Mojo EDK: Introduce MojoQueryHandleSignalsState API

mojo/public/cpp/system/handle.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_PUBLIC_CPP_SYSTEM_HANDLE_H_
 #define MOJO_PUBLIC_CPP_SYSTEM_HANDLE_H_
 
 #include <stdint.h>
 #include <limits>
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "mojo/public/c/system/functions.h"
 #include "mojo/public/c/system/types.h"
+#include "mojo/public/cpp/system/handle_signals_state.h"
 
 namespace mojo {
 
 // OVERVIEW
 //
 // |Handle| and |...Handle|:
 //
 // |Handle| is a simple, copyable wrapper for the C type |MojoHandle| (which is
 // just an integer). Its purpose is to increase type-safety, not provide
 // lifetime management. For the same purpose, we have trivial *subclasses* of
@@ skipping 137 matching lines @@
   MojoHandle* mutable_value() { return &value_; }
   void set_value(MojoHandle value) { value_ = value; }
 
   void Close() {
     DCHECK(is_valid());
     MojoResult result = MojoClose(value_);
     ALLOW_UNUSED_LOCAL(result);
     DCHECK_EQ(MOJO_RESULT_OK, result);
   }
 
+  HandleSignalsState QuerySignalsState() const {
+    HandleSignalsState signals_state;
+    MojoResult result = MojoQueryHandleSignalsState(
+        value_, static_cast<MojoHandleSignalsState*>(&signals_state));
+    DCHECK_EQ(MOJO_RESULT_OK, result);
+    return static_cast<HandleSignalsState>(signals_state);

[yzshen1, 2017/03/14 18:20:45]

nit: no need to static_cast

[Ken Rockot(use gerrit already), 2017/03/14 19:16:19]

Oops, done

+  }
+
  private:
   MojoHandle value_;
 
   // Copying and assignment allowed.
 };
 
 // Should have zero overhead.
 static_assert(sizeof(Handle) == sizeof(MojoHandle), "Bad size for C++ Handle");
 
 // The scoper should also impose no more overhead.
@@ skipping 116 matching lines @@
 }
 
 // Comparison, so that |Handle|s can be used as keys in hash maps.
 inline bool operator==(const Handle a, const Handle b) {
   return a.value() == b.value();
 }
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_SYSTEM_HANDLE_H_