/* search.c - code for non-incremental searching in emacs and vi modes. */

/* Copyright (C) 1992-2017 Free Software Foundation, Inc.

   This file is part of the GNU Readline Library (Readline), a library
   for reading lines of text with interactive input and history editing.      

   Readline is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   Readline is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Readline.  If not, see <http://www.gnu.org/licenses/>.
*/

#define READLINE_LIBRARY

#if defined (HAVE_CONFIG_H)
#  include <config.h>
#endif

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

#if defined (HAVE_UNISTD_H)
#  include <unistd.h>
#endif

#if defined (HAVE_STDLIB_H)
#  include <stdlib.h>
#else
#  include "ansi_stdlib.h"
#endif

#include "rldefs.h"
#include "rlmbutil.h"

#include "readline.h"
#include "history.h"
#include "histlib.h"

#include "rlprivate.h"
#include "xmalloc.h"

#ifdef abs
#  undef abs
#endif
#define abs(x)		(((x) >= 0) ? (x) : -(x))

_rl_search_cxt *_rl_nscxt = 0;

extern HIST_ENTRY *_rl_saved_line_for_history;

/* Functions imported from the rest of the library. */
extern void _rl_free_history_entry PARAMS((HIST_ENTRY *));

static char *noninc_search_string = (char *) NULL;
static int noninc_history_pos;

static char *prev_line_found = (char *) NULL;

static int rl_history_search_len;
static int rl_history_search_pos;
static int rl_history_search_flags;

static char *history_search_string;
static int history_string_size;

static void make_history_line_current PARAMS((HIST_ENTRY *));
static int noninc_search_from_pos PARAMS((char *, int, int, int, int *));
static int noninc_dosearch PARAMS((char *, int, int));
static int noninc_search PARAMS((int, int));
static int rl_history_search_internal PARAMS((int, int));
static void rl_history_search_reinit PARAMS((int));

static _rl_search_cxt *_rl_nsearch_init PARAMS((int, int));
static void _rl_nsearch_abort PARAMS((_rl_search_cxt *));
static int _rl_nsearch_dispatch PARAMS((_rl_search_cxt *, int));

/* Make the data from the history entry ENTRY be the contents of the
   current line.  This doesn't do anything with rl_point; the caller
   must set it. */
static void
make_history_line_current (HIST_ENTRY *entry)
{
  _rl_replace_text (entry->line, 0, rl_end);
  _rl_fix_point (1);
#if defined (VI_MODE)
  if (rl_editing_mode == vi_mode)
    /* POSIX.2 says that the `U' command doesn't affect the copy of any
       command lines to the edit line.  We're going to implement that by
       making the undo list start after the matching line is copied to the
       current editing buffer. */
    rl_free_undo_list ();
#endif

  if (_rl_saved_line_for_history)
    _rl_free_history_entry (_rl_saved_line_for_history);
  _rl_saved_line_for_history = (HIST_ENTRY *)NULL;
}

/* Search the history list for STRING starting at absolute history position
   POS.  If STRING begins with `^', the search must match STRING at the
   beginning of a history line, otherwise a full substring match is performed
   for STRING.  DIR < 0 means to search backwards through the history list,
   DIR >= 0 means to search forward. */
static int
noninc_search_from_pos (char *string, int pos, int dir, int flags, int *ncp)
{
  int ret, old, sflags;
  char *s;

  if (pos < 0)
    return -1;

  old = where_history ();
  if (history_set_pos (pos) == 0)
    return -1;

  RL_SETSTATE(RL_STATE_SEARCH);
  /* These functions return the match offset in the line; history_offset gives
     the matching line in the history list */
  if (flags & SF_PATTERN)
    {
      s = string;
      sflags = 0;		/* Non-anchored search */
      if (*s == '^')
	{
	  sflags |= ANCHORED_SEARCH;
	  s++;
	}
      ret = _hs_history_patsearch (s, dir, sflags);
    }
  else if (*string == '^')
    ret = history_search_prefix (string + 1, dir);
  else
    ret = history_search (string, dir);
  RL_UNSETSTATE(RL_STATE_SEARCH);

  if (ncp)
    *ncp = ret;		/* caller will catch -1 to indicate no-op */

  if (ret != -1)
    ret = where_history ();

  history_set_pos (old);
  return (ret);
}

/* Search for a line in the history containing STRING.  If DIR is < 0, the
   search is backwards through previous entries, else through subsequent
   entries.  Returns 1 if the search was successful, 0 otherwise. */
static int
noninc_dosearch (char *string, int dir, int flags)
{
  int oldpos, pos;
  HIST_ENTRY *entry;

  if (string == 0 || *string == '\0' || noninc_history_pos < 0)
    {
      rl_ding ();
      return 0;
    }

  pos = noninc_search_from_pos (string, noninc_history_pos + dir, dir, flags, (int *)0);
  if (pos == -1)
    {
      /* Search failed, current history position unchanged. */
      rl_maybe_unsave_line ();
      rl_clear_message ();
      rl_point = 0;
      rl_ding ();
      return 0;
    }

  noninc_history_pos = pos;

  oldpos = where_history ();
  history_set_pos (noninc_history_pos);
  entry = current_history ();		/* will never be NULL after successful search */
  
