Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!hao!ames!aurora!labrea!decwrl!pyramid!uccba!hal!ncoast!allbery
From: simon@its63b.ed.ac.uk (Simon Brown)
Newsgroups: comp.sources.misc
Subject: Re: e - a friendly interface to vi
Message-ID: <4932@ncoast.UUCP>
Date: Fri, 23-Oct-87 20:44:34 EST
Article-I.D.: ncoast.4932
Posted: Fri Oct 23 20:44:34 1987
Date-Received: Mon, 26-Oct-87 01:39:34 EST
Sender: allbery@ncoast.UUCP
Organization: Computer Science Department, Edinburgh University
Lines: 989
Approved: allbery@ncoast.UUCP
X-Archive: comp.sources.misc/8710/17


Here's a cleaned-up (I hope) version of e -
	o Ported to System V.
	o Puts history in the correct file even if you try to edit
	  files not in the current directory.
	o "e -" and "e ." use the same numbering scheme.
	o Multiple file-entries in history-files no longer occur.
	o Uses $EDITOR instead of always using "vi".

Warning: this changed version has not been tested under BSD (cos I was
too lazy).

------------------------ cut here -------------------
#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create:
#	e.c
# This archive created: Thu Oct 15 20:17:37 1987
# By:	Simon Brown (Computer Science Department, Edinburgh University)
export PATH; PATH=/bin:/usr/bin:$PATH
echo shar: "extracting 'e.c'" '(19244 characters)'
if test -f 'e.c'
then
	echo shar: "will not over-write existing file 'e.c'"
else
cat << \SHAR_EOF > 'e.c'
/*
 * e.c - a friendly interface to vi
 *
 * Terry Jones    {ihnp4,allegra,decvax,utzoo,utcsri}!watmath!watdragon!tcjones
 * Department of Computer Science
 * University of Waterloo
 * Waterloo, Ontario, Canada. N2L 3G1
 *
 *
 * best vi'ed with ts=4 sw=4
 * to compile: cc -o e -O e.c
 */

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>

#ifdef sysV
#  ifdef GEC
#    include <local/ndir.h>
#  else
#    include <ndir.h>
#  endif
#  include <termio.h>
#  include <string.h>
#  include <fcntl.h>
#else
#  include <sys/dir.h>
#  ifdef NFS
#    include <ufs/inode.h>
#  else
#    include <sys/inode.h>
#  endif
#  include <sgtty.h>
#  include <strings.h>
#endif sysV

#include <signal.h>
#include <ctype.h>

#ifdef sysV
#  define VI "/usr/bin/vi"
#  define index strchr
#  define rindex strrchr
#else
#  define VI "/usr/ucb/vi"
#endif sysV

#ifndef L_SET
# define L_SET 0
#endif
#ifndef IREAD
# define IREAD	0400
# define IWRITE	0200
#endif

#define HIST ".e"
#define HIST_LINES 8
#define HIST_CHARS 512
#define ARG_CHARS 100
#define MAX_ARGS 10
#define RUBOUT '\177'
#define HFILELEN 512

char history[HIST_CHARS];
char arg[ARG_CHARS];
char *hist[HIST_LINES];
char temp[HIST_CHARS];
char *tmp_file="._vihistXXXXXX";
char dotstring[] = ".";
char rubout = RUBOUT;

#ifdef sysV
struct termio oldblk;
#else
struct sgttyb oldblk;
#endif sysV

int  term_messy = 0;

char *got_vi();

void 
do_vi(thing)
char *thing;
{
	/* split the arguments in 'thing' up and exec vi on them */
	char *args[MAX_ARGS];
	char *this,*next;
	register i;
	char *getenv();

	if ((args[0]=getenv("EDITOR")) == 0) args[0]=VI;
	args[1]=thing;

	i=1;
	while (*thing!='\0'&&(thing=index(thing,' '))!=NULL){
		*thing++='\0';
		if (*thing!='\0'){
			args[++i]=thing;
		}
	}
	args[++i]=NULL;
		
	if (execvp(args[0],args)==-1){
		perror(args[0]);
		exit(1);
	}
}

main(c,v)
int c;
char **v;
{
	extern clean_up();

