dbus: add support for passing file descriptors

dbus/message_unittest.cc

 // Copyright (c) 2012 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.
 
 #include "dbus/message.h"
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "dbus/object_path.h"
@@ skipping 22 matching lines @@
 
   // Try to get another byte. Should fail.
   ASSERT_FALSE(reader.PopByte(&byte_value));
 }
 
 // Check all basic types can be properly written and read.
 TEST(MessageTest, AppendAndPopBasicDataTypes) {
   scoped_ptr<dbus::Response> message(dbus::Response::CreateEmpty());
   dbus::MessageWriter writer(message.get());
 
-  // Append 0, 1, 2, 3, 4, 5, 6, 7, 8, "string", "/object/path".
+  // Append 0, 1, 2, 3, 4, 5, 6, 7, 8, "string", "/object/path", stdout.
   writer.AppendByte(0);
   writer.AppendBool(true);
   writer.AppendInt16(2);
   writer.AppendUint16(3);
   writer.AppendInt32(4);
   writer.AppendUint32(5);
   writer.AppendInt64(6);
   writer.AppendUint64(7);
   writer.AppendDouble(8.0);
   writer.AppendString("string");
@@ skipping 33 matching lines @@
   EXPECT_EQ(3U, uint16_value);
   EXPECT_EQ(4, int32_value);
   EXPECT_EQ(5U, uint32_value);
   EXPECT_EQ(6, int64_value);
   EXPECT_EQ(7U, uint64_value);
   EXPECT_DOUBLE_EQ(8.0, double_value);
   EXPECT_EQ("string", string_value);
   EXPECT_EQ(dbus::ObjectPath("/object/path"), object_path_value);
 }
 
+#if defined(DBUS_TYPE_UNIX_FD)
+// Check all basic types can be properly written and read.
+TEST(MessageTest, AppendAndPopFileDescriptor) {

[satorux1, 2012/03/28 00:32:43]

If we are to go with  kDBusTypeUnixFdIsSupported,  you can add

  if (!kDBusTypeUnixFdIsSupported)
    return;

and get rid of #ifdef around the function.

[Sam Leffler, 2012/03/28 17:28:09]

Unless kDBusTypeUnixFdIsSupported is defined in message.h or similar I'll be
replacing 1 #if by 6+ lines of boilerplate.

+  scoped_ptr<dbus::Response> message(dbus::Response::CreateEmpty());
+  dbus::MessageWriter writer(message.get());
+
+  // Append stdout.
+  writer.AppendFileDescriptor(dbus::FileDescriptor(1));
+
+  FileDescriptor fd_value;
+
+  dbus::MessageReader reader(message.get());
+  ASSERT_TRUE(reader.HasMoreData());
+  ASSERT_TRUE(reader.PopFileDescriptor(&fd_value));
+  ASSERT_FALSE(reader.HasMoreData());
+
+  // stdout should be returned.
+  EXPECT_EQ(1, fd_value.value());

[keybuk, 2012/03/27 22:36:35]

does this pass? I would be hella-surprised if the returned file descriptor was
actually == 1, it should be a new file descriptor referring to the same
underlying file

[Sam Leffler, 2012/03/27 23:20:40]

It did pass but what you say seems right so let me re-check.

+}
+#endif
+
 // Check all variant types can be properly written and read.
 TEST(MessageTest, AppendAndPopVariantDataTypes) {
   scoped_ptr<dbus::Response> message(dbus::Response::CreateEmpty());
   dbus::MessageWriter writer(message.get());
 
   // Append 0, 1, 2, 3, 4, 5, 6, 7, 8, "string", "/object/path".
   writer.AppendVariantOfByte(0);
   writer.AppendVariantOfBool(true);
   writer.AppendVariantOfInt16(2);
   writer.AppendVariantOfUint16(3);
@@ skipping 426 matching lines @@
 
   EXPECT_EQ("org.chromium.destination", message->GetDestination());
   EXPECT_EQ(dbus::ObjectPath("/org/chromium/path"), message->GetPath());
   EXPECT_EQ("org.chromium.interface", message->GetInterface());
   EXPECT_EQ("member", message->GetMember());
   EXPECT_EQ("org.chromium.error", message->GetErrorName());
   EXPECT_EQ(":1.2", message->GetSender());
   EXPECT_EQ(123U, message->GetSerial());
   EXPECT_EQ(456U, message->GetReplySerial());
 }