Implement ServiceManager

mojo/shell/service_manager.cc

+// Copyright 2013 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 "mojo/shell/service_manager.h"
+
+#include "base/bind.h"
+#include "base/callback_helpers.h"
+#include "base/command_line.h"
+#include "base/file_util.h"
+#include "base/scoped_native_library.h"
+#include "base/threading/simple_thread.h"
+#include "mojo/public/bindings/lib/remote_ptr.h"
+#include "mojo/shell/context.h"
+#include "mojo/shell/switches.h"
+#include "mojom/shell.h"
+
+typedef MojoResult (*MojoMainFunction)(MojoHandle pipe);
+
+namespace mojo {
+namespace shell {
+
+class ServiceManager::Service : public ::shell::ShellStub {
+ public:
+  Service(ServiceManager* manager, const GURL& url)
+      : manager_(manager),
+        url_(url) {
+    ScopedMessagePipeHandle shell_handle, service_handle;
+    CreateMessagePipe(&shell_handle, &service_handle);
+    shell_client_.reset(shell_handle.Pass());
+    shell_client_.SetPeer(this);
+    manager_->GetLoaderForURL(url)->Load(url, manager_, service_handle.Pass());
+  }
+
+  virtual ~Service() {}
+
+  void ConnectToClient(ScopedMessagePipeHandle handle) {
+    if (handle.is_valid())
+      shell_client_->AcceptConnection(handle.Pass());
+  }
+
+  virtual void Connect(const String& url,
+                       ScopedMessagePipeHandle client_pipe) MOJO_OVERRIDE {
+    manager_->Connect(GURL(url.To<std::string>()), client_pipe.Pass());
+  }
+
+ private:
+  ServiceManager* manager_;
+  GURL url_;
+  RemotePtr< ::shell::ShellClient> shell_client_;
+  DISALLOW_COPY_AND_ASSIGN(Service);
+};
+
+class ServiceManager::DynamicLoader : public ServiceManager::Loader {
+ public:
+  DynamicLoader(ServiceManager* manager) : manager_(manager) {}

[abarth-chromium, 2013/12/15 22:54:10]

Please mark one-argument constructors explicit.

[DaveMoore, 2013/12/16 17:40:22]

Done.

+  virtual ~DynamicLoader() {}
+
+ private:
+  class Context : public mojo::shell::Loader::Delegate,
+                  public base::DelegateSimpleThread::Delegate {

[abarth-chromium, 2013/12/15 22:54:10]

I think we're going a bit crazy here with nested classes.  This class is now
nested three levels deep...

[DaveMoore, 2013/12/16 17:40:22]

It may be going too far, but it keeps the publicly visible api much cleaner. 
On 2013/12/15 22:54:10, abarth wrote:

+   public:
+    Context(DynamicLoader* loader,
+            const GURL& url,
+            ScopedMessagePipeHandle service_handle)
+        : loader_(loader),
+          url_(url),
+          service_handle_(service_handle.Pass()),
+          weak_factory_(this) {
+      url_ = url;
+      if (url.scheme() == "mojo") {
+        const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+        std::string origin =
+            command_line.GetSwitchValueASCII(switches::kOrigin);
+#if defined(OS_WIN)
+        std::string lib(url.ExtractFileName() + ".dll");
+#elif defined(OS_LINUX)
+        std::string lib("lib" + url.ExtractFileName() + ".so");
+#else
+        std::string lib;
+        NOTREACHED() << "dynamic loading of services not supported";
+        return;
+#endif
+        url_ = GURL(origin + std::string("/") + lib);
+      }
+      request_ = loader_->manager_->context_->loader()->Load(url_, this);
+    }
+
+   private:
+    friend class base::WeakPtrFactory<Context>;
+
+    // From Loader::Delegate.
+    virtual void DidCompleteLoad(const GURL& app_url,
+                                 const base::FilePath& app_path) OVERRIDE {
+      base::AutoLock lock(lock_);

[abarth-chromium, 2013/12/15 22:54:10]

Why is this lock needed?  This is the only line of code that takes this lock,
and this line of code is only ever executed once per instance.

