fish-shell/expand.cpp

/**\file expand.c

String expansion functions. These functions perform several kinds of
parameter expansion. 

*/

#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <wchar.h>
#include <string.h>
#include <wctype.h>
#include <errno.h>
#include <pwd.h>
#include <unistd.h>
#include <sys/types.h>
#include <termios.h>
#include <dirent.h>
#include <sys/stat.h>
#include <unistd.h>
#include <signal.h>

#include <assert.h>
#include <vector>

#ifdef SunOS
#include <procfs.h>
#endif

#include "fallback.h"
#include "util.h"

#include "common.h"
#include "wutil.h"
#include "env.h"
#include "proc.h"
#include "parser.h"
#include "expand.h"
#include "wildcard.h"
#include "exec.h"
#include "signal.h"
#include "tokenizer.h"
#include "complete.h"

#include "parse_util.h"

/**
   Error issued on invalid variable name
*/
#define COMPLETE_VAR_DESC _( L"The '$' character begins a variable name. The character '%lc', which directly followed a '$', is not allowed as a part of a variable name, and variable names may not be zero characters long. To learn more about variable expansion in fish, type 'help expand-variable'.")

/**
   Error issued on invalid variable name
*/
#define COMPLETE_VAR_NULL_DESC _( L"The '$' begins a variable name. It was given at the end of an argument. Variable names may not be zero characters long. To learn more about variable expansion in fish, type 'help expand-variable'.")

/**
   Error issued on invalid variable name
*/
#define COMPLETE_VAR_BRACKET_DESC _( L"Did you mean %ls{$%ls}%ls? The '$' character begins a variable name. A bracket, which directly followed a '$', is not allowed as a part of a variable name, and variable names may not be zero characters long. To learn more about variable expansion in fish, type 'help expand-variable'." )

/**
   Error issued on invalid variable name
*/
#define COMPLETE_VAR_PARAN_DESC _( L"Did you mean (COMMAND)? In fish, the '$' character is only used for accessing variables. To learn more about command substitution in fish, type 'help expand-command-substitution'.")

/**
   Description for child process
*/
#define COMPLETE_CHILD_PROCESS_DESC _( L"Child process")

/**
   Description for non-child process
*/
#define COMPLETE_PROCESS_DESC _( L"Process")

/**
   Description for long job
*/
#define COMPLETE_JOB_DESC _( L"Job")

/**
   Description for short job. The job command is concatenated
*/
#define COMPLETE_JOB_DESC_VAL _( L"Job: %ls")

/**
   Description for the shells own pid
*/
#define COMPLETE_SELF_DESC _( L"Shell process")

/**
   Description for the shells own pid
*/
#define COMPLETE_LAST_DESC _( L"Last background job")

/**
   String in process expansion denoting ourself
*/
#define SELF_STR L"self"

/**
   String in process expansion denoting last background job
*/
#define LAST_STR L"last"

/**
   Characters which make a string unclean if they are the first
   character of the string. See \c expand_is_clean().
*/
#define UNCLEAN_FIRST L"~%"
/**
   Unclean characters. See \c expand_is_clean().
*/
#define UNCLEAN L"$*?\\\"'({})"

int expand_is_clean( const wchar_t *in )
{

	const wchar_t * str = in;

	CHECK( in, 1 );

	/*
	  Test characters that have a special meaning in the first character position
	*/
	if( wcschr( UNCLEAN_FIRST, *str ) )
		return 0;

	/*
	  Test characters that have a special meaning in any character position
	*/
	while( *str )
	{
		if( wcschr( UNCLEAN, *str ) )
			return 0;
		str++;
	}

	return 1;
}

/**
   Return the environment variable value for the string starting at \c in.
*/
static env_var_t expand_var(const wchar_t *in)
{
	if( !in )
		return env_var_t::missing_var();
	return env_get_string( in );
}

/**
   Test if the specified string does not contain character which can
   not be used inside a quoted string.
*/
static int is_quotable( const wchar_t *str )
{
	switch( *str )
	{
		case 0:
			return 1;

		case L'\n':
		case L'\t':
		case L'\r':
		case L'\b':
		case L'\x1b':
			return 0;

		default:
			return is_quotable(str+1);
	}
	return 0;

}

static int is_quotable(const wcstring &str) {
    return is_quotable(str.c_str());
}

wcstring expand_escape_variable( const wcstring &in )
{

	wcstring_list_t lst;
	wcstring buff;

	tokenize_variable_array( in, lst );

	switch( lst.size() )
	{
		case 0:
			buff.append(L"''");
			break;
			
		case 1:
		{
            const wcstring &el = lst.at(0);

			if( el.find(L' ') != wcstring::npos && is_quotable( el ) )
			{
                buff.append(L"'");
                buff.append(el);
                buff.append(L"'");
			}
			else
			{
                buff.append(escape_string(el, 1));
			}
			break;
		}
		default:
		{
			for( size_t j=0; j<lst.size(); j++ )
			{
				const wcstring &el = lst.at(j);
				if( j )
					buff.append(L"  " );

				if( is_quotable( el ) )
				{
                    buff.append(L"'");
                    buff.append(el);
                    buff.append(L"'");
				}
				else
				{
                    buff.append(escape_string(el, 1));
				}
			}
		}
	}
	return buff;
}

