/*
 * Copyright 1993-2002 Christopher Seiwald and Perforce Software, Inc.
 *
 * This file is part of Jam - see jam.c for Copyright information.
 */

# include "jam.h"
# include "lists.h"
# include "variable.h"
# include "expand.h"
# include "pathsys.h"
# include "newstr.h"
# include <assert.h>

# ifdef OS_CYGWIN
#  include <sys/cygwin.h>
#  include <windows.h>
#  include <stdlib.h>
# endif

/*
 * expand.c - expand a buffer, given variable values
 *
 * External routines:
 *
 *	var_expand() - variable-expand input string into list of strings
 *
 * Internal routines:
 *
 *	var_edit_parse() - parse : modifiers into PATHNAME structure
 *	var_edit_file() - copy input target name to output, modifying filename
 *	var_edit_shift() - do upshift/downshift mods
 *
 * 01/25/94 (seiwald) - $(X)$(UNDEF) was expanding like plain $(X)
 * 04/13/94 (seiwald) - added shorthand L0 for null list pointer
 * 01/11/01 (seiwald) - added support for :E=emptyvalue, :J=joinval
 */

typedef struct {
	PATHNAME	f;		/* :GDBSMR -- pieces */
	char		parent;		/* :P -- go to parent directory */
	char		filemods;	/* one of the above applied */
	char		downshift;	/* :L -- downshift result */
	char		upshift;	     /* :U -- upshift result */
    char        to_slashes;    /* :T -- convert "\" to "/" */
    char        to_windows;    /* :W -- convert cygwin to native paths */
	PATHPART	empty;		/* :E -- default for empties */
	PATHPART	join;		/* :J -- join list with char */
} VAR_EDITS ;

static void var_edit_parse( char *mods, VAR_EDITS *edits );
static void var_edit_file( char *in, string *out, VAR_EDITS *edits );
static void var_edit_shift( string *out, VAR_EDITS *edits );

# define MAGIC_COLON	'\001'
# define MAGIC_LEFT	'\002'
# define MAGIC_RIGHT	'\003'

/*
 * var_expand() - variable-expand input string into list of strings
 *
 * Would just copy input to output, performing variable expansion, 
 * except that since variables can contain multiple values the result
 * of variable expansion may contain multiple values (a list).  Properly
 * performs "product" operations that occur in "$(var1)xxx$(var2)" or
 * even "$($(var2))".
 *
 * Returns a newly created list.
 */

LIST *
var_expand( 
	LIST	*l,
	char	*in,
	char	*end,
	LOL	*lol,
	int	cancopyin )
{
    char out_buf[ MAXSYM ];
    string buf[1];
    string out1[1]; /* Temporary buffer */
    size_t prefix_length;
    char *out;
    char *inp = in;
    char *ov;		/* for temp copy of variable in outbuf */
    int depth;

    if( DEBUG_VAREXP )
        printf( "expand '%.*s'\n", end - in, in );

    /* This gets alot of cases: $(<) and $(>) */

    if( in[0] == '$' && in[1] == '(' && in[3] == ')' && !in[4] )
    {
        switch( in[2] )
        {
        case '1':
        case '<':
            return list_copy( l, lol_get( lol, 0 ) );

        case '2':
        case '>':
            return list_copy( l, lol_get( lol, 1 ) );
        }
    }

    /* Just try simple copy of in to out. */

    while( in < end )
        if( *in++ == '$' && *in == '(' ) 
            goto expand;