#if defined (VI_MODE)
  if (rl_editing_mode != vi_mode)
#endif
    history_set_pos (oldpos);

  make_history_line_current (entry);

  rl_point = 0;
  rl_mark = rl_end;

  rl_clear_message ();
  return 1;
}

static _rl_search_cxt *
_rl_nsearch_init (int dir, int pchar)
{
  _rl_search_cxt *cxt;
  char *p;

  cxt = _rl_scxt_alloc (RL_SEARCH_NSEARCH, 0);
  if (dir < 0)
    cxt->sflags |= SF_REVERSE;		/* not strictly needed */
#if defined (VI_MODE)
  if (VI_COMMAND_MODE() && (pchar == '?' || pchar == '/'))
    cxt->sflags |= SF_PATTERN;
#endif

  cxt->direction = dir;
  cxt->history_pos = cxt->save_line;

  rl_maybe_save_line ();

  /* Clear the undo list, since reading the search string should create its
     own undo list, and the whole list will end up being freed when we
     finish reading the search string. */
  rl_undo_list = 0;

  /* Use the line buffer to read the search string. */
  rl_line_buffer[0] = 0;
  rl_end = rl_point = 0;

  p = _rl_make_prompt_for_search (pchar ? pchar : ':');
  rl_message ("%s", p);
  xfree (p);

  RL_SETSTATE(RL_STATE_NSEARCH);

  _rl_nscxt = cxt;

  return cxt;
}

int
_rl_nsearch_cleanup (_rl_search_cxt *cxt, int r)
{
  _rl_scxt_dispose (cxt, 0);
  _rl_nscxt = 0;

  RL_UNSETSTATE(RL_STATE_NSEARCH);

  return (r != 1);
}

static void
_rl_nsearch_abort (_rl_search_cxt *cxt)
{
  rl_maybe_unsave_line ();
  rl_clear_message ();
  rl_point = cxt->save_point;
  rl_mark = cxt->save_mark;
  rl_restore_prompt ();

  RL_UNSETSTATE (RL_STATE_NSEARCH);
}

/* Process just-read character C according to search context CXT.  Return -1
   if the caller should abort the search, 0 if we should break out of the
   loop, and 1 if we should continue to read characters. */
static int
_rl_nsearch_dispatch (_rl_search_cxt *cxt, int c)
{
  if (c < 0)
    c = CTRL ('C');  

  switch (c)
    {
    case CTRL('W'):
      rl_unix_word_rubout (1, c);
      break;

    case CTRL('U'):
      rl_unix_line_discard (1, c);
      break;

    case RETURN:
    case NEWLINE:
      return 0;

    case CTRL('H'):
    case RUBOUT:
      if (rl_point == 0)
	{
	  _rl_nsearch_abort (cxt);
	  return -1;
	}
      _rl_rubout_char (1, c);
      break;

    case CTRL('C'):
    case CTRL('G'):
      rl_ding ();
      _rl_nsearch_abort (cxt);
      return -1;

    default:
#if defined (HANDLE_MULTIBYTE)
      if (MB_CUR_MAX > 1 && rl_byte_oriented == 0)
	rl_insert_text (cxt->mb);
      else
#endif
	_rl_insert_char (1, c);
      break;
    }

  (*rl_redisplay_function) ();
  return 1;
}

/* Perform one search according to CXT, using NONINC_SEARCH_STRING.  Return
   -1 if the search should be aborted, any other value means to clean up
   using _rl_nsearch_cleanup ().  Returns 1 if the search was successful,
   0 otherwise. */
static int
_rl_nsearch_dosearch (_rl_search_cxt *cxt)
{
  rl_mark = cxt->save_mark;

  /* If rl_point == 0, we want to re-use the previous search string and
     start from the saved history position.  If there's no previous search
     string, punt. */
  if (rl_point == 0)
    {
      if (noninc_search_string == 0)
	{
	  rl_ding ();
	  rl_restore_prompt ();
	  RL_UNSETSTATE (RL_STATE_NSEARCH);
	  return -1;
	}
    }
  else
    {
      /* We want to start the search from the current history position. */
      noninc_history_pos = cxt->save_line;
      FREE (noninc_search_string);
      noninc_search_string = savestring (rl_line_buffer);