/**
   Tests if all characters in the wide string are numeric
*/
static int iswnumeric( const wchar_t *n )
{
	for( ; *n; n++ )
	{
		if( *n < L'0' || *n > L'9' )
		{
			return 0;
		}
	}
	return 1;
}

/**
   See if the process described by \c proc matches the commandline \c
   cmd
*/
static int match_pid( const wchar_t *cmd,
					  const wchar_t *proc,
					  int flags,
					  int *offset)
{
	/* Test for direct match */
	
	if( wcsncmp( cmd, proc, wcslen( proc ) ) == 0 )
	{
		if( offset )
			*offset = 0;
		return 1;
	}
	
	/*
	  Test if the commandline is a path to the command, if so we try
	  to match against only the command part
	*/
	wchar_t *first_token = tok_first( cmd );
	if( first_token == 0 )
		return 0;

	wchar_t *start=0;
	wchar_t prev=0;
	wchar_t *p;

	/*
	  This should be done by basename(), if it wasn't for the fact
	  that is does not accept wide strings
	*/
	for( p=first_token; *p; p++ )
	{
		if( *p == L'/' && prev != L'\\' )
			start = p;
		prev = *p;
	}
	if( start )
	{

		if( wcsncmp( start+1, proc, wcslen( proc ) ) == 0 )
		{
			if( offset )
				*offset = start+1-first_token;
			
			free( first_token );

			return 1;
		}
	}
	free( first_token );

	return 0;

}

/**
   Searches for a job with the specified job id, or a job or process
   which has the string \c proc as a prefix of its commandline.

   If the ACCEPT_INCOMPLETE flag is set, the remaining string for any matches
   are inserted.

   Otherwise, any job matching the specified string is matched, and
   the job pgid is returned. If no job matches, all child processes
   are searched. If no child processes match, and <tt>fish</tt> can
   understand the contents of the /proc filesystem, all the users
   processes are searched for matches.
*/

static int find_process( const wchar_t *proc,
						 int flags,
						 std::vector<completion_t> &out )
{
	DIR *dir;
	wchar_t *pdir_name;
	wchar_t *pfile_name;
	wchar_t *cmd=0;
	int sz=0;
	int found = 0;

	const job_t *j;

	if( iswnumeric(proc) || (wcslen(proc)==0) )
	{
		/*
		  This is a numeric job string, like '%2'
		*/

		if( flags & ACCEPT_INCOMPLETE )
		{
            job_iterator_t jobs;
            while ((j = jobs.next()))
			{
				wchar_t jid[16];
				if( j->command_is_empty() )
					continue;

				swprintf( jid, 16, L"%d", j->job_id );

				if( wcsncmp( proc, jid, wcslen(proc ) )==0 )
				{
                    wcstring desc_buff = format_string(COMPLETE_JOB_DESC_VAL, j->command_wcstr());
					completion_allocate( out, 
										 jid+wcslen(proc),
										 desc_buff,
										 0 );
				}
			}

		}
		else
		{

			int jid;
			wchar_t *end;
			
			errno = 0;
			jid = wcstol( proc, &end, 10 );
			if( jid > 0 && !errno && !*end )
			{
				j = job_get( jid );
				if( (j != 0) && (j->command_wcstr() != 0 ) )
				{
					
					{
                        wcstring result = to_string((long)j->pgid);
						out.push_back(completion_t(result));
						found = 1;
					}
				}
			}
		}
	}
	if( found )
		return 1;

    job_iterator_t jobs;
    while ((j = jobs.next()))
	{
		int offset;
		
		if( j->command_wcstr() == 0 )
			continue;
		
		if( match_pid( j->command_wcstr(), proc, flags, &offset ) )
		{
			if( flags & ACCEPT_INCOMPLETE )
			{
				completion_allocate( out, 
									 j->command_wcstr() + offset + wcslen(proc),
									 COMPLETE_JOB_DESC,
									 0 );
			}
			else
			{
                wcstring result = to_string((long)j->pgid);
                out.push_back(completion_t(result));
				found = 1;
			}
		}
	}

	if( found )
	{
		return 1;
	}

    jobs.reset();
    while ((j = jobs.next()))
	{
		process_t *p;
		if( j->command_is_empty() )
			continue;
		for( p=j->first_process; p; p=p->next )
		{
			int offset;
			
			if( p->actual_cmd == 0 )
				continue;

