Make wrapper name unique using its source hash

[jneira]

• Before this the wrapper used the project version to cache the wrapper executable

• That led to false negatives testing the compilation and execution of the wrapper using the bios-test test suite cause the tests reused a previous wrapper executable between commits of the same version

  • Devs had to remember delete manually %XDG_DIRECTORY%\hie-bios to avoid it

• I've used GHC.Fingerprint to hash the source file and cache the executable using its source (the most accurate one although non semantic changes will cause a cache miss)

  • And i've put the source near the executable to be able to check it quicky without have to go to hie-bios source

• I've cherry-picked my changes onto 0.3.0 and 0.3.1 to check the test suite with them:

  • 0.3.0: https://ci.appveyor.com/project/jneira/hie-bios/builds/29673096/job/9x5k66k9ittfyvy0
  • 0.3.1: https://ci.appveyor.com/project/jneira/hie-bios/builds/29673244/job/nxkbys8o1gt737vq

• In both cases the test suite fails.

  • To be fair it had failed in the windows ci without these changes cause we are not caching %XDG_DIRECTORY%\hie-bios between ci builds and the wrapper would be compiled every time.
  • But if we start caching %XDG_DIRECTORY%\hie-bios in ci for some reason it will suffer the false negatives as well

• I am using a new en var %HIE_BIOS_CACHE_DIR% to let users change the default one (without change the general %XDG_CACHEDIR%). It is not strictly necessary but it is a common practice to avoid issues with file permissions (in some envs the creation of executable files inside user directory is forbidden f.e.)

Fixes #114

[fendor]

More Documentation for this function please!
Also, getCacheDir is probably a misnomer.

[jneira]

Mmm it retrieves the cache directory used by the lib, getHieBiosCacheDir would be better or you are thinking in another deficiency?

[fendor]

Or maybe a misnomer... Mainly adding documentation for the env variable and so on suffices for me.