[Fuchsia] Add helper for working with fuchsia.sys.StartupInfo.

StartupContext creates helper classes wrapping the incoming and outgoing
service directory handles, to simplify use of them by component
implementations.

WebRunner & CastRunner are updated to use the StartupInfo helper, and
the CastRunner test StartCastComponent helper is updated to place the
CastChannel service in the component's incoming service directory, for
now.

Bug: 920920
Test: Existing component tests (e.g. cast_runner_integration_tests)
Change-Id: I92e9f0f0aad26aecef0da036684bb66733a267ac
Reviewed-on: https://chromium-review.googlesource.com/c/1473820
Auto-Submit: Wez <wez@chromium.org>
Reviewed-by: Kevin Marshall <kmarshall@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632744}

base/BUILD.gn

@@ -1421,6 +1421,8 @@ jumbo_component("base") {
       "fuchsia/service_directory_client.h",
       "fuchsia/service_provider_impl.cc",
       "fuchsia/service_provider_impl.h",
+      "fuchsia/startup_context.cc",
+      "fuchsia/startup_context.h",
       "memory/platform_shared_memory_region_fuchsia.cc",
       "memory/protected_memory_posix.cc",
       "memory/shared_memory_fuchsia.cc",

base/fuchsia/service_provider_impl.h

@@ -12,8 +12,10 @@
 #include <lib/zx/channel.h>
 #include <string>
 
+#include "base/base_export.h"
 #include "base/callback.h"
 #include "base/fuchsia/service_directory_client.h"
+#include "base/macros.h"
 
 namespace base {
 namespace fuchsia {

base/fuchsia/startup_context.cc

+// Copyright 2019 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 "base/fuchsia/startup_context.h"
+
+#include <fuchsia/io/cpp/fidl.h>
+
+namespace base {
+namespace fuchsia {
+
+StartupContext::StartupContext(::fuchsia::sys::StartupInfo startup_info)
+    : startup_info_(std::move(startup_info)) {
+  // Component manager generates |flat_namespace|, so things are horribly broken
+  // if |flat_namespace| is malformed.
+  CHECK_EQ(startup_info_.flat_namespace.directories.size(),
+           startup_info_.flat_namespace.paths.size());
+
+  // Find the /svc directory and wrap it into a ServiceDirectoryClient.
+  for (size_t i = 0; i < startup_info_.flat_namespace.paths.size(); ++i) {
+    if (startup_info_.flat_namespace.paths[i] == "/svc") {
+      incoming_services_ = std::make_unique<ServiceDirectoryClient>(
+          fidl::InterfaceHandle<::fuchsia::io::Directory>(
+              std::move(startup_info_.flat_namespace.directories[i])));
+      break;
+    }
+  }
+}
+
+StartupContext::~StartupContext() = default;
+
+base::fuchsia::ServiceDirectory* StartupContext::public_services() {
+  if (!public_services_ && startup_info_.launch_info.directory_request) {
+    public_services_ = std::make_unique<ServiceDirectory>(
+        fidl::InterfaceRequest<::fuchsia::io::Directory>(
+            std::move(startup_info_.launch_info.directory_request)));
+  }
+  return public_services_.get();
+}
+
+}  // namespace fuchsia
+}  // namespace base

base/fuchsia/startup_context.h

+// Copyright 2019 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 BASE_FUCHSIA_STARTUP_CONTEXT_H_
+#define BASE_FUCHSIA_STARTUP_CONTEXT_H_
+
+#include <fuchsia/sys/cpp/fidl.h>
+#include <memory>
+
+#include "base/base_export.h"
+#include "base/fuchsia/service_directory.h"
+#include "base/fuchsia/service_directory_client.h"
+#include "base/macros.h"
+
+namespace base {
+namespace fuchsia {
+
+// Helper for unpacking a fuchsia.sys.StartupInfo and creating convenience
+// wrappers for the various fields (e.g. the incoming & outgoing service
+// directories, resolve launch URL etc).
+// Embedders may derived from StartupContext to e.g. add bound pointers to
+// embedder-specific services, as required.
+class BASE_EXPORT StartupContext {
+ public:
+  explicit StartupContext(::fuchsia::sys::StartupInfo startup_info);
+  virtual ~StartupContext();
+
+  // Returns the namespace of services published for use by the component.
+  const ServiceDirectoryClient* incoming_services() const {
+    return incoming_services_.get();
+  }
+
+  // Returns the "public" directory into which this component binds services.
+  // Note that all services should be bound immediately after the first call to
+  // this API, before returning control to the message loop, at which point we
+  // will start processing service connection requests.
+  ServiceDirectory* public_services();
+
+ private:
+  ::fuchsia::sys::StartupInfo startup_info_;
+
+  std::unique_ptr<ServiceDirectoryClient> incoming_services_;
+  std::unique_ptr<ServiceDirectory> public_services_;
+
+  DISALLOW_COPY_AND_ASSIGN(StartupContext);
+};
+
+}  // namespace fuchsia
+}  // namespace base
+
+#endif  // BASE_FUCHSIA_STARTUP_CONTEXT_H_

