rid = db_int(0, "SELECT rid FROM vcache"
                  " WHERE vid=%d AND fname=%Q", vid, zName);
  if( rid && content_get(rid, pContent)==0 ){
    rid = 0;
  }
  return rid;
}

/*
** Check to verify that z[i] is contained within HTML markup.
**
** This works by looking backwards in the string for the most recent
** '<' or '>' character.  If a '<' is found first, then we assume that
** z[i] is within markup.  If a '>' is seen or neither character is seen,
** then z[i] is not within markup.
*/
static int isWithinHtmlMarkup(const char *z, int i){
  while( i>=0 && z[i]!='>' && z[i]!='<' ){ i--; }
  return z[i]=='<';
}

/*
** Check to see if z[i] is contained within an href='...' of markup.
*/
static int isWithinHref(const char *z, int i){
  while( i>5
     && !fossil_isspace(z[i])
     && z[i]!='\'' && z[i]!='"'
     && z[i]!='>'
  ){ i--; }
  if( i<=6 ) return 0;
  if( z[i]!='\'' && z[i]!='\"' ) return 0;
  if( strncmp(&z[i-5],"href=",5)!=0 ) return 0;
  if( !fossil_isspace(z[i-6]) ) return 0;
  return 1;
}

/*
** Transfer content to the output.  During the transfer, when text of
** the following form is seen:
**
**       href="$ROOT/
**       action="$ROOT/

  for(base=0, i=7; i<n; i++){
    if( z[i]=='$'
     && strncmp(&z[i],"$ROOT/", 6)==0
     && (z[i-1]=='\'' || z[i-1]=='"')
     && i-base>=9
     && ((fossil_strnicmp(&z[i-6],"href=",5)==0 && fossil_isspace(z[i-7])) ||
         (fossil_strnicmp(&z[i-8],"action=",7)==0 && fossil_isspace(z[i-9])) )
     && isWithinHtmlMarkup(z, i-6)
    ){
      blob_append(cgi_output_blob(), &z[base], i-base);
      blob_appendf(cgi_output_blob(), "%R");
      base = i+5;
    }else
    if( z[i]=='$'
     && strncmp(&z[i-5],"/doc/$SELF/", 11)==0
     && isWithinHref(z,i-5)
     && isWithinHtmlMarkup(z, i-5)
     && strncmp(g.zPath, "doc/",4)==0
    ){
      int j;
      for(j=4; g.zPath[j] && g.zPath[j]!='/'; j++){}
      blob_append(cgi_output_blob(), &z[base], i-base);
      blob_appendf(cgi_output_blob(), "%.*s", j-4, g.zPath+4);
      base = i+5;
    }
  }
  blob_append(cgi_output_blob(), &z[base], i-base);
}

/*
** Render a document as the reply to the HTTP request.  The body

# Markdown Link-test

This document exist solely as a test for some of the hyperlinking
capabilities of Markdown as implemented by Fossil.

## Relative-Path Links

  *   The index: [](../index.wiki)

  *   Load management: [](../loadmgmt.md)

  *   Site-map:  [](../../../../sitemap)

  *   Windows CGI: [](../server/windows/cgi.md)

## The Magic $ROOT Path Prefix

In text of the form `href="$ROOT/..."` in the HTML that markdown
generates, the $ROOT is replaced by the complete URI for the root 
of the document tree.
Note that the $ROOT translation only occurs within the `<a href="...">`
element, not within the text of the hyperlink.  So you should see the
$ROOT text on this page, but if you mouse-over the hyperlink the $ROOT
value should have been expanded to the actual document root.

  *   Timeline: []($ROOT/timeline)

  *   Site-map:  []($ROOT/sitemap)

The $ROOT prefix on markdown links is superfluous.  The same link
works without the $ROOT prefix.  (Though: the $ROOT prefix is required
for HTML documents.)

  *   Timeline:  [](/timeline)

  *   Help: [](/help?cmd=help)

  *   Site-map:  [](/sitemap)

## The Magic $SELF Document Version Translation

In URI text of the form `.../doc/$SELF/...` the
$SELF value is converted to the version number of the document
currently being displayed.  This conversion happens after translation
into HTML and only occurs on href='...' attributes so it does not occur
for plain text.

  *   Document index:  [](/doc/$SELF/www/index.wiki)

Both the $ROOT and the $SELF conversions can occur on the same link.

  *   Document index:  []($ROOT/doc/$SELF/www/index.wiki)

The translations must be contained within HTML markup in order to work.
They do not work for ordinary text that appears to be an href= attribute.

  *   `x href='$ROOT/timeline'`
  *   `x action="$ROOT/whatever"`
  *   `x href="https://some-other-site.com/doc/$SELF/tail"`