TraceFileWriter

class TraceFileWriter

Abstract base class for writing trace files in various formats.

This class provides an interface for writing protobuf messages to trace files. Different implementations can support various file formats like .osi, .mcap or .txth.

The WriteMessage() method accepts any protobuf message via the type-erased google::protobuf::Message base class. For MCAP format, the topic parameter selects the channel; for single-channel formats (.osi, .txth) it is ignored.

Concrete implementations also provide template<typename T> WriteMessage() overloads for compile-time type safety when the message type is known.

Note

Thread Safety: Instances are not thread-safe. Concurrent calls on the same writer must be externally synchronized.

Note

Error Strategy: Open returns false and logs to std::cerr on failure. WriteMessage returns false on write errors.

Subclassed by osi3::MCAPTraceFileWriter, osi3::SingleChannelBinaryTraceFileWriter, osi3::TXTHTraceFileWriter

Public Functions

virtual ~TraceFileWriter() = default

Virtual destructor.

TraceFileWriter() = default

Default constructor.

TraceFileWriter(const TraceFileWriter&) = delete

Deleted copy constructor.

TraceFileWriter &operator=(const TraceFileWriter&) = delete

Deleted copy assignment operator.

TraceFileWriter(TraceFileWriter&&) = delete

Deleted move constructor.

TraceFileWriter &operator=(TraceFileWriter&&) = delete

Deleted move assignment operator.

virtual bool Open(const std::filesystem::path &file_path) = 0

Opens a file for writing.

Parameters:

file_path – Path to the file to be created/opened

Returns:

true if successful, false otherwise

virtual bool WriteMessage(const google::protobuf::Message &message, const std::string &topic = "") = 0

Writes a protobuf message to the trace file.

Type-erased write method that accepts any protobuf message. The behavior of the topic parameter depends on the writer implementation:

• MCAP: topic selects the channel. If the topic has not been registered via AddChannel(), it is auto-registered using the message’s descriptor. Required file metadata is also auto-added on first write if not set.

• Binary (.osi) and Text (.txth): topic is ignored (single-channel formats).

Parameters:

• message – The protobuf message to write

• topic – Channel/topic name (required for MCAP, ignored for .osi/.txth)

Returns:

true if successful, false otherwise

virtual void Close() = 0

Closes the trace file.