Mojo: Use network service to load non-local Mojo Apps.

mojo/shell/dynamic_service_loader.cc

 // 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.
 
 #include "mojo/shell/dynamic_service_loader.h"
 
-#include "base/location.h"
+#include "base/bind.h"
+#include "base/command_line.h"
+#include "base/file_util.h"
+#include "base/files/file_path.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "mojo/common/data_pipe_utils.h"
+#include "mojo/services/public/interfaces/network/url_loader.mojom.h"
 #include "mojo/shell/context.h"
 #include "mojo/shell/keep_alive.h"
+#include "mojo/shell/switches.h"
+#include "net/base/filename_util.h"
 
 namespace mojo {
 namespace shell {
-
 namespace {
 
-std::string MakeSharedLibraryName(const std::string& file_name) {
-#if defined(OS_WIN)
-  return file_name + ".dll";
-#elif defined(OS_LINUX)
-  return "lib" + file_name + ".so";
-#elif defined(OS_MACOSX)
-  return "lib" + file_name + ".dylib";
-#else
-  NOTREACHED() << "dynamic loading of services not supported";
-  return std::string();
-#endif
-}
+class Loader {
+ public:
+  explicit Loader(scoped_ptr<DynamicServiceRunner> runner)
+      : runner_(runner.Pass()) {
+  }
 
-}  // namespace
+  virtual void Start(const GURL& url,
+                     ScopedMessagePipeHandle service_handle,
+                     Context* context) = 0;
 
-class DynamicServiceLoader::LoadContext : public mojo::shell::Loader::Delegate {
+  void StartService(const base::FilePath& path,
+                    ScopedMessagePipeHandle service_handle,
+                    bool path_is_valid) {
+    if (path_is_valid) {
+      runner_->Start(path, service_handle.Pass(),
+                     base::Bind(&Loader::AppCompleted, base::Unretained(this)));
+    } else {
+      AppCompleted();
+    }
+  }
+
+ protected:
+  virtual ~Loader() {}
+
+ private:
+  void AppCompleted() {
+    delete this;
+  }
+
+  scoped_ptr<DynamicServiceRunner> runner_;
+};
+
+// For loading services via file:// URLs.
+class LocalLoader : public Loader {
  public:
-  LoadContext(DynamicServiceLoader* loader,
-              const GURL& url,
-              ScopedMessagePipeHandle service_handle,
-              scoped_ptr<DynamicServiceRunner> runner)
-      : loader_(loader),
-        url_(url),
-        service_handle_(service_handle.Pass()),
-        runner_(runner.Pass()),
-        keep_alive_(loader->context_) {
-    GURL url_to_load;
+  explicit LocalLoader(scoped_ptr<DynamicServiceRunner> runner)
+      : Loader(runner.Pass()) {
+  }
 
-    if (url.SchemeIs("mojo")) {
-      std::string lib = MakeSharedLibraryName(url.ExtractFileName());
-      url_to_load = GURL(loader->context_->mojo_origin() + "/" + lib);
-    } else {
-      url_to_load = url;
+  virtual void Start(const GURL& url,
+                     ScopedMessagePipeHandle service_handle,
+                     Context* context) OVERRIDE {
+    base::FilePath path;
+    net::FileURLToFilePath(url, &path);
+
+    // TODO(darin): Check if the given file path exists.
+
+    // Complete asynchronously for consistency with NetworkServiceLoader.
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&Loader::StartService,
+                   base::Unretained(this),
+                   path,
+                   base::Passed(&service_handle),
+                   true));
+  }
+};
+
+// For loading services via the network stack.
+class NetworkLoader : public Loader, public URLLoaderClient {
+ public:
+  explicit NetworkLoader(scoped_ptr<DynamicServiceRunner> runner,
+                         NetworkService* network_service)
+      : Loader(runner.Pass()) {
+    network_service->CreateURLLoader(Get(&url_loader_));
+    url_loader_.set_client(this);
+  }
+
+  virtual void Start(const GURL& url,
+                    ScopedMessagePipeHandle service_handle,
+                    Context* context) OVERRIDE {
+    service_handle_ = service_handle.Pass();
+
+    URLRequestPtr request(URLRequest::New());
+    request->url = url.spec();
+    request->follow_redirects = true;
+
+    if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+            switches::kDisableCache)) {
+      request->bypass_cache = true;
     }
 
-    request_ = loader_->context_->loader()->Load(url_to_load, this);
-  }
+    DataPipe data_pipe;
+    url_loader_->Start(request.Pass(), data_pipe.producer_handle.Pass());
 
