Creating a pexe content handler to translate and run pexes.

services/nacl/pexe_translator_app.cc

+// Copyright 2015 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.
+

[Mark Seaborn, 2015/10/20 22:28:58]

Nit: Can you name this using similar naming to the IRT interface, perhaps?

i.e. "pnacl_translator_compile/link" or (shorter) "pnacl_compile/link"?

[Sean Klein, 2015/10/22 21:50:01]

Done.

+#include <fcntl.h>
+
+#include "base/files/file_util.h"
+#include "mojo/nacl/nonsfi/nexe_launcher_nonsfi.h"
+#include "mojo/public/c/system/main.h"
+#include "mojo/public/cpp/application/application_connection.h"
+#include "mojo/public/cpp/application/application_delegate.h"
+#include "mojo/public/cpp/application/application_runner.h"
+#include "mojo/public/cpp/application/interface_factory.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "services/nacl/pexe_translator.mojom.h"
+
+namespace mojo {
+namespace nacl {
+
+class PexeTranslatorImpl : public PexeTranslator {
+  public:
+   void PexeTranslate(ScopedMessagePipeHandle handle) override {

[Mark Seaborn, 2015/10/20 22:28:58]

Nit: fix indentation -- this is indented by 3

[Sean Klein, 2015/10/22 21:50:01]

Done.

+//     int nexe_fd = open("native_client/toolchain/linux_x86/pnacl_translator"
+//                        "/translator/x86-32-nonsfi/bin/pnacl-llc.nexe",
+     int nexe_fd = open("sean_out/pnacl-llc.nexe", O_RDONLY);
+     if (nexe_fd < 0)
+       LOG(FATAL) << "Could not open compiler nexe";

[Mark Seaborn, 2015/10/20 22:28:58]

It would be nice to report the filename in these error messages.

[Sean Klein, 2015/10/22 21:50:01]

Done.

+     ::nacl::MojoLaunchNexeNonsfi(nexe_fd, handle.Pass().get().value());

[Mark Seaborn, 2015/10/20 22:28:58]

I think you can do handle.release().value() instead of
handle.Pass().get().value().

[Sean Klein, 2015/10/22 21:50:01]

Done.

+   }
+};
+
+class StrongBindingPexeTranslatorImpl : public PexeTranslatorImpl {

[Mark Seaborn, 2015/10/20 22:28:58]

How come this is a separate class from PexeTranslatorImpl?  Can't the two
classes be combined?

[Sean Klein, 2015/10/22 21:50:01]

This is based on the echo server's model here:
https://github.com/domokit/mojo/blob/master/examples/echo/echo_server.cc
I figured they should be separated for the distinction of StrongBinding.

+  public:
+   explicit StrongBindingPexeTranslatorImpl(InterfaceRequest<PexeTranslator>
+                                            request)
+       : strong_binding_(this, request.Pass()) {}
+
+  private:
+   StrongBinding<PexeTranslator> strong_binding_;
+};
+
+class MultiPexeTranslator : public mojo::ApplicationDelegate,

[Mark Seaborn, 2015/10/20 22:28:58]

What does the "Multi" part mean?  If we try to translate multiple pexes, will
the system create separate translator processes for that, or try to reuse one
process?

[Sean Klein, 2015/10/22 21:50:01]

As I mentioned earlier, I followed a similar structure to the echo server
(https://github.com/domokit/mojo/blob/master/examples/echo/echo_server.cc), and
although it is called "Multi", I think the entire process will be taken over
once the nexe is launched.

Also, as I mentioned in the description:

-I'm unsure how this translation process will react to translating multiple
pexes at the same time (this behavior is thus far untested -- what's the best
way to go about doing these tests?).

I would like to test this behavior, but I do not know how to do so currently
with the Mojo shell.
Ideally, each service request to the pexe_translator_app will get an entirely
new process responding.

+                            public mojo::InterfaceFactory<PexeTranslator> {
+  public:
+   MultiPexeTranslator() {}
+
+   // From ApplicationDelegate
+   bool ConfigureIncomingConnection(
+       mojo::ApplicationConnection* connection) override {
+     connection->AddService<PexeTranslator>(this);
+     return true;
+   }
+
+   // From InterfaceFactory
+   void Create(mojo::ApplicationConnection* connection,
+               mojo::InterfaceRequest<PexeTranslator> request) override {
+     new StrongBindingPexeTranslatorImpl(request.Pass());
+   }
+};
+
+}  // namespace nacl
+}  // namespace mojo
+
+MojoResult MojoMain(MojoHandle application_request) {
+  mojo::ApplicationRunner runner(new mojo::nacl::MultiPexeTranslator());
+  return runner.Run(application_request);
+}