("" < 3.4) always evaluates to true, which unconditionally

[dragonfly.git] / contrib / less-381 / cmdbuf.c

/*
 * Copyright (C) 1984-2002  Mark Nudelman
 *
 * You may distribute under the terms of either the GNU General Public
 * License or the Less License, as specified in the README file.
 *
 * For more information about less, or for information on how to 
 * contact the author, see the README file.
 */


/*
 * Functions which manipulate the command buffer.
 * Used only by command() and related functions.
 */

#include "less.h"
#include "cmd.h"

extern int sc_width;

static char cmdbuf[CMDBUF_SIZE]; /* Buffer for holding a multi-char command */
static int cmd_col;             /* Current column of the cursor */
static int prompt_col;          /* Column of cursor just after prompt */
static char *cp;                /* Pointer into cmdbuf */
static int cmd_offset;          /* Index into cmdbuf of first displayed char */
static int literal;             /* Next input char should not be interpreted */

#if TAB_COMPLETE_FILENAME
static int cmd_complete();
/*
 * These variables are statics used by cmd_complete.
 */
static int in_completion = 0;
static char *tk_text;
static char *tk_original;
static char *tk_ipoint;
static char *tk_trial;
static struct textlist tk_tlist;
#endif

static int cmd_left();
static int cmd_right();

#if SPACES_IN_FILENAMES
public char openquote = '"';
public char closequote = '"';
#endif

#if CMD_HISTORY
/*
 * A mlist structure represents a command history.
 */
struct mlist
{
        struct mlist *next;
        struct mlist *prev;
        struct mlist *curr_mp;
        char *string;
};

/*
 * These are the various command histories that exist.
 */
struct mlist mlist_search =  
        { &mlist_search,  &mlist_search,  &mlist_search,  NULL };
public void * constant ml_search = (void *) &mlist_search;

struct mlist mlist_examine = 
        { &mlist_examine, &mlist_examine, &mlist_examine, NULL };
public void * constant ml_examine = (void *) &mlist_examine;

#if SHELL_ESCAPE || PIPEC
struct mlist mlist_shell =   
        { &mlist_shell,   &mlist_shell,   &mlist_shell,   NULL };
public void * constant ml_shell = (void *) &mlist_shell;
#endif

#else /* CMD_HISTORY */

/* If CMD_HISTORY is off, these are just flags. */
public void * constant ml_search = (void *)1;
public void * constant ml_examine = (void *)2;
#if SHELL_ESCAPE || PIPEC
public void * constant ml_shell = (void *)3;
#endif

#endif /* CMD_HISTORY */

/*
 * History for the current command.
 */
static struct mlist *curr_mlist = NULL;
static int curr_cmdflags;


/*
 * Reset command buffer (to empty).
 */
        public void
cmd_reset()
{
        cp = cmdbuf;
        *cp = '\0';
        cmd_col = 0;
        cmd_offset = 0;
        literal = 0;
}

/*
 * Clear command line on display.
 */
        public void
clear_cmd()
{
        clear_bot();
        cmd_col = prompt_col = 0;
}

/*
 * Display a string, usually as a prompt for input into the command buffer.
 */
        public void
cmd_putstr(s)
        char *s;
{
        putstr(s);
        cmd_col += strlen(s);
        prompt_col += strlen(s);
}

/*
 * How many characters are in the command buffer?
 */
        public int
len_cmdbuf()
{
        return (strlen(cmdbuf));
}

/*
 * Repaint the line from cp onwards.
 * Then position the cursor just after the char old_cp (a pointer into cmdbuf).
 */
        static void
cmd_repaint(old_cp)
        char *old_cp;
{
        char *p;

        /*
         * Repaint the line from the current position.
         */
        clear_eol();
        for ( ;  *cp != '\0';  cp++)
        {
                p = prchar(*cp);
                if (cmd_col + (int)strlen(p) >= sc_width)
                        break;
                putstr(p);
                cmd_col += strlen(p);
        }

        /*
         * Back up the cursor to the correct position.
         */
        while (cp > old_cp)
                cmd_left();
}