			if( match_pid( p->actual_cmd, proc, flags, &offset ) )
			{
				if( flags & ACCEPT_INCOMPLETE )
				{
					completion_allocate( out, 
										 p->actual_cmd + offset + wcslen(proc),
										 COMPLETE_CHILD_PROCESS_DESC,
										 0 );
				}
				else
				{
                    wcstring result = to_string<int>(p->pid);
					out.push_back(completion_t(result));
					found = 1;
				}
			}
		}
	}

	if( found )
	{
		return 1;
	}

	if( !(dir = opendir( "/proc" )))
	{
		/*
		  This system does not have a /proc filesystem.
		*/
		return 1;
	}

	pdir_name = (wchar_t *)malloc( sizeof(wchar_t)*256 );
	pfile_name = (wchar_t *)malloc( sizeof(wchar_t)*64 );
	wcscpy( pdir_name, L"/proc/" );
	
    wcstring nameStr;
    while (wreaddir(dir, nameStr))
	{
		const wchar_t *name = nameStr.c_str();
		struct stat buf;

		if( !iswnumeric( name ) )
			continue;

		wcscpy( pdir_name + 6, name );
		if( wstat( pdir_name, &buf ) )
		{
			continue;
		}
		if( buf.st_uid != getuid() )
		{
			continue;
		}
		wcscpy( pfile_name, pdir_name );
		wcscat( pfile_name, L"/cmdline" );

		if( !wstat( pfile_name, &buf ) )
		{
			/*
			  the 'cmdline' file exists, it should contain the commandline
			*/
			FILE *cmdfile;

			if((cmdfile=wfopen( pfile_name, "r" ))==0)
			{
				wperror( L"fopen" );
				continue;
			}

			signal_block();
			fgetws2( &cmd, &sz, cmdfile );
			signal_unblock();
			
			fclose( cmdfile );
		}
		else
		{
#ifdef SunOS
			wcscpy( pfile_name, pdir_name );
			wcscat( pfile_name, L"/psinfo" );
			if( !wstat( pfile_name, &buf ) )
			{
				psinfo_t info;

				FILE *psfile;

				if((psfile=wfopen( pfile_name, "r" ))==0)
				{
					wperror( L"fopen" );
					continue;
				}

				if( fread( &info, sizeof(info), 1, psfile ) )
				{
					if( cmd != 0 )
						free( cmd );
					cmd = str2wcs( info.pr_fname );
				}
				fclose( psfile );
			}
			else
#endif
			{
				if( cmd != 0 )
				{
					*cmd = 0;
				}
			}
		}

		if( cmd != 0 )
		{
			int offset;
			
			if( match_pid( cmd, proc, flags, &offset ) )
			{
				if( flags & ACCEPT_INCOMPLETE )
				{
					completion_allocate( out, 
										 cmd + offset + wcslen(proc),
										 COMPLETE_PROCESS_DESC,
										 0 );
				}
				else
				{
                    if (name)
                        out.push_back(completion_t(name));
				}
			}
		}
	}

	if( cmd != 0 )
		free( cmd );

	free( pdir_name );
	free( pfile_name );

	closedir( dir );

	return 1;
}

/**
   Process id expansion
*/
static int expand_pid( const wcstring &instr,
					   int flags,
					   std::vector<completion_t> &out )
{
 
	if( instr.empty() || instr.at(0) != PROCESS_EXPAND )
	{
		out.push_back(completion_t(instr));
		return 1;
	}
    
    const wchar_t * const in = instr.c_str();

	if( flags & ACCEPT_INCOMPLETE )
	{
		if( wcsncmp( in+1, SELF_STR, wcslen(in+1) )==0 )
		{
			completion_allocate( out, 
								 SELF_STR+wcslen(in+1),
								 COMPLETE_SELF_DESC, 
								 0 );
		}
		else if( wcsncmp( in+1, LAST_STR, wcslen(in+1) )==0 )
		{
			completion_allocate( out, 
								 LAST_STR+wcslen(in+1), 
								 COMPLETE_LAST_DESC, 
								 0 );
		}
	}
	else
	{
		if( wcscmp( (in+1), SELF_STR )==0 )
		{

			const wcstring pid_str = to_string<int>(getpid());
			out.push_back(completion_t(pid_str));

			return 1;
		}
		if( wcscmp( (in+1), LAST_STR )==0 )
		{
			if( proc_last_bg_pid > 0 )
			{
                const wcstring pid_str = to_string<int>(proc_last_bg_pid);
				out.push_back( completion_t(pid_str));
			}

			return 1;
		}
	}

	size_t prev = out.size();
	if( !find_process( in+1, flags, out ) )
		return 0;

	if( prev ==  out.size() )
	{
		if(  ! (flags & ACCEPT_INCOMPLETE) )
		{
			return 0;
		}
	}

	return 1;
}


void expand_variable_error( parser_t &parser, const wchar_t *token, int token_pos, int error_pos )
{
	int stop_pos = token_pos+1;
	
