Initialize IPC:ChannelHandle from existing HANDLE

ipc/ipc_channel_win.cc

Index: ipc/ipc_channel_win.cc
diff --git a/ipc/ipc_channel_win.cc b/ipc/ipc_channel_win.cc
index cd313d21a96fbd83af6189696ba60960091d8870..9fc3b89f89d1ee976f79c854d886a4799f588686 100644
--- a/ipc/ipc_channel_win.cc
+++ b/ipc/ipc_channel_win.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
@@ -114,11 +114,41 @@ const std::wstring Channel::ChannelImpl::PipeName(
 bool Channel::ChannelImpl::CreatePipe(const IPC::ChannelHandle &channel_handle,
                                       Mode mode) {
   DCHECK_EQ(INVALID_HANDLE_VALUE, pipe_);
-  const std::wstring pipe_name = PipeName(channel_handle.name);
-  if (mode & MODE_SERVER_FLAG) {
+  std::wstring pipe_name;
+  // If we already have a valid pipe for channel just copy it.
+  if (channel_handle.pipe.handle) {
+    DCHECK(channel_handle.name.empty());
+    pipe_name = L"Not Available";  // Just used for LOG
+    if (!DuplicateHandle(GetCurrentProcess(),
+                         channel_handle.pipe.handle,
+                         GetCurrentProcess(),
+                         &pipe_,
+                         0,
+                         FALSE,
+                         DUPLICATE_SAME_ACCESS)) {
+      LOG(WARNING) << "DuplicateHandle failed. Error :" << GetLastError();
+      return false;
+    }
+#ifndef NDEBUG
+    // Check that the given pipe confirms to the specified mode.  We can
+    // only check for PIPE_TYPE_MESSAGE & PIPE_SERVER_END flags since the
+    // other flags (PIPE_TYPE_BYTE, and PIPE_CLIENT_END) are defined as 0.
+    DWORD flags = 0;
+    GetNamedPipeInfo(channel_handle.pipe.handle, &flags, NULL, NULL, NULL);
+    DCHECK(!(flags & PIPE_TYPE_MESSAGE));
+    if (mode & MODE_SERVER_FLAG) {
+      DCHECK(flags & PIPE_SERVER_END);

[cpu_(ooo_6.6-7.5), 2012/01/23 18:55:34]

This should be return false; here and in line 142.

[amit, 2012/01/23 19:58:41]

Done.

+    } else  if (mode & MODE_CLIENT_FLAG) {
+      DCHECK(!(flags & PIPE_SERVER_END));
+    }
+#endif  // NDEBUG
+  } else if (mode & MODE_SERVER_FLAG) {
+    DCHECK(!channel_handle.pipe.handle);
+    const DWORD open_mode = PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED |
+                            FILE_FLAG_FIRST_PIPE_INSTANCE;
+    pipe_name = PipeName(channel_handle.name);
     pipe_ = CreateNamedPipeW(pipe_name.c_str(),
-                             PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED |
-                              FILE_FLAG_FIRST_PIPE_INSTANCE,
+                             open_mode,
                              PIPE_TYPE_BYTE | PIPE_READMODE_BYTE,
                              1,
                              Channel::kReadBufferSize,
@@ -126,6 +156,8 @@ bool Channel::ChannelImpl::CreatePipe(const IPC::ChannelHandle &channel_handle,
                              5000,
                              NULL);
   } else if (mode & MODE_CLIENT_FLAG) {
+    DCHECK(!channel_handle.pipe.handle);
+    pipe_name = PipeName(channel_handle.name);
     pipe_ = CreateFileW(pipe_name.c_str(),
                         GENERIC_READ | GENERIC_WRITE,
                         0,
@@ -137,6 +169,7 @@ bool Channel::ChannelImpl::CreatePipe(const IPC::ChannelHandle &channel_handle,
   } else {
     NOTREACHED();
   }
+
   if (pipe_ == INVALID_HANDLE_VALUE) {
     // If this process is being closed, the pipe may be gone already.
     LOG(WARNING) << "Unable to create pipe \"" << pipe_name <<