/*
 * Put the cursor at "home" (just after the prompt),
 * and set cp to the corresponding char in cmdbuf.
 */
        static void
cmd_home()
{
        while (cmd_col > prompt_col)
        {
                putbs();
                cmd_col--;
        }

        cp = &cmdbuf[cmd_offset];
}

/*
 * Shift the cmdbuf display left a half-screen.
 */
        static void
cmd_lshift()
{
        char *s;
        char *save_cp;
        int cols;

        /*
         * Start at the first displayed char, count how far to the
         * right we'd have to move to reach the center of the screen.
         */
        s = cmdbuf + cmd_offset;
        cols = 0;
        while (cols < (sc_width - prompt_col) / 2 && *s != '\0')
                cols += strlen(prchar(*s++));

        cmd_offset = s - cmdbuf;
        save_cp = cp;
        cmd_home();
        cmd_repaint(save_cp);
}

/*
 * Shift the cmdbuf display right a half-screen.
 */
        static void
cmd_rshift()
{
        char *s;
        char *p;
        char *save_cp;
        int cols;

        /*
         * Start at the first displayed char, count how far to the
         * left we'd have to move to traverse a half-screen width
         * of displayed characters.
         */
        s = cmdbuf + cmd_offset;
        cols = 0;
        while (cols < (sc_width - prompt_col) / 2 && s > cmdbuf)
        {
                p = prchar(*--s);
                cols += strlen(p);
        }

        cmd_offset = s - cmdbuf;
        save_cp = cp;
        cmd_home();
        cmd_repaint(save_cp);
}

/*
 * Move cursor right one character.
 */
        static int
cmd_right()
{
        char *p;
        
        if (*cp == '\0')
        {
                /* 
                 * Already at the end of the line.
                 */
                return (CC_OK);
        }
        p = prchar(*cp);
        if (cmd_col + (int)strlen(p) >= sc_width)
                cmd_lshift();
        else if (cmd_col + (int)strlen(p) == sc_width - 1 && cp[1] != '\0')
                cmd_lshift();
        cp++;
        putstr(p);
        cmd_col += strlen(p);
        return (CC_OK);
}

/*
 * Move cursor left one character.
 */
        static int
cmd_left()
{
        char *p;
        
        if (cp <= cmdbuf)
        {
                /* Already at the beginning of the line */
                return (CC_OK);
        }
        p = prchar(cp[-1]);
        if (cmd_col < prompt_col + (int)strlen(p))
                cmd_rshift();
        cp--;
        cmd_col -= strlen(p);
        while (*p++ != '\0')
                putbs();
        return (CC_OK);
}

/*
 * Insert a char into the command buffer, at the current position.
 */
        static int
cmd_ichar(c)
        int c;
{
        char *s;
        
        if (strlen(cmdbuf) >= sizeof(cmdbuf)-2)
        {
                /*
                 * No room in the command buffer for another char.
                 */
                bell();
                return (CC_ERROR);
        }
                
        /*
         * Insert the character into the buffer.
         */
        for (s = &cmdbuf[strlen(cmdbuf)];  s >= cp;  s--)
                s[1] = s[0];
        *cp = c;
        /*
         * Reprint the tail of the line from the inserted char.
         */
        cmd_repaint(cp);
        cmd_right();
        return (CC_OK);
}

/*
 * Backspace in the command buffer.
 * Delete the char to the left of the cursor.
 */
        static int
cmd_erase()
{
        register char *s;

        if (cp == cmdbuf)
        {
                /*
                 * Backspace past beginning of the buffer:
                 * this usually means abort the command.
                 */
                return (CC_QUIT);
        }
        /*
         * Move cursor left (to the char being erased).
         */
        cmd_left();
        /*
         * Remove the char from the buffer (shift the buffer left).
         */
        for (s = cp;  *s != '\0';  s++)
                s[0] = s[1];
        /*
         * Repaint the buffer after the erased char.
         */
        cmd_repaint(cp);
        
