First cut at "content handling" support in Mojo.

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/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/common_type_converters.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 {
 
-class Loader {
- public:
-  explicit Loader(scoped_ptr<DynamicServiceRunner> runner)
-      : runner_(runner.Pass()) {
-  }
-
-  virtual void Start(const GURL& url,
-                     ScopedMessagePipeHandle service_handle,
-                     Context* context) = 0;
-
-  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:
-  explicit LocalLoader(scoped_ptr<DynamicServiceRunner> runner)
-      : Loader(runner.Pass()) {
-  }
-
-  virtual void Start(const GURL& url,
-                     ScopedMessagePipeHandle service_handle,
-                     Context* context) OVERRIDE {
-    base::FilePath path;
-    net::FileURLToFilePath(url, &path);
-
-    // Complete asynchronously for consistency with NetworkServiceLoader.
-    base::MessageLoop::current()->PostTask(
-        FROM_HERE,
-        base::Bind(&Loader::StartService,
-                   base::Unretained(this),
-                   path,
-                   base::Passed(&service_handle),
-                   base::PathExists(path)));
-  }
-};
-
-// For loading services via the network stack.
-class NetworkLoader : public Loader {
- public:
-  explicit NetworkLoader(scoped_ptr<DynamicServiceRunner> runner,
-                         NetworkService* network_service)
-      : Loader(runner.Pass()) {
-    network_service->CreateURLLoader(Get(&url_loader_));
-  }
-
-  virtual void Start(const GURL& url,
-                    ScopedMessagePipeHandle service_handle,
-                    Context* context) OVERRIDE {
-    service_handle_ = service_handle.Pass();
-    context_ = context;
-
-    URLRequestPtr request(URLRequest::New());
-    request->url = String::From(url);
-    request->auto_follow_redirects = true;
-
-    if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-            switches::kDisableCache)) {
-      request->bypass_cache = true;
-    }
-
-    url_loader_->Start(request.Pass(),
-                       base::Bind(&NetworkLoader::OnReceivedResponse,
-                                  base::Unretained(this)));
-  }
-
- private:
-  virtual ~NetworkLoader() {
-    if (!file_.empty())
-      base::DeleteFile(file_, false);
-  }
-
-  void OnReceivedResponse(URLResponsePtr response) {
-    if (response->error) {
-      LOG(ERROR) << "Error (" << response->error->code << ": "
-                 << response->error->description << ") while fetching "
-                 << response->url;
-    }
-
-    base::CreateTemporaryFile(&file_);
-    common::CopyToFile(response->body.Pass(),
-                       file_,
-                       context_->task_runners()->blocking_pool(),
-                       base::Bind(&Loader::StartService,
-                                  base::Unretained(this),
-                                  file_,
-                                  base::Passed(&service_handle_)));
-  }
-
-  Context* context_;
-  NetworkServicePtr network_service_;
-  URLLoaderPtr url_loader_;
-  ScopedMessagePipeHandle service_handle_;
-  base::FilePath file_;
-};
+void RunLibraryComplete(DynamicServiceRunner* runner,
+                        const base::FilePath& temp_file) {
+  delete runner;
+  if (!temp_file.empty())
+    base::DeleteFile(temp_file, false);
+}
 
 }  // namespace
 
 DynamicServiceLoader::DynamicServiceLoader(
     Context* context,
     scoped_ptr<DynamicServiceRunnerFactory> runner_factory)
     : context_(context),
-      runner_factory_(runner_factory.Pass()) {
+      runner_factory_(runner_factory.Pass()),
+      weak_ptr_factory_(this) {
 }
 
 DynamicServiceLoader::~DynamicServiceLoader() {
 }
 
-void DynamicServiceLoader::LoadService(ServiceManager* manager,
-                                       const GURL& url,
-                                       ScopedMessagePipeHandle shell_handle) {
-  scoped_ptr<DynamicServiceRunner> runner = runner_factory_->Create(context_);
+void DynamicServiceLoader::set_content_handler(

[darin (slow to review), 2014/08/06 23:10:02]

nit: perhaps this method should be called RegisterContentHandler? it seems to be
registering a mime type -> content handler mapping.

[Aaron Boodman, 2014/08/07 00:03:12]

Fair enough. Done.