	switch( token[stop_pos] )
	{
		case BRACKET_BEGIN:
		{
			wchar_t *cpy = wcsdup( token );
			*(cpy+token_pos)=0;
			wchar_t *name = &cpy[stop_pos+1];
			wchar_t *end = wcschr( name, BRACKET_END );
			wchar_t *post;
			int is_var=0;
			if( end )
			{
				post = end+1;
				*end = 0;
				
				if( !wcsvarname( name ) )
				{
					is_var = 1;
				}
			}
			
			if( is_var )
			{
				parser.error( SYNTAX_ERROR,
					   error_pos,
					   COMPLETE_VAR_BRACKET_DESC,
					   cpy,
					   name,
					   post );				
			}
			else
			{
				parser.error( SYNTAX_ERROR,
					   error_pos,
					   COMPLETE_VAR_BRACKET_DESC,
					   L"",
					   L"VARIABLE",
					   L"" );
			}
			free( cpy );
			
			break;
		}
		
		case INTERNAL_SEPARATOR:
		{
			parser.error( SYNTAX_ERROR,
				   error_pos,
				   COMPLETE_VAR_PARAN_DESC );	
			break;
		}
		
		case 0:
		{
			parser.error( SYNTAX_ERROR,
				   error_pos,
				   COMPLETE_VAR_NULL_DESC );
			break;
		}
		
		default:
		{
			parser.error( SYNTAX_ERROR,
				   error_pos,
				   COMPLETE_VAR_DESC,
				   token[stop_pos] );
			break;
		}
	}
}

/**
   Parse an array slicing specification
 */
static int parse_slice( const wchar_t *in, wchar_t **end_ptr, std::vector<long> &idx )
{
	
	
	wchar_t *end;
	
	int pos = 1;
    
    //	debug( 0, L"parse_slice on '%ls'", in );
	
    
	while( 1 )
	{
		long tmp;
		
		while( iswspace(in[pos]) || (in[pos]==INTERNAL_SEPARATOR))
			pos++;		
		
		if( in[pos] == L']' )
		{
			pos++;
			break;
		}
		
		errno=0;
		tmp = wcstol( &in[pos], &end, 10 );
		if( ( errno ) || ( end == &in[pos] ) )
		{
			return 1;
		}
        //		debug( 0, L"Push idx %d", tmp );
		
        idx.push_back(tmp);
		pos = end-in;
	}
	
	if( end_ptr )
	{
        //		debug( 0, L"Remainder is '%ls', slice def was %d characters long", in+pos, pos );
		
		*end_ptr = (wchar_t *)(in+pos);
	}
    //	debug( 0, L"ok, done" );
	
	return 0;
}



/**
   Expand all environment variables in the string *ptr.

   This function is slow, fragile and complicated. There are lots of
   little corner cases, like $$foo should do a double expansion,
   $foo$bar should not double expand bar, etc. Also, it's easy to
   accidentally leak memory on array out of bounds errors an various
   other situations. All in all, this function should be rewritten,
   split out into multiple logical units and carefully tested. After
   that, it can probably be optimized to do fewer memory allocations,
   fewer string scans and overall just less work. But until that
   happens, don't edit it unless you know exactly what you are doing,
   and do proper testing afterwards.
*/
static int expand_variables_internal( parser_t &parser, wchar_t * const in, std::vector<completion_t> &out, int last_idx );

static int expand_variables2( parser_t &parser, const wcstring &instr, std::vector<completion_t> &out, int last_idx ) {
    wchar_t *in = wcsdup(instr.c_str());
    int result = expand_variables_internal(parser, in, out, last_idx);
    free(in);
    return result;
}

static int expand_variables_internal( parser_t &parser, wchar_t * const in, std::vector<completion_t> &out, int last_idx )
{
	int is_ok= 1;
	int empty=0;
	
    wcstring var_tmp;
    std::vector<long> var_idx_list;
    
    //	CHECK( out, 0 );
	
	for( int i=last_idx; (i>=0) && is_ok && !empty; i-- )
	{
		const wchar_t c = in[i];
		if( ( c == VARIABLE_EXPAND ) || (c == VARIABLE_EXPAND_SINGLE ) )
		{
			int start_pos = i+1;
			int stop_pos;
			int var_len;
			int is_single = (c==VARIABLE_EXPAND_SINGLE);
			
			stop_pos = start_pos;
            
			while( 1 )
			{
				if( !(in[stop_pos ]) )
					break;
				if( !( iswalnum( in[stop_pos] ) ||
                      (wcschr(L"_", in[stop_pos])!= 0)  ) )
					break;
                
				stop_pos++;
			}

            /*			printf( "Stop for '%c'\n", in[stop_pos]);*/
            
			var_len = stop_pos - start_pos;
            
			if( var_len == 0 )
			{
				expand_variable_error( parser, in, stop_pos-1, -1 );				
				