        /*
         * We say that erasing the entire command string causes us
         * to abort the current command, if CF_QUIT_ON_ERASE is set.
         */
        if ((curr_cmdflags & CF_QUIT_ON_ERASE) && cp == cmdbuf && *cp == '\0')
                return (CC_QUIT);
        return (CC_OK);
}

/*
 * Delete the char under the cursor.
 */
        static int
cmd_delete()
{
        if (*cp == '\0')
        {
                /*
                 * At end of string; there is no char under the cursor.
                 */
                return (CC_OK);
        }
        /*
         * Move right, then use cmd_erase.
         */
        cmd_right();
        cmd_erase();
        return (CC_OK);
}

/*
 * Delete the "word" to the left of the cursor.
 */
        static int
cmd_werase()
{
        if (cp > cmdbuf && cp[-1] == ' ')
        {
                /*
                 * If the char left of cursor is a space,
                 * erase all the spaces left of cursor (to the first non-space).
                 */
                while (cp > cmdbuf && cp[-1] == ' ')
                        (void) cmd_erase();
        } else
        {
                /*
                 * If the char left of cursor is not a space,
                 * erase all the nonspaces left of cursor (the whole "word").
                 */
                while (cp > cmdbuf && cp[-1] != ' ')
                        (void) cmd_erase();
        }
        return (CC_OK);
}

/*
 * Delete the "word" under the cursor.
 */
        static int
cmd_wdelete()
{
        if (*cp == ' ')
        {
                /*
                 * If the char under the cursor is a space,
                 * delete it and all the spaces right of cursor.
                 */
                while (*cp == ' ')
                        (void) cmd_delete();
        } else
        {
                /*
                 * If the char under the cursor is not a space,
                 * delete it and all nonspaces right of cursor (the whole word).
                 */
                while (*cp != ' ' && *cp != '\0')
                        (void) cmd_delete();
        }
        return (CC_OK);
}

/*
 * Delete all chars in the command buffer.
 */
        static int
cmd_kill()
{
        if (cmdbuf[0] == '\0')
        {
                /*
                 * Buffer is already empty; abort the current command.
                 */
                return (CC_QUIT);
        }
        cmd_offset = 0;
        cmd_home();
        *cp = '\0';
        cmd_repaint(cp);

        /*
         * We say that erasing the entire command string causes us
         * to abort the current command, if CF_QUIT_ON_ERASE is set.
         */
        if (curr_cmdflags & CF_QUIT_ON_ERASE)
                return (CC_QUIT);
        return (CC_OK);
}

/*
 * Select an mlist structure to be the current command history.
 */
        public void
set_mlist(mlist, cmdflags)
        void *mlist;
        int cmdflags;
{
        curr_mlist = (struct mlist *) mlist;
        curr_cmdflags = cmdflags;
}

#if CMD_HISTORY
/*
 * Move up or down in the currently selected command history list.
 */
        static int
cmd_updown(action)
        int action;
{
        char *s;
        
        if (curr_mlist == NULL)
        {
                /*
                 * The current command has no history list.
                 */
                bell();
                return (CC_OK);
        }
        cmd_home();
        clear_eol();
        /*
         * Move curr_mp to the next/prev entry.
         */
        if (action == EC_UP)
                curr_mlist->curr_mp = curr_mlist->curr_mp->prev;
        else
                curr_mlist->curr_mp = curr_mlist->curr_mp->next;
        /*
         * Copy the entry into cmdbuf and echo it on the screen.
         */
        s = curr_mlist->curr_mp->string;
        if (s == NULL)
                s = "";
        for (cp = cmdbuf;  *s != '\0';  s++)
        {
                *cp = *s;
                cmd_right();
        }
        *cp = '\0';
        return (CC_OK);
}
#endif

/*
 * Add a string to a history list.
 */
        public void
cmd_addhist(mlist, cmd)
        struct mlist *mlist;
        char *cmd;
{
#if CMD_HISTORY
        struct mlist *ml;
        
