misc/cgo/test: add Test8517

CL 145890044 did not provide test. Rectify that.

Update #8517

LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/148790043

misc/cgo/test/cgo_test.go

@@ -58,6 +58,7 @@ func Test5242(t *testing.T)                  { test5242(t) }
 func Test8092(t *testing.T)                  { test8092(t) }
 func Test7978(t *testing.T)                  { test7978(t) }
 func Test8694(t *testing.T)                  { test8694(t) }
+func Test8517(t *testing.T)                  { test8517(t) }
 func TestReturnAfterGrow(t *testing.T)       { testReturnAfterGrow(t) }
 func TestReturnAfterGrowFromGo(t *testing.T) { testReturnAfterGrowFromGo(t) }
 

misc/cgo/test/issue8517.go

+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !windows
+
+package cgotest
+
+import "testing"
+
+func test8517(t *testing.T) {
+	t.Skip("skipping windows only test")
+}

misc/cgo/test/issue8517_windows.c

+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "windows.h"
+
+extern void testHandleLeaksCallback();
+
+DWORD WINAPI testHandleLeaksFunc(LPVOID lpThreadParameter)
+{
+	int i;
+	for(i = 0; i < 100; i++) {
+		testHandleLeaksCallback();
+	}
+	return 0;
+}
+
+void testHandleLeaks()
+{
+	HANDLE h;
+	h = CreateThread(NULL, 0, &testHandleLeaksFunc, 0, 0, NULL);
+	WaitForSingleObject(h, INFINITE);
+	CloseHandle(h);
+}

misc/cgo/test/issue8517_windows.go

+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package cgotest
+
+//void testHandleLeaks();
+import "C"
+
+import (
+	"syscall"
+	"testing"
+	"unsafe"
+)
+
+var issue8517counter int
+
+var (
+	kernel32              = syscall.MustLoadDLL("kernel32.dll")
+	getProcessHandleCount = kernel32.MustFindProc("GetProcessHandleCount")
+)
+
+func processHandleCount(t *testing.T) int {
+	const current_process = ^uintptr(0)
+	var c uint32
+	r, _, err := getProcessHandleCount.Call(current_process, uintptr(unsafe.Pointer(&c)))
+	if r == 0 {
+		t.Fatal(err)
+	}
+	return int(c)
+}
+
+func test8517(t *testing.T) {
+	c1 := processHandleCount(t)
+	C.testHandleLeaks()
+	c2 := processHandleCount(t)
+	if c1+issue8517counter <= c2 {
+		t.Fatalf("too many handles leaked: issue8517counter=%v c1=%v c2=%v", issue8517counter, c1, c2)
+	}
+}
+
+//export testHandleLeaksCallback
+func testHandleLeaksCallback() {
+	issue8517counter++
+}