				is_ok = 0;
				break;
			}
            
            var_tmp.append(in + start_pos, var_len);
			env_var_t var_val = expand_var(var_tmp.c_str() );
            
			if( ! var_val.missing() )
			{
				int all_vars=1;
                wcstring_list_t var_item_list;
                
				if( in[stop_pos] == L'[' )
				{
					wchar_t *slice_end;
					all_vars=0;
					
					if( parse_slice( in + stop_pos, &slice_end, var_idx_list ) )
					{
						parser.error( SYNTAX_ERROR,
                                     -1,
                                     L"Invalid index value" );						
						is_ok = 0;
					}					
					stop_pos = (slice_end-in);
				}				
                
				if( is_ok )
				{
					tokenize_variable_array( var_val.c_str(), var_item_list );                    
                    
					if( !all_vars )
					{
                        wcstring_list_t string_values(var_idx_list.size());
                        
						for( size_t j=0; j<var_idx_list.size(); j++)
						{
							long tmp = var_idx_list.at(j);
							if( tmp < 0 )
							{
								tmp = ((long)var_item_list.size())+tmp+1;
							}
                            
							/*
                             Check that we are within array
                             bounds. If not, truncate the list to
                             exit.
                             */
							if( tmp < 1 || (size_t)tmp > var_item_list.size() )
							{
								parser.error( SYNTAX_ERROR,
                                             -1,
                                             ARRAY_BOUNDS_ERR );
								is_ok=0;
								var_idx_list.resize(j);
								break;
							}
							else
							{
								/* Replace each index in var_idx_list inplace with the string value at the specified index */
								//al_set( var_idx_list, j, wcsdup((const wchar_t *)al_get( &var_item_list, tmp-1 ) ) );
                                string_values.at(j) = var_item_list.at(tmp-1);
							}
						}
                        
                        // string_values is the new var_item_list
                        var_item_list.swap(string_values);
					}
				}
                
				if( is_ok )
				{
					
					if( is_single )
					{
                        in[i]=0;
                        wcstring res = in;
                        res.push_back(INTERNAL_SEPARATOR);
                        
						for( size_t j=0; j<var_item_list.size(); j++ )
						{
                            const wcstring &next = var_item_list.at(j);							
							if( is_ok )
							{
								if( j != 0 )
									res.append(L" ");
								res.append(next);
							}
						}
                        res.append(in + stop_pos);
						is_ok &= expand_variables2( parser, res, out, i );
					}
					else
					{
						for( size_t j=0; j<var_item_list.size(); j++ )
						{
							const wcstring &next = var_item_list.at(j);
							if( is_ok && (i == 0) && (!in[stop_pos]) )
							{
								out.push_back(completion_t(next));
							}
							else
							{
								
								if( is_ok )
								{
                                    wcstring new_in;
                                    
                                    if (start_pos > 0)
                                        new_in.append(in, start_pos - 1);
                                    
                                    // at this point new_in.size() is start_pos - 1
                                    if(start_pos>1 && new_in[start_pos-2]!=VARIABLE_EXPAND)
                                    {
                                        new_in.push_back(INTERNAL_SEPARATOR);
                                    }                                    
                                    new_in.append(next);
                                    new_in.append(in + stop_pos);                                    
                                    is_ok &= expand_variables2( parser, new_in, out, i );
								}
							}
							
						}
					}
				}
				
				return is_ok;
			}
			else
			{
				/*
                 Expand a non-existing variable
                 */
				if( c == VARIABLE_EXPAND )
				{
					/*
                     Regular expansion, i.e. expand this argument to nothing
                     */
					empty = 1;
				}
				else
				{
					/*
                     Expansion to single argument.
                     */
					wcstring res;
                    in[i] = 0;
                    res.append(in);
                    res.append(in + stop_pos);
                    
					is_ok &= expand_variables2( parser, res, out, i );
					return is_ok;
				}
			}
            
            
		}
	}
    
	if( !empty )
	{
		out.push_back(completion_t(in));
	}
    
	return is_ok;
}

/**
   Perform bracket expansion
*/
static int expand_brackets(parser_t &parser, const wchar_t *in, int flags, std::vector<completion_t> &out )
{
	const wchar_t *pos;
	int syntax_error=0;
	int bracket_count=0;

	const wchar_t *bracket_begin=0, *bracket_end=0;
	const wchar_t *last_sep=0;

	const wchar_t *item_begin;
	int len1, len2, tot_len;

	CHECK( in, 0 );
//	CHECK( out, 0 );
	
	for( pos=in;
		 (*pos) && !syntax_error;
		 pos++ )
	{
		switch( *pos )
		{
			case BRACKET_BEGIN:
			{
				bracket_begin = pos;

				bracket_count++;
				break;