    /* No variables expanded - just add copy of input string to list. */

    /* Cancopyin is an optimization: if the input was already a list */
    /* item, we can use the copystr() to put it on the new list. */
    /* Otherwise, we use the slower newstr(). */

    if( cancopyin ) 
    {
        return list_new( l, copystr( inp ) );
    }
    else
    {
        LIST* r;
        string_new( buf );
        string_append_range( buf, inp, end );

        r = list_new( l, newstr( buf->value) );
        string_free( buf );
        return r;
    }

expand:
    string_new( buf );
    string_append_range( buf, inp, in - 1); /* copy the part before '$'. */
    /*
     * Input so far (ignore blanks):
     *
     *  stuff-in-outbuf $(variable) remainder
     *                   ^                   ^
     *                   in                  end
     * Output so far:
     *
     *  stuff-in-outbuf $
     *  ^                ^
     *  out_buf          out
     *
     *
     * We just copied the $ of $(...), so back up one on the output.
     * We now find the matching close paren, copying the variable and
     * modifiers between the $( and ) temporarily into out_buf, so that
     * we can replace :'s with MAGIC_COLON.  This is necessary to avoid
     * being confused by modifier values that are variables containing
     * :'s.  Ugly.
     */

    depth = 1;
    inp = ++in; /* skip over the '(' */

    while( in < end && depth )
    {
        switch( *in++ )
        {
        case '(': depth++; break;
        case ')': depth--; break;
        }
    }

    /*
     * Input so far (ignore blanks):
     *
     *  stuff-in-outbuf $(variable) remainder
     *                    ^        ^         ^
     *                    inp      in        end
     */
    prefix_length = buf->size;
    string_append_range( buf, inp, in - 1 );

    out = buf->value + prefix_length;
    for ( ov = out; ov < buf->value + buf->size; ++ov )
    {
        switch( *ov )
        {
        case ':': *ov = MAGIC_COLON; break;
        case '[': *ov = MAGIC_LEFT; break;
        case ']': *ov = MAGIC_RIGHT; break;
        }
    }

    /*
     * Input so far (ignore blanks):
     *
     *  stuff-in-outbuf $(variable) remainder
     *                              ^        ^
     *                              in       end
     * Output so far:
     *
     *  stuff-in-outbuf variable
     *  ^               ^       ^
     *  out_buf         out     ov
     *
     * Later we will overwrite 'variable' in out_buf, but we'll be
     * done with it by then.  'variable' may be a multi-element list, 
     * so may each value for '$(variable element)', and so may 'remainder'.
     * Thus we produce a product of three lists.
     */

    {
        LIST *variables = 0;
        LIST *remainder = 0;
        LIST *vars;

        /* Recursively expand variable name & rest of input */

        if( out < ov )
            variables = var_expand( L0, out, ov, lol, 0 );
        if( in < end )
            remainder = var_expand( L0, in, end, lol, 0 );

        /* Now produce the result chain */

        /* For each variable name */

        for( vars = variables; vars; vars = list_next( vars ) )
        {
            LIST *value, *evalue = 0;
            char *colon;
            char *bracket;
            string variable[1];
            char *varname;
            int sub1 = 0, sub2 = -1;
            VAR_EDITS edits;

            /* Look for a : modifier in the variable name */
            /* Must copy into varname so we can modify it */

            string_copy( variable, vars->string );
            varname = variable->value;

            if( colon = strchr( varname, MAGIC_COLON ) )
            {
                string_truncate( variable, colon - varname );
                var_edit_parse( colon + 1, &edits );
            }

            /* Look for [x-y] subscripting */
            /* sub1 and sub2 are x and y. */

            if ( bracket = strchr( varname, MAGIC_LEFT ) )
            {
                /*
                ** Make all syntax errors in [] subscripting
                ** result in the same behavior: silenty return an empty
                ** expansion (by setting sub2 = 0). Brute force parsing;
                ** May get moved into yacc someday.
                */

                char *s = bracket + 1;

                string_truncate( variable, bracket - varname );

                do  /* so we can use "break" */
                {
                    /* Allow negative indexes. */
                    if (! isdigit( *s ) && ! ( *s == '-') )
                    {
                        sub2 = 0;
                        break;
                    }
                    sub1 = atoi(s);