	/* make sure we reset the terminal on our way out if we get interrupted */
	if (signal(SIGINT, SIG_IGN) != SIG_IGN){
		signal(SIGINT, clean_up);
	}

	switch (c){
		case 1: 
			/* just go and vi the last file that was vi'ed */
			last_file();
			do_vi(arg);
			break;
		
		case 2:
			switch ((*++v)[0]){
				case '-':
					if ((c=(*v)[1])=='\0'){
						/* this is a select from history, ask what they want */
						ask_hist();
						do_vi(arg);
					}
					else if (isdigit(c)){
						/* get the nth last file from the history and vi it */
						nth_hist(c-'0');
						do_vi(arg);
					}
					else if (c=='t'&&(*v)[2]=='\0'){
						/* this is an empty tag - ignore it */
						do_vi(*v);
					}
					else if (c=='r'&&(*v)[2]=='\0'){
						/* a recover, just pass it to vi and don't interfere */
						do_vi(*v);
					}
					else{
						/* this is a pattern - try to match it */
						find_match(++*v);
						do_vi(arg);
					}
					break;

				case '+':
					/* a command, put it before the last file name etc */
					insert_command(*v);
					do_vi(arg);
					break;

				case '.':
					/* just give a history list if there is only a dot */
					if ((*v)[1]=='\0'){
						register ct;
						register i;

						read_hist(dotstring);
						ct=split_hist();

						for (i=0;i<ct;i++){
							fprintf(stderr,"\t[%d]: %s\n",ct-i-1,hist[ct-i-1]);
						}
						exit(0);
					}
					/* 
					   WARNING!
					   the switch falls through in the case where there is a
					   pattern that starts with a period
					*/

				default :
					/* looks like it's just a plain old file name. vi it! */
					normal(*v);
					do_vi(arg);
					break;
			}
		default:
			/* a bunch of arguments, fix the history & vi them all as normal */
			multiple(c,v);
			do_vi(arg);
			break;
	}
}



read_hist(dirname)
char *dirname;
{
	/*
	   read the history file and break it up into lines in the global variable
	   'history'. do the appropriate checks to see that it exists etc...
	*/

	register vh;
	register bytes;
	register offset;
	struct stat buf;
	char dirbuffer[HFILELEN];


	/* 
	   if there is no history file then say so and get out of here - they 
	   had nobusiness asking for access to the history
	*/
	sprintf(dirbuffer,"%s/%s", dirname, HIST);
	if ((vh=open(dirbuffer,O_RDONLY))==-1){
		perror(dirbuffer);
		exit(1);
	}

	/* stat it */
	if (fstat(vh,&buf)==-1){
		perror(dirbuffer);
		exit(1);
	}

	/* 
	   set 'offset' so that we can read the last portion of the history
	   file only. if there are less than HIST_CHARS characters in the
	   file then we will start reading at 0, otherwise at HIST_CHARS
	   characters before the end of the file.
	*/
	offset=(int)buf.st_size-HIST_CHARS<0 ? 0 : buf.st_size-HIST_CHARS;

	/* move to that place in the file */
	if (lseek(vh,(long)offset,L_SET)==-1){
		perror(dirbuffer);
		exit(1);
	}

	/* and READ! */
	if ((bytes=read(vh,history,HIST_CHARS))==-1){
		perror(dirbuffer);
		exit(1);
	}

	/* if we didn't come up with ANYTHING we may as well leave */
	if (!bytes){
		fprintf(stderr,"Empty %s file.\n",dirbuffer);
		exit(1);
	}

	/* zap the newline (which should be there) for now */
	if (history[--bytes]=='\n'){
		history[bytes]='\0';	
	}

	/* and get out of here */
	return(bytes);
}

last_file()
{
	/*
	   get the last name from the 'history' array and put it into 'arg'
	*/

	read_hist(dotstring);
	if (index(history,'\n')==NULL){
		if (*history=='\0'){
			fprintf(stderr,"%s: badly formatted.\n",HIST);
			exit(1);
		}
		else{
			sprintf(arg,"%s",history);
		}
	}
	else{
		sprintf(arg,"%s",rindex(history,'\n')+1);
	}
}

split_hist()
{
	/*
	   set the array of pointers in 'hist' to point to the succesive names
	   in the 'history' array. these are delimited (presumably) by newlines
	   and so they're easy to catch...