      /* If we don't want the subsequent undo list generated by the search
	 matching a history line to include the contents of the search string,
	 we need to clear rl_line_buffer here.  For now, we just clear the
	 undo list generated by reading the search string.  (If the search
	 fails, the old undo list will be restored by rl_maybe_unsave_line.) */
      rl_free_undo_list ();
    }

  rl_restore_prompt ();
  return (noninc_dosearch (noninc_search_string, cxt->direction, cxt->sflags&SF_PATTERN));
}

/* Search non-interactively through the history list.  DIR < 0 means to
   search backwards through the history of previous commands; otherwise
   the search is for commands subsequent to the current position in the
   history list.  PCHAR is the character to use for prompting when reading
   the search string; if not specified (0), it defaults to `:'. */
static int
noninc_search (int dir, int pchar)
{
  _rl_search_cxt *cxt;
  int c, r;

  cxt = _rl_nsearch_init (dir, pchar);

  if (RL_ISSTATE (RL_STATE_CALLBACK))
    return (0);

  /* Read the search string. */
  r = 0;
  while (1)
    {
      c = _rl_search_getchar (cxt);

      if (c < 0)
	{
	  _rl_nsearch_abort (cxt);
	  return 1;
	}
	  
      if (c == 0)
	break;

      r = _rl_nsearch_dispatch (cxt, c);
      if (r < 0)
        return 1;
      else if (r == 0)
	break;        
    }

  r = _rl_nsearch_dosearch (cxt);
  return ((r >= 0) ? _rl_nsearch_cleanup (cxt, r) : (r != 1));
}

/* Search forward through the history list for a string.  If the vi-mode
   code calls this, KEY will be `?'. */
int
rl_noninc_forward_search (int count, int key)
{
  return noninc_search (1, (key == '?') ? '?' : 0);
}

/* Reverse search the history list for a string.  If the vi-mode code
   calls this, KEY will be `/'. */
int
rl_noninc_reverse_search (int count, int key)
{
  return noninc_search (-1, (key == '/') ? '/' : 0);
}

/* Search forward through the history list for the last string searched
   for.  If there is no saved search string, abort.  If the vi-mode code
   calls this, KEY will be `N'. */
int
rl_noninc_forward_search_again (int count, int key)
{
  int r;

  if (!noninc_search_string)
    {
      rl_ding ();
      return (1);
    }
#if defined (VI_MODE)
  if (VI_COMMAND_MODE() && key == 'N')
    r = noninc_dosearch (noninc_search_string, 1, SF_PATTERN);
  else
#endif
    r = noninc_dosearch (noninc_search_string, 1, 0);
  return (r != 1);
}

/* Reverse search in the history list for the last string searched
   for.  If there is no saved search string, abort.  If the vi-mode code
   calls this, KEY will be `n'. */
int
rl_noninc_reverse_search_again (int count, int key)
{
  int r;

  if (!noninc_search_string)
    {
      rl_ding ();
      return (1);
    }
#if defined (VI_MODE)
  if (VI_COMMAND_MODE() && key == 'n')
    r = noninc_dosearch (noninc_search_string, -1, SF_PATTERN);
  else
#endif
    r = noninc_dosearch (noninc_search_string, -1, 0);
  return (r != 1);
}

#if defined (READLINE_CALLBACKS)
int
_rl_nsearch_callback (_rl_search_cxt *cxt)
{
  int c, r;

  c = _rl_search_getchar (cxt);
  if (c <= 0)
    {
      if (c < 0)
        _rl_nsearch_abort (cxt);
      return 1;
    }
  r = _rl_nsearch_dispatch (cxt, c);
  if (r != 0)
    return 1;

  r = _rl_nsearch_dosearch (cxt);
  return ((r >= 0) ? _rl_nsearch_cleanup (cxt, r) : (r != 1));
}
#endif
  
static int
rl_history_search_internal (int count, int dir)
{
  HIST_ENTRY *temp;
  int ret, oldpos, newcol;
  char *t;

  rl_maybe_save_line ();
  temp = (HIST_ENTRY *)NULL;

  /* Search COUNT times through the history for a line matching
     history_search_string.  If history_search_string[0] == '^', the
     line must match from the start; otherwise any substring can match.
     When this loop finishes, TEMP, if non-null, is the history line to
     copy into the line buffer. */
  while (count)
    {
      RL_CHECK_SIGNALS ();
      ret = noninc_search_from_pos (history_search_string, rl_history_search_pos + dir, dir, 0, &newcol);
      if (ret == -1)
	break;

      /* Get the history entry we found. */
      rl_history_search_pos = ret;
      oldpos = where_history ();
      history_set_pos (rl_history_search_pos);
      temp = current_history ();	/* will never be NULL after successful search */
      history_set_pos (oldpos);

