[mojo-edk] Bind a child token to child launches and port reservations.

mojo/edk/embedder/embedder.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_EDK_EMBEDDER_EMBEDDER_H_
 #define MOJO_EDK_EMBEDDER_EMBEDDER_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 22 matching lines @@
 
 // |Init()| sets up the basic Mojo system environment, making the |Mojo...()|
 // functions available and functional. This is never shut down (except in tests
 // -- see test_embedder.h).
 
 // Allows changing the default max message size. Must be called before Init.
 MOJO_SYSTEM_IMPL_EXPORT void SetMaxMessageSize(size_t bytes);
 
 // Called in the parent process for each child process that is launched.
 MOJO_SYSTEM_IMPL_EXPORT void ChildProcessLaunched(
-    base::ProcessHandle child_process, ScopedPlatformHandle server_pipe);
+    base::ProcessHandle child_process,
+    ScopedPlatformHandle server_pipe,
+    const std::string& child_token);
+
+// Called in the parent process when a child process fails to launch.
+// Exactly one of ChildProcessLaunched() or ChildProcessLaunchFailed() must be
+// called per child process launch attempt.
+MOJO_SYSTEM_IMPL_EXPORT void ChildProcessLaunchFailed(
+    const std::string& child_token);
 
 // Should be called as early as possible in the child process with the handle
 // that the parent received from ChildProcessLaunched.
 MOJO_SYSTEM_IMPL_EXPORT void SetParentPipeHandle(ScopedPlatformHandle pipe);
 
 // Same as above but extracts the pipe handle from the command line. See
 // PlatformChannelPair for details.
 MOJO_SYSTEM_IMPL_EXPORT void SetParentPipeHandleFromCommandLine();
 
 // Must be called first, or just after setting configuration parameters, to
@@ skipping 89 matching lines @@
 // the channel must also be passed to this function. Either endpoint can be in
 // any process.
 //
 // Note that the channel is only used to negotiate pipe connection, not as the
 // transport for messages on the pipe.
 MOJO_SYSTEM_IMPL_EXPORT ScopedMessagePipeHandle
 CreateMessagePipe(ScopedPlatformHandle platform_handle);
 
 // Creates a message pipe from a token. A child embedder must also have this
 // token and call CreateChildMessagePipe() with it in order for the pipe to get
-// connected.
+// connected. |child_token| identifies the child process and should be the same
+// as the token passed into ChildProcessLaunched(). If they are different, the
+// returned message pipe will not be signaled of peer closure if the child
+// process dies before establishing connection to the pipe.
 MOJO_SYSTEM_IMPL_EXPORT ScopedMessagePipeHandle
-CreateParentMessagePipe(const std::string& token);
+CreateParentMessagePipe(const std::string& token,
+                        const std::string& child_token);
 
 // Creates a message pipe from a token in a child process. The parent must also
 // have this token and call CreateParentMessagePipe() with it in order for the
 // pipe to get connected.
 MOJO_SYSTEM_IMPL_EXPORT ScopedMessagePipeHandle
 CreateChildMessagePipe(const std::string& token);
 
 // Generates a random ASCII token string for use with CreateParentMessagePipe()
 // and CreateChildMessagePipe() above. The generated token is suitably random so
 // as to not have to worry about collisions with other generated tokens.
 MOJO_SYSTEM_IMPL_EXPORT std::string GenerateRandomToken();
 
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_EMBEDDER_EMBEDDER_H_