fuchsia/runners/cast/cast_component.cc

@@ -20,31 +20,22 @@ constexpr int kBindingsFailureExitCode = 129;
 
 CastComponent::CastComponent(
     CastRunner* runner,
-    fuchsia::sys::StartupInfo startup_info,
+    std::unique_ptr<base::fuchsia::StartupContext> context,
     fidl::InterfaceRequest<fuchsia::sys::ComponentController>
         controller_request)
-    : WebComponent(runner,
-                   std::move(startup_info),
-                   std::move(controller_request)),
+    : WebComponent(runner, std::move(context), std::move(controller_request)),
       navigation_observer_binding_(this) {
   base::AutoReset<bool> constructor_active_reset(&constructor_active_, true);
 
-  if (!additional_services() || std::find(additional_service_names().begin(),
-                                          additional_service_names().end(),
-                                          chromium::cast::CastChannel::Name_) ==
-                                    additional_service_names().end()) {
-    LOG(ERROR) << "Component instantiated without required service: "
-               << chromium::cast::CastChannel::Name_;
-    DestroyComponent(1, fuchsia::sys::TerminationReason::UNSUPPORTED);
-    return;
-  }
-
   cast_channel_ = std::make_unique<CastChannelBindings>(
       frame(), &connector_,
-      additional_services()->ConnectToService<chromium::cast::CastChannel>(),
+      startup_context()
+          ->incoming_services()
+          ->ConnectToService<chromium::cast::CastChannel>(),
       base::BindOnce(&CastComponent::DestroyComponent, base::Unretained(this),
                      kBindingsFailureExitCode,
                      fuchsia::sys::TerminationReason::INTERNAL_ERROR));
+
   frame()->SetNavigationEventObserver(
       navigation_observer_binding_.NewBinding());
 }

fuchsia/runners/cast/cast_component.h

@@ -21,7 +21,7 @@ class CastComponent : public WebComponent,
                       public chromium::web::NavigationEventObserver {
  public:
   CastComponent(CastRunner* runner,
-                fuchsia::sys::StartupInfo startup_info,
+                std::unique_ptr<base::fuchsia::StartupContext> startup_context,
                 fidl::InterfaceRequest<fuchsia::sys::ComponentController>
                     controller_request);
   ~CastComponent() override;

fuchsia/runners/cast/cast_runner.cc

@@ -48,16 +48,18 @@ void CastRunner::StartComponent(
   const std::string cast_app_id(cast_url.GetContent());
   app_config_manager_->GetConfig(
       cast_app_id,
-      [this, startup_info = std::move(startup_info),
+      [this,
+       startup_context = std::make_unique<base::fuchsia::StartupContext>(
+           std::move(startup_info)),
        controller_request = std::move(controller_request)](
           chromium::cast::ApplicationConfigPtr app_config) mutable {
-        GetConfigCallback(std::move(startup_info),
+        GetConfigCallback(std::move(startup_context),
                           std::move(controller_request), std::move(app_config));
       });
 }
 
 void CastRunner::GetConfigCallback(
-    fuchsia::sys::StartupInfo startup_info,
+    std::unique_ptr<base::fuchsia::StartupContext> startup_context,
     fidl::InterfaceRequest<fuchsia::sys::ComponentController>
         controller_request,
     chromium::cast::ApplicationConfigPtr app_config) {
@@ -66,6 +68,7 @@ void CastRunner::GetConfigCallback(
 
