importre,os,sysfromdifflibimportSequenceMatcher,context_difffromdatetimeimportdatetimefromitertoolsimportislicevline=re.compile(r'\.V(?:_\S+)? (\S+) (\S+) ?(.*)').matchnline=re.compile(r'\.N (.*)').matchcline=re.compile(r'\.C (\d+) (\d+)').matchiline=re.compile(r'\.I (\d+)').matchdefget_version(repo_fn,v=None):# Return version *v* or the last version if *v* is None.ifnotos.path.exists(repo_fn):return''currver=0curr=[]f=iter(open(repo_fn,'r'))line=next(f,'')whilelineand(visNoneorcurrver<v):# Start building up next version from the lastcurrver+=1prev,curr=curr,[]# Process mandatory .V line and optional .N msg linesassertline.startswith('.V')forlineinf:ifnotline.startswith('.N'):break# Process the .I and .C instructionswhilelineandline.startswith(('.I','.C')):ifline.startswith('.I'):n=int(iline(line).group(1))curr.extend(islice(f,n))else:m,n=map(int,cline(line).groups())curr.extend(prev[m-1:n])line=next(f,'')return''.join(curr)defprint_log(repo_fn,v=None):# Print log entries. *v* is a specific version number or None to print all.currver=0f=iter(open(repo_fn,'r'))line=next(f,'')whileline:# Process mandatory .V line and optional .N msg linesassertline.startswith('.V')repo_fn,datetime,msg=vline(line).groups()forlineinf:ifline.startswith('.N'):msg+='\n'+nline(line).group(1)else:breakcurrver+=1ifvisNone:print"%s%d%18s%s"%(repo_fn,currver,datetime,msg)elifcurrver==v:print"%s%d%18s%s"%(repo_fn,currver,datetime,msg)return# Skip through the .I and .C instructionswhilelineandline.startswith(('.I','.C')):ifline.startswith('.I'):n=int(iline(line).group(1))forlineinislice(f,n):passline=next(f,'')defdiff(repo_fn,vnum1=None,vnum2=None,context=False):# vnum1 or vnum2 can be None to indicate last version in repository# vnum2 can be a filename to compare tov1=get_version(repo_fn,vnum1).splitlines(True)ifisinstance(vnum2,int)orvnum2isNone:v2=get_version(repo_fn,vnum2).splitlines(True)else:v2=open(vnum2).readlines()results=[]ifcontext:return''.join(context_diff(v1,v2))fortag,i1,i2,j1,j2inSequenceMatcher(None,v1,v2).get_opcodes():iftagin('replace','insert'):results.append('.I%d\n'%(j2-j1))results.extend(v2[j1:j2])eliftag=='equal':results.append('.C%d%d\n'%(i1+1,i2))return''.join(results)defmake_header(filename,msg,create):first='_,03000'ifcreateelse''datestring=datetime.now().strftime('%d-%b-%y,%H:%M:%S')return'.V%(first)s%(filename)s%(datestring)s%(msg)s'%locals()defget_repo_fn(filename):path,fullname=os.path.split(filename)base,ext=os.path.splitext(fullname)ext=extor'.'newext=ext[:2]+'$'+ext[3:]result=os.path.join(repo_dir,base+newext)returnresultrepo_dir=os.environ.get('VCS','.')# ------- Command-line interface -------help_msg='''Usage:    vcs add foo.bar "Checkin message"    vcs extract foo.bar [revnum]    vcs log foo.bar [revnum]    vcs diff foo.bar [revnum1 [revnum2]]Repository:%s    '''%repo_dirdeftalkback(msg,help=False,code=1):print>>sys.stderr,msgifhelp:print>>sys.stderr,'\n'+help_msgsys.exit(code)defmain(argv):# XXX add support for branching# XXX support .N for outputiflen(argv)<=1:talkback(help_msg,code=0)iflen(argv)<3:talkback('Not enough arguments. Need a command and filename.',help=True)command=argv[1].lower()ifcommandnotin'log extract diff add update l e d a u'.split():talkback('Unknown command: '+command,help=True)command=command[:1]filename=argv[2]repo_fn=get_repo_fn(filename)ifcommandin'le':ifnotos.path.exists(repo_fn):talkback(repo_fn+' not found')v=int(argv[3])iflen(argv)>=4elseNoneifcommand=='l':print_log(repo_fn,v)else:printget_version(repo_fn,v),elifcommand=='d':v1=int(argv[3])iflen(argv)>=4elseNonev2=int(argv[4])iflen(argv)>=5elsefilenameprintdiff(repo_fn,v1,v2,context=True),elifcommandin'au':ifnotos.path.exists(filename):talkback('Cannot find file: '+filename)d=diff(repo_fn,None,filename)iflen(d.splitlines())==1:talkback('File is already current. There are no changes.',code=0)msg=' '.join(argv[3:])create=notos.path.exists(repo_fn)repo_file=open(repo_fn,'a+')print>>repo_file,make_header(filename,msg,create)print>>repo_file,d,repo_file.close()talkback('Added to '+repo_fn,code=0)else:talkback('Unreachable')if__name__=='__main__':main(sys.argv)