htmulti.c

www工具包. 这是W3C官方支持的www支撑库. 其中提供通用目的的客户端的WebAPI: complete HTTP/1.1 (with caching, pipelining, PUT, POS

/*
**	CONTENT NEGOTIATION
**
**	(c) COPYRIGHT MIT 1995.
**	Please first read the full copyright statement in the file COPYRIGH.
**	@(#) $Id: HTMulti.c,v 2.36 2000/01/06 10:48:50 kahan Exp $
**
** History:
**	March 94  AL	Separated from HTFile.c because
**			multiformat handling would be a mess in VMS.
*/

/* Library include files */
#include "wwwsys.h"
#include "WWWUtil.h"
#include "WWWCore.h"
#include "HTMulti.h"
#include "HTBind.h"
#include "HTFile.h"

#define MULTI_SUFFIX	".multi"/* Extension for scanning formats */
#define MAX_SUFF	15	/* Maximum number of suffixes for a file */
#define VARIANTS	4	/* We start with this array size */

typedef struct _HTContentDescription {
    char *	filename;
    HTFormat	content_type;
    HTLanguage	content_language;
    HTEncoding	content_encoding;
    HTEncoding	content_transfer;
    int		content_length;
    double	quality;
} HTContentDescription;

PRIVATE HTList * welcome_names = NULL;	/* Welcome.html, index.html etc. */

/* ------------------------------------------------------------------------- */

/*
**  Sort the q values in descending order
*/
PRIVATE int VariantSort (const void * a, const void * b)
{
    HTContentDescription * aa = *(HTContentDescription **) a;
    HTContentDescription * bb = *(HTContentDescription **) b;
    if (aa && bb) return (aa->quality > bb->quality) ? -1 : 1;
    return bb - aa;
}

/*
 * Added by [e-mail] (94/04/08)
 */
PRIVATE BOOL lang_match (HTAtom * tmplate, HTAtom * actual)
{
    const char *t, *a;
    char *st, *sa;
    BOOL match = NO;

    if (tmplate && actual &&
	(t = HTAtom_name(tmplate)) && (a = HTAtom_name(actual))) {
	st = strchr(t, '_');
	sa = strchr(a, '_');
	if ((st != NULL) && (sa != NULL)) {
	    if (!strcasecomp(t, a))
	      match = YES;
	    else
	      match = NO;
	}
	else {
	    if (st != NULL) *st = 0;
	    if (sa != NULL) *sa = 0;
	    if (!strcasecomp(t, a))
	      match = YES;
	    else
	      match = NO;
	    if (st != NULL) *st = '_';
	    if (sa != NULL) *sa = '_';
	}
    }
    return match;
}

PRIVATE double type_value (HTAtom * content_type, HTList * accepted)
{
    if (!content_type) return (1.0);
    if (accepted) {
	HTList * cur = accepted;
	HTPresentation * pres;
	HTPresentation * wild = NULL;
	while ((pres = (HTPresentation *) HTList_nextObject(cur))) {
	    if (pres->rep == content_type)
		return pres->quality;
	    else if (HTMIMEMatch(pres->rep, content_type))
		wild = pres;
	}
	if (wild) return wild->quality;
	else return (0.0);				  /* Nothing matched */
    }
    return (1.0);				      /* We accept all types */
}

PRIVATE double lang_value (HTAtom * language, HTList * accepted)
{
    if (!language) return (1.0);
    if (accepted) {
	HTList * cur = accepted;
	HTAcceptNode * node;
	HTAcceptNode * wild = NULL;
	while ((node = (HTAcceptNode *) HTList_nextObject(cur))) {
	    if (node->atom == language)
		return node->quality;
	    /*
	     * patch by [e-mail] (94/04/08)
	     * the original line was
	     * else if (HTMIMEMatch(node->atom, language)) {
	     * and the new line is
	     */
	    else if (lang_match(node->atom, language))
		wild = node;
	}
	if (wild) return wild->quality;
	else return (0.0);				  /* Nothing matched */
    }
    return (1.0);				  /* We accept all languages */
}

PRIVATE double encoding_value (HTAtom * encoding, HTList * accepted)
{
    if (!encoding) return (1.0);
    if (accepted) {
	HTList * cur = accepted;
	HTAcceptNode * node;
	HTAcceptNode * wild = NULL;
	const char * e = HTAtom_name(encoding);
	if (!strcmp(e, "7bit") || !strcmp(e, "8bit") || !strcmp(e, "binary"))
	    return (1.0);
	while ((node = (HTAcceptNode*)HTList_nextObject(cur))) {
	    if (node->atom == encoding)
		return node->quality;
	    else if (HTMIMEMatch(node->atom, encoding))
		wild = node;
	}
	if (wild) return wild->quality;
	else return (0.0);				  /* Nothing matched */
    }
    return (1.0);				  /* We accept all encodings */
}