	   what in fact is done is that the history array is copied and we set
	   the pointers up and set the newlines to be '\0' s. this way we don't
	   mess up the history array as we will want it intact later on (maybe).
	*/

	char *tmp;
	register count;

	/* copy it */
	sprintf(temp,"%s",history);

	/* 
	   now run through breaking it up, setting pointers and return the number 
	   of lines we found.
	*/
	for (count=0;count<HIST_LINES;count++){
		if ((tmp=hist[count]=rindex(temp,'\n'))==NULL){
			break;
		}
		*tmp='\0';
		hist[count]++;
	}
	if (count<HIST_LINES){
		hist[count++]=temp;
	}
	return(count);
}

nth_hist(n)
int n;
{
	/*
	   get the nth last filename from the list. make use (of course) of
	   read_hist and split_hist.
	*/
	register count;
	register i;

	read_hist(dotstring);
	count=split_hist();
	if (n>count-1){
		if (count>1){
			fprintf(stderr,"Only %d history items exist.\n",count);
		}
		else{
			fprintf(stderr,"Only one history item exists.\n");
		}
		exit(1);
	}
	sprintf(arg,"%s",hist[n]);

	/* rebuild the history with the selected name at the bottom */
	reconstruct(n,count,dotstring);
}

ask_hist()
{
	/*
	   ask the outside world which of the files in the history is wanted.
	   set the terminal to cbreak.
	*/
	register i;
	register count;
	char *last;
	register option;

	/* read and split the history file */
	read_hist(dotstring);
	count=split_hist();

	/* print the history */
	for (i=0;i<count;i++){
		fprintf(stderr,"\t[%d]: %s\n",count-(i+1),hist[count-i-1]);
	}

	/* give them a prompt (of sorts) */
	fprintf(stderr,"select -> ");

	/* set the terminal up */
	set_term();

	/* get their response */
	option=getc(stdin);

	/* make the terminal 'safe' again */
	unset_term();

	/* 
	   process the option and put the appropriate file name into the 
	   arg variable.
	*/
	if (option=='\n'){
		/* they want the last file of the list */
		fprintf(stderr,"%s\n",hist[0]);
		sprintf(arg,"%s",hist[0]);
		return;
	}
	else if (option==rubout){
		/* they want to leave */
		fprintf(stderr,"\n");
		exit(1);
	}
	else if (option>='0' && option<='0'+count){
		/* they have requested a file by it's number */
		option=option-'0';
		fprintf(stderr,"%s\n",hist[option]);
		sprintf(arg,"%s",hist[option]);
	}
	else{
		/* 
		   looks like they want to name a specific file. echo the 
		   characters back to the screen.
		*/
		fprintf(stderr,"%c",option);
		arg[0]=option;
		i=1;
		while ((arg[i]=getc(stdin))!='\n'){
			i++;
		}
		arg[i]='\0';
		option=count-1;		/* a kludge for the history re-make to follow */

		/* seeing as they typed in the name, try and help with spelling */
		spell_help();
	}

	/* rebuild the history with the selected name at the bottom */
	reconstruct(option-1,count,dotstring);
}

FILE *
get_temp()
{
	/* get ourselves a temporary file for the reconstructed history */
	FILE *fp,*fopen();

	mktemp(tmp_file);
	if ((fp=fopen(tmp_file,"w"))==NULL){
		perror(tmp_file);
		exit(1);
	}
	return(fp);
}

close_temp(fp,filename)
FILE *fp;
char *filename;
{
	/* move the temporary file to be the new history */
	FILE *fclose();
	char dirbuffer[HFILELEN];
	char *fptr;

	if (fclose(fp)==(FILE *)EOF){
		fprintf(stderr,"Could not close %s\n",tmp_file);
		exit(1);
	}

	strcpy(dirbuffer, filename);
	if ((fptr=rindex(dirbuffer,'/'))==0){
		strcpy(dirbuffer,dotstring);
		fptr = &dirbuffer[1];
	}
	sprintf(fptr,"/%s", HIST);
		