      /* Don't find multiple instances of the same line. */
      if (prev_line_found && STREQ (prev_line_found, temp->line))
        continue;
      prev_line_found = temp->line;
      count--;
    }

  /* If we didn't find anything at all, return. */
  if (temp == 0)
    {
      rl_maybe_unsave_line ();
      rl_ding ();
      /* If you don't want the saved history line (last match) to show up
         in the line buffer after the search fails, change the #if 0 to
         #if 1 */
#if 0
      if (rl_point > rl_history_search_len)
        {
          rl_point = rl_end = rl_history_search_len;
          rl_line_buffer[rl_end] = '\0';
          rl_mark = 0;
        }
#else
      rl_point = rl_history_search_len;	/* rl_maybe_unsave_line changes it */
      rl_mark = rl_end;
#endif
      return 1;
    }

  /* Copy the line we found into the current line buffer. */
  make_history_line_current (temp);

  /* decide where to put rl_point -- need to change this for pattern search */
  if (rl_history_search_flags & ANCHORED_SEARCH)
    rl_point = rl_history_search_len;	/* easy case */
  else
    {
#if 0
      t = strstr (rl_line_buffer, history_search_string);	/* XXX */
      rl_point = t ? (int)(t - rl_line_buffer) + rl_history_search_len : rl_end;
#else
      rl_point = (newcol >= 0) ? newcol : rl_end;
#endif
    }
  rl_mark = rl_end;

  return 0;
}

static void
rl_history_search_reinit (int flags)
{
  int sind;

  rl_history_search_pos = where_history ();
  rl_history_search_len = rl_point;
  rl_history_search_flags = flags;

  prev_line_found = (char *)NULL;
  if (rl_point)
    {
      /* Allocate enough space for anchored and non-anchored searches */
      if (rl_history_search_len >= history_string_size - 2)
	{
	  history_string_size = rl_history_search_len + 2;
	  history_search_string = (char *)xrealloc (history_search_string, history_string_size);
	}
      sind = 0;
      if (flags & ANCHORED_SEARCH)
	history_search_string[sind++] = '^';
      strncpy (history_search_string + sind, rl_line_buffer, rl_point);
      history_search_string[rl_point + sind] = '\0';
    }
  _rl_free_saved_history_line ();
}

/* Search forward in the history for the string of characters
   from the start of the line to rl_point.  This is a non-incremental
   search.  The search is anchored to the beginning of the history line. */
int
rl_history_search_forward (int count, int ignore)
{
  if (count == 0)
    return (0);

  if (rl_last_func != rl_history_search_forward &&
      rl_last_func != rl_history_search_backward)
    rl_history_search_reinit (ANCHORED_SEARCH);

  if (rl_history_search_len == 0)
    return (rl_get_next_history (count, ignore));
  return (rl_history_search_internal (abs (count), (count > 0) ? 1 : -1));
}

/* Search backward through the history for the string of characters
   from the start of the line to rl_point.  This is a non-incremental
   search. */
int
rl_history_search_backward (int count, int ignore)
{
  if (count == 0)
    return (0);

  if (rl_last_func != rl_history_search_forward &&
      rl_last_func != rl_history_search_backward)
    rl_history_search_reinit (ANCHORED_SEARCH);

  if (rl_history_search_len == 0)
    return (rl_get_previous_history (count, ignore));
  return (rl_history_search_internal (abs (count), (count > 0) ? -1 : 1));
}

/* Search forward in the history for the string of characters
   from the start of the line to rl_point.  This is a non-incremental
   search.  The search succeeds if the search string is present anywhere
   in the history line. */
int
rl_history_substr_search_forward (int count, int ignore)
{
  if (count == 0)
    return (0);

  if (rl_last_func != rl_history_substr_search_forward &&
      rl_last_func != rl_history_substr_search_backward)
    rl_history_search_reinit (NON_ANCHORED_SEARCH);

  if (rl_history_search_len == 0)
    return (rl_get_next_history (count, ignore));
  return (rl_history_search_internal (abs (count), (count > 0) ? 1 : -1));
}

/* Search backward through the history for the string of characters
   from the start of the line to rl_point.  This is a non-incremental
   search. */
int
rl_history_substr_search_backward (int count, int ignore)
{
  if (count == 0)
    return (0);

  if (rl_last_func != rl_history_substr_search_forward &&
      rl_last_func != rl_history_substr_search_backward)
    rl_history_search_reinit (NON_ANCHORED_SEARCH);

  if (rl_history_search_len == 0)
    return (rl_get_previous_history (count, ignore));
  return (rl_history_search_internal (abs (count), (count > 0) ? -1 : 1));
}