			}
			case BRACKET_END:
			{
				bracket_count--;
				if( bracket_end < bracket_begin )
				{
					bracket_end = pos;
				}
				
				if( bracket_count < 0 )
				{
					syntax_error = 1;
				}
				break;
			}
			case BRACKET_SEP:
			{
				if( bracket_count == 1 )
					last_sep = pos;
			}
		}
	}

	if( bracket_count > 0 )
	{
		if( !(flags & ACCEPT_INCOMPLETE) )
		{
			syntax_error = 1;
		}
		else
		{
            wcstring mod;
			if( last_sep )
			{
				mod.append( in, bracket_begin-in+1 );
				mod.append( last_sep+1 );
				mod.push_back( BRACKET_END );
			}
			else
			{
                mod.append(in);
                mod.push_back(BRACKET_END);
			}

			return expand_brackets( parser, mod.c_str(), 1, out );
		}
	}

	if( syntax_error )
	{
		parser.error( SYNTAX_ERROR,
			   -1,
			   _(L"Mismatched brackets") );
		return 0;
	}

	if( bracket_begin == 0 )
	{
		out.push_back(completion_t(in));
		return 1;
	}

	len1 = (bracket_begin-in);
	len2 = wcslen(bracket_end)-1;
	tot_len = len1+len2;
	item_begin = bracket_begin+1;
	for( pos=(bracket_begin+1); 1; pos++ )
	{
		if( bracket_count == 0 )
		{
			if( (*pos == BRACKET_SEP) || (pos==bracket_end) )
			{
				wchar_t *whole_item;
				int item_len = pos-item_begin;

				whole_item = (wchar_t *)malloc( sizeof(wchar_t)*(tot_len + item_len + 1) );
				wcslcpy( whole_item, in, len1+1 );
				wcslcpy( whole_item+len1, item_begin, item_len+1 );
				wcscpy( whole_item+len1+item_len, bracket_end+1 );

				expand_brackets( parser, whole_item, flags, out );

				item_begin = pos+1;
				if( pos == bracket_end )
					break;
			}
		}

		if( *pos == BRACKET_BEGIN )
		{
			bracket_count++;
		}

		if( *pos == BRACKET_END )
		{
			bracket_count--;
		}
	}
	return 1;
}

/**
 Perform cmdsubst expansion
 */
static int expand_cmdsubst( parser_t &parser, const wcstring &input, std::vector<completion_t> &outList )
{
	wchar_t *paran_begin=0, *paran_end=0;
	int len1;
    std::vector<wcstring> sub_res;
	size_t i, j;
	wchar_t *tail_begin = 0;	
    
    const wchar_t * const in = input.c_str();
    
	int parse_ret;
	switch( parse_ret = parse_util_locate_cmdsubst(in,
                                                   &paran_begin,
                                                   &paran_end,
                                                   0 ) )
	{
		case -1:
			parser.error( SYNTAX_ERROR,
                         -1,
                         L"Mismatched parans" );
			return 0;
		case 0:
            outList.push_back(completion_t(input));
			return 1;
		case 1:
            
			break;
	}
    
	len1 = (paran_begin-in);
    
    const wcstring subcmd(paran_begin + 1, paran_end-paran_begin - 1);
    
	if( exec_subshell( subcmd, sub_res) == -1 )
	{
		parser.error( CMDSUBST_ERROR, -1, L"Unknown error while evaulating command substitution" );
		return 0;
	}
    
	tail_begin = paran_end + 1;
	if( *tail_begin == L'[' )
	{
        std::vector<long> slice_idx;
		wchar_t *slice_end;
		
		if( parse_slice( tail_begin, &slice_end, slice_idx ) )
		{
			parser.error( SYNTAX_ERROR, -1, L"Invalid index value" );
			return 0;
		}
		else
		{
            std::vector<wcstring> sub_res2;
			tail_begin = slice_end;
			for( i=0; i < slice_idx.size(); i++ )
			{
				long idx = slice_idx.at(i);
				if( idx < 0 )
				{
					idx = sub_res.size() + idx + 1;
				}
				
				if( idx < 1 || (size_t)idx > sub_res.size() )
				{
					parser.error( SYNTAX_ERROR, -1, L"Invalid index value" );
					return 0;
				}
				
				idx = idx-1;
				
                sub_res2.push_back(sub_res.at(idx));
                //				debug( 0, L"Pushing item '%ls' with index %d onto sliced result", al_get( sub_res, idx ), idx );
				//sub_res[idx] = 0; // ??
			}
			sub_res = sub_res2;			
		}
	}
    
    
	/*
     Recursively call ourselves to expand any remaining command
     substitutions. The result of this recursive call using the tail
     of the string is inserted into the tail_expand array list
     */
    std::vector<completion_t> tail_expand;
	expand_cmdsubst( parser, tail_begin, tail_expand );
    
