Return status code instead of bool in IParser

[gavv]

Summary

packet::IParser is interface for protocol-specific deserializators. See documentation.

Currently its methods return bool (true on success or false on error). We need to replace bool with status::StatusCode and return code that described why the operation failed.

Implementation

• Update IParser interface and implementations:
  • rtp::Parser
  • fec::Parser
  • rtcp::Parser
• Report appropriate statuses:
  • when allocation failed, return StatusNoMem
  • when buffer is too small, return StatusBadBuffer
  • when packet is malformed, return StatusBadPacket
  • on success, return StatusOK
• Update users of parsers and composers. They should forward status to upper level:
  • fec::BlockReader
  • rtcp::Communicator

Testing

• Add unit tests for rtp::Parser and fec::Parser that check returned statuses in case of errors.
• Add unit tests for components which use parsers, and check that they forward statuses from parser to the upper level (e.g. if Parser fails with StatusNoMem, BlockReader::read() returns StatusNoMem). One test per component should be enough.