Re: Logging Library-GSOC

[Werner LEMBERG]

> I wanted to ask that after selecting desirable external library how
> should I proceed:

[For David T.: The idea is to statically link the library into
 FreeType using a git submodule.  In other words, it's 'external' only
 because it is developed by other people.]

> 1. Should I stick to the existing debugging facility in which
>    filtering of log messages is based on debug level comparisons of
>    various FreeType's components and only use the external library
>    to write log messages to file instead of stderr?

Basically yes.  As an improvement, I would like that the value of the
`FT_COMPONENT` macro can be displayed optionally, e.g.

  [afhints] foo bar
  [ttgxvar] sproink
  ...

The idea is that you first do a run with `FT2_DEBUG=any:7:labels` to
see all those tags, then redo it with, say,

  FT2_DEBUG=afhints:7

to get only the 'afhints' debug messages if this is what you need for
debugging.

> 2. Most external libraries provide some log levels capabilities
>    themselves, so, should I think in direction of utilizing
>    those. In case yes, then how should that be utilized?

Please elaborate and show examples.

> In the 2nd case, FreeType's logger will completely depend on the
> external library, and developers will also need to learn some new
> information to use the logger.  And In the worst-case scenario, if
> the external library drops some functionality, we will need to make
> amendments to the logger.

I agree.

> According to me, the 1st option is better since the experience of
> using the logger will be the same for the client and developers and
> the only dependency of FreeType on external library will be of
> writing log messages to a file.

Yep.


    Werner