htparse.c

elinks下lynx是最重要的二个文本浏览器, 在linux下非常实用, lynx比elinks早的多, 目前好像停止开发, 这是lynx源代码

/*		Parse HyperText Document Address		HTParse.c
**		================================
*/

#include <HTUtils.h>
#include <HTParse.h>

#include <LYUtils.h>
#include <LYLeaks.h>
#include <LYStrings.h>
#include <LYCharUtils.h>

#ifdef HAVE_ALLOCA_H
#include <alloca.h>
#else
#ifdef __MINGW32__
#include <malloc.h>
#endif /* __MINGW32__ */
#endif

#define HEX_ESCAPE '%'

struct struct_parts {
	char * access;
	char * host;
	char * absolute;
	char * relative;
	char * search;		/* treated normally as part of path */
	char * anchor;
};


/*	Strip white space off a string.				HTStrip()
**	-------------------------------
**
** On exit,
**	Return value points to first non-white character, or to 0 if none.
**	All trailing white space is OVERWRITTEN with zero.
*/
PUBLIC char * HTStrip ARGS1(
	char *,		s)
{
#define SPACE(c) ((c == ' ') || (c == '\t') || (c == '\n'))
    char * p = s;
    for (p = s; *p; p++)
	;			/* Find end of string */
    for (p--; p >= s; p--) {
	if (SPACE(*p))
	    *p = '\0';		/* Zap trailing blanks */
	else
	    break;
    }
    while (SPACE(*s))
	s++;			/* Strip leading blanks */
    return s;
}

/*	Scan a filename for its constituents.			scan()
**	-------------------------------------
**
** On entry,
**	name	points to a document name which may be incomplete.
** On exit,
**	absolute or relative may be nonzero (but not both).
**	host, anchor and access may be nonzero if they were specified.
**	Any which are nonzero point to zero terminated strings.
*/
PRIVATE void scan ARGS2(
	char *,			name,
	struct struct_parts *,	parts)
{
    char * after_access;
    char * p;

    parts->access = NULL;
    parts->host = NULL;
    parts->absolute = NULL;
    parts->relative = NULL;
    parts->search = NULL;	/* normally not used - kw */
    parts->anchor = NULL;

    /*
    **	Scan left-to-right for a scheme (access).
    */
    after_access = name;
    for (p = name; *p; p++) {
	if (*p==':') {
	    *p = '\0';
	    parts->access = name;	/* Access name has been specified */
	    after_access = (p + 1);
	    break;
	}
	if (*p == '/' || *p == '#' || *p == ';' || *p == '?')
	    break;
    }

    /*
    **	Scan left-to-right for a fragment (anchor).
    */
    for (p = after_access; *p; p++) {
	if (*p =='#') {
	    parts->anchor = (p + 1);
	    *p = '\0';			/* terminate the rest */
	    break;		/* leave things after first # alone - kw */
	}
    }

    /*
    **	Scan left-to-right for a host or absolute path.
    */
    p = after_access;
    if (*p == '/') {
	if (p[1] == '/') {
	    parts->host = (p + 2);	  /* host has been specified	*/
	    *p = '\0';			  /* Terminate access		*/
	    p = strchr(parts->host, '/'); /* look for end of host name if any */
	    if (p != NULL) {
		*p = '\0';			/* Terminate host */
		parts->absolute = (p + 1);	/* Root has been found */
	    } else {
		p = strchr(parts->host, '?');
		if (p != NULL) {
		    *p = '\0';			/* Terminate host */
		    parts->search = (p + 1);
		}
	    }
	} else {
	    parts->absolute = (p + 1);		/* Root found but no host */
	}
    } else {
	parts->relative = (*after_access) ?
			     after_access : NULL; /* NULL for "" */
    }

    /*
    **	Check schemes that commonly have unescaped hashes.
    */
    if (parts->access && parts->anchor &&
		/* optimize */ strchr("lnsdLNSD", *parts->access) != NULL) {
	if ((!parts->host && strcasecomp(parts->access, "lynxcgi")) ||
	    !strcasecomp(parts->access, "nntp") ||
	    !strcasecomp(parts->access, "snews") ||
	    !strcasecomp(parts->access, "news") ||
	    !strcasecomp(parts->access, "data")) {
	    /*
	     *	Access specified but no host and not a lynxcgi URL, so the
	     *	anchor may not really be one, e.g., news:j462#[e-mail],
	     *	or it's an nntp or snews URL, or news URL with a host.
	     *	Restore the '#' in the address.
	     */
	    /* but only if we have found a path component of which this will
	     * become part. - kw  */
	    if (parts->relative || parts->absolute) {
		*(parts->anchor - 1) = '#';
		parts->anchor = NULL;
	    }
	}
    }
} /*scan */

