
+// Invariants: current_threads <= max_queue_threads
+// (current_threads == max_queue_threads) || (waiting_next_calls == 0)
+
+int CompletionQueueAsyncWorker::current_threads;
+int CompletionQueueAsyncWorker::waiting_next_calls;
+
+CompletionQueueAsyncWorker::CompletionQueueAsyncWorker()
+    : Nan::AsyncWorker(NULL) {}
+
+CompletionQueueAsyncWorker::~CompletionQueueAsyncWorker() {}
+
+void CompletionQueueAsyncWorker::Execute() {
+  result =
+      grpc_completion_queue_next(queue, gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+  if (!result.success) {
+    SetErrorMessage("The async function encountered an error");
+  }
+}
+
+grpc_completion_queue *CompletionQueueAsyncWorker::GetQueue() { return queue; }
+
+void CompletionQueueAsyncWorker::Next() {
+#ifndef GRPC_UV
+  Nan::HandleScope scope;
+  if (current_threads < max_queue_threads) {
+    current_threads += 1;
+    CompletionQueueAsyncWorker *worker = new CompletionQueueAsyncWorker();
+    Nan::AsyncQueueWorker(worker);
+  } else {
+    waiting_next_calls += 1;
+  }
+  GPR_ASSERT(current_threads <= max_queue_threads);
+  GPR_ASSERT((current_threads == max_queue_threads) ||
+             (waiting_next_calls == 0));
+#endif
+}
+
+void CompletionQueueAsyncWorker::Init(Local<Object> exports) {
+  Nan::HandleScope scope;
+  current_threads = 0;
+  waiting_next_calls = 0;
+  queue = grpc_completion_queue_create(NULL);
+}
+
+void CompletionQueueAsyncWorker::HandleOKCallback() {
+  Nan::HandleScope scope;
+  if (waiting_next_calls > 0) {
+    waiting_next_calls -= 1;
+    // Old worker removed, new worker added. current_threads += 0
+    CompletionQueueAsyncWorker *worker = new CompletionQueueAsyncWorker();
+    Nan::AsyncQueueWorker(worker);
+  } else {
+    current_threads -= 1;
+  }
+  GPR_ASSERT(current_threads <= max_queue_threads);
+  GPR_ASSERT((current_threads == max_queue_threads) ||
+             (waiting_next_calls == 0));
+  Nan::Callback *callback = GetTagCallback(result.tag);
+  Local<Value> argv[] = {Nan::Null(), GetTagNodeValue(result.tag)};
+  callback->Call(2, argv);
+
+  DestroyTag(result.tag);
+}
+
+void CompletionQueueAsyncWorker::HandleErrorCallback() {
+  if (waiting_next_calls > 0) {
+    waiting_next_calls -= 1;
+    // Old worker removed, new worker added. current_threads += 0
+    CompletionQueueAsyncWorker *worker = new CompletionQueueAsyncWorker();
+    Nan::AsyncQueueWorker(worker);
+  } else {
+    current_threads -= 1;
+  }
+  GPR_ASSERT(current_threads <= max_queue_threads);
+  GPR_ASSERT((current_threads == max_queue_threads) ||
+             (waiting_next_calls == 0));
+  Nan::HandleScope scope;
+  Nan::Callback *callback = GetTagCallback(result.tag);
+  Local<Value> argv[] = {Nan::Error(ErrorMessage())};
+
+  callback->Call(1, argv);
+
+  DestroyTag(result.tag);
+}
+
+}  // namespace
+
+grpc_completion_queue *GetCompletionQueue() {
+  return CompletionQueueAsyncWorker::GetQueue();
+}
+
+void CompletionQueueNext() {
+  CompletionQueueAsyncWorker::Next();
+}
+
+void CompletionQueueInit(Local<Object> exports) {
+  CompletionQueueAsyncWorker::Init(exports);
+}
+
+}  // namespace node
+}  // namespace grpc
+
+#endif  /* GRPC_UV */