                    /* Skip over the first symbol, which is either a digit or dash. */
                    s++;
                    while ( isdigit( *s ) ) s++;

                    if ( *s == MAGIC_RIGHT )
                    {
                        sub2 = sub1;
                        break;
                    }

                    if ( *s != '-')
                    {
                        sub2 = 0;
                        break;
                    }

                    s++;

                    if ( *s == MAGIC_RIGHT )
                    {
                        sub2 = -1;
                        break;
                    }

                    if (! isdigit( *s ) && ! ( *s == '-') )
                    {
                        sub2 = 0;
                        break;
                    }

                    /* First, compute the index of the last element. */
                    sub2 = atoi(s);               
                    s++;
                    while ( isdigit( *s ) ) s++;

                    if ( *s != MAGIC_RIGHT)
                        sub2 = 0;

                } while (0);

                /*
                ** Anything but the end of the string, or the colon
                ** introducing a modifier is a syntax error.
                */

                s++;                
                if (*s && *s != MAGIC_COLON)
                    sub2 = 0;

                *bracket = '\0';
            }

            /* Get variable value, specially handling $(<), $(>), $(n) */
		
            if( varname[0] == '<' && !varname[1] )
                value = lol_get( lol, 0 );
            else if( varname[0] == '>' && !varname[1] )
                value = lol_get( lol, 1 );
            else if( varname[0] >= '1' && varname[0] <= '9' && !varname[1] )
                value = lol_get( lol, varname[0] - '1' );
            else 
                value = var_get( varname );

            /* Handle negitive indexes: part two. */
            {
                int length = list_length( value );

                if (sub1 < 0)
                    sub1 = length + sub1;
                else
                    sub1 -= 1;

                if (sub2 < 0)
                    sub2 = length + 1 + sub2 - sub1;
                else
                    sub2 -= sub1;
                /*
                ** The "sub2 < 0" test handles the semantic error
                ** of sub2 < sub1.
                */
                if ( sub2 < 0 )
                    sub2 = 0;
            }



            /* The fast path: $(x) - just copy the variable value. */
            /* This is only an optimization */

            if( out == out_buf && !bracket && !colon && in == end )
            {
                string_free( variable );
                l = list_copy( l, value );
                continue;
            }

            /* Handle start subscript */

            while( sub1 > 0 && value )
                --sub1, value = list_next( value );

            /* Empty w/ :E=default? */

            if( !value && colon && edits.empty.ptr )
                evalue = value = list_new( L0, newstr( edits.empty.ptr ) );

            /* For each variable value */

            string_new( out1 );
            for( ; value; value = list_next( value ) )
            {
                LIST *rem;
                size_t postfix_start;

                /* Handle end subscript (length actually) */

                if( sub2 >= 0 && --sub2 < 0 )
                    break;

                string_truncate( buf, prefix_length );

                /* Apply : mods, if present */

                if( colon && edits.filemods )
                    var_edit_file( value->string, out1, &edits );
                else
                    string_append( out1, value->string );

                if( colon && ( edits.upshift || edits.downshift || edits.to_slashes || edits.to_windows ) )
                    var_edit_shift( out1, &edits );

                /* Handle :J=joinval */
                /* If we have more values for this var, just */
                /* keep appending them (with the join value) */
                /* rather than creating separate LIST elements. */

                if( colon && edits.join.ptr && 
                    ( list_next( value ) || list_next( vars ) ) )
                {
                    string_append( out1, edits.join.ptr );
                    continue;
                }

                string_append( buf, out1->value );
                string_free( out1 );
                string_new( out1 );

                /* If no remainder, append result to output chain. */

                if( in == end )
                {
                    l = list_new( l, newstr( buf->value ) );
                    continue;
                }

                /* For each remainder, append the complete string */
                /* to the output chain. */
                /* Remember the end of the variable expansion so */
                /* we can just tack on each instance of 'remainder' */

                postfix_start = buf->size;

                for( rem = remainder; rem; rem = list_next( rem ) )
                {
                    string_truncate( buf, postfix_start );
                    string_append( buf, rem->string );
                    l = list_new( l, newstr( buf->value ) );
                }
            }
            string_free( out1 );

