[bug-grep] restructure patch for review

[Claudio Fontana]

Hello,

I would like to show you this patch,
whose aim is to begin to make grep more maintenable
for the future.

* main() function has been drastically cut, with all
options related data and functions moved to grepopt.c
and grepopt.h . Other functionalities that were
formerly blobbed in main() have now a nicely named
function (get_program_name ..)

* I have written support for prioritizing action
options in grep. This means that it's easier to deal
with current and future posix constraints ('-q > -l,
-l > ...'). It's a simple mask, where low value
actions have more priority. See grepopt.c, grepopt.h

* the chaotic grep recursion has been restructured
following Stepan's design (grep_parameter, grep_stdin,
grep_fd, grep_dir). A lot of duplicated code removed,
and a lot of function exit points have been collapsed
into one. Things can be further improved here.

* dosbuf.c is not brutally included in grep.c anymore,
it now exposes a clean interface to grep.c using
dosbuf.h. 

* prline madness has been addressed, with one small
function and one auxiliary function called only for
partial line printing, named prline_part().

* search.c translation table for kwsinit() is now
built once and for all before compiling any regex.
This avoids the need to loop each time in kwsinit().

* Gcompile and Ecompile functionality has been merged.
They now call EGcompile_aux with an additional syntax
parameter, where only the base syntax (RE_SYNTAX_GREP,
RE_SYNTAX_POSIX_EGREP, RE_SYNTAX_AWK...) must be
specified. A lot of duplication was thus removed.

When doing these changes I found myself in a specific
area where existing patches were available.

I included the changes for RE_ICASE in
lib/posix/regex.h also available in the redhat
2.5.1-oi patch, 

http://cvs.fedora.redhat.com/viewcvs/devel/grep/grep-2.5.1-oi.patch

This was inevitable to be able to decently restructure
Gcompile, Ecompile and prline without breaking
correctness.

Idea for further work: in my opinion the recursion can
be cleaned much more, and all functions modifying the
global options regarding grep state (buffering,
descriptor, current file name, etc) should document
their behaviour (with a small comment). I would also
advocate wrapping all those global variables in a
struct in grep.c, namely struct grep_state s;

I tested the patch to my best. I am not very familiar
with the procedure, however here it is.

http://cmdftp.sourceforge.net/grep-restructure.patch

Built using diff -Naur, so apply using -p1

Claudio




                
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