        /*
         * Don't save a trivial command.
         */
        if (strlen(cmd) == 0)
                return;
        /*
         * Don't save if a duplicate of a command which is already 
         * in the history.
         * But select the one already in the history to be current.
         */
        for (ml = mlist->next;  ml != mlist;  ml = ml->next)
        {
                if (strcmp(ml->string, cmd) == 0)
                        break;
        }
        if (ml == mlist)
        {
                /*
                 * Did not find command in history.
                 * Save the command and put it at the end of the history list.
                 */
                ml = (struct mlist *) ecalloc(1, sizeof(struct mlist));
                ml->string = save(cmd);
                ml->next = mlist;
                ml->prev = mlist->prev;
                mlist->prev->next = ml;
                mlist->prev = ml;
        }
        /*
         * Point to the cmd just after the just-accepted command.
         * Thus, an UPARROW will always retrieve the previous command.
         */
        mlist->curr_mp = ml->next;
#endif
}

/*
 * Accept the command in the command buffer.
 * Add it to the currently selected history list.
 */
        public void
cmd_accept()
{
#if CMD_HISTORY
        /*
         * Nothing to do if there is no currently selected history list.
         */
        if (curr_mlist == NULL)
                return;
        cmd_addhist(curr_mlist, cmdbuf);
#endif
}

/*
 * Try to perform a line-edit function on the command buffer,
 * using a specified char as a line-editing command.
 * Returns:
 *      CC_PASS The char does not invoke a line edit function.
 *      CC_OK   Line edit function done.
 *      CC_QUIT The char requests the current command to be aborted.
 */
        static int
cmd_edit(c)
        int c;
{
        int action;
        int flags;

#if TAB_COMPLETE_FILENAME
#define not_in_completion()     in_completion = 0
#else
#define not_in_completion()
#endif
        
        /*
         * See if the char is indeed a line-editing command.
         */
        flags = 0;
#if CMD_HISTORY
        if (curr_mlist == NULL)
                /*
                 * No current history; don't accept history manipulation cmds.
                 */
                flags |= EC_NOHISTORY;
#endif
#if TAB_COMPLETE_FILENAME
        if (curr_mlist == ml_search)
                /*
                 * In a search command; don't accept file-completion cmds.
                 */
                flags |= EC_NOCOMPLETE;
#endif

        action = editchar(c, flags);

        switch (action)
        {
        case EC_RIGHT:
                not_in_completion();
                return (cmd_right());
        case EC_LEFT:
                not_in_completion();
                return (cmd_left());
        case EC_W_RIGHT:
                not_in_completion();
                while (*cp != '\0' && *cp != ' ')
                        cmd_right();
                while (*cp == ' ')
                        cmd_right();
                return (CC_OK);
        case EC_W_LEFT:
                not_in_completion();
                while (cp > cmdbuf && cp[-1] == ' ')
                        cmd_left();
                while (cp > cmdbuf && cp[-1] != ' ')
                        cmd_left();
                return (CC_OK);
        case EC_HOME:
                not_in_completion();
                cmd_offset = 0;
                cmd_home();
                cmd_repaint(cp);
                return (CC_OK);
        case EC_END:
                not_in_completion();
                while (*cp != '\0')
                        cmd_right();
                return (CC_OK);
        case EC_INSERT:
                not_in_completion();
                return (CC_OK);
        case EC_BACKSPACE:
                not_in_completion();
                return (cmd_erase());
        case EC_LINEKILL:
                not_in_completion();
                return (cmd_kill());
        case EC_W_BACKSPACE:
                not_in_completion();
                return (cmd_werase());
        case EC_DELETE:
                not_in_completion();
                return (cmd_delete());
        case EC_W_DELETE:
                not_in_completion();
                return (cmd_wdelete());
        case EC_LITERAL:
                literal = 1;
                return (CC_OK);
#if CMD_HISTORY
        case EC_UP:
        case EC_DOWN:
                not_in_completion();
                return (cmd_updown(action));
#endif
#if TAB_COMPLETE_FILENAME
        case EC_F_COMPLETE:
        case EC_B_COMPLETE:
        case EC_EXPAND:
                return (cmd_complete(action));
#endif
        case EC_NOACTION:
                return (CC_OK);
        default:
                not_in_completion();
                return (CC_PASS);
        }
}