	/*
     Combine the result of the current command substitution with the
     result of the recursive tail expansion
     */
    for( i=0; i<sub_res.size(); i++ )
    {
        wcstring sub_item = sub_res.at(i);
        wcstring sub_item2 = escape_string(sub_item, 1);
        
        for( j=0; j < tail_expand.size(); j++ )
        {
            
            wcstring whole_item;
            
            wcstring tail_item = tail_expand.at(j).completion;
            
            //sb_append_substring( &whole_item, in, len1 );
            whole_item.append(in, len1);
            
            //sb_append_char( &whole_item, INTERNAL_SEPARATOR );
            whole_item.push_back(INTERNAL_SEPARATOR);
            
            //sb_append_substring( &whole_item, sub_item2, item_len );
			whole_item.append(sub_item2);
            
            //sb_append_char( &whole_item, INTERNAL_SEPARATOR );
            whole_item.push_back(INTERNAL_SEPARATOR);
            
            //sb_append( &whole_item, tail_item );
            whole_item.append(tail_item);
			
			//al_push( out, whole_item.buff );
            outList.push_back(completion_t(whole_item));
        }
    }
    
	return 1;
}

/**
   Wrapper around unescape funtion. Issues an error() on failiure.
*/
__attribute__((unused))
static wchar_t *expand_unescape( parser_t &parser, const wchar_t * in, int escape_special )
{
	wchar_t *res = unescape( in, escape_special );
	if( !res )
		parser.error( SYNTAX_ERROR, -1, L"Unexpected end of string" );
	return res;
}

static wcstring expand_unescape_string( const wcstring &in, int escape_special )
{
    wcstring tmp = in;
    unescape_string(tmp, escape_special);
    /* Need to detect error here */
	return tmp;
}

/**
   Attempts tilde expansion of the string specified, modifying it in place.
*/
static void expand_tilde_internal( wcstring &input )
{
    const wchar_t * const in = input.c_str();
	if( in[0] == HOME_DIRECTORY )
	{
		int tilde_error = 0;
        size_t tail_idx;
        wcstring home;

		if( in[1] == '/' || in[1] == '\0' )
		{
			/* Current users home directory */

			home = env_get_string( L"HOME" );
            tail_idx = 1;
		}
		else
		{
			/* Some other users home directory */
			const wchar_t *name_end = wcschr( in, L'/' );
            if (name_end)
            {
                tail_idx = name_end - in;
            }
            else
            {
                tail_idx = wcslen( in );
            }
            wcstring name_str = input.substr(1, tail_idx - 1);
            std::string name_cstr = wcs2string(name_str);
			struct passwd *userinfo = getpwnam( name_cstr.c_str() );

			if( userinfo == NULL )
			{
				tilde_error = 1;
                input[0] = L'~';
			}
			else
			{
				home = str2wcstring(userinfo->pw_dir);
			}
		}

        if (! tilde_error)
        {
            input.replace(input.begin(), input.begin() + tail_idx, home);
        }
	}
}

void expand_tilde( wcstring &input)
{
	if( ! input.empty() && input.at(0) == L'~' )
	{
		input.at(0) = HOME_DIRECTORY;
		expand_tilde_internal( input );
	}
}

/**
   Remove any internal separators. Also optionally convert wildcard characters to
   regular equivalents. This is done to support EXPAND_SKIP_WILDCARDS.
*/
static void remove_internal_separator( const void *s, int conv )
{
	wchar_t *in = (wchar_t *)s;
	wchar_t *out=in;
	
	CHECK( s, );

	while( *in )
	{
		switch( *in )
		{
			case INTERNAL_SEPARATOR:
				in++;
				break;
				
			case ANY_CHAR:
				in++;
				*out++ = conv?L'?':ANY_CHAR;
				break;

			case ANY_STRING:
				in++;
				*out++ = conv?L'*':ANY_STRING;
				break;

			case ANY_STRING_RECURSIVE:
				in++;
				*out++ = conv?L'*':ANY_STRING_RECURSIVE;
				break;

			default:
				*out++ = *in++;
		}
	}
	*out=0;
}

static void remove_internal_separator2( wcstring &s, int conv )
{
    wchar_t *tmp = wcsdup(s.c_str());
    remove_internal_separator(tmp, conv);
    s = tmp;
    free(tmp);
}


int expand_string( const wcstring &input, std::vector<completion_t> &output, expand_flags_t flags )
{
	parser_t parser(PARSER_TYPE_ERRORS_ONLY, true /* show errors */);
   	std::vector<completion_t> list1, list2;
	std::vector<completion_t> *in, *out;
    
	size_t i;
	int res = EXPAND_OK;
    
	if( (!(flags & ACCEPT_INCOMPLETE)) && expand_is_clean( input.c_str() ) )
	{
		output.push_back(completion_t(input));
		return EXPAND_OK;
	}
    
	if( EXPAND_SKIP_CMDSUBST & flags )
	{
		wchar_t *begin, *end;
		