	if (rename(tmp_file,dirbuffer)!=0){
		perror("rename");
		exit(1);
	}
}

set_term()
{
	/* go into cbreak and no echo mode */
#ifdef sysV
	struct termio	blk;

	ioctl(0, TCGETA, &blk);
	oldblk = blk;
	rubout = blk.c_cc[VERASE];
	blk.c_lflag &= ~(ICANON|ECHO|ECHONL);
	blk.c_cc[VMIN] = 1;
	blk.c_cc[VTIME] = 0;
	ioctl(0, TCSETA, &blk);
#else
	struct sgttyb	blk;

	gtty(0, &blk);
	oldblk = blk;
	rubout = blk.sg_erase;
	blk.sg_flags |= CBREAK;
	blk.sg_flags ^= ECHO;
	stty(0, &blk);
#endif sysV
	term_messy = 1;
}

unset_term()
{
	/* get out of cbreak and no echo */
	if (term_messy) {
#ifdef sysV
		ioctl(0, TCSETA, &oldblk);
#else
		stty(0, &oldblk);
#endif sysV
		term_messy = 0;
	}
}

match(argument,pattern)
char	*argument;
char	*pattern;
{
	/*
	   boneheaded but easy pattern matcher. just see if the 'pattern'
	   exists anywhere in the 'argument'. boyer-moore who?
	*/
	register length=strlen(pattern);

	while (strlen(argument)>=length){
		if (!strncmp(argument++,pattern,length)){
			return(1);
		}
	}
	return(0);
}

find_match(pattern)
char *pattern;
{
	/*
	   find the name in the history list that contains the 'pattern'.
	   if it exists then put it into the 'arg' variable and otherwise
	   announce that a match couldn't be found and leave.
	*/
	register count;
	register i;

	/* read and split the history file */
	read_hist(dotstring);
	count=split_hist();

	/* try for a match with each file in turn (note that we are working
	   from most-recently-used backwards - probably a good thing)
	*/
	for (i=0;i<count;i++){
		if (match(hist[i],pattern)){
			sprintf(arg,"%s",hist[i]);
			reconstruct(i,count,dotstring);
			return;
		}
	}

	/* we couldn't match so get out of here */
	fprintf(stderr,"Unable to match with \"%s\"\n",pattern);
	exit(1);
}

insert_command(command)
char *command;
{
	/*
	   they want the last file in the history but want to preceed it
	   this time with a command - no problems here.
	*/
	register count;
	char *place;

	/* read and split the history */
	read_hist(dotstring);
	count=split_hist();
	
	/* 
	   if there was already a command there (indicated by a '+') then we
	   want to get rid of it. if there is a '+' but no ' ' after it then
	   the history file is in disarray and we will not try to recover
	*/
	if (*hist[0]=='+'){
		if ((place=index(hist[0],' '))==NULL){
			fprintf("Serious weirdenss in insert_command\n");
			exit(1);
		}
		/* move over white space - if there is any */
		while (*place==' '||*place=='\t'){
			place++;
		}
	}
	else{
		/* there was no command preceeding the last file in the history */
		place=hist[0];
	}

	/* put the new command and the filename into 'arg' */
	sprintf(arg,"%s %s",command,place);

	/* rebuild the history with the selected command and name at the bottom */
	reconstruct(0,count,dotstring);
}

reconstruct(except,count,dirname)
int	except;
int	count;
char	*dirname;
{
	/* 
	   reconstruct history file excepting the 'except' last.
	   so just copy all lines but the 'except'th last and then put in 'arg'
	   which contains the new line for the history
	*/
	register i;
	FILE *tv,*get_temp();
	char *fptr;

	/* get a temporary file */
	tv=get_temp();

	/* grab tail of file name. */
	if (fptr=rindex(arg,'/')) fptr++;
	else fptr=arg;

	/* put in the line we still want - ignoring duplicates of this file */
	for (i=count-1;i>=0;i--){
		if (i!=except && strcmp(hist[i],fptr)!=0){
			fprintf(tv,"%s\n",hist[i]);
		}
	}

	/* put in the new line from 'arg' */
	fprintf(tv,"%s\n",fptr);

