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echoping/SRC/HTParse.c
Stephane Bortzmeyer 40d676b534 Initial revision
2000-04-13 09:19:23 +00:00

720 lines
17 KiB
C
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/* Parse HyperText Document Address HTParse.c
** ================================
*/
#include "HTParse.h"
#define TRACE 0
#define FREE(x) if (x) {free(x); x = NULL;}
struct struct_parts
{
char *access;
char *host;
char *absolute;
char *relative;
/* char * search; no - treated as part of path */
char *anchor;
};
/* Strings of any length
** ---------------------
*/
PUBLIC int strcasecomp
ARGS2 (
CONST char *, a,
CONST char *, b)
{
CONST char *p = a;
CONST char *q = b;
for (p = a, q = b; *p && *q; p++, q++)
{
int diff = TOLOWER (*p) - TOLOWER (*q);
if (diff)
return diff;
}
if (*p)
return 1; /* p was longer than q */
if (*q)
return -1; /* p was shorter than q */
return 0; /* Exact match */
}
/* With count limit
** ----------------
*/
PUBLIC int strncasecomp
ARGS3 (
CONST char *, a,
CONST char *, b,
int, n)
{
CONST char *p = a;
CONST char *q = b;
for (p = a, q = b;;
p++, q++)
{
int diff;
if (p == (a + n))
return 0; /* Match up to n characters */
if (!(*p && *q))
return (*p - *q);
diff = TOLOWER (*p) - TOLOWER (*q);
if (diff)
return diff;
}
/*NOTREACHED */
}
/* Allocate a new copy of a string, and returns it
*/
PUBLIC char *HTSACopy
ARGS2 (
char **, dest,
CONST char *, src)
{
FREE (*dest);
if (src)
{
*dest = (char *) malloc (strlen (src) + 1);
if (*dest == NULL)
outofmem (__FILE__, "HTSACopy");
strcpy (*dest, src);
}
return *dest;
}
/* String Allocate and Concatenate
*/
PUBLIC char *HTSACat
ARGS2 (
char **, dest,
CONST char *, src)
{
if (src && *src)
{
if (*dest)
{
int length = strlen (*dest);
*dest = (char *) realloc (*dest, length + strlen (src) + 1);
if (*dest == NULL)
outofmem (__FILE__, "HTSACat");
strcpy (*dest + length, src);
}
else
{
*dest = (char *) malloc (strlen (src) + 1);
if (*dest == NULL)
outofmem (__FILE__, "HTSACat");
strcpy (*dest, src);
}
}
return *dest;
}
/* 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 consituents. 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;
/* int length = strlen (name); */
parts->access = NULL;
parts->host = NULL;
parts->absolute = NULL;
parts->relative = NULL;
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;
}
#ifdef NOTDEFINED
for (p = (name + length - 1); p >= name; p--)
{
#endif /* NOTDEFINED */
/*
** 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 */
}
}
/*
** 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
{
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)
{
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#36487@foo.bar,
* or it's an nntp or snews URL, or news URL with a host.
* Restore the '#' in the address.
*/
*(parts->anchor - 1) = '#';
parts->anchor = NULL;
}
}
#ifdef NOT_DEFINED /* search is just treated as part of path */
{
char *p = (relative ? relative : absolute);
if (p != NULL)
{
char *q = strchr (p, '?'); /* Any search string? */
if (q != NULL)
{
*q = '\0'; /* If so, chop that off. */
parts->search = (q + 1);
}
}
}
#endif /* NOT_DEFINED */
} /*scan */
/* 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 *return_value = NULL;
int len;
char *name = NULL;
char *rel = NULL;
char *p;
char *access;
struct struct_parts given, related;
if (TRACE)
fprintf (stderr,
"HTParse: aName:%s relatedName:%s\n", aName, relatedName);
/*
** Allocate the output string.
*/
len = strlen (aName) + strlen (relatedName) + 10;
result = (char *) malloc (len); /* Lots of space: more than enough */
if (result == NULL)
outofmem (__FILE__, "HTParse");
result[0] = '\0'; /* Clear string */
/*
** Make working copies of the input strings to cut up.
*/
StrAllocCopy (name, aName);
StrAllocCopy (rel, relatedName);
/*
** Cut up the strings into URL fields.
*/
scan (name, &given);
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 = "";
}
access = given.access ? given.access : related.access;
if (wanted & PARSE_ACCESS)
{
if (access)
{
strcat (result, access);
if (wanted & PARSE_PUNCTUATION)
strcat (result, ":");
}
}
/*
** 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 strncasecomp() 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.anchor = NULL;
}
/*
** Handle the host field.
*/
if (wanted & PARSE_HOST)
if (given.host || related.host)
{
char *tail = result + strlen (result);
if (wanted & PARSE_PUNCTUATION)
strcat (result, "//");
strcat (result, 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.