		if( parse_util_locate_cmdsubst( input.c_str(),
                                       &begin,
                                       &end,
                                       1 ) != 0 )
		{
			parser.error( CMDSUBST_ERROR, -1, L"Command substitutions not allowed" );
			return EXPAND_ERROR;
		}
		list1.push_back(completion_t(input));
	}
	else
	{
        int cmdsubst_ok = expand_cmdsubst(parser, input, list1);
        if (! cmdsubst_ok)
            return EXPAND_ERROR;
	}

    in = &list1;
    out = &list2;
    
    for( i=0; i < in->size(); i++ )
    {
        /*
         We accept incomplete strings here, since complete uses
         expand_string to expand incomplete strings from the
         commandline.
         */
        int unescape_flags = UNESCAPE_SPECIAL | UNESCAPE_INCOMPLETE;            
        wcstring next = expand_unescape_string( in->at(i).completion, unescape_flags );
        
        if( EXPAND_SKIP_VARIABLES & flags )
        {
            for (size_t i=0; i < next.size(); i++) {
                if (next.at(i) == VARIABLE_EXPAND) {
                    next[i] = L'$';
                }
            }
            out->push_back(completion_t(next));
        }
        else
        {
            if(!expand_variables2( parser, next, *out, next.size() - 1 ))
            {
                return EXPAND_ERROR;
            }
        }
    }
    
    in->clear();
    
    in = &list2;
    out = &list1;
    
    for( i=0; i < in->size(); i++ )
    {
        wcstring next = in->at(i).completion;
        
        if( !expand_brackets( parser, next.c_str(), flags, *out ))
        {
            return EXPAND_ERROR;
        }
    }
    in->clear();
    
    in = &list1;
    out = &list2;
    
    for( i=0; i < in->size(); i++ )
    {
        wcstring next = in->at(i).completion;
        
        expand_tilde_internal(next);
        
        
        if( flags & ACCEPT_INCOMPLETE )
        {
            if( next[0] == PROCESS_EXPAND )
            {
                /*
                 If process expansion matches, we are not
                 interested in other completions, so we
                 short-circut and return
                 */
                if (! (flags & EXPAND_SKIP_PROCESS ))
                    expand_pid( next, flags, output );
                return EXPAND_OK;
            }
            else
            {
                out->push_back(completion_t(next));
            }
        }
        else
        {
            if( ! (flags & EXPAND_SKIP_PROCESS ) && ! expand_pid( next, flags, *out ) )
            {
                return EXPAND_ERROR;
            }
        }
    }
    
    in->clear();
    
    in = &list2;
    out = &list1;
    
    for( i=0; i < in->size(); i++ )
    {
        wcstring next_str = in->at(i).completion;
        int wc_res;
        
        remove_internal_separator2( next_str, EXPAND_SKIP_WILDCARDS & flags );			
        const wchar_t *next = next_str.c_str();
        
        if( ((flags & ACCEPT_INCOMPLETE) && (!(flags & EXPAND_SKIP_WILDCARDS))) ||
           wildcard_has( next, 1 ) )
        {
            const wchar_t *start, *rest;
            std::vector<completion_t> *list = out;
            
            if( next[0] == '/' )
            {
                start = L"/";
                rest = &next[1];
            }
            else
            {
                start = L"";
                rest = next;
            }
            
            if( flags & ACCEPT_INCOMPLETE )
            {
                list = &output;
            }
            
            wc_res = wildcard_expand_string(rest, start, flags, *list);
            
            if( !(flags & ACCEPT_INCOMPLETE) )
            {
                
                switch( wc_res )
                {
                    case 0:
                    {
                        if( !(flags & ACCEPT_INCOMPLETE) )
                        {
                            if( res == EXPAND_OK )
                                res = EXPAND_WILDCARD_NO_MATCH;
                            break;
                        }
                    }
                        
                    case 1:
                    {
                        size_t j;
                        res = EXPAND_WILDCARD_MATCH;
                        sort_completions( *out );
                        
                        for( j=0; j< out->size(); j++ )
                        {
                            output.push_back( out->at(j) );
                        }
                        out->clear();
                        break;
                    }
                        
                    case -1:
                    {
                        return EXPAND_ERROR;
                    }
                        
                }
            }
            
        }
        else
        {
            if( flags & ACCEPT_INCOMPLETE)
            {
            }
            else
            {
                output.push_back(completion_t(next));
            }
        }
        
    }
    
	return res;
}

bool expand_one(wcstring &string, expand_flags_t flags) {
	std::vector<completion_t> completions;
	bool result = false;
	
	if( (!(flags & ACCEPT_INCOMPLETE)) &&  expand_is_clean( string.c_str() ) )
	{
        return true;
	}
	
    if (expand_string(string, completions, flags)) {
        if (completions.size() == 1) {
            string = completions.at(0).completion;
            result = true;
        }
    }
	return result;
}