Cloning a bunch of stuff from the native_client repository at r6528

ppapi/native_client/src/shared/ppapi_proxy/browser_upcall.cc

Index: ppapi/native_client/src/shared/ppapi_proxy/browser_upcall.cc
===================================================================
--- ppapi/native_client/src/shared/ppapi_proxy/browser_upcall.cc	(revision 0)
+++ ppapi/native_client/src/shared/ppapi_proxy/browser_upcall.cc	(revision 0)
@@ -0,0 +1,91 @@
+// Copyright (c) 2010 The Native Client Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
+//
+// This is an early draft of background thread support.
+// Until it is complete, we assume that all functions proxy functions
+// (but CallOnMainThread) are called on the main thread.
+//
+// WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
+//
+// Support for "upcalls" -- RPCs to the browser that are done from other than
+// the main thread.  These calls are synchronized by the ppapi_proxy library
+// at the plugin end.
+
+#include "native_client/src/shared/ppapi_proxy/browser_upcall.h"
+
+#include <new>
+
+#include "native_client/src/include/portability.h"
+#include "native_client/src/include/nacl_macros.h"
+#include "native_client/src/include/nacl_scoped_ptr.h"
+#include "native_client/src/shared/platform/nacl_threads.h"
+#include "native_client/src/shared/ppapi_proxy/browser_callback.h"
+#include "native_client/src/shared/ppapi_proxy/browser_globals.h"
+#include "native_client/src/shared/ppapi_proxy/utility.h"
+#include "native_client/src/shared/srpc/nacl_srpc.h"
+#include "native_client/src/trusted/desc/nacl_desc_wrapper.h"
+#include "ppapi/c/pp_completion_callback.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/c/ppb_core.h"
+#include "srpcgen/upcall.h"
+
+using nacl::DescWrapper;
+using nacl::DescWrapperFactory;
+
+namespace {
+
+// Structure for passing information to the thread.  Shares ownership of
+// the descriptor with the creating routine.  This allows passing ownership
+// to the upcall thread.
+struct UpcallInfo {
+  nacl::scoped_ptr<DescWrapper> wrapper;
+  NaClSrpcChannel* channel;
+};
+
+void WINAPI UpcallThread(void* arg) {
+  // The memory for info was allocated on the creating (browser UI) thread,
+  // but ownership was conferred to the upcall thread for deletion.
+  nacl::scoped_ptr<UpcallInfo> info(reinterpret_cast<UpcallInfo*>(arg));
+  NaClSrpcServerLoop(info->wrapper->desc(),
+                     PpbUpcalls::srpc_methods,
+                     info->channel);
+}
+
+}  // namespace
+
+namespace ppapi_proxy {
+
+DescWrapper* BrowserUpcall::Start(struct NaClThread* nacl_thread,
+                                  NaClSrpcChannel* upcall_channel) {
+  // Create a socket pair for the upcall server.
+  DescWrapperFactory factory;
+  DescWrapper* pair[2] = { NULL, NULL };
+  if (factory.MakeSocketPair(pair)) {
+    return NULL;
+  }
+  nacl::scoped_ptr<DescWrapper> browser_end(pair[0]);
+  nacl::scoped_ptr<DescWrapper> plugin_end(pair[1]);
+  // Create an info node to pass to the thread.
+  nacl::scoped_ptr<UpcallInfo> info(new UpcallInfo);
+  info->wrapper.reset(browser_end.get());
+  info->channel = upcall_channel;
+  // On success, info took ownership of browser_end.
+  browser_end.release();
+  // Create a thread and an SRPC "upcall" server.
+  const int kThreadStackSize = 128 * 1024;
+  if (!NaClThreadCreateJoinable(nacl_thread,
+                                UpcallThread,
+                                info.get(),
+                                kThreadStackSize)) {
+    return NULL;
+  }
+  // On successful thread creation, ownership of info passes to the thread.
+  info.release();
+  // On successful return, the caller gets the plugin_end of the socketpair.
+  return plugin_end.release();
+}
+
+}  // namespace ppapi_proxy