builtins/mapfile.def

This file is mapfile.def, from which is created mapfile.c.
It implements the builtin "mapfile" in Bash.

Copyright (C) 2005-2006 Rocky Bernstein for Free Software Foundation, Inc.
Copyright (C) 2008-2012 Free Software Foundation, Inc.

This file is part of GNU Bash, the Bourne Again SHell.

Bash 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.

Bash 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 Bash.  If not, see <http://www.gnu.org/licenses/>.

$PRODUCES mapfile.c

$BUILTIN mapfile
$FUNCTION mapfile_builtin
$SHORT_DOC mapfile [-n count] [-O origin] [-s count] [-t] [-u fd] [-C callback] [-c quantum] [array]
Read lines from the standard input into an indexed array variable.

Read lines from the standard input into the indexed array variable ARRAY, or
from file descriptor FD if the -u option is supplied.  The variable MAPFILE
is the default ARRAY.

Options:
  -n count	Copy at most COUNT lines.  If COUNT is 0, all lines are copied.
  -O origin	Begin assigning to ARRAY at index ORIGIN.  The default index is 0.
  -s count 	Discard the first COUNT lines read.
  -t		Remove a trailing newline from each line read.
  -u fd		Read lines from file descriptor FD instead of the standard input.
  -C callback	Evaluate CALLBACK each time QUANTUM lines are read.
  -c quantum	Specify the number of lines read between each call to CALLBACK.

Arguments:
  ARRAY		Array variable name to use for file data.

If -C is supplied without -c, the default quantum is 5000.  When
CALLBACK is evaluated, it is supplied the index of the next array
element to be assigned and the line to be assigned to that element
as additional arguments.

If not supplied with an explicit origin, mapfile will clear ARRAY before
assigning to it.

Exit Status:
Returns success unless an invalid option is given or ARRAY is readonly or
not an indexed array.
$END

$BUILTIN readarray
$FUNCTION mapfile_builtin
$SHORT_DOC readarray [-n count] [-O origin] [-s count] [-t] [-u fd] [-C callback] [-c quantum] [array]
Read lines from a file into an array variable.

A synonym for `mapfile'.
$END

#include <config.h>

#include "builtins.h"
#include "posixstat.h"

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

#include "bashansi.h"
#include "bashintl.h"

#include <stdio.h>
#include <errno.h>

#include "../bashintl.h"
#include "../shell.h"
#include "common.h"
#include "bashgetopt.h"

#if !defined (errno)
#include <errno.h>
#endif

#if defined (ARRAY_VARS)

static int run_callback __P((const char *, unsigned int, const char *));

#define DEFAULT_ARRAY_NAME	"MAPFILE"
#define DEFAULT_VARIABLE_NAME	"MAPLINE"	/* not used right now */

/* The value specifying how frequently `mapfile'  calls the callback. */
#define DEFAULT_QUANTUM 5000

/* Values for FLAGS */
#define MAPF_CLEARARRAY	0x01
#define MAPF_CHOP	0x02

static int
run_callback (callback, curindex, curline)
     const char *callback;
     unsigned int curindex;
     const char *curline;
{
  unsigned int execlen;
  char  *execstr, *qline;
  int flags;

  qline = sh_single_quote (curline);
  execlen = strlen (callback) + strlen (qline) + 10;
  /* 1 for each space between %s and %d,
     another 1 for the last nul char for C string. */
  execlen += 3;
  execstr = xmalloc (execlen);

  flags = SEVAL_NOHIST;
#if 0
  if (interactive)
    flags |= SEVAL_INTERACT;
#endif
  snprintf (execstr, execlen, "%s %d %s", callback, curindex, qline);
  free (qline);
  return evalstring (execstr, NULL, flags);
}

static void
do_chop(line)
     char * line;
{
  int length;

  length = strlen (line);
  if (length && line[length-1] == '\n') 
    line[length-1] = '\0';
}

static int
mapfile (fd, line_count_goal, origin, nskip, callback_quantum, callback, array_name, flags)
     int fd;
     long line_count_goal, origin, nskip, callback_quantum;
     char *callback, *array_name;
     int flags;
{
  char *line;
  size_t line_length;
  unsigned int array_index, line_count;
  SHELL_VAR *entry;
  int unbuffered_read;
  
  line = NULL;
  line_length = 0;
  unbuffered_read = 0;

  /* The following check should be done before reading any lines.  Doing it
     here allows us to call bind_array_element instead of bind_array_variable
     and skip the variable lookup on every call. */
  entry = find_or_make_array_variable (array_name, 1);
  if (entry == 0 || readonly_p (entry) || noassign_p (entry))
    {
      if (entry && readonly_p (entry))
	err_readonly (array_name);
	
      return (EXECUTION_FAILURE);
    }
  else if (array_p (entry) == 0)
    {
      builtin_error (_("%s: not an indexed array"), array_name);
      return (EXECUTION_FAILURE);
    }
  else if (invisible_p (entry))
    VUNSETATTR (entry, att_invisible);	/* no longer invisible */
      
  if (flags & MAPF_CLEARARRAY)
    array_flush (array_cell (entry));

