replace native implementation of curl_multi_await with a systemlib one

Summary:
- this actually performs better for most cases than spinning up another thread
 - we've never got the native implementation actually reliable

fixes #8043
fixes #7485

Reviewed By: jano

Differential Revision: D6602518

fbshipit-source-id: a9dce3e46dba474b4fce00604e8dee54c316fc1b

hphp/runtime/ext/curl/config.cmake

@@ -1,13 +1,11 @@
 HHVM_DEFINE_EXTENSION("curl"
   SOURCES
-    curl-multi-await.cpp
     curl-multi-resource.cpp
     curl-pool.cpp
     curl-resource.cpp
     ext_curl.cpp
     curl-share-resource.cpp
   HEADERS
-    curl-multi-await.h
     curl-multi-resource.h
     curl-pool.h
     curl-resource.h

hphp/runtime/ext/curl/ext_curl.cpp

@@ -16,7 +16,6 @@
 */
 
 #include "hphp/runtime/ext/curl/ext_curl.h"
-#include "hphp/runtime/ext/curl/curl-multi-await.h"
 #include "hphp/runtime/ext/curl/curl-multi-resource.h"
 #include "hphp/runtime/ext/curl/curl-pool.h"
 #include "hphp/runtime/ext/curl/curl-resource.h"
@@ -594,19 +593,6 @@ Variant HHVM_FUNCTION(curl_multi_select, const Resource& mh,
   return ret;
 }
 
-Object HHVM_FUNCTION(curl_multi_await, const Resource& mh,
-                                       double timeout /*=1.0*/) {
-  CHECK_MULTI_RESOURCE_THROW(curlm);
-  auto ev = new CurlMultiAwait(curlm, timeout);
-  try {
-    return Object{ev->getWaitHandle()};
-  } catch (...) {
-    assert(false);
-    ev->abandon();
-    throw;
-  }
-}
-
 Variant HHVM_FUNCTION(curl_multi_getcontent, const Resource& ch) {
   CHECK_RESOURCE(curl);
   return curl->getContents();
@@ -1480,7 +1466,6 @@ struct CurlExtension final : Extension {
     HHVM_FE(curl_multi_remove_handle);
     HHVM_FE(curl_multi_exec);
     HHVM_FE(curl_multi_select);
-    HHVM_FE(curl_multi_await);
     HHVM_FE(curl_multi_getcontent);
     HHVM_FE(curl_multi_setopt);
     HHVM_FE(fb_curl_multi_fdset);

hphp/runtime/ext/curl/ext_curl.php

@@ -280,7 +280,7 @@ function curl_multi_select(resource $mh,
  *
  * @param $mh - A cURL multi handle returned from
  *              [`curl_multi_init`](http://php.net/manual/en/function.curl-multi-init.php).
- * @param $timeout - The time to wait for a response indicating some activity.
+ * @param $timeout - The time (in seconds) to wait for a response indicating some activity.
  *
  * @return Awaitable<int> - An `Awaitable` representing the `int` result of the
  *                          activity. If returned `int` is positive, that
@@ -291,12 +291,21 @@ function curl_multi_select(resource $mh,
  *
  * @guide /hack/async/introduction
  * @guide /hack/async/extensions
- *
- * See curl_exec() wrt NoFCallBuiltin.
  */
-<<__Native("NoFCallBuiltin")>>
-function curl_multi_await(resource $mh,
-                          float $timeout = 1.0): Awaitable<int>;
+async function curl_multi_await(
+  resource $mh,
+  float $timeout = 1.0,
+): Awaitable<int> {
+  $finish_by = \microtime(true) + $timeout;
+  do {
+    $result = \curl_multi_select($mh, 0.0);
+    if ($result !== 0) {
+      return $result;
+    }
+    await \HH\Asio\later();
+  } while (\microtime(true) < $finish_by);
+  return 0;
+}
 
 /**
  * Wait for activity on any curl_multi connection