*/
{
char *p, *h;
p = strchr (tail, ':');
if (p != NULL && !isdigit ((unsigned char) p[1]))
/*
** Colon not followed by a port number.
*/
*p = '\0';
if (p != NULL && p != '\0' && access != NULL)
{
/*
** Port specified.
*/
if ((!strcmp (access, "http") && !strcmp (p, ":80")) ||
(!strcmp (access, "gopher") && !strcmp (p, ":70")) ||
(!strcmp (access, "ftp") && !strcmp (p, ":21")) ||
(!strcmp (access, "wais") && !strcmp (p, ":210")) ||
(!strcmp (access, "nntp") && !strcmp (p, ":119")) ||
(!strcmp (access, "news") && !strcmp (p, ":119")) ||
(!strcmp (access, "snews") && !strcmp (p, ":563")) ||
(!strcmp (access, "finger") && !strcmp (p, ":79")) ||
(!strcmp (access, "cso") && !strcmp (p, ":105")))
*p = '\0'; /* It is the default: ignore it */
}
if (p == NULL)
{
int len = strlen (tail);
if (len > 0)
{
h = tail + len - 1; /* last char of hostname */
if (*h == '.')
*h = '\0'; /* chop final . */
}
}
else
{
h = p;
h--; /* End of hostname */
if (*h == '.')
{
/*
** Slide p over h.
*/
while (*p != '\0')
*h++ = *p++;
*h = '\0'; /* terminate */
}
}
}
#endif /* CLEAN_URLS */
}
/*
** If different hosts, inherit no path.
*/
if (given.host && related.host)
if (strcmp (given.host, related.host) != 0)
{
related.absolute = NULL;
related.relative = NULL;
related.anchor = NULL;
}
/*
** Handle the path.
*/
if (wanted & PARSE_PATH)
{
if (access && !given.absolute && given.relative)
{
if (!strcasecomp (access, "nntp") ||
!strcasecomp (access, "snews") ||
(!strcasecomp (access, "news") &&
!strncasecomp (result, "news://", 7)))
{
/*
* Treat all given nntp or snews paths,
* or given paths for news URLs with a host,
* as absolute.
*/
given.absolute = given.relative;
given.relative = NULL;
}
}
if (given.absolute)
{ /* All is given */
if (wanted & PARSE_PUNCTUATION)
strcat (result, "/");
strcat (result, given.absolute);
if (TRACE)
fprintf (stderr, "1\n");
}
else if (related.absolute)
{ /* Adopt path not name */
strcat (result, "/");
strcat (result, related.absolute);
if (given.relative)
{
p = strchr (result, '?'); /* Search part? */
if (p == NULL)
p = (result + strlen (result) - 1);
for (; *p != '/'; p--)
; /* last / */
p[1] = '\0'; /* Remove filename */
strcat (result, given.relative); /* Add given one */
HTSimplify (result);
}
if (TRACE)
fprintf (stderr, "2\n");
}
else if (given.relative)
{
strcat (result, given.relative); /* what we've got */
if (TRACE)
fprintf (stderr, "3\n");
}
else if (related.relative)
{
strcat (result, related.relative);
if (TRACE)
fprintf (stderr, "4\n");
}
else
{ /* No inheritance */
if (strncasecomp (aName, "lynxcgi:", 8) &&
strncasecomp (aName, "lynxexec:", 9) &&
strncasecomp (aName, "lynxprog:", 9))
{
strcat (result, "/");
}
if (!strcmp (result, "news:/"))
result[5] = '*';
if (TRACE)
fprintf (stderr, "5\n");
}
}
/*
** Handle the fragment (anchor).
*/
if (wanted & PARSE_ANCHOR)
if ((given.anchor && *given.anchor) ||
(!given.anchor && related.anchor))
{
if (wanted & PARSE_PUNCTUATION)
strcat (result, "#");
strcat (result, (given.anchor) ?
