util._matcher: speed up regexp matching.
In 4babaa52badf, Benoit made a change that substantially slows matching
when a big .hgignore file is in play, because it calls into the regexp
matching engine potentially hundreds of times per file to be matched.
I've partly rolled back his change, so that we only call into the matcher
once per file, but preserved the ability to report a meaningful error
message if there's a syntax error in the regexp.
% init
% setup
% delete an empty directory
empty_dir
Removing directory empty_dir
directory
r1
% delete an untracked directory
untracked_dir/untracked_file1
untracked_dir/untracked_file2
Removing file untracked_dir/untracked_file1
Removing file untracked_dir/untracked_file2
Removing directory untracked_dir
directory
r1
% delete an untracked file
untracked_file
Removing file untracked_file
directory
r1
% delete an untracked file in a tracked directory
directory/untracked_file
Removing file directory/untracked_file
directory
r1
% delete nested directories
untracked_directory/nested_directory
Removing directory untracked_directory/nested_directory
Removing directory untracked_directory
directory
r1
% delete nested directories from a subdir
untracked_directory/nested_directory
Removing directory untracked_directory/nested_directory
Removing directory untracked_directory
directory
r1
% delete only part of the tree
untracked_directory/nested_directory
Removing directory untracked_directory/nested_directory
Removing directory untracked_directory
directory
r1
directory/untracked_file
% delete ignored files
ignored
Removing file ignored
directory
r1
% abort with missing files until we support name mangling filesystems
refused to run
untracked_file still around
untracked_file
refused to run
untracked_file still around
Removing file untracked_file
directory
r1