Create the pthread.h portability header

Summary: The primary issue is that the pthread implementation we use for Windows defines `pthread_t` as a struct (yes, it is allowed to do this), which breaks a lot of things.

Reviewed By: yfeldblum

Differential Revision: D2862671

fb-gh-sync-id: 551569b6a9e2e374cf77e186e148b6b397f8f25f
fbshipit-source-id: 551569b6a9e2e374cf77e186e148b6b397f8f25f

folly/Conv.h

@@ -792,6 +792,17 @@ toAppend(const Ts&... vs) {
   ::folly::detail::toAppendStrImpl(vs...);
 }
 
+#ifdef _MSC_VER
+// Special case pid_t on MSVC, because it's a void* rather than an
+// integral type. We can't do a global special case because this is already
+// dangerous enough (as most pointers will implicitly convert to a void*)
+// just doing it for MSVC.
+template <class Tgt>
+void toAppend(const pid_t a, Tgt* res) {
+  toAppend(uint64_t(a), res);
+}
+#endif
+
 /**
  * Special version of the call that preallocates exaclty as much memory
  * as need for arguments to be stored in target. This means we are

folly/Makefile.am

@@ -275,6 +275,7 @@ nobase_follyinclude_HEADERS = \
 	portability/IOVec.h \
 	portability/Malloc.h \
 	portability/Memory.h \
+	portability/PThread.h \
 	portability/String.h \
 	portability/Strings.h \
 	portability/SysFile.h \

folly/io/async/EventBase.cpp

@@ -132,7 +132,7 @@ static std::mutex libevent_mutex_;
 EventBase::EventBase(bool enableTimeMeasurement)
   : runOnceCallbacks_(nullptr)
   , stop_(false)
-  , loopThread_(0)
+  , loopThread_()
   , queue_(nullptr)
   , fnRunner_(nullptr)
   , maxLatency_(0)
@@ -177,7 +177,7 @@ EventBase::EventBase(bool enableTimeMeasurement)
 EventBase::EventBase(event_base* evb, bool enableTimeMeasurement)
   : runOnceCallbacks_(nullptr)
   , stop_(false)
-  , loopThread_(0)
+  , loopThread_()
   , evb_(evb)
   , queue_(nullptr)
   , fnRunner_(nullptr)
@@ -426,7 +426,7 @@ bool EventBase::loopBody(int flags) {
     return false;
   }
 
-  loopThread_.store(0, std::memory_order_release);
+  loopThread_.store({}, std::memory_order_release);
 
   VLOG(5) << "EventBase(): Done with loop.";
   return true;

folly/io/async/NotificationQueue.h

@@ -243,7 +243,7 @@ class NotificationQueue {
       : eventfd_(-1),
         pipeFds_{-1, -1},
         advisoryMaxQueueSize_(maxSize),
-      pid_(getpid()),
+        pid_(pid_t(getpid())),
         queue_() {
 
     RequestContext::saveContext();
@@ -438,9 +438,7 @@ class NotificationQueue {
    * check ensures that we catch the problem in the misbehaving child process
    * code, and crash before signalling the parent process.
    */
-  void checkPid() const {
-    CHECK_EQ(pid_, getpid());
-  }
+  void checkPid() const { CHECK_EQ(pid_, pid_t(getpid())); }
 
  private:
   // Forbidden copy constructor and assignment operator

folly/io/async/SSLContext.cpp

@@ -696,6 +696,8 @@ static unsigned long callbackThreadID() {
   return static_cast<unsigned long>(
 #ifdef __APPLE__
     pthread_mach_thread_np(pthread_self())
+#elif _MSC_VER
+    pthread_getw32threadid_np(pthread_self())
 #else
     pthread_self()
 #endif

folly/portability/PThread.h

+/*
+ * Copyright 2016 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <pthread.h>
+
+#ifdef _WIN32
+// We implement a sane comparison operand for
+// pthread_t and an integer so that it may be
+// compared against 0.
+
+inline bool operator==(pthread_t ptA, unsigned int b) {
+  if (ptA.p == nullptr) {
+    return b == 0;
+  }
+  return pthread_getw32threadid_np(ptA) == b;
+}
+
+inline bool operator!=(pthread_t ptA, unsigned int b) {
+  if (ptA.p == nullptr) {
+    return b != 0;
+  }
+  return pthread_getw32threadid_np(ptA) != b;
+}
+
+inline bool operator==(pthread_t ptA, pthread_t ptB) {
+  return pthread_equal(ptA, ptB) != 0;
+}
+
+inline bool operator!=(pthread_t ptA, pthread_t ptB) {
+  return pthread_equal(ptA, ptB) == 0;
+}
+
+inline bool operator<(pthread_t ptA, pthread_t ptB) {
+  return ptA.p < ptB.p;
+}
+
+inline bool operator!(pthread_t ptA) {
+  return ptA == 0;
+}
+
+inline int pthread_attr_getstack(
+    pthread_attr_t* attr,
+    void** stackaddr,
+    size_t* stacksize) {
+  if (pthread_attr_getstackaddr(attr, stackaddr) != 0) {
+    return -1;
+  }
+  if (pthread_attr_getstacksize(attr, stacksize) != 0) {
+    return -1;
+  }
+  return 0;
+}
+
+inline int
+pthread_attr_setstack(pthread_attr_t* attr, void* stackaddr, size_t stacksize) {
+  if (pthread_attr_setstackaddr(attr, stackaddr) != 0) {
+    return -1;
+  }
+  if (pthread_attr_setstacksize(attr, stacksize) != 0) {
+    return -1;
+  }
+  return 0;
+}
+
+inline int pthread_attr_getguardsize(pthread_attr_t* attr, size_t* guardsize) {
+  *guardsize = 0;
+  return 0;
+}
+
+#include <xstddef>
+namespace std {
+template <>
+struct hash<pthread_t> {
+  std::size_t operator()(const pthread_t& k) const {
+    return 0 ^ std::hash<decltype(k.p)>(k.p) ^ std::hash<decltype(k.x)>(k.x);
+  }
+};
+}
+#endif