inspector: implement --cpu-prof[-path]

This patch introduces a CLI flag --cpu-prof that starts the V8
CPU profiler on start up, and ends the profiler then writes the
CPU profile before the Node.js instance (on the main thread or
the worker thread) exits. By default the profile is written to
`${cwd}/CPU.${yyyymmdd}.${hhmmss}.${pid}.${tid}.${seq}.cpuprofile`.
The patch also introduces a --cpu-prof-path flag for the user
to specify the path the profile will be written to.

Refs: https://github.com/nodejs/node/issues/26878
PR-URL: https://github.com/nodejs/node/pull/27147
Reviewed-By: Anna Henningsen <anna@addaleax.net>

1 files changed, 18 insertions, 0 deletions

diff --git a/src/inspector_profiler.h b/src/inspector_profiler.h
index 43a8d54163..7120819c13 100644
--- a/src/inspector_profiler.h
+++ b/src/inspector_profiler.h
@@ -68,6 +68,24 @@ class V8CoverageConnection : public V8ProfilerConnection {
   bool ending_ = false;
 };
 
+class V8CpuProfilerConnection : public V8ProfilerConnection {
+ public:
+  explicit V8CpuProfilerConnection(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:
+  void WriteCpuProfile(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