	/* rename the temporary to be the new history file */
	close_temp(tv,arg);
}

normal(string)
char *string;
{
	/* 
	   a normal filename was found, put it into arg. first of all if there
	   is a history and the file is already in it (which means they could
	   have gotten to this file in other ways), then reconstruct the history
	   as though they had. also offer spelling help.
	*/
	register count;
	register i;
	char *edir;

	/* put it into 'arg' */
	sprintf(arg,"%s",string);

	/* if there is a history file */
	if (edir=got_vi(string)){

		/* read it and split it up */
		read_hist(edir);
		count=split_hist();

		/* if it is in the history then reconstruct and return */
		for (i=0;i<count;i++){
			if (!strcmp(hist[i],arg)){
				reconstruct(i,count, edir);
				return;
			}
		}

		/* it's not in the history, help with spelling then reconstruct */
		spell_help();
		reconstruct(HIST_LINES,count,edir);
	}
	else{

		/* 
		   there is no history around so help with spelling and set up a 
		   history for next time.
		*/
		spell_help();
		new_vi(string);
	}

}

multiple(number, args)
int number;
char **args;
{
	/*
	   there were several names on the command line so we just strcat them
	   into the 'arg' array.
	*/
	register count;
	register i;
	char *edir;

	*arg='\0';
	while (--number){
		strcat(arg,*++args);
		if (number>1){
			strcat(arg," ");
		}
	}

	/*
	   now if there is a history file and we can find an identical line
	   then reconstruct with that line at the bottom.
	*/
	if (edir=got_vi(*--args)){
		read_hist(edir);
		count=split_hist();
		for (i=0;i<count;i++){
			if (!strcmp(hist[i],arg)){
				reconstruct(i,count,edir);
				return;
			}
		}
		/* 
		   rebuild, including everything but the counth last (i.e. make
		   a new history by omitting the oldest file in the current one and
		   putting 'arg' on the end.
		*/
		reconstruct(HIST_LINES,count,edir);
	}
	else{
		/* there was no history file so try to give them one for next time */
		new_vi(*args);
	}
}

char *
got_vi(filename)
char *filename;
{
	/* indicate if there is a history file that they own or otherwise */
	struct stat buf;
	static char dirbuffer[HFILELEN];
	char *fptr;

	strcpy(dirbuffer, filename);
	if ((fptr=rindex(dirbuffer,'/'))==0) {
		for (fptr=dirbuffer; *fptr; fptr++);
		*fptr='/';
	}
	fptr++;
	strcpy(fptr,HIST);
	if (stat(dirbuffer,&buf)==-1 || getuid()!=buf.st_uid){
		return((char *)0);
	}
	else{
		*--fptr = '\0';
		return(dirbuffer);
	}
}

new_vi(filename)
{
	/* attempt to make a new history file - several things could go wrong */
	FILE *vh,*fopen(),*fclose();
	struct stat buf;
	char dirbuffer[HFILELEN];
	char *fptr;

	/* grab directory of filename */
	strcpy(dirbuffer, filename);
	if (fptr=rindex(dirbuffer,'/')) *++fptr = '\0';
	else {
		strcpy(dirbuffer,"./");
		fptr = &dirbuffer[2];
	}

	/* if you can't read the current directory, get out */
	if (stat(dirbuffer,buf)==-1){
		perror("stat");
		exit(1);
	}

	/* if you own the directory (you can't normally get a history in /tmp) */
	if (getuid()==buf.st_uid){

		/* if we can't make a history, get out */
		strcat(dirbuffer,HIST);
		if ((vh=fopen(dirbuffer,"w"))==NULL){
			perror(dirbuffer);
			exit(1);
		}

		/* put in the 'arg' that we will be vi'ing in a second,
		   after extracting it's tail. */
		if (fptr=rindex(arg,'/')) fptr++;
		else fptr=arg;
		fprintf(vh,"%s\n",fptr);

		/* close the history */
		if (fclose(vh)==(FILE *)EOF){
			fprintf(stderr,"Could not close %s\n",dirbuffer);
			exit(1);
		}