     // For test purposes, we need to call RegisterComponent even if there is no
     // URL to launch.
+    // TODO: Replace this hack, e.g. with an test-specific callback.
     RegisterComponent(std::unique_ptr<WebComponent>(nullptr));
     return;
   }
@@ -73,7 +76,7 @@ void CastRunner::GetConfigCallback(
   // If a config was returned then use it to launch a component.
   GURL cast_app_url(app_config->web_url);
   auto component = std::make_unique<CastComponent>(
-      this, std::move(startup_info), std::move(controller_request));
+      this, std::move(startup_context), std::move(controller_request));
   component->LoadUrl(std::move(cast_app_url));
   RegisterComponent(std::move(component));
 }

fuchsia/runners/cast/cast_runner.h

@@ -6,6 +6,7 @@
 #define FUCHSIA_RUNNERS_CAST_CAST_RUNNER_H_
 
 #include "base/callback.h"
+#include "base/fuchsia/startup_context.h"
 #include "base/macros.h"
 #include "fuchsia/fidl/chromium/cast/cpp/fidl.h"
 #include "fuchsia/fidl/chromium/web/cpp/fidl.h"
@@ -29,7 +30,7 @@ class CastRunner : public WebContentRunner {
 
  private:
   void GetConfigCallback(
-      fuchsia::sys::StartupInfo startup_info,
+      std::unique_ptr<base::fuchsia::StartupContext> startup_context,
       fidl::InterfaceRequest<fuchsia::sys::ComponentController>
           controller_request,
       chromium::cast::ApplicationConfigPtr app_config);

fuchsia/runners/cast/test_common.cc

@@ -21,7 +21,6 @@ fidl::InterfaceHandle<fuchsia::io::Directory> StartCastComponent(
     fidl::Binding<chromium::cast::CastChannel>* cast_channel_binding) {
   // Construct, bind, and populate a ServiceDirectory for publishing
   // the CastChannel service to the CastComponent.
-  auto service_list = std::make_unique<fuchsia::sys::ServiceList>();
   fidl::InterfaceHandle<fuchsia::io::Directory> directory;
   base::fuchsia::ServiceDirectory cast_channel_directory(
       directory.NewRequest());
@@ -35,21 +34,20 @@ fidl::InterfaceHandle<fuchsia::io::Directory> StartCastComponent(
       },
       base::Passed(service_connect_runloop.QuitClosure()),
       base::Unretained(cast_channel_binding)));
-  service_list->names.push_back(chromium::cast::CastChannel::Name_);
-  service_list->host_directory = directory.TakeChannel();
 
   // Configure the Runner, including a service directory channel to publish
   // services to.
   fuchsia::sys::StartupInfo startup_info;
   startup_info.launch_info.url = cast_url.as_string();
-  startup_info.launch_info.additional_services = std::move(service_list);
+
   fidl::InterfaceHandle<fuchsia::io::Directory> component_services;
   startup_info.launch_info.directory_request =
       component_services.NewRequest().TakeChannel();
 
-  // The FlatNamespace vectors must be non-null, but may be empty.
-  startup_info.flat_namespace.paths.resize(0);
-  startup_info.flat_namespace.directories.resize(0);
+  // Publish the ServiceDirectory into the FlatNamespace for CastChannel to be
+  // picked up from.
+  startup_info.flat_namespace.paths.emplace_back("/svc");
+  startup_info.flat_namespace.directories.emplace_back(directory.TakeChannel());
 
   fuchsia::sys::Package package;
   package.resolved_url = cast_url.as_string();

fuchsia/runners/common/web_component.cc

@@ -37,23 +37,14 @@ void WebComponent::LoadUrl(const GURL& url) {
 
 WebComponent::WebComponent(
     WebContentRunner* runner,
-    fuchsia::sys::StartupInfo startup_info,
+    std::unique_ptr<base::fuchsia::StartupContext> context,
     fidl::InterfaceRequest<fuchsia::sys::ComponentController>
         controller_request)
-    : runner_(runner), controller_binding_(this) {
+    : runner_(runner),
+      startup_context_(std::move(context)),
+      controller_binding_(this) {
   DCHECK(runner);
 
-  // Handle the incoming services directory for this component.
-  if (startup_info.launch_info.additional_services &&
-      startup_info.launch_info.additional_services->host_directory) {
-    additional_services_ =
-        std::make_unique<base::fuchsia::ServiceDirectoryClient>(
-            fidl::InterfaceHandle<fuchsia::io::Directory>(std::move(
-                startup_info.launch_info.additional_services->host_directory)));
-    additional_service_names_ =
-        std::move(startup_info.launch_info.additional_services->names);
-  }
-
   // If the ComponentController request is valid then bind it, and configure it
   // to destroy this component on error.
   if (controller_request.is_valid()) {
@@ -70,17 +61,12 @@ WebComponent::WebComponent(
   // Create the underlying Frame and get its NavigationController.
   runner_->context()->CreateFrame(frame_.NewRequest());
 
