Add ScopedTaskSuspend and its test

util/mach/scoped_task_suspend_test.cc

Index: util/mach/scoped_task_suspend_test.cc
diff --git a/util/mach/scoped_task_suspend_test.cc b/util/mach/scoped_task_suspend_test.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c8606a0f6948696020ea0d3e6f7716ac84d6a62b
--- /dev/null
+++ b/util/mach/scoped_task_suspend_test.cc
@@ -0,0 +1,87 @@
+// Copyright 2014 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "util/mach/scoped_task_suspend.h"
+
+#include <mach/mach.h>
+
+#include "gtest/gtest.h"
+#include "util/file/fd_io.h"
+#include "util/test/mac/mach_errors.h"
+#include "util/test/mac/mach_multiprocess.h"
+
+namespace crashpad {
+namespace test {
+namespace {
+
+int SuspendCount(task_t task) {
+  // As of the 10.8 SDK, the preferred routine is MACH_TASK_BASIC_INFO.
+  // TASK_BASIC_INFO_64 is equivalent and works on earlier systems.
+  task_basic_info_64 task_basic_info;
+  mach_msg_type_number_t task_basic_info_count = TASK_BASIC_INFO_64_COUNT;
+  kern_return_t kr = task_info(task,
+                               TASK_BASIC_INFO_64,
+                               reinterpret_cast<task_info_t>(&task_basic_info),
+                               &task_basic_info_count);
+  if (kr != KERN_SUCCESS) {
+    ADD_FAILURE() << MachErrorMessage(kr, "task_info");
+    return -1;
+  }
+
+  return task_basic_info.suspend_count;
+}
+
+class ScopedTaskSuspendTest final : public MachMultiprocess {
+ public:
+  ScopedTaskSuspendTest() : MachMultiprocess() {}
+  ~ScopedTaskSuspendTest() {}
+
+ private:
+  // MachMultiprocess:
+
+  virtual void MachMultiprocessParent() override {
+    task_t child_task = ChildTask();
+
+    EXPECT_EQ(0, SuspendCount(child_task));
+
+    {
+      ScopedTaskSuspend suspend(child_task);
+      EXPECT_EQ(1, SuspendCount(child_task));
+
+      {
+        ScopedTaskSuspend suspend_again(child_task);
+        EXPECT_EQ(2, SuspendCount(child_task));
+      }
+
+      EXPECT_EQ(1, SuspendCount(child_task));
+    }
+
+    EXPECT_EQ(0, SuspendCount(child_task));
+  }
+
+  virtual void MachMultiprocessChild() override {
+    CheckedReadFDAtEOF(ReadPipeFD());
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedTaskSuspendTest);
+};
+
+TEST(ScopedTaskSuspend, ScopedTaskSuspend) {
+  ScopedTaskSuspendTest scoped_task_suspend_test;
+  scoped_task_suspend_test.Run();
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace crashpad