unix, windows: add uv_stop, stop running event loop

build.mk

@@ -85,6 +85,7 @@ TESTS= \
 	test/test-ipc.o \
 	test/test-ipc-send-recv.o \
 	test/test-loop-handles.o \
+	test/test-loop-stop.o \
 	test/test-multiple-listen.o \
 	test/test-mutexes.o \
 	test/test-pass-always.o \

include/uv.h

@@ -258,6 +258,14 @@ UV_EXTERN uv_loop_t* uv_default_loop(void);
  */
 UV_EXTERN int uv_run(uv_loop_t*, uv_run_mode mode);
 
+/*
+ * This function will stop the event loop by forcing uv_run to end
+ * as soon as possible, but not sooner than the next loop iteration.
+ * If this function was called before blocking for i/o, the loop won't
+ * block for i/o on this iteration.
+ */
+UV_EXTERN void uv_stop(uv_loop_t*);
+
 /*
  * Manually modify the event loop's reference count. Useful if the user wants
  * to have a handle or timeout that doesn't keep the loop alive.
@@ -1934,6 +1942,8 @@ struct uv_loop_s {
   unsigned int active_handles;
   ngx_queue_t handle_queue;
   ngx_queue_t active_reqs;
+  /* Internal flag to signal loop stop */
+  unsigned int stop_flag;
   UV_LOOP_PRIVATE_FIELDS
 };
 

src/unix/core.c

@@ -280,18 +280,26 @@ static int uv__loop_alive(uv_loop_t* loop) {
 
 
 int uv_run(uv_loop_t* loop, uv_run_mode mode) {
-  int r;
+  int r, timeout;
 
   if (!uv__loop_alive(loop))
     return 0;
 
   do {
+    if (loop->stop_flag) {
+      loop->stop_flag = 0;
+      return uv__loop_alive(loop);
+    }
     uv__update_time(loop);
     uv__run_timers(loop);
     uv__run_idle(loop);
     uv__run_prepare(loop);
     uv__run_pending(loop);
-    uv__io_poll(loop, (mode & UV_RUN_NOWAIT ? 0 : uv_backend_timeout(loop)));
+    if (mode & UV_RUN_NOWAIT || loop->stop_flag)
+      timeout = 0;
+    else
+      timeout = uv_backend_timeout(loop);
+    uv__io_poll(loop, timeout);
     uv__run_check(loop);
     uv__run_closing_handles(loop);
     r = uv__loop_alive(loop);

src/unix/loop.c

@@ -57,6 +57,7 @@ int uv__loop_init(uv_loop_t* loop, int default_loop) {
   loop->emfile_fd = -1;
 
   loop->timer_counter = 0;
+  loop->stop_flag = 0;
 
   if (uv__platform_loop_init(loop, default_loop))
     return -1;

src/uv-common.c

@@ -377,3 +377,8 @@ void uv_ref(uv_handle_t* handle) {
 void uv_unref(uv_handle_t* handle) {
   uv__handle_unref(handle);
 }
+
+
+void uv_stop(uv_loop_t* loop) {
+  loop->stop_flag = 1;
+}

src/win/core.c

@@ -270,6 +270,10 @@ int uv_run(uv_loop_t *loop, uv_run_mode mode) {
     return 0;
 
   do {
+    if (loop->stop_flag) {
+      loop->stop_flag = 0;
+      return uv__loop_alive(loop);
+    }
     uv_update_time(loop);
     uv_process_timers(loop);
 
@@ -287,6 +291,7 @@ int uv_run(uv_loop_t *loop, uv_run_mode mode) {
     (*poll)(loop, loop->idle_handles == NULL &&
                   loop->pending_reqs_tail == NULL &&
                   loop->endgame_handles == NULL &&
+                  !loop->stop_flag &&
                   (loop->active_handles > 0 ||
                    !ngx_queue_empty(&loop->active_reqs)) &&
                   !(mode & UV_RUN_NOWAIT));

test/test-list.h

@@ -23,6 +23,7 @@ TEST_DECLARE   (platform_output)
 TEST_DECLARE   (callback_order)
 TEST_DECLARE   (run_once)
 TEST_DECLARE   (run_nowait)
+TEST_DECLARE   (loop_stop)
 TEST_DECLARE   (barrier_1)
 TEST_DECLARE   (barrier_2)
 TEST_DECLARE   (barrier_3)
@@ -230,6 +231,7 @@ TASK_LIST_START
 #endif
   TEST_ENTRY  (run_once)
   TEST_ENTRY  (run_nowait)
+  TEST_ENTRY  (loop_stop)
   TEST_ENTRY  (barrier_1)
   TEST_ENTRY  (barrier_2)
   TEST_ENTRY  (barrier_3)

test/test-loop-stop.c

@@ -0,0 +1,55 @@
+/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "uv.h"
+#include "task.h"
+
+static uv_timer_t timer_handle;
+static int timer_called = 0;
+static int num_ticks = 10;
+
+
+static void timer_cb(uv_timer_t* handle, int status) {
+  ASSERT(handle == &timer_handle);
+  ASSERT(status == 0);
+  timer_called++;
+  if (timer_called == 1)
+    uv_stop(uv_default_loop());
+  else if (timer_called == num_ticks)
+    uv_timer_stop(handle);
+}
+
+
+TEST_IMPL(loop_stop) {
+  int r;
+  uv_timer_init(uv_default_loop(), &timer_handle);
+  uv_timer_start(&timer_handle, timer_cb, 100, 100);
+
+  r = uv_run(uv_default_loop(), UV_RUN_DEFAULT);
+  ASSERT(r != 0);
+  ASSERT(timer_called == 1);
+
+  r = uv_run(uv_default_loop(), UV_RUN_DEFAULT);
+  ASSERT(r == 0);
+  ASSERT(timer_called == 10);
+
+  return 0;
+}

uv.gyp

@@ -280,6 +280,7 @@
         'test/test-ipc-send-recv.c',
         'test/test-list.h',
         'test/test-loop-handles.c',
+        'test/test-loop-stop.c',
         'test/test-walk-handles.c',
         'test/test-multiple-listen.c',
         'test/test-pass-always.c',