#if TAB_COMPLETE_FILENAME
/*
 * Insert a string into the command buffer, at the current position.
 */
        static int
cmd_istr(str)
        char *str;
{
        char *s;
        int action;
        
        for (s = str;  *s != '\0';  s++)
        {
                action = cmd_ichar(*s);
                if (action != CC_OK)
                {
                        bell();
                        return (action);
                }
        }
        return (CC_OK);
}

/*
 * Find the beginning and end of the "current" word.
 * This is the word which the cursor (cp) is inside or at the end of.
 * Return pointer to the beginning of the word and put the
 * cursor at the end of the word.
 */
        static char *
delimit_word()
{
        char *word;
#if SPACES_IN_FILENAMES
        char *p;
        int delim_quoted = 0;
        int meta_quoted = 0;
        char *esc = get_meta_escape();
        int esclen = strlen(esc);
#endif
        
        /*
         * Move cursor to end of word.
         */
        if (*cp != ' ' && *cp != '\0')
        {
                /*
                 * Cursor is on a nonspace.
                 * Move cursor right to the next space.
                 */
                while (*cp != ' ' && *cp != '\0')
                        cmd_right();
        } else if (cp > cmdbuf && cp[-1] != ' ')
        {
                /*
                 * Cursor is on a space, and char to the left is a nonspace.
                 * We're already at the end of the word.
                 */
                ;
#if 0
        } else
        {
                /*
                 * Cursor is on a space and char to the left is a space.
                 * Huh? There's no word here.
                 */
                return (NULL);
#endif
        }
        /*
         * Find the beginning of the word which the cursor is in.
         */
        if (cp == cmdbuf)
                return (NULL);
#if SPACES_IN_FILENAMES
        /*
         * If we have an unbalanced quote (that is, an open quote
         * without a corresponding close quote), we return everything
         * from the open quote, including spaces.
         */
        for (word = cmdbuf;  word < cp;  word++)
                if (*word != ' ')
                        break;
        if (word >= cp)
                return (cp);
        for (p = cmdbuf;  p < cp;  p++)
        {
                if (meta_quoted)
                {
                        meta_quoted = 0;
                } else if (esclen > 0 && p + esclen < cp &&
                           strncmp(p, esc, esclen) == 0)
                {
                        meta_quoted = 1;
                        p += esclen - 1;
                } else if (delim_quoted)
                {
                        if (*p == closequote)
                                delim_quoted = 0;
                } else /* (!delim_quoted) */
                {
                        if (*p == openquote)
                                delim_quoted = 1;
                        else if (*p == ' ')
                                word = p+1;
                }
        }
#endif
        return (word);
}

/*
 * Set things up to enter completion mode.
 * Expand the word under the cursor into a list of filenames 
 * which start with that word, and set tk_text to that list.
 */
        static void
init_compl()
{
        char *word;
        char c;
        
        /*
         * Get rid of any previous tk_text.
         */
        if (tk_text != NULL)
        {
                free(tk_text);
                tk_text = NULL;
        }
        /*
         * Find the original (uncompleted) word in the command buffer.
         */
        word = delimit_word();
        if (word == NULL)
                return;
        /*
         * Set the insertion point to the point in the command buffer
         * where the original (uncompleted) word now sits.
         */
        tk_ipoint = word;
        /*
         * Save the original (uncompleted) word
         */
        if (tk_original != NULL)
                free(tk_original);
        tk_original = (char *) ecalloc(cp-word+1, sizeof(char));
        strncpy(tk_original, word, cp-word);
        /*
         * Get the expanded filename.
         * This may result in a single filename, or
         * a blank-separated list of filenames.
         */
        c = *cp;
        *cp = '\0';
        if (*word != openquote)
        {
                tk_text = fcomplete(word);
        } else
        {
                char *qword = shell_quote(word+1);
                if (qword == NULL)
                        tk_text = fcomplete(word+1);
                else
                {
                        tk_text = fcomplete(qword);
                        free(qword);
                }
        }
        *cp = c;
}