            /* Toss used empty */

            if( evalue )
                list_free( evalue );

            string_free( variable );
        }

        /* variables & remainder were gifts from var_expand */
        /* and must be freed */

        if( variables )
            list_free( variables );
        if( remainder)
            list_free( remainder );

        if( DEBUG_VAREXP )
        {
            printf( "expanded to " );
            list_print( l );
            printf( "\n" );
        }

        string_free( buf );
        return l;
    }
}

/*
 * var_edit_parse() - parse : modifiers into PATHNAME structure
 *
 * The : modifiers in a $(varname:modifier) currently support replacing
 * or omitting elements of a filename, and so they are parsed into a 
 * PATHNAME structure (which contains pointers into the original string).
 *
 * Modifiers of the form "X=value" replace the component X with
 * the given value.  Modifiers without the "=value" cause everything 
 * but the component X to be omitted.  X is one of:
 *
 *	G <grist>
 *	D directory name
 *	B base name
 *	S .suffix
 *	M (member)
 *	R root directory - prepended to whole path
 *
 * This routine sets:
 *
 *	f->f_xxx.ptr = 0
 *	f->f_xxx.len = 0
 *		-> leave the original component xxx
 *
 *	f->f_xxx.ptr = string
 *	f->f_xxx.len = strlen( string )
 *		-> replace component xxx with string
 *
 *	f->f_xxx.ptr = ""
 *	f->f_xxx.len = 0
 *		-> omit component xxx
 *
 * var_edit_file() below and path_build() obligingly follow this convention.
 */

static void
var_edit_parse(
	char		*mods,
	VAR_EDITS	*edits )
{
	int havezeroed = 0;
	memset( (char *)edits, 0, sizeof( *edits ) );

	while( *mods )
	{
	    char *p;
	    PATHPART *fp;

	    switch( *mods++ )
	    {
	    case 'L': edits->downshift = 1; continue;
	    case 'U': edits->upshift = 1; continue;
	    case 'P': edits->parent = edits->filemods = 1; continue;
	    case 'E': fp = &edits->empty; goto strval;
	    case 'J': fp = &edits->join; goto strval;
	    case 'G': fp = &edits->f.f_grist; goto fileval;
	    case 'R': fp = &edits->f.f_root; goto fileval;
	    case 'D': fp = &edits->f.f_dir; goto fileval;
	    case 'B': fp = &edits->f.f_base; goto fileval;
	    case 'S': fp = &edits->f.f_suffix; goto fileval;
	    case 'M': fp = &edits->f.f_member; goto fileval;
            case 'T': edits->to_slashes = 1; continue;
            case 'W': edits->to_windows = 1; continue;

	    default: return; /* should complain, but so what... */
	    }

	fileval:

	    /* Handle :CHARS, where each char (without a following =) */
	    /* selects a particular file path element.  On the first such */
	    /* char, we deselect all others (by setting ptr = "", len = 0) */
	    /* and for each char we select that element (by setting ptr = 0) */

	    edits->filemods = 1;

	    if( *mods != '=' )
	    {
		int i;

		if( !havezeroed++ )
		    for( i = 0; i < 6; i++ )
		{
		    edits->f.part[ i ].len = 0;
		    edits->f.part[ i ].ptr = "";
		}

		fp->ptr = 0;
		continue;
	    }

	strval:

	    /* Handle :X=value, or :X */

	    if( *mods != '=' )
	    {
		fp->ptr = "";
		fp->len = 0;
	    }
	    else if( p = strchr( mods, MAGIC_COLON ) )
	    {
		*p = 0;
		fp->ptr = ++mods;
		fp->len = p - mods;
		mods = p + 1;
	    }
	    else
	    {
		fp->ptr = ++mods;
		fp->len = strlen( mods );
		mods += fp->len;
	    }
	}
}

/*
 * var_edit_file() - copy input target name to output, modifying filename
 */
	
static void
var_edit_file( 
	char	*in,
	string	*out,
	VAR_EDITS *edits )
{
	PATHNAME pathname;