#ifndef __CYGWIN__
  unbuffered_read = (lseek (fd, 0L, SEEK_CUR) < 0) && (errno == ESPIPE);
#else
  unbuffered_read = 1;
#endif

  zreset ();

  /* Skip any lines at beginning of file? */
  for (line_count = 0; line_count < nskip; line_count++)
    if (zgetline (fd, &line, &line_length, unbuffered_read) < 0)
      break;

  line = 0;
  line_length = 0;    

  /* Reset the buffer for bash own stream */
  for (array_index = origin, line_count = 1; 
 	zgetline (fd, &line, &line_length, unbuffered_read) != -1;
	array_index++) 
    {
      /* Remove trailing newlines? */
      if (flags & MAPF_CHOP)
	do_chop (line);
	  
      /* Has a callback been registered and if so is it time to call it? */
      if (callback && line_count && (line_count % callback_quantum) == 0) 
	{
	  run_callback (callback, array_index, line);

	  /* Reset the buffer for bash own stream. */
	  if (unbuffered_read == 0)
	    zsyncfd (fd);
	}

      /* XXX - bad things can happen if the callback modifies ENTRY, e.g.,
	 unsetting it or changing it to a non-indexed-array type. */
      bind_array_element (entry, array_index, line, 0);

      /* Have we exceeded # of lines to store? */
      line_count++;
      if (line_count_goal != 0 && line_count > line_count_goal) 
	break;
    }

  xfree (line);

  if (unbuffered_read == 0)
    zsyncfd (fd);

  return EXECUTION_SUCCESS;
}

int
mapfile_builtin (list)
     WORD_LIST *list;
{
  int opt, code, fd, clear_array, flags;
  intmax_t intval;
  long lines, origin, nskip, callback_quantum;
  char *array_name, *callback;

  clear_array = 1;
  fd = 0;
  lines = origin = nskip = 0;
  flags = MAPF_CLEARARRAY;
  callback_quantum = DEFAULT_QUANTUM;
  callback = 0;

  reset_internal_getopt ();
  while ((opt = internal_getopt (list, "u:n:O:tC:c:s:")) != -1)
    {
      switch (opt)
	{
	case 'u':
	  code = legal_number (list_optarg, &intval);
	  if (code == 0 || intval < 0 || intval != (int)intval)
	    {
	      builtin_error (_("%s: invalid file descriptor specification"), list_optarg);
	      return (EXECUTION_FAILURE);
	    }
	  else
	    fd = intval;

	  if (sh_validfd (fd) == 0)
	    {
	      builtin_error (_("%d: invalid file descriptor: %s"), fd, strerror (errno));
	      return (EXECUTION_FAILURE);
	    }
	  break;	  

	case 'n':
	  code = legal_number (list_optarg, &intval);
	  if (code == 0 || intval < 0 || intval != (unsigned)intval)
	    {
	      builtin_error (_("%s: invalid line count"), list_optarg);
	      return (EXECUTION_FAILURE);
	    }
	  else
	    lines = intval;
	  break;

	case 'O':
	  code = legal_number (list_optarg, &intval);
	  if (code == 0 || intval < 0 || intval != (unsigned)intval)
	    {
	      builtin_error (_("%s: invalid array origin"), list_optarg);
	      return (EXECUTION_FAILURE);
	    }
	  else
	    origin = intval;
	  flags &= ~MAPF_CLEARARRAY;
	  break;
	case 't':
	  flags |= MAPF_CHOP;
	  break;
	case 'C':
	  callback = list_optarg;
	  break;
	case 'c':
	  code = legal_number (list_optarg, &intval);
	  if (code == 0 || intval <= 0 || intval != (unsigned)intval)
	    {
	      builtin_error (_("%s: invalid callback quantum"), list_optarg);
	      return (EXECUTION_FAILURE);
	    }
	  else
	    callback_quantum = intval;
	  break;
	case 's':
	  code = legal_number (list_optarg, &intval);
	  if (code == 0 || intval < 0 || intval != (unsigned)intval)
	    {
	      builtin_error (_("%s: invalid line count"), list_optarg);
	      return (EXECUTION_FAILURE);
	    }
	  else
	    nskip = intval;
	  break;
	default:
	  builtin_usage ();
	  return (EX_USAGE);
	}
    }
  list = loptend;

  if (list == 0) 
    array_name = DEFAULT_ARRAY_NAME;
  else if (list->word == 0 || list->word->word == 0)
    {
      builtin_error ("internal error: getting variable name");
      return (EXECUTION_FAILURE);
    }
  else if (list->word->word[0] == '\0')
    {
      builtin_error (_("empty array variable name"));
      return (EX_USAGE);
    } 
  else
    array_name = list->word->word;
  
  if (legal_identifier (array_name) == 0 && valid_array_reference (array_name) == 0)
    {
      sh_invalidid (array_name);
      return (EXECUTION_FAILURE);
    }

  return mapfile (fd, lines, origin, nskip, callback_quantum, callback, array_name, flags);
}

#else

int
mapfile_builtin (list)
     WORD_LIST *list;
{
  builtin_error (_("array variable support required"));
  return (EXECUTION_FAILURE);
}

#endif  /* ARRAY_VARS */