		/* give the history some protection - for those who want it! */
		if (chmod(dirbuffer,IREAD|IWRITE)==-1){
			perror("chmod");
			exit(1);
		}
	}
}

clean_up()
{
	/* just get out after making sure things are tidy */
	fprintf(stderr,"Interrupt.\n");
	unlink(tmp_file);
	unset_term();
	exit(1);
}

spell_help()
{
	/*
	   unashamedly stolen (and modified) from "The UNIX Programming
	   Environment" - Kernighan and Pike

	   read the directory and if the file they want (in 'arg') does not
	   exist then see if there is one that does that has similar spelling
	   to what they requested. offer the change and handle the reply.
	*/

	char new[ARG_CHARS];
	register dist=3;
	register new_dist;
	DIR *dp, *opendir();
	struct direct *readdir();
	struct direct *entry;
	register len;
	struct stat buf;
	char dirbuffer[HFILELEN];
	char *fptr;

	/* if the file already exists just return - they don't need help */
	if (stat(arg,&buf)==0){
		return;
	}

	/* if the current directory can't be read then return */
	strcpy(dirbuffer, arg);
	if (fptr=rindex(dirbuffer,'/')) *fptr++='\0';
	else {
		strcpy(dirbuffer, dotstring);
		fptr=arg;
	}
	if ((dp=opendir(dirbuffer))==NULL){
		return;
	}
	
	/* get the length of what we are seeking to cut down on strcmping time */
	len=strlen(fptr);

	for (entry=readdir(dp);entry!=NULL;entry=readdir(dp)){

		/* if this entry has length = sought length +/- 1 then it may be ok */
		if (entry->d_ino&&entry->d_namlen>=len-1&&entry->d_namlen<=len+1){

			/* get the 'distance' between what we want and this file name */
			new_dist=sp_dist(entry->d_name,fptr);

			/* if this name is close enough and better than our current best */
			if (new_dist<=dist&&new_dist!=3){

				if (!new_dist){
					/* if the dist is 0 then they are identical */
					closedir(dp);
					return;
				}
				/* remember the new name and distance */
				strcpy(new,entry->d_name);
				dist=new_dist;
			}
		}
	}

	/* close up. if we got no suitable result then simply return */
	closedir(dp);
	if (dist==3){
		return;
	}

	/* offer them "new" */
	set_term();
	fprintf(stderr,"correct to %s [y]? ",new);

	/* process the reply */
	switch (getc(stdin)){
		case 'N':
		case 'n':
			fprintf(stderr,"no\n");
			break;
		case 'q':
		case 'Q':
			fprintf(stderr,"quit\n");
			unset_term();
			exit(0);
			break;
		default :
			fprintf(stderr,"yes\n");
			if (fptr==arg)
				strcpy(arg,new);
			else sprintf(arg,"%s/%s", dirbuffer, new);
	}
	unset_term();
}

sp_dist(s,t)
char *s;
char *t;
{
	/* 
	   stolen from the same place as spell_help() above.

	   work out the distance between the strings 's' and 't' according
	   to the rough metric that
	   
	   identical = 0
	   interchanged characters = 1
	   wrong character/extra character/missing character = 2
	   forget it = 3
	*/

	while (*s++==*t){
		if (*t++=='\0'){
			/* identical */
			return(0);
		}
	}

	if (*--s){
		if (*t){
			if (s[1]&&t[1]&&*s==t[1]&&*t==s[1]&&!strcmp(s+2,t+2)){
				/* interchanged chars */
				return(1);
			}
			if (!strcmp(s+1,t+1)){
				/* wrong char */
				return(2);
			}
		}
		if (!strcmp(s+1,t)){
			/* extra char in 't' */
			return(2);
		}
	}
	if (!strcmp(s,t+1)){
		/* extra char in 's' */
		return(2);
	}

	/* forget it */
	return(3);
}
SHAR_EOF
chmod +x 'e.c'
fi
exit 0
#	End of shell archive
-- 
----------------------------------
| Simon Brown                    | UUCP:  seismo!mcvax!ukc!{lfcs,its63b}!simon
| Department of Computer Science | JANET: simon@uk.ac.ed.{lfcs,its63b}
| University of Edinburgh,       | ARPA:  simon%lfcs.ed.ac.uk@cs.ucl.ac.uk
| Scotland, UK.                  |     or simon%its63b.ed.ac.uk@cs.ucl.ac.uk
----------------------------------     or simon%cstvax.ed.ac.uk@cs.ucl.ac.uk
                      "Life's like that, you know"