win: open child stdio handles in overlapped-mode (#8113)

This will be used e.g. by the python client for native asyncio support

src/nvim/event/libuv_process.c

@@ -51,12 +51,19 @@ int libuv_process_spawn(LibuvProcess *uvproc)
 
   if (!proc->in.closed) {
     uvproc->uvstdio[0].flags = UV_CREATE_PIPE | UV_READABLE_PIPE;
+#ifdef WIN32
+    uvproc->uvstdio[0].flags |= UV_OVERLAPPED_PIPE;
+#endif
     uvproc->uvstdio[0].data.stream = STRUCT_CAST(uv_stream_t,
                                                  &proc->in.uv.pipe);
   }
 
   if (!proc->out.closed) {
     uvproc->uvstdio[1].flags = UV_CREATE_PIPE | UV_WRITABLE_PIPE;
+#ifdef WIN32
+    // pipe must be readable for IOCP to work.
+    uvproc->uvstdio[1].flags |= UV_READABLE_PIPE | UV_OVERLAPPED_PIPE;
+#endif
     uvproc->uvstdio[1].data.stream = STRUCT_CAST(uv_stream_t,
                                                  &proc->out.uv.pipe);
   }

third-party/cmake/BuildLibuv.cmake

@@ -7,7 +7,7 @@ function(BuildLibuv)
   cmake_parse_arguments(_libuv
     "BUILD_IN_SOURCE"
     "TARGET"
-    "CONFIGURE_COMMAND;BUILD_COMMAND;INSTALL_COMMAND"
+    "PATCH_COMMAND;CONFIGURE_COMMAND;BUILD_COMMAND;INSTALL_COMMAND"
     ${ARGN})
 
   if(NOT _libuv_CONFIGURE_COMMAND AND NOT _libuv_BUILD_COMMAND
@@ -31,6 +31,7 @@ function(BuildLibuv)
       -DUSE_EXISTING_SRC_DIR=${USE_EXISTING_SRC_DIR}
       -P ${CMAKE_CURRENT_SOURCE_DIR}/cmake/DownloadAndExtractFile.cmake
     BUILD_IN_SOURCE ${_libuv_BUILD_IN_SOURCE}
+    PATCH_COMMAND "${_libuv_PATCH_COMMAND}"
     CONFIGURE_COMMAND "${_libuv_CONFIGURE_COMMAND}"
     BUILD_COMMAND "${_libuv_BUILD_COMMAND}"
     INSTALL_COMMAND "${_libuv_INSTALL_COMMAND}")
@@ -41,6 +42,11 @@ set(UNIX_CFGCMD sh ${DEPS_BUILD_DIR}/src/libuv/autogen.sh &&
   --prefix=${DEPS_INSTALL_DIR} --libdir=${DEPS_INSTALL_DIR}/lib
   CC=${DEPS_C_COMPILER})
 
+set(LIBUV_PATCH_COMMAND
+${GIT_EXECUTABLE} -C ${DEPS_BUILD_DIR}/src/libuv init
+  COMMAND ${GIT_EXECUTABLE} -C ${DEPS_BUILD_DIR}/src/libuv apply
+    ${CMAKE_CURRENT_SOURCE_DIR}/patches/libuv-overlapped.patch)
+
 if(UNIX)
   BuildLibuv(
     CONFIGURE_COMMAND ${UNIX_CFGCMD} MAKE=${MAKE_PRG}
@@ -54,6 +60,7 @@ elseif(MINGW AND CMAKE_CROSSCOMPILING)
 
   # Build libuv for the target
   BuildLibuv(
+    PATCH_COMMAND ${LIBUV_PATCH_COMMAND}
     CONFIGURE_COMMAND ${UNIX_CFGCMD} --host=${CROSS_TARGET}
     INSTALL_COMMAND ${MAKE_PRG} V=1 install)
 
@@ -61,6 +68,7 @@ elseif(MINGW)
 
   # Native MinGW
   BuildLibUv(BUILD_IN_SOURCE
+    PATCH_COMMAND ${LIBUV_PATCH_COMMAND}
     BUILD_COMMAND ${CMAKE_MAKE_PROGRAM} -f Makefile.mingw
     INSTALL_COMMAND ${CMAKE_COMMAND} -E make_directory ${DEPS_INSTALL_DIR}/lib
       COMMAND ${CMAKE_COMMAND} -E copy ${DEPS_BUILD_DIR}/src/libuv/libuv.a ${DEPS_INSTALL_DIR}/lib
@@ -72,6 +80,7 @@ elseif(WIN32 AND MSVC)
 
   set(UV_OUTPUT_DIR ${DEPS_BUILD_DIR}/src/libuv/${CMAKE_BUILD_TYPE})
   BuildLibUv(BUILD_IN_SOURCE
+    PATCH_COMMAND ${LIBUV_PATCH_COMMAND}
     CONFIGURE_COMMAND ${CMAKE_COMMAND} -E copy
         ${CMAKE_CURRENT_SOURCE_DIR}/cmake/LibuvCMakeLists.txt
         ${DEPS_BUILD_DIR}/src/libuv/CMakeLists.txt

third-party/patches/libuv-overlapped.patch

@@ -0,0 +1,33 @@
+diff --git a/include/uv.h b/include/uv.h
+index cdd251d8..79b7930e 100644
+--- a/include/uv.h
++++ b/include/uv.h
+@@ -865,7 +865,8 @@ typedef enum {
+    * flags may be specified to create a duplex data stream.
+    */
+   UV_READABLE_PIPE  = 0x10,
+-  UV_WRITABLE_PIPE  = 0x20
++  UV_WRITABLE_PIPE  = 0x20,
++  UV_OVERLAPPED_PIPE = 0x40
+ } uv_stdio_flags;
+ 
+ typedef struct uv_stdio_container_s {
+diff --git a/src/win/process-stdio.c b/src/win/process-stdio.c
+index 032e3093..b53bdea7 100644
+--- a/src/win/process-stdio.c
++++ b/src/win/process-stdio.c
+@@ -131,12 +131,13 @@ static int uv__create_stdio_pipe_pair(uv_loop_t* loop,
+   sa.lpSecurityDescriptor = NULL;
+   sa.bInheritHandle = TRUE;
+ 
++  BOOL overlap = server_pipe->ipc || (flags & UV_OVERLAPPED_PIPE);
+   child_pipe = CreateFileA(pipe_name,
+                            client_access,
+                            0,
+                            &sa,
+                            OPEN_EXISTING,
+-                           server_pipe->ipc ? FILE_FLAG_OVERLAPPED : 0,
++                           overlap ? FILE_FLAG_OVERLAPPED : 0,
+                            NULL);
+   if (child_pipe == INVALID_HANDLE_VALUE) {
+     err = GetLastError();