+    const std::string& mime_type,
+    const GURL& content_handler_url) {
+  mime_type_to_url_[mime_type] = content_handler_url;
+}
 
+void DynamicServiceLoader::LoadService(
+    ServiceManager* manager,
+    const GURL& url,
+    scoped_refptr<LoadServiceCallbacks> callbacks) {
   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_) {
-      context_->service_manager()->ConnectToService(
-          GURL("mojo:mojo_network_service"),
-          &network_service_);
-    }
-    loader = new NetworkLoader(runner.Pass(), network_service_.get());
+  if (resolved_url.SchemeIsFile())
+    LoadLocalService(resolved_url, callbacks);
+  else
+    LoadNetworkService(resolved_url, callbacks);
+}
+
+void DynamicServiceLoader::LoadLocalService(
+    const GURL& resolved_url,
+    scoped_refptr<LoadServiceCallbacks> callbacks) {
+  base::FilePath path;
+  net::FileURLToFilePath(resolved_url, &path);
+  const bool kDeleteFileAfter = false;
+
+  // Async for consistency with network case.
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&DynamicServiceLoader::RunLibrary,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 path,
+                 callbacks,
+                 kDeleteFileAfter,
+                 base::PathExists(path)));
+}
+
+void DynamicServiceLoader::LoadNetworkService(
+    const GURL& resolved_url,
+    scoped_refptr<LoadServiceCallbacks> callbacks) {
+  if (!network_service_) {
+    context_->service_manager()->ConnectToService(
+        GURL("mojo:mojo_network_service"),
+        &network_service_);
   }
-  loader->Start(resolved_url, shell_handle.Pass(), context_);
+  if (!url_loader_)
+    network_service_->CreateURLLoader(Get(&url_loader_));
+
+  URLRequestPtr request(URLRequest::New());
+  request->url = String::From(resolved_url);
+  request->auto_follow_redirects = true;
+
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableCache)) {
+    request->bypass_cache = true;
+  }
+
+  url_loader_->Start(
+      request.Pass(),
+      base::Bind(&DynamicServiceLoader::OnLoadNetworkServiceComplete,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 callbacks));
+}
+
+void DynamicServiceLoader::OnLoadNetworkServiceComplete(
+    scoped_refptr<LoadServiceCallbacks> callbacks, URLResponsePtr response) {
+  if (response->error) {
+    LOG(ERROR) << "Error (" << response->error->code << ": "
+               << response->error->description << ") while fetching "
+               << response->url;
+  }
+
+  MimeTypeToURLMap::iterator iter =
+      mime_type_to_url_.find(response->mime_type);
+  if (iter != mime_type_to_url_.end()) {
+    callbacks->LoadWithContentHandler(iter->second, response.Pass());
+    return;
+  }
+
+  base::FilePath file;
+  base::CreateTemporaryFile(&file);
+
+  const bool kDeleteFileAfter = true;
+  common::CopyToFile(response->body.Pass(),
+                     file,
+                     context_->task_runners()->blocking_pool(),
+                     base::Bind(&DynamicServiceLoader::RunLibrary,
+                                weak_ptr_factory_.GetWeakPtr(),
+                                file,
+                                callbacks,
+                                kDeleteFileAfter));
+}
+
+void DynamicServiceLoader::RunLibrary(
+    const base::FilePath& path,
+    scoped_refptr<LoadServiceCallbacks> callbacks,
+    bool delete_file_after,
+    bool path_exists) {
+  // TODO(aa): We need to create a runner, even if we're not going to use it,
+  // because it getting destroyed is what causes shell to shut down. If we don't
+  // create this, in the case where shell never successfully creates even one
+  // app, then shell will never shut down, because no runners are ever
+  // destroyed.
+  scoped_ptr<DynamicServiceRunner> runner(runner_factory_->Create(context_));
+  if (!path_exists)
+    return;
+
+  ScopedMessagePipeHandle shell_handle = callbacks->RegisterApplication();
+  if (!shell_handle.is_valid())
+    return;
+
+  DynamicServiceRunner* runner_raw = runner.release();
+  runner_raw->Start(path,
+                    shell_handle.Pass(),
+                    base::Bind(&RunLibraryComplete,
+                               base::Unretained(runner_raw),
+                               delete_file_after ? path : base::FilePath()));
 }
 
 void DynamicServiceLoader::OnServiceError(ServiceManager* manager,
                                           const GURL& url) {
   // 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