PRIVATE BOOL HTRank (HTRequest * request, HTArray * variants)
{
    HTContentDescription * cd;
    void ** data;
    if (!variants) {
	HTTRACE(PROT_TRACE, "Ranking..... No variants\n");
	return NO;
    }
    /* 
    **  Walk through the list of local and global preferences and find the
    **  overall q factor for each variant
    */
    cd = (HTContentDescription *) HTArray_firstObject(variants, data);
    while (cd) {
	double ctq_local  = type_value(cd->content_type, HTRequest_conversion(request));
	double ctq_global = type_value(cd->content_type, HTFormat_conversion());
	double clq_local  = lang_value(cd->content_language, HTRequest_language(request));
	double clq_global = lang_value(cd->content_language, HTFormat_language());
	double ceq_local  = encoding_value(cd->content_encoding, HTRequest_encoding(request));
	double ceq_global = encoding_value(cd->content_encoding, HTFormat_contentCoding());
	HTTRACE(PROT_TRACE, "Qualities... Content type: %.3f, Content language: %.3f, Content encoding: %.3f\n" _ 
		    HTMAX(ctq_local, ctq_global) _ 
		    HTMAX(clq_local, clq_global) _ 
		    HTMAX(ceq_local, ceq_global));
	cd->quality *= (HTMAX(ctq_local, ctq_global) *
			HTMAX(clq_local, clq_global) *
			HTMAX(ceq_local, ceq_global));
	cd = (HTContentDescription *) HTArray_nextObject(variants, data);
    }

    /* Sort the array of all our accepted preferences */
    HTArray_sort(variants, VariantSort);

    /* Write out the result */
#ifdef HTDEBUG 
    if (PROT_TRACE) {
	int cnt = 1;
	cd = (HTContentDescription *) HTArray_firstObject(variants, data);
	HTTRACE(PROT_TRACE, "Ranking.....\n");
	HTTRACE(PROT_TRACE, "RANK QUALITY CONTENT-TYPE         LANGUAGE ENCODING  FILE\n");
	while (cd) {
	    HTTRACE(PROT_TRACE, "%d.   %.4f  %-20.20s %-8.8s %-10.10s %s\n" _
		    cnt++ _
		    cd->quality _
		    cd->content_type ? HTAtom_name(cd->content_type) : "-" _
		    cd->content_language?HTAtom_name(cd->content_language):"-" _
		    cd->content_encoding?HTAtom_name(cd->content_encoding):"-" _
		    cd->filename ? cd->filename :"-");
	    cd = (HTContentDescription *) HTArray_nextObject(variants, data);
	}
    }
#endif /* HTDEBUG */
    return YES;
}

/* PUBLIC						HTSplitFilename()
**
**	Split the filename to an array of suffixes.
**	Return the number of parts placed to the array.
**	Array should have MAX_SUFF+1 items.
*/
PRIVATE int HTSplitFilename (char * s_str, char ** s_arr)
{
    const char *delimiters = HTBind_delimiters();
    char * start = s_str;
    char * end;
    char save;
    int i;

    if (!s_str || !s_arr) return 0;

    for (i=0; i < MAX_SUFF && *start; i++) {
	for(end=start+1; *end && !strchr(delimiters, *end); end++);
	save = *end;
	*end = 0;
	StrAllocCopy(s_arr[i], start);	/* Frees the previous value */
	*end = save;
	start = end;
    }
    HT_FREE(s_arr[i]);       /* Terminating NULL */
    return i;
}


/*
**	Set default file name for welcome page on each directory.
*/
PUBLIC void HTAddWelcome (char * name)
{
    if (name) {
	char * mycopy = NULL;
	StrAllocCopy(mycopy,name);

	if (!welcome_names)
	    welcome_names = HTList_new();
	HTList_addObject(welcome_names, (void*)mycopy);
    }
}


#ifdef HAVE_READDIR

/* PRIVATE						multi_match()
**
**	Check if actual filename (split in parts) fulfills
**	the requirements.
*/
PRIVATE BOOL multi_match (char ** required, int m, char ** actual, int n)
{
    int c;
    int i,j;

#ifdef VMS
    for(c=0;  c<m && c<n && !strcasecomp(required[c], actual[c]);  c++);
#else /* not VMS */
    for(c=0;  c<m && c<n && !strcmp(required[c], actual[c]);  c++);
#endif /* not VMS */

    if (!c) return NO;		/* Names differ rigth from start */

    for(i=c; i<m; i++) {
	BOOL found = NO;
	for(j=c; j<n; j++) {
#ifdef VMS
	    if (!strcasecomp(required[i], actual[j])) {
#else /* not VMS */
	    if (!strcmp(required[i], actual[j])) {
#endif /* not VMS */
		found = YES;
		break;
	    }
	}
	if (!found) return NO;
    }
    return YES;
}


/*
**	Get multi-match possibilities for a given file
**	----------------------------------------------
** On entry:
**	path	absolute path to one file in a directory,
**		may end in .multi.
** On exit:
**	returns	a list of ContentDesription structures
**		describing the mathing files.
**
*/