Factor out loading & running of DSOs

mojo/shell/dynamic_service_runner.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_SHELL_DYNAMIC_SERVICE_RUNNER_H_
 #define MOJO_SHELL_DYNAMIC_SERVICE_RUNNER_H_
 
 #include "base/callback_forward.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/native_library.h"
 #include "mojo/public/cpp/system/core.h"
 
 namespace base {
 class FilePath;
 }
 
 namespace mojo {
 namespace shell {
 
 class Context;
 
 // Abstraction for loading a service (from the file system) and running it (on
 // another thread or in a separate process).
 class DynamicServiceRunner {
  public:
   virtual ~DynamicServiceRunner() {}
 
   // Takes ownership of the file at |app_path|. Loads the app in that file and
   // runs it on some other thread/process. |app_completed_callback| is posted
   // (to the thread on which |Start()| was called) after |MojoMain()| completes.
   virtual void Start(const base::FilePath& app_path,
                      ScopedMessagePipeHandle service_handle,
                      const base::Closure& app_completed_callback) = 0;
+
+  // Loads the service in the DSO specificed by |app_path| and prepares it for
+  // execution. Runs the exported function MojoMain() and blocks until it

[viettrungluu, 2014/10/29 23:11:43]

Just say "Runs the DSO's exported MojoMain() on the current thread."

[DaveMoore, 2014/10/30 15:32:56]

Done.

+  // returns.
+  // The NativeLibrary is returned and ownership transfered to the caller.

[viettrungluu, 2014/10/29 23:11:43]

"transfered" -> "transferred"

[DaveMoore, 2014/10/30 15:32:56]

Done.

+  // This is primarilly so if it is to be unloaded through

[viettrungluu, 2014/10/29 23:11:43]

"primarilly" -> "primarily"

Maybe just say:

This is so if it is unloaded at all, this can be done safely after this thread
is destroyed and any thread-local destructors have been executed.

[DaveMoore, 2014/10/30 15:32:56]

Done.

+  // base::UnloadNativeLibrary it can be done so safely after the thread that
+  // the library was loaded on has been destroyed, after safely executing any
+  // thread local destructors.
+  static base::NativeLibrary LoadAndRunService(
+      const base::FilePath& app_path,
+      ScopedMessagePipeHandle service_handle);
 };
 
 class DynamicServiceRunnerFactory {
  public:
   virtual ~DynamicServiceRunnerFactory() {}
   virtual scoped_ptr<DynamicServiceRunner> Create(Context* context) = 0;
 };
 
 // A generic factory.
 template <class DynamicServiceRunnerImpl>
 class DynamicServiceRunnerFactoryImpl : public DynamicServiceRunnerFactory {
  public:
   DynamicServiceRunnerFactoryImpl() {}
   virtual ~DynamicServiceRunnerFactoryImpl() {}
   virtual scoped_ptr<DynamicServiceRunner> Create(Context* context) override {
     return scoped_ptr<DynamicServiceRunner>(
         new DynamicServiceRunnerImpl(context));
   }
 };
 
 }  // namespace shell
 }  // namespace mojo
 
 #endif  // MOJO_SHELL_DYNAMIC_SERVICE_RUNNER_H_