[fuchsia] allow injecting the inspect node

This CL allows users to inject the inspect node used inside the
os_fuchsia.cc file instead of having it get created automatically.
This allows us to use inspect in other areas of the flutter/dart
runners. This code needs to be soft transitioned so there will be
follow up CLs after the runners are migrated.

TEST=This was tested against the current version of the runner that does
not use these new codepaths and against a version that does.

Change-Id: I2fff36223aa4021da9cd2051daf6312d2b115492
Bug: fxbug.dev/69558
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/190960
Commit-Queue: Chase Latta <chaselatta@google.com>
Reviewed-by: Zach Anderson <zra@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>

runtime/platform/BUILD.gn

@@ -18,11 +18,20 @@ library_for_all_configs("libdart_platform") {
 
   if (is_fuchsia) {
     if (using_fuchsia_gn_sdk) {
-      extra_deps += [ "$fuchsia_sdk_root/pkg/sys_cpp" ]
+      extra_deps += [
+        "$fuchsia_sdk_root/pkg/sys_cpp",
+        "$fuchsia_sdk_root/pkg/sys_inspect_cpp",
+      ]
     } else if (using_fuchsia_sdk) {
-      extra_deps += [ "$fuchsia_sdk_root/pkg:sys_cpp" ]
+      extra_deps += [
+        "$fuchsia_sdk_root/pkg:sys_cpp",
+        "$fuchsia_sdk_root/pkg:sys_inspect_cpp",
+      ]
     } else {
-      extra_deps += [ "//sdk/lib/sys/cpp" ]
+      extra_deps += [
+        "//sdk/lib/sys/cpp",
+        "//sdk/lib/sys/inspect/cpp",
+      ]
     }
   }
 }

runtime/platform/utils_fuchsia.cc

@@ -6,8 +6,10 @@
 #if defined(HOST_OS_FUCHSIA)
 
 #include <memory>
+#include <utility>
 
 #include "lib/sys/cpp/component_context.h"
+#include "lib/sys/inspect/cpp/component.h"
 #include "platform/utils.h"
 #include "platform/utils_fuchsia.h"
 
@@ -57,6 +59,23 @@ sys::ComponentContext* ComponentContext() {
   return context.get();
 }
 
+std::unique_ptr<inspect::Node> vm_node;
+void SetDartVmNode(std::unique_ptr<inspect::Node> node) {
+  vm_node = std::move(node);
+}
+
+std::unique_ptr<inspect::Node> TakeDartVmNode() {
+  // TODO(fxbug.dev/69558) Remove the creation of the node_ from this call
+  // after the runners have been migrated to injecting this object.
+  if (vm_node == nullptr) {
+    static std::unique_ptr<sys::ComponentInspector> component_inspector =
+        std::make_unique<sys::ComponentInspector>(dart::ComponentContext());
+    inspect::Node& root = component_inspector->inspector()->GetRoot();
+    vm_node = std::make_unique<inspect::Node>(root.CreateChild("vm"));
+  }
+  return std::move(vm_node);
+}
+
 }  // namespace dart
 
 #endif  // defined(HOST_OS_FUCHSIA)

runtime/platform/utils_fuchsia.h

@@ -6,6 +6,7 @@
 #define RUNTIME_PLATFORM_UTILS_FUCHSIA_H_
 
 #include <endian.h>
+#include <memory>
 
 namespace sys {
 
@@ -14,6 +15,13 @@ class ComponentContext;
 
 }  // namespace sys
 
+namespace inspect {
+
+// From Fuchsia SDK.
+class Node;
+
+}  // namespace inspect
+
 namespace dart {
 
 inline uint16_t Utils::HostToBigEndian16(uint16_t value) {
@@ -57,6 +65,18 @@ inline char* Utils::StrError(int err, char* buffer, size_t bufsize) {
 // call sys::ComponentContext::Create().
 sys::ComponentContext* ComponentContext();
 
+// Sets the inspect node set to be used in the dart vm
+//
+// This method will take ownership of the node
+void SetDartVmNode(std::unique_ptr<inspect::Node> node);
+
+// Returns the inspect node set in SetDartVmNode().
+//
+// The caller should take ownership of the returned node because
+// the value will be set to null after this call.
+// This call may return null if no node is provided.
+std::unique_ptr<inspect::Node> TakeDartVmNode();
+
 }  // namespace dart
 
