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#ifndef SRC_TRACING_AGENT_H_
#define SRC_TRACING_AGENT_H_
#include "libplatform/v8-tracing.h"
#include "uv.h"
#include "util.h"
#include "node_mutex.h"
#include <list>
#include <set>
#include <string>
#include <unordered_map>
namespace v8 {
class ConvertableToTraceFormat;
class TracingController;
} // namespace v8
namespace node {
namespace tracing {
using v8::platform::tracing::TraceConfig;
using v8::platform::tracing::TraceObject;
class Agent;
class AsyncTraceWriter {
public:
virtual ~AsyncTraceWriter() = default;
virtual void AppendTraceEvent(TraceObject* trace_event) = 0;
virtual void Flush(bool blocking) = 0;
virtual void InitializeOnThread(uv_loop_t* loop) {}
};
class TracingController : public v8::platform::tracing::TracingController {
public:
TracingController() : v8::platform::tracing::TracingController() {}
int64_t CurrentTimestampMicroseconds() override {
return uv_hrtime() / 1000;
}
void AddMetadataEvent(
const unsigned char* category_group_enabled,
const char* name,
int num_args,
const char** arg_names,
const unsigned char* arg_types,
const uint64_t* arg_values,
std::unique_ptr<v8::ConvertableToTraceFormat>* convertable_values,
unsigned int flags);
};
class AgentWriterHandle {
public:
inline AgentWriterHandle() = default;
inline ~AgentWriterHandle() { reset(); }
inline AgentWriterHandle(AgentWriterHandle&& other);
inline AgentWriterHandle& operator=(AgentWriterHandle&& other);
inline bool empty() const { return agent_ == nullptr; }
inline void reset();
inline void Enable(const std::set<std::string>& categories);
inline void Disable(const std::set<std::string>& categories);
inline bool IsDefaultHandle();
inline Agent* agent() { return agent_; }
inline v8::TracingController* GetTracingController();
AgentWriterHandle(const AgentWriterHandle& other) = delete;
AgentWriterHandle& operator=(const AgentWriterHandle& other) = delete;
private:
inline AgentWriterHandle(Agent* agent, int id) : agent_(agent), id_(id) {}
Agent* agent_ = nullptr;
int id_ = 0;
friend class Agent;
};
class Agent {
public:
Agent();
~Agent();
TracingController* GetTracingController() {
TracingController* controller = tracing_controller_.get();
CHECK_NOT_NULL(controller);
return controller;
}
enum UseDefaultCategoryMode {
kUseDefaultCategories,
kIgnoreDefaultCategories
};
// Destroying the handle disconnects the client
AgentWriterHandle AddClient(const std::set<std::string>& categories,
std::unique_ptr<AsyncTraceWriter> writer,
enum UseDefaultCategoryMode mode);
// A handle that is only used for managing the default categories
// (which can then implicitly be used through using `USE_DEFAULT_CATEGORIES`
// when adding a client later).
AgentWriterHandle DefaultHandle();
// Returns a comma-separated list of enabled categories.
std::string GetEnabledCategories() const;
// Writes to all writers registered through AddClient().
void AppendTraceEvent(TraceObject* trace_event);
void AddMetadataEvent(std::unique_ptr<TraceObject> event);
// Flushes all writers registered through AddClient().
void Flush(bool blocking);
TraceConfig* CreateTraceConfig() const;
private:
friend class AgentWriterHandle;
void InitializeWritersOnThread();
void Start();
void StopTracing();
void Disconnect(int client);
void Enable(int id, const std::set<std::string>& categories);
void Disable(int id, const std::set<std::string>& categories);
uv_thread_t thread_;
uv_loop_t tracing_loop_;
bool started_ = false;
class ScopedSuspendTracing;
// Each individual Writer has one id.
int next_writer_id_ = 1;
enum { kDefaultHandleId = -1 };
// These maps store the original arguments to AddClient(), by id.
std::unordered_map<int, std::multiset<std::string>> categories_;
std::unordered_map<int, std::unique_ptr<AsyncTraceWriter>> writers_;
std::unique_ptr<TracingController> tracing_controller_;
// Variables related to initializing per-event-loop properties of individual
// writers, such as libuv handles.
Mutex initialize_writer_mutex_;
ConditionVariable initialize_writer_condvar_;
uv_async_t initialize_writer_async_;
std::set<AsyncTraceWriter*> to_be_initialized_;
Mutex metadata_events_mutex_;
std::list<std::unique_ptr<TraceObject>> metadata_events_;
};
void AgentWriterHandle::reset() {
if (agent_ != nullptr)
agent_->Disconnect(id_);
agent_ = nullptr;
}
AgentWriterHandle& AgentWriterHandle::operator=(AgentWriterHandle&& other) {
reset();
agent_ = other.agent_;
id_ = other.id_;
other.agent_ = nullptr;
return *this;
}
AgentWriterHandle::AgentWriterHandle(AgentWriterHandle&& other) {
*this = std::move(other);
}
void AgentWriterHandle::Enable(const std::set<std::string>& categories) {
if (agent_ != nullptr) agent_->Enable(id_, categories);
}
void AgentWriterHandle::Disable(const std::set<std::string>& categories) {
if (agent_ != nullptr) agent_->Disable(id_, categories);
}
bool AgentWriterHandle::IsDefaultHandle() {
return agent_ != nullptr && id_ == Agent::kDefaultHandleId;
}
inline v8::TracingController* AgentWriterHandle::GetTracingController() {
return agent_ != nullptr ? agent_->GetTracingController() : nullptr;
}
} // namespace tracing
} // namespace node
#endif // SRC_TRACING_AGENT_H_
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