#if defined(HAVE_ALLOCA) && !defined(LY_FIND_LEAKS)
#define LYalloca(x)        alloca(x)
#define LYalloca_free(x)   {}
#else
#define LYalloca(x)        malloc(x)
#define LYalloca_free(x)   free(x)
#endif

/*	Parse a Name relative to another name.			HTParse()
**	--------------------------------------
**
**	This returns those parts of a name which are given (and requested)
**	substituting bits from the related name where necessary.
**
** On entry,
**	aName		A filename given
**	relatedName	A name relative to which aName is to be parsed
**	wanted		A mask for the bits which are wanted.
**
** On exit,
**     returns         A pointer to a malloc'd string which MUST BE FREED
*/
PUBLIC char * HTParse ARGS3(
	CONST char *,	aName,
	CONST char *,	relatedName,
	int,		wanted)
{
    char * result = NULL;
    char * tail = NULL;  /* a pointer to the end of the 'result' string */
    char * return_value = NULL;
    int len, len1, len2;
    char * name = NULL;
    char * rel = NULL;
    char * p;
    char * acc_method;
    struct struct_parts given, related;

    CTRACE((tfp, "HTParse: aName:`%s'\n", aName));
    CTRACE((tfp, "   relatedName:`%s'\n", relatedName));

    if (wanted & (PARSE_STRICTPATH | PARSE_QUERY)) { /* if detail wanted... */
	if ((wanted & (PARSE_STRICTPATH | PARSE_QUERY))
	    == (PARSE_STRICTPATH | PARSE_QUERY)) /* if strictpath AND query */
	    wanted |= PARSE_PATH; /* then treat as if PARSE_PATH wanted */
	if (wanted & PARSE_PATH) /* if PARSE_PATH wanted */
	    wanted &= ~(PARSE_STRICTPATH | PARSE_QUERY); /* ignore details */
    }
    CTRACE((tfp, "   want:%s%s%s%s%s%s%s\n",
	    wanted & PARSE_PUNCTUATION ? " punc"   : "",
	    wanted & PARSE_ANCHOR      ? " anchor" : "",
	    wanted & PARSE_PATH        ? " path"   : "",
	    wanted & PARSE_HOST        ? " host"   : "",
	    wanted & PARSE_ACCESS      ? " access" : "",
	    wanted & PARSE_STRICTPATH  ? " PATH"   : "",
	    wanted & PARSE_QUERY       ? " QUERY"  : ""));

    /*
    ** Allocate the temporary string. Optimized.
    */
    len1 = strlen(aName) + 1;
    len2 = strlen(relatedName) + 1;
    len = len1 + len2 + 8;     /* Lots of space: more than enough */

    result = tail = (char*)LYalloca(len * 2 + len1 + len2);
    if (result == NULL) {
	outofmem(__FILE__, "HTParse");
    }
    *result = '\0';
    name = result + len;
    rel = name + len1;

    /*
    **	Make working copy of the input string to cut up.
    */
    memcpy(name, aName, len1);

    /*
    **	Cut up the string into URL fields.
    */
    scan(name, &given);

    /*
    **	Now related string.
    */
    if ((given.access && given.host && given.absolute) || !*relatedName) {
	/*
	**  Inherit nothing!
	*/
	related.access = NULL;
	related.host = NULL;
	related.absolute = NULL;
	related.relative = NULL;
	related.search = NULL;
	related.anchor = NULL;
    } else {
	memcpy(rel, relatedName, len2);
	scan(rel,  &related);
    }


    /*
    **	Handle the scheme (access) field.
    */
    if (given.access && given.host && !given.relative && !given.absolute) {
	if (!strcmp(given.access, "http") ||
	    !strcmp(given.access, "https") ||
	    !strcmp(given.access, "ftp"))
	    /*
	    **	Assume root.
	    */
	    given.absolute = "";
    }
    acc_method = given.access ? given.access : related.access;
    if (wanted & PARSE_ACCESS) {
	if (acc_method) {
	    strcpy(tail, acc_method);
	    tail += strlen(tail);
	    if (wanted & PARSE_PUNCTUATION) {
		*tail++ = ':';
		*tail = '\0';
	    }
	}
    }