-  virtual ~LoadContext() {
+    base::CreateTemporaryFile(&file_);
+    common::CopyToFile(data_pipe.consumer_handle.Pass(),
+                       file_,
+                       context->task_runners()->blocking_pool(),
+                       base::Bind(&Loader::StartService,
+                                  base::Unretained(this),
+                                  file_,
+                                  base::Passed(&service_handle_)));
   }
 
  private:
-  // |Loader::Delegate| method:
-  virtual void DidCompleteLoad(const GURL& app_url,
-                               const base::FilePath& app_path,
-                               const std::string* mime_type) OVERRIDE {
-    DVLOG(2) << "Completed load of " << app_url << " (" << url_ << ") to "
-             << app_path.value();
-    DCHECK(loader_->context_->task_runners()->ui_runner()->
-               BelongsToCurrentThread());
+  // URLLoaderClient methods:
+  virtual void OnReceivedRedirect(URLResponsePtr response,
+                                  const String& new_url,
+                                  const String& new_method) OVERRIDE {
+    // TODO(darin): Handle redirects properly!
+  }
+  virtual void OnReceivedResponse(URLResponsePtr response) OVERRIDE {}
+  virtual void OnReceivedError(NetworkErrorPtr error) OVERRIDE {}
+  virtual void OnReceivedEndOfResponseBody() OVERRIDE {}
 
-    runner_->Start(
-        app_path,
-        service_handle_.Pass(),
-        base::Bind(&DynamicServiceLoader::AppCompleted,
-                   base::Unretained(loader_), url_));
-  }
+  NetworkServicePtr network_service_;
+  URLLoaderPtr url_loader_;
+  ScopedMessagePipeHandle service_handle_;
+  base::FilePath file_;
+};
 
-  DynamicServiceLoader* const loader_;
-  const GURL url_;
-  scoped_ptr<mojo::shell::Loader::Job> request_;
-  ScopedMessagePipeHandle service_handle_;
-  scoped_ptr<DynamicServiceRunner> runner_;
-  KeepAlive keep_alive_;
-
-  DISALLOW_COPY_AND_ASSIGN(LoadContext);
-};
+}  // namespace
 
 DynamicServiceLoader::DynamicServiceLoader(
     Context* context,
     scoped_ptr<DynamicServiceRunnerFactory> runner_factory)
     : context_(context),
       runner_factory_(runner_factory.Pass()) {
 }
 
 DynamicServiceLoader::~DynamicServiceLoader() {
-  DCHECK(url_to_load_context_.empty());
 }
 
 void DynamicServiceLoader::LoadService(ServiceManager* manager,
                                        const GURL& url,
                                        ScopedMessagePipeHandle service_handle) {
-  DCHECK(url_to_load_context_.find(url) == url_to_load_context_.end());
-  url_to_load_context_[url] = new LoadContext(
-      this, url, service_handle.Pass(), runner_factory_->Create(context_));
+  scoped_ptr<DynamicServiceRunner> runner = runner_factory_->Create(context_);
+
+  GURL resolved_url;
+  if (url.SchemeIs("mojo")) {
+    resolved_url = context_->mojo_url_resolver()->Resolve(url);
+  } else {
+    resolved_url = url;
+  }
+
+  Loader* loader;
+  if (resolved_url.SchemeIsFile()) {
+    loader = new LocalLoader(runner.Pass());
+  } else {
+    if (!network_service_.get()) {
+      context_->service_manager()->ConnectTo(GURL("mojo:mojo_network_service"),
+                                             &network_service_,
+                                             GURL());
+    }
+    loader = new NetworkLoader(runner.Pass(), network_service_.get());
+  }
+  loader->Start(resolved_url, service_handle.Pass(), context_);
 }
 
 void DynamicServiceLoader::OnServiceError(ServiceManager* manager,
                                           const GURL& url) {
-}
-
-void DynamicServiceLoader::AppCompleted(const GURL& url) {
-  DCHECK(context_->task_runners()->ui_runner()->BelongsToCurrentThread());
-  DVLOG(2) << "App completed (url: " << url << ")";
-
-  LoadContextMap::iterator it = url_to_load_context_.find(url);
-  DCHECK(it != url_to_load_context_.end()) << url;
-
-  LoadContext* doomed = it->second;
-  url_to_load_context_.erase(it);
-
-  delete doomed;
+  // TODO(darin): What should we do about service errors? This implies that
+  // the app closed its handle to the service manager. Maybe we don't care?
 }
 
 }  // namespace shell
 }  // namespace mojo