Refactor how filtering works

[sebastianbergmann]

Right now, File_Iterator is used to crawl the filesystem for files that match the criteria specified in the (PHPUnit) configuration resulting in a list (array) of files that are to be included in the code coverage report. This crawling is responsible for a slowdown in the startup of PHPUnit.

It would be better to store the information ("all *.php files in directory src) instead and match the filenames against that instead of a list generated through crawling.

[alister]

Also, if you exclude a directory,

<filter><whitelist><exclude>
      <directory>vendor</directory>

even if there are no files that have previously been white-listed within the directory, PHP_CodeCoverage_Filter::removeDirectoryFromWhitelist will collect the entire file list and attempt to unset the whitelist of each file.

[AndrewFeeney]

@sebastianbergmann Is your proposal here that we should have a single flat map of files in an array or object instead of a recursive nested directory tree? Would that array or object then be included with the serialized output?

[sebastianbergmann]

Is your proposal here that we should have a single flat map of files in an array

That is the status quo and what I meant in #386 (comment) when I wrote "list (array) of files that are to be included in the code coverage report".