given.anchor : related.anchor);
}
if (TRACE)
fprintf (stderr, "HTParse: result:%s\n", result);
FREE (rel);
FREE (name);
StrAllocCopy (return_value, result);
FREE (result);
return return_value; /* exactly the right length */
}
/* Simplify a filename. HTSimplify()
** --------------------
**
** A unix-style file is allowed to contain the seqeunce xxx/../ which may
** be replaced by "" , and the seqeunce "/./" which may be replaced by "/".
** Simplification helps us recognize duplicate filenames.
**
** Thus, /etc/junk/../fred becomes /etc/fred
** /etc/junk/./fred becomes /etc/junk/fred
**
** but we should NOT change
** http://fred.xxx.edu/../..
**
** or ../../albert.html
*/
PUBLIC void HTSimplify ARGS1 (
char *, filename)
{
char *p;
char *q, *q1;
if (filename == NULL)
return;
if ((filename[0] && filename[1]) && strchr (filename, '/') != NULL)
{
for (p = (filename + 2); *p; p++)
{
if (*p == '/')
{
if ((p[1] == '.') && (p[2] == '.') &&
(p[3] == '/' || p[3] == '\0'))
{
/*
** Handle "/../" or "/..".
*/
for (q = (p - 1); (q >= filename) && (*q != '/'); q--)
/*
** Back up to previous slash or beginning of string.
*/
;
if ((q[0] == '/') && strncmp (q, "/../", 4) &&
!((q - 1) > filename && q[-1] == '/'))
{
/*
** Not at beginning of string or in a
** host field, so remove the "/xxx/..".
*/
q1 = (p + 3);
p = q;
while (*q1 != '\0')
*p++ = *q1++;
*p = '\0'; /* terminate */
#ifdef NOTDEFINED
/*
** Make sure filename has at least one slash.
*/
if (*filename == '\0')
{
*filename = '/';
*(filename + 1) = '\0';
}
#endif /* NOTDEFINED */
/*
** Start again with previous slash.
*/
p = (q - 1);
}
}
else if (p[1] == '.' && p[2] == '/')
{
/*
** Handle "./" by removing the characters.
*/
q = p;
q1 = (p + 2);
while (*q1 != '\0')
*q++ = *q1++;
*q = '\0'; /* terminate */
p--;
}
else if (p[1] == '.' && p[2] == '\0')
{
/*
** Handle terminal "." by removing the character.
*/
p[1] = '\0';
}
}
}
}
}
/* Make Relative Name. HTRelative()
** -------------------
**
** This function creates and returns a string which gives an expression of
** one address as related to another. Where there is no relation, an absolute
** address is retured.
**
** On entry,
** Both names must be absolute, fully qualified names of nodes
** (no anchor bits)
**
** On exit,
** The return result points to a newly allocated name which, if
** parsed by HTParse relative to relatedName, will yield aName.
** The caller is responsible for freeing the resulting name later.
**
*/
PUBLIC char *HTRelative ARGS2 (
CONST char *, aName,
CONST char *, relatedName)
{
char *result = NULL;
CONST char *p = aName;
CONST char *q = relatedName;
CONST char *after_access = NULL;
CONST char *path = NULL;
CONST char *last_slash = NULL;
int slashes = 0;
for (; *p; p++, q++)
{ /* Find extent of match */
if (*p != *q)
break;
if (*p == ':')
after_access = p + 1;
if (*p == '/')
{
last_slash = p;
slashes++;
if (slashes == 3)
path = p;
}
}
/* q, p point to the first non-matching character or zero */
if (!after_access)
{ /* Different access */
StrAllocCopy (result, aName);
}
else if (slashes < 3)
{ /* Different nodes */
StrAllocCopy (result, after_access);
}
else if (slashes == 3)
{ /* Same node, different path */
StrAllocCopy (result, path);
}
else
{ /* Some path in common */
int levels = 0;
for (; *q && (*q != '#'); q++)
if (*q == '/')
levels++;
result = (char *) malloc (3 * levels + strlen (last_slash) + 1);
if (result == NULL)
outofmem (__FILE__, "HTRelative");
result[0] = '\0';
for (; levels; levels--)
strcat (result, "../");
strcat (result, last_slash + 1);
}
if (TRACE)
fprintf (stderr, "HT: `%s' expressed relative to\n `%s' is\n `%s'.",
aName, relatedName, result);
return result;
}
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