src: port coverage serialization to C++

This patch moves the serialization of coverage profiles into
C++. With this we no longer need to patch `process.reallyExit`
and hook into the exit events, but instead hook into relevant
places in C++ which are safe from user manipulation. This also
makes the code easier to reuse for other types of profiles.

PR-URL: https://github.com/nodejs/node/pull/26874
Reviewed-By: Ben Coe <bencoe@gmail.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/src/inspector_profiler.h b/src/inspector_profiler.h
new file mode 100644
index 0000000000..43a8d54163
--- /dev/null
+++ b/src/inspector_profiler.h
@@ -0,0 +1,75 @@
+#ifndef SRC_INSPECTOR_PROFILER_H_
+#define SRC_INSPECTOR_PROFILER_H_
+
+#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#if !HAVE_INSPECTOR
+#error("This header can only be used when inspector is enabled")
+#endif
+
+#include "env.h"
+#include "inspector_agent.h"
+
+namespace node {
+// Forward declaration to break recursive dependency chain with src/env.h.
+class Environment;
+
+namespace profiler {
+
+class V8ProfilerConnection {
+ public:
+  class V8ProfilerSessionDelegate : public inspector::InspectorSessionDelegate {
+   public:
+    explicit V8ProfilerSessionDelegate(V8ProfilerConnection* connection)
+        : connection_(connection) {}
+
+    void SendMessageToFrontend(
+        const v8_inspector::StringView& message) override {
+      connection_->OnMessage(message);
+    }
+
+   private:
+    V8ProfilerConnection* connection_;
+  };
+
+  explicit V8ProfilerConnection(Environment* env);
+  virtual ~V8ProfilerConnection() = default;
+  Environment* env() { return env_; }
+
+  // Use DispatchMessage() to dispatch necessary inspector messages
+  virtual void Start() = 0;
+  virtual void End() = 0;
+  // Override this to respond to the messages sent from the session.
+  virtual void OnMessage(const v8_inspector::StringView& message) = 0;
+  virtual bool ending() const = 0;
+
+  void DispatchMessage(v8::Local<v8::String> message);
+  // Write the result to a path
+  bool WriteResult(const char* path, v8::Local<v8::String> result);
+
+ private:
+  std::unique_ptr<inspector::InspectorSession> session_;
+  Environment* env_ = nullptr;
+};
+
+class V8CoverageConnection : public V8ProfilerConnection {
+ public:
+  explicit V8CoverageConnection(Environment* env) : V8ProfilerConnection(env) {}
+
+  void Start() override;
+  void End() override;
+  void OnMessage(const v8_inspector::StringView& message) override;
+  bool ending() const override { return ending_; }
+
+ private:
+  bool WriteCoverage(v8::Local<v8::String> message);
+  v8::MaybeLocal<v8::String> GetResult(v8::Local<v8::String> message);
+  std::unique_ptr<inspector::InspectorSession> session_;
+  bool ending_ = false;
+};
+
+}  // namespace profiler
+}  // namespace node
+
+#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+#endif  // SRC_INSPECTOR_PROFILER_H_