add: refcount in tracing (#269)

[VasilyStepanov]

This pull request significantly refactors the tracing infrastructure by implementing a robust reference counting mechanism for TraceEvent objects, ensuring proper resource management. Concurrently, it modernizes the trace message generation by transitioning from std::ostringstream to a more efficient and flexible printf-style variadic argument approach, streamlining how diagnostic information is captured and logged throughout the system.

Highlights

• Reference Counting for Trace Events: Introduced a reference counting mechanism for TraceEvent objects to manage their lifecycle and prevent resource leaks.
• Printf-style Tracing: Migrated the tracing macros (RAWSTOR_TRACE_EVENT, RAWSTOR_TRACE_EVENT_MESSAGE) to use printf-style variadic arguments, replacing std::ostringstream for message formatting.
• Expanded Logging API: Added new C-style functions (rawstor_trace_event_va_begin, rawstor_trace_event_inc, rawstor_trace_event_dec, rawstor_trace_event_va_message) to the logging API to support the new reference counting and variadic argument approach.
• Codebase-wide Trace Update: Updated existing trace message calls across various files in librawstorio and src to conform to the new printf-style formatting.

(cherry picked from commit 4953d92)

[gemini-code-assist]

Summary of Changes

Hello @VasilyStepanov, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the tracing infrastructure by introducing a robust reference counting mechanism for TraceEvent objects, ensuring proper resource management. It also modernizes trace message generation by transitioning from std::ostringstream to a more efficient printf-style variadic argument approach, streamlining diagnostic information capture and logging throughout the system.

Highlights

• Reference Counting for Trace Events: Introduced a reference counting mechanism for TraceEvent objects to manage their lifecycle and prevent resource leaks.
• Printf-style Tracing: Migrated the tracing macros (RAWSTOR_TRACE_EVENT, RAWSTOR_TRACE_EVENT_MESSAGE) to use printf-style variadic arguments, replacing std::ostringstream for message formatting.
• Expanded Logging API: Added new C-style functions (rawstor_trace_event_va_begin, rawstor_trace_event_inc, rawstor_trace_event_dec, rawstor_trace_event_va_message) to the logging API to support the new reference counting and variadic argument approach.
• Codebase-wide Trace Update: Updated existing trace message calls across various files in librawstorio and src to conform to the new printf-style formatting.

Changelog

• librawstorio/src/poll_event.cpp
  • Updated trace messages to use printf-style formatting.
• librawstorio/src/poll_event.hpp
  • Modified trace event message calls to align with the new printf-style format.
• librawstorio/src/task.cpp
  • Converted trace event initialization and messages to use printf-style formatting.
• librawstorio/src/uring_buffer.cpp
  • Updated trace messages to use printf-style formatting.
• librawstorstd/include/rawstorstd/logging.h
  • Introduced new C-style functions for TraceEvent reference counting (rawstor_trace_event_inc, rawstor_trace_event_dec) and va_list based message formatting (rawstor_trace_event_va_begin, rawstor_trace_event_va_message).
• librawstorstd/include/rawstorstd/logging.hpp
  • Refactored the TraceEvent class and its associated macros (RAWSTOR_TRACE_EVENT, RAWSTOR_TRACE_EVENT_MESSAGE) to support printf-style variadic arguments and implement reference counting logic, including a copy constructor and updated destructor.
• librawstorstd/src/logging.cpp
  • Implemented the core logic for TraceEvent reference counting within the Event class and provided definitions for the new C-style va_list based tracing functions.
• src/ost_session.cpp
  • Updated trace messages to use printf-style formatting.
• src/task.hpp
  • Converted trace event initialization to use printf-style formatting.

Activity

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[gemini-code-assist]

Code Review

This pull request is a solid improvement, refactoring the tracing infrastructure to use reference counting for TraceEvent objects and switching to more efficient printf-style logging. The implementation is clean and the changes are applied consistently across the codebase. I've found one potential high-severity issue in the TraceEvent copy constructor that could lead to a crash under certain conditions. Once that is addressed, this PR will be in great shape.