	/* Parse apart original filename, putting parts into "pathname" */

	path_parse( in, &pathname );

	/* Replace any pathname with edits->f */

	if( edits->f.f_grist.ptr )
	    pathname.f_grist = edits->f.f_grist;

	if( edits->f.f_root.ptr )
	    pathname.f_root = edits->f.f_root;

	if( edits->f.f_dir.ptr )
	    pathname.f_dir = edits->f.f_dir;

	if( edits->f.f_base.ptr )
	    pathname.f_base = edits->f.f_base;

	if( edits->f.f_suffix.ptr )
	    pathname.f_suffix = edits->f.f_suffix;

	if( edits->f.f_member.ptr )
	    pathname.f_member = edits->f.f_member;

	/* If requested, modify pathname to point to parent */

	if( edits->parent )
	    path_parent( &pathname );

	/* Put filename back together */

    path_build( &pathname, out, 0 );
}

/*
 * var_edit_shift() - do upshift/downshift mods
 */

static void
var_edit_shift( 
	string	*out,
	VAR_EDITS *edits )
{
	/* Handle upshifting, downshifting and slash translation now */

    char *p;
    for ( p = out->value; *p; ++p)
    {
        if (edits->upshift)
        {
            *p = toupper( *p );
        }
        else if ( edits->downshift )
        {
            *p = tolower( *p );
        } 
        if ( edits->to_slashes )
        {
            if ( *p == '\\')
                *p = '/';
        }
# ifdef OS_CYGWIN
        if ( edits->to_windows )
        {
            char result[MAX_PATH + 1];
            cygwin_conv_to_win32_path(out->value, result);
            assert(strlen(result) <= MAX_PATH);
            string_free( out );
            string_copy( out, result );
        }
# endif
    }
    out->size = p - out->value;
}

#ifndef NDEBUG
void var_expand_unit_test()
{
    LOL lol[1];
    LIST* l, *l2;
    LIST *expected = list_new( list_new( L0, newstr( "axb" ) ), newstr( "ayb" ) );
    LIST *e2;
    char axyb[] = "a$(xy)b";
    char azb[] = "a$($(z))b";
    char path[] = "$(p:W)";
    
    # ifdef OS_CYGWIN
    char cygpath[256];
    cygwin_conv_to_posix_path("c:\\foo\\bar", cygpath);
    # else
    char cygpath[] = "/cygdrive/c/foo/bar";
    # endif
        
    lol_init(lol);
    var_set("xy", list_new( list_new( L0, newstr( "x" ) ), newstr( "y" ) ), VAR_SET );
    var_set("z", list_new( L0, newstr( "xy" ) ), VAR_SET );
    var_set("p", list_new( L0, newstr( cygpath ) ), VAR_SET );

    l = var_expand( 0, axyb, axyb + sizeof(axyb) - 1, lol, 0 );
    for ( l2 = l, e2 = expected; l2 && e2; l2 = list_next(l2), e2 = list_next(e2) )
        assert( !strcmp( e2->string, l2->string ) );
    assert(l2 == 0 && e2 == 0);
    list_free(l);
    
    l = var_expand( 0, azb, azb + sizeof(azb) - 1, lol, 0 );
    for ( l2 = l, e2 = expected; l2 && e2; l2 = list_next(l2), e2 = list_next(e2) )
        assert( !strcmp( e2->string, l2->string ) );
    assert(l2 == 0 && e2 == 0);
    list_free(l);

    l = var_expand( 0, path, path + sizeof(path) - 1, lol, 0 );
    assert(l != 0);
    assert(list_next(l) == 0);
    # ifdef OS_CYGWIN
    assert( !strcmp( l->string, "c:\\foo\\bar" ) );
    # else 
    assert( !strcmp( l->string, cygpath ) );
    # endif   
    list_free(l);

    list_free(expected);
    
    lol_free(lol);
}
#endif

/*
     Local Variables:
     tab-width: 8
     End:
 */