[DaveMoore, 2013/12/16 17:40:22]

Removed.
On 2013/12/15 22:54:10, abarth wrote:

+      app_path_ = app_path;
+      ack_closure_ =
+          base::Bind(&ServiceManager::DynamicLoader::Context::AppCompleted,
+                     weak_factory_.GetWeakPtr());
+      thread_.reset(new base::DelegateSimpleThread(this, "app_thread"));

[abarth-chromium, 2013/12/15 22:54:10]

You don't create the other thread until here....

[DaveMoore, 2013/12/16 17:40:22]

Done.

+      thread_->Start();
+    }
+
+    // From base::DelegateSimpleThread::Delegate.
+    virtual void Run() OVERRIDE {
+      base::ScopedClosureRunner app_deleter(
+          base::Bind(base::IgnoreResult(&base::DeleteFile), app_path_, false));
+      base::ScopedNativeLibrary app_library(
+          base::LoadNativeLibrary(app_path_, NULL));
+      if (!app_library.is_valid()) {
+        LOG(ERROR) << "Failed to load library: " << app_path_.value().c_str();
+        return;
+      }
+
+      MojoMainFunction main_function = reinterpret_cast<MojoMainFunction>(
+          app_library.GetFunctionPointer("MojoMain"));
+      if (!main_function) {
+        LOG(ERROR) << "Entrypoint MojoMain not found.";
+        return;
+      }
+
+      MojoHandle handle = service_handle_.release().value();
+      // |MojoMain()| takes ownership of the app handle.
+      MojoResult result = main_function(handle);
+      if (result < MOJO_RESULT_OK) {
+        LOG(ERROR) << "MojoMain returned an error: " << result;
+        return;
+      }
+      loader_->manager_->context_->task_runners()->ui_runner()->PostTask(
+          FROM_HERE,
+          ack_closure_);
+    }
+
+    void AppCompleted() {
+      thread_->Join();
+      thread_.reset();
+      loader_->url_to_context_.erase(url_);
+      delete this;
+    }
+
+    DynamicLoader* loader_;
+    GURL url_;
+    base::Lock lock_;
+    base::FilePath app_path_;
+    base::Closure ack_closure_;
+    scoped_ptr<mojo::shell::Loader::Job> request_;
+    scoped_ptr<base::DelegateSimpleThread> thread_;
+    ScopedMessagePipeHandle service_handle_;
+    base::WeakPtrFactory<Context> weak_factory_;
+  };
+
+  virtual void Load(const GURL& url,
+                    ServiceManager* manager,
+                    ScopedMessagePipeHandle service_handle)
+      MOJO_OVERRIDE {
+    DCHECK(url_to_context_.find(url) == url_to_context_.end());
+    url_to_context_[url] = new Context(this, url, service_handle.Pass());
+  }
+
+  typedef std::map<GURL, Context*> ContextMap;
+  ContextMap url_to_context_;
+  ServiceManager* manager_;
+};
+
+ServiceManager::Loader::Loader() {}
+ServiceManager::Loader::~Loader() {}
+
+ServiceManager::ServiceManager(Context* context)
+    : context_(context),
+      default_loader_(new DynamicLoader(this)) {
+}
+
+ServiceManager::~ServiceManager() {
+}
+
+void ServiceManager::SetLoaderForURL(Loader* loader, const GURL& gurl) {
+  DCHECK(url_to_loader_.find(gurl) == url_to_loader_.end());
+  url_to_loader_[gurl] = loader;
+}
+
+ServiceManager::Loader* ServiceManager::GetLoaderForURL(const GURL& gurl) {
+  LoaderMap::const_iterator it = url_to_loader_.find(gurl);
+  if (it != url_to_loader_.end())
+    return it->second;
+  return default_loader_.get();
+}
+
+void ServiceManager::Connect(const GURL& url,
+                             ScopedMessagePipeHandle client_handle) {
+  ServiceMap::const_iterator service_it = url_to_service_.find(url);
+  Service* service;
+  if (service_it != url_to_service_.end()) {
+    service = service_it->second;
+  } else {
+    service = new Service(this, url);
+    url_to_service_[url] = service;
+  }
+  service->ConnectToClient(client_handle.Pass());
+}
+
+}  // namespace shell
+}  // namespace mojo