Fix #245, Opaque CFE_SB_MsgId_t values

[jphickey]

Describe the contribution

Ensures that all CFE core apps outside of SB itself treat the CFE_SB_MsgId_t type as an opaque/abstract value and do not assume it is an integer.

This pull request is primarily a concept/preview of this idea in action for CCB discussion. It does work though and could be merged as-is although I expect some change requests.

Currently the type safe enforcement is enabled based on a compile definition CFE_SB_OPAQUE_MSGIDS. This could be moved into the "omit deprecated" switch instead rather than a new switch.

The type-safe enforcement switches CFE_SB_MsgId_t from being a simple integer value to a structure wrapper, so it cannot be implicitly exchanged with other integers, nor can it be involved in any arithmetic calculation. However, this is a breaking API change due to the way most apps specify their msgid values as integers via #define macros.

Fixes #245

Testing performed
Build CFE for SIMULATION=native (64 bit linux)
Execute all unit tests
Sanity check CFE by booting and sending commands with cmdUtil
In particular check all CFE SB routing info, map info commands and compare file output before and after change to make sure data is the same.

Expected behavior changes
No externally-visible changes (i.e. CMD/TLM, files, tables, etc).
API changes when building with enforcing mode:

• All CFE SB API operations that accept or return a CFE_SB_MsgId_t (Subscribe, etc) must be supplied with an instance of CFE_SB_MsgId_t only, not an integer. Passing or assigning to a bare integer triggers a compiler error.
• Macros/conversions are provided to bridge the gap, and allow printing as integer for syslog/events as well as converting from an integer
• No longer can switch() on a MsgId -- must use CFE_SB_MsgId_Equal and a nested if.
• This also exposes CFE_SB_IsMsgIdValid() in the public API.

System(s) tested on

• Ubuntu 18.04 LTS 64 bit

Contributor Info - All information REQUIRED for consideration of pull request
Joseph Hickey, Vantage Systems, Inc.

[skliper]

Please separate exposing CFE_SB_IsValidMsgId changes into a different pull request. It's fixing #263 and a priority for this round of certification.

[skliper]

@jwilmot @acudmore - Requesting a full design review of the entire concept (much bigger than this change) w/ stakeholder involvement, defined requirements, schedule, and committed resources.

[astrogeco]

CCB 20200408 - Push to later date, maybe Fall 2020 or later? Requires a longer design discussion involving more stakeholders. Split into different, smaller pieces.

[skliper]

Just to document - I'm ok with switching cFE to use the appropriate wrappers/macros (where possible and it makes sense) that already exist in the code. I'd prefer CFE_SB_MSGID_LITERAL or other approaches get discussed at a design level first (and consider phasing vs just going directly to a more permanent solution.)

[astrogeco]

Marking based on CCB 20200408

[skliper]

How do we want to handle this one? Close for now and resubmit when the design has been reviewed and approved by our stakeholders? My sense is the design will evolve as part of the review, so keeping this pull request open doesn't seem all that beneficial.

[jphickey]

The pull request can be closed, but the issue ticket should remain open.