Fix #145, Clean up CF return codes

[thnkslprpt]

Checklist

• [x] I reviewed the Contributing Guide.
• [x] I signed and emailed the appropriate Contributor License Agreement to GSFC-SoftwareRelease@mail.nasa.gov and copied cfs-program@lists.nasa.gov.

Describe the contribution Fixes #145

• most int/int32 return types were converted to CFE_Status_t (cases of specifically unsigned or intentionally long/short types (e.g. uint64, uint8) were not changed)
• successful returns now almost all represented by CFE_SUCCESS rather than 0 (zero)
• unsuccessful returns now almost all represented by CF_ERROR macro, or specific error macros where appropriate for repeat cases
• new error return macros all negative (unlike previously where some were positive enum values)
• CF_Timer_Expired() changed to bool return type
• converted CF_SendRet_t enum error return values to macros (all negative)
  • deleted unused CF_SendRet_FAILURE enum value
• converted CF_RxEofRet_t enum error return values to macros (all negative)
  • deleted unused CF_RxEofRet_INVALID enum value

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Minor changes:

• updated this test message: should say (failed), not (success):
  • https://github.com/nasa/CF/blob/19c18b9dbdb0093e9bea78322de777e8f282acfb/unit-test/cf_cmd_tests.c#L3569
• couple of typos that were noticed along the way (e.g. deode instead of decode)
• added documentation for @retval CF_SEND_PDU_NO_BUF_AVAIL_ERROR (previously CF_SendRet_NO_MSG) for CF_CFDP_SendNak() (was simply missing)
• @retval CF_SEND_PDU_ERROR (previously CF_SendRet_ERROR) was not actually implemented/used and was removed from the prototype descriptions of:
  • CF_CFDP_SendFin()
  • CF_CFDP_SendAck()
  • CF_CFDP_SendMd()
  • CF_CFDP_SendEof()
• removed /* error return path */ comments that are no longer relevant since the goto's were removed

Testing performed GitHub CI actions (incl. Build + Run, Unit Tests etc.) all passing successfully.

Expected behavior changes Behavior essentially unchanged. Removing positive error return values eases future maintainability. Using a defined set of error return macros improves code clarity and makes CF more consistent with cFE and the other cFS apps. Synchronizing the return types to CFE_Status_t simplifies the code, and makes it more type-safe.

Could consider adding to this PR, or in the future, defining unique error return macros for each unique return type.

Contributor Info Avi Weiss @thnkslprpt

[dzbaker]

Hey @thnkslprpt, would you be able to resolve the conflicts? Thanks!