/*
 * Return the next word in the current completion list.
 */
        static char *
next_compl(action, prev)
        int action;
        char *prev;
{
        switch (action)
        {
        case EC_F_COMPLETE:
                return (forw_textlist(&tk_tlist, prev));
        case EC_B_COMPLETE:
                return (back_textlist(&tk_tlist, prev));
        }
        /* Cannot happen */
        return ("?");
}

/*
 * Complete the filename before (or under) the cursor.
 * cmd_complete may be called multiple times.  The global in_completion
 * remembers whether this call is the first time (create the list),
 * or a subsequent time (step thru the list).
 */
        static int
cmd_complete(action)
        int action;
{
        char *s;

        if (!in_completion || action == EC_EXPAND)
        {
                /*
                 * Expand the word under the cursor and 
                 * use the first word in the expansion 
                 * (or the entire expansion if we're doing EC_EXPAND).
                 */
                init_compl();
                if (tk_text == NULL)
                {
                        bell();
                        return (CC_OK);
                }
                if (action == EC_EXPAND)
                {
                        /*
                         * Use the whole list.
                         */
                        tk_trial = tk_text;
                } else
                {
                        /*
                         * Use the first filename in the list.
                         */
                        in_completion = 1;
                        init_textlist(&tk_tlist, tk_text);
                        tk_trial = next_compl(action, (char*)NULL);
                }
        } else
        {
                /*
                 * We already have a completion list.
                 * Use the next/previous filename from the list.
                 */
                tk_trial = next_compl(action, tk_trial);
        }
        
        /*
         * Remove the original word, or the previous trial completion.
         */
        while (cp > tk_ipoint)
                (void) cmd_erase();
        
        if (tk_trial == NULL)
        {
                /*
                 * There are no more trial completions.
                 * Insert the original (uncompleted) filename.
                 */
                in_completion = 0;
                if (cmd_istr(tk_original) != CC_OK)
                        goto fail;
        } else
        {
                /*
                 * Insert trial completion.
                 */
                if (cmd_istr(tk_trial) != CC_OK)
                        goto fail;
                /*
                 * If it is a directory, append a slash.
                 */
                if (is_dir(tk_trial))
                {
                        if (cp > cmdbuf && cp[-1] == closequote)
                                (void) cmd_erase();
                        s = lgetenv("LESSSEPARATOR");
                        if (s == NULL)
                                s = PATHNAME_SEP;
                        if (cmd_istr(s) != CC_OK)
                                goto fail;
                }
        }
        
        return (CC_OK);
        
fail:
        in_completion = 0;
        bell();
        return (CC_OK);
}

#endif /* TAB_COMPLETE_FILENAME */

/*
 * Process a single character of a multi-character command, such as
 * a number, or the pattern of a search command.
 * Returns:
 *      CC_OK           The char was accepted.
 *      CC_QUIT         The char requests the command to be aborted.
 *      CC_ERROR        The char could not be accepted due to an error.
 */
        public int
cmd_char(c)
        int c;
{
        int action;

        if (literal)
        {
                /*
                 * Insert the char, even if it is a line-editing char.
                 */
                literal = 0;
                return (cmd_ichar(c));
        }
                
        /*
         * See if it is a special line-editing character.
         */
        if (in_mca())
        {
                action = cmd_edit(c);
                switch (action)
                {
                case CC_OK:
                case CC_QUIT:
                        return (action);
                case CC_PASS:
                        break;
                }
        }
        
        /*
         * Insert the char into the command buffer.
         */
        return (cmd_ichar(c));
}

/*
 * Return the number currently in the command buffer.
 */
        public LINENUM
cmd_int()
{
        register char *p;
        LINENUM n = 0;

        for (p = cmdbuf;  *p != '\0';  p++)
                n = (10 * n) + (*p - '0');
        return (n);
}

/*
 * Return a pointer to the command buffer.
 */
        public char *
get_cmdbuf()
{
        return (cmdbuf);
}