-  // Create a ServiceDirectory for this component, and publish a ViewProvider
-  // into it, for the caller to use to create a View for this component.
-  // Note that we must publish ViewProvider before returning control to the
-  // message-loop, to ensure that it is available before the ServiceDirectory
-  // starts processing requests.
-  service_directory_ = std::make_unique<base::fuchsia::ServiceDirectory>(
-      fidl::InterfaceRequest<fuchsia::io::Directory>(
-          std::move(startup_info.launch_info.directory_request)));
+  // Publish ViewProvider before returning control to the message-loop, to
+  // ensure that it is available before the ServiceDirectory starts processing
+  // requests.
   view_provider_binding_ = std::make_unique<
       base::fuchsia::ScopedServiceBinding<fuchsia::ui::app::ViewProvider>>(
-      service_directory_.get(), this);
+      startup_context()->public_services(), this);
 }
 
 void WebComponent::Kill() {

fuchsia/runners/common/web_component.h

@@ -17,6 +17,7 @@
 #include "base/fuchsia/scoped_service_binding.h"
 #include "base/fuchsia/service_directory.h"
 #include "base/fuchsia/service_directory_client.h"
+#include "base/fuchsia/startup_context.h"
 #include "base/logging.h"
 #include "fuchsia/fidl/chromium/web/cpp/fidl.h"
 #include "url/gurl.h"
@@ -32,12 +33,12 @@ class WebComponent : public fuchsia::sys::ComponentController,
                      public fuchsia::ui::app::ViewProvider {
  public:
   // Creates a WebComponent encapsulating a web.Frame. A ViewProvider service
-  // will be published to the service-directory specified in |startup_info|, and
-  // if |controller_request| is valid then it will be bound to this component,
-  // and the component configured to teardown if that channel closes.
+  // will be published to the service-directory specified by |startup_context|,
+  // and if |controller_request| is valid then it will be bound to this
+  // component, and the componentconfigured to teardown if that channel closes.
   // |runner| must outlive this component.
   WebComponent(WebContentRunner* runner,
-               fuchsia::sys::StartupInfo startup_info,
+               std::unique_ptr<base::fuchsia::StartupContext> startup_context,
                fidl::InterfaceRequest<fuchsia::sys::ComponentController>
                    controller_request);
 
@@ -65,23 +66,15 @@ class WebComponent : public fuchsia::sys::ComponentController,
   virtual void DestroyComponent(int termination_exit_code,
                                 fuchsia::sys::TerminationReason reason);
 
-  // Returns the directory of incoming services provided to the component, or
-  // nullptr if none was provided.
-  base::fuchsia::ServiceDirectoryClient* additional_services() const {
-    return additional_services_.get();
-  }
-
-  // Returns the names of services available in additional_services().
-  const std::vector<std::string>& additional_service_names() const {
-    return additional_service_names_;
-  }
-
-  base::fuchsia::ServiceDirectory* service_directory() const {
-    return service_directory_.get();
+  // Returns the component's startup context (e.g. incoming services, public
+  // service directory, etc).
+  base::fuchsia::StartupContext* startup_context() const {
+    return startup_context_.get();
   }
 
  private:
   WebContentRunner* const runner_ = nullptr;
+  const std::unique_ptr<base::fuchsia::StartupContext> startup_context_;
 
   chromium::web::FramePtr frame_;
 

fuchsia/runners/common/web_content_runner.cc

@@ -15,6 +15,7 @@
 #include "base/fuchsia/scoped_service_binding.h"
 #include "base/fuchsia/service_directory.h"
 #include "base/fuchsia/service_directory_client.h"
+#include "base/fuchsia/startup_context.h"
 #include "base/logging.h"
 #include "fuchsia/runners/common/web_component.h"
 #include "url/gurl.h"
@@ -74,7 +75,9 @@ void WebContentRunner::StartComponent(
   }
 
   std::unique_ptr<WebComponent> component = std::make_unique<WebComponent>(
-      this, std::move(startup_info), std::move(controller_request));
+      this,
+      std::make_unique<base::fuchsia::StartupContext>(std::move(startup_info)),
+      std::move(controller_request));
   component->LoadUrl(url);
   RegisterComponent(std::move(component));
 }