    /*
    **	If different schemes, inherit nothing.
    **
    **	We'll try complying with RFC 1808 and
    **	the Fielding draft, and inherit nothing
    **	if both schemes are given, rather than
    **	only when they differ, except for
    **	file URLs - FM
    **
    **	After trying it for a while, it's still
    **	premature, IHMO, to go along with it, so
    **	this is back to inheriting for identical
    **	schemes whether or not they are "file".
    **	If you want to try it again yourself,
    **	uncomment the strcasecomp() below. - FM
    */
    if ((given.access && related.access) &&
	(/* strcasecomp(given.access, "file") || */
	 strcmp(given.access, related.access))) {
	related.host = NULL;
	related.absolute = NULL;
	related.relative = NULL;
	related.search = NULL;
	related.anchor = NULL;
    }

    /*
    **	Handle the host field.
    */
    if (wanted & PARSE_HOST) {
	if (given.host || related.host) {
	    if (wanted & PARSE_PUNCTUATION) {
		*tail++ = '/';
		*tail++ = '/';
	    }
	    strcpy(tail, given.host ? given.host : related.host);
#define CLEAN_URLS
#ifdef CLEAN_URLS
	    /*
	    **	Ignore default port numbers, and trailing dots on FQDNs,
	    **	which will only cause identical addresses to look different.
	    **  (related is already a clean url).
	    */
	    {
		char *p2, *h;
		if ((p2 = strchr(result, '@')) != NULL)
		   tail = (p2 + 1);
		p2 = strchr(tail, ':');
		if (p2 != NULL && !isdigit(UCH(p2[1])))
		    /*
		    **	Colon not followed by a port number.
		    */
		    *p2 = '\0';
		if (p2 != NULL && *p2 != '\0' && acc_method != NULL) {
		    /*
		    **	Port specified.
		    */
		    if ((!strcmp(acc_method, "http"	 ) && !strcmp(p2, ":80" )) ||
			(!strcmp(acc_method, "https"	 ) && !strcmp(p2, ":443")) ||
			(!strcmp(acc_method, "gopher"	 ) && !strcmp(p2, ":70" )) ||
			(!strcmp(acc_method, "ftp"	 ) && !strcmp(p2, ":21" )) ||
			(!strcmp(acc_method, "wais"	 ) && !strcmp(p2, ":210")) ||
			(!strcmp(acc_method, "nntp"	 ) && !strcmp(p2, ":119")) ||
			(!strcmp(acc_method, "news"	 ) && !strcmp(p2, ":119")) ||
			(!strcmp(acc_method, "newspost"  ) && !strcmp(p2, ":119")) ||
			(!strcmp(acc_method, "newsreply" ) && !strcmp(p2, ":119")) ||
			(!strcmp(acc_method, "snews"	 ) && !strcmp(p2, ":563")) ||
			(!strcmp(acc_method, "snewspost" ) && !strcmp(p2, ":563")) ||
			(!strcmp(acc_method, "snewsreply") && !strcmp(p2, ":563")) ||
			(!strcmp(acc_method, "finger"	 ) && !strcmp(p2, ":79" )) ||
			(!strcmp(acc_method, "telnet"	 ) && !strcmp(p2, ":23" )) ||
			(!strcmp(acc_method, "tn3270"	 ) && !strcmp(p2, ":23" )) ||
			(!strcmp(acc_method, "rlogin"	 ) && !strcmp(p2, ":513")) ||
			(!strcmp(acc_method, "cso"	 ) && !strcmp(p2, ":105")))
		    *p2 = '\0'; /* It is the default: ignore it */
		}
		if (p2 == NULL) {
		    int len3 = strlen(tail);

		    if (len3 > 0) {
			h = tail + len3 - 1;	/* last char of hostname */
			if (*h == '.')
			    *h = '\0';		/* chop final . */
		    }
		} else if (p2 != result) {
		    h = p2;
		    h--;		/* End of hostname */
		    if (*h == '.') {
			/*
			**  Slide p2 over h.
			*/
			while (*p2 != '\0')
			    *h++ = *p2++;
			*h = '\0';	/* terminate */