 #endif  // RUNTIME_PLATFORM_UTILS_FUCHSIA_H_

runtime/vm/os_fuchsia.cc

@@ -80,23 +80,21 @@ enum class TZDataStatus {
 // Under normal operation, all metric values below should be zero.
 class InspectMetrics {
  public:
-  // Does not take ownership of inspector.
-  explicit InspectMetrics(inspect::Inspector* inspector)
-      : inspector_(inspector),
-        root_(inspector_->GetRoot()),
-        metrics_(root_.CreateChild("os")),
-        dst_status_(metrics_.CreateInt("dst_status", kUninitialized)),
-        tz_data_status_(metrics_.CreateInt("tz_data_status", kUninitialized)),
+  // Takes ownership of the vm_node.
+  explicit InspectMetrics(std::unique_ptr<inspect::Node> vm_node)
+      : vm_node_(std::move(vm_node)),
+        dst_status_(vm_node_->CreateInt("dst_status", kUninitialized)),
+        tz_data_status_(vm_node_->CreateInt("tz_data_status", kUninitialized)),
         tz_data_close_status_(
-            metrics_.CreateInt("tz_data_close_status", kUninitialized)),
+            vm_node_->CreateInt("tz_data_close_status", kUninitialized)),
         get_profile_status_(
-            metrics_.CreateInt("get_profile_status", kUninitialized)),
+            vm_node_->CreateInt("get_profile_status", kUninitialized)),
         profiles_timezone_content_status_(
-            metrics_.CreateInt("timezone_content_status", kOk)),
-        num_get_profile_calls_(metrics_.CreateInt("num_get_profile_calls", 0)),
-        num_on_change_calls_(metrics_.CreateInt("num_on_change_calls", 0)),
+            vm_node_->CreateInt("timezone_content_status", kOk)),
+        num_get_profile_calls_(vm_node_->CreateInt("num_get_profile_calls", 0)),
+        num_on_change_calls_(vm_node_->CreateInt("num_on_change_calls", 0)),
         num_intl_provider_errors_(
-            metrics_.CreateInt("num_intl_provider_errors", 0)) {}
+            vm_node_->CreateInt("num_intl_provider_errors", 0)) {}
 
   // Registers a single call to GetProfile callback.
   void RegisterGetProfileCall() { num_get_profile_calls_.Add(1); }
@@ -131,14 +129,8 @@ class InspectMetrics {
   }
 
  private:
-  // The inspector that all metrics are being reported into.
-  inspect::Inspector* inspector_;
-
-  // References inspector_ state.
-  inspect::Node& root_;
-
   // The OS metrics node.
-  inspect::Node metrics_;
+  std::unique_ptr<inspect::Node> vm_node_;
 
   // The status of the last GetTimeZoneOffset call.
   inspect::IntProperty dst_status_;
@@ -305,7 +297,6 @@ class TimezoneName final {
 std::set<const std::string> timezone_names;
 
 // Initialized on OS:Init(), deinitialized on OS::Cleanup.
-std::unique_ptr<sys::ComponentInspector> component_inspector;
 std::shared_ptr<InspectMetrics> metrics;
 std::shared_ptr<TimezoneName> timezone_name;
 async_loop_t* message_loop = nullptr;
@@ -603,9 +594,11 @@ void OS::Init() {
     async_loop_start_thread(message_loop, "Fuchsia async loop", nullptr);
   }
 
-  sys::ComponentContext* context = dart::ComponentContext();
-  component_inspector = std::make_unique<sys::ComponentInspector>(context);
-  metrics = std::make_shared<InspectMetrics>(component_inspector->inspector());
+  auto vm_node = dart::TakeDartVmNode();
+
+  // TODO(fxbug.dev/69558) allow vm_node to be null and not crash
+  ASSERT(vm_node != nullptr);
+  metrics = std::make_shared<InspectMetrics>(std::move(vm_node));
 
   InitializeTZData();
   auto services = sys::ServiceDirectory::CreateFromNamespace();
@@ -620,7 +613,6 @@ void OS::Cleanup() {
   }
   timezone_name.reset();
   metrics.reset();
-  component_inspector.reset();
 
   if (message_loop != nullptr) {
     // Check message_loop is still the default dispatcher before clearing it.