libextractor

man_extractor.c (7055B)

---

 /*
      This file is part of libextractor.
      Copyright (C) 2002, 2003, 2004, 2009, 2012 Vidyut Samanta and Christian Grothoff
 
      libextractor is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published
      by the Free Software Foundation; either version 3, or (at your
      option) any later version.
 
      libextractor is distributed in the hope that it will be useful, but
      WITHOUT ANY WARRANTY; without even the implied warranty of
      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      General Public License for more details.
 
      You should have received a copy of the GNU General Public License
      along with libextractor; see the file COPYING.  If not, write to the
      Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
      Boston, MA 02110-1301, USA.
  */
 /**
  * @file plugins/man_extractor.c
  * @brief plugin to support man pages
  * @author Christian Grothoff
  */
 #include "platform.h"
 #include "extractor.h"
 #include <ctype.h>
 
 
 /**
  * Create string from first 'n' characters of 'str'.  See 'strndup'.
  *
  * @param str input string
  * @param n desired output length (plus 0-termination)
  * @return copy of first 'n' bytes from 'str' plus 0-terminator, NULL on error
  */
 static char *
 stndup (const char *str, size_t n)
 {
   char *tmp;
 
   if (NULL == (tmp = malloc (n + 1)))
     return NULL;
   tmp[n] = '\0';
   memcpy (tmp, str, n);
   return tmp;
 }
 
 
 /**
  * Give a metadata item to LE.  Removes double-quotes and
  * makes sure we don't pass empty strings or NULL pointers.
  *
  * @param type metadata type to use
  * @param keyword metadata value; freed in the process
  * @param proc function to call with meta data
  * @param proc_cls closure for 'proc'
  * @return 0 to continue extracting, 1 if we are done
  */
 static int
 add_keyword (enum EXTRACTOR_MetaType type,
              char *keyword,
              EXTRACTOR_MetaDataProcessor proc,
              void *proc_cls)
 {
   int ret;
   char *value;
 
   if (NULL == keyword)
     return 0;
   if ( (keyword[0] == '\"') &&
        (keyword[strlen (keyword) - 1] == '\"') )
   {
     keyword[strlen (keyword) - 1] = '\0';
     value = &keyword[1];
   }
   else
     value = keyword;
   if (0 == strlen (value))
   {
     free (keyword);
     return 0;
   }
   ret = proc (proc_cls,
               "man",
               type,
               EXTRACTOR_METAFORMAT_UTF8,
               "text/plain",
               value,
               strlen (value) + 1);
   free (keyword);
   return ret;
 }
 
 
 /**
  * Find the end of the current token (which may be quoted).
  *
  * @param end beginning of the current token, updated to its end; set to size + 1 if the token does not end properly
  * @param buf input buffer with the characters
  * @param size number of bytes in buf
  */
 static void
 find_end_of_token (size_t *end,
                    const char *buf,
                    const size_t size)
 {
   int quot;
 
   quot = 0;
   while ( (*end < size) &&
           ( (0 != (quot & 1)) ||
             ((' ' != buf[*end])) ) )
   {
     if ('\"' == buf[*end])
       quot++;
     (*end)++;
   }
   if (1 == (quot & 1))
     (*end) = size + 1;
 }
 
 
 /**
  * How many bytes do we actually try to scan? (from the beginning
  * of the file).
  */
 #define MAX_READ (16 * 1024)
 
 
 /**
  * Add a keyword to LE.
  *
  * @param t type to use
  * @param s keyword to give to LE
  */
 #define ADD(t,s) do { if (0 != add_keyword (t, s, ec->proc, ec->cls)) return; \
 } while (0)
 
 
 /**
  * Main entry method for the man page extraction plugin.
  *
  * @param ec extraction context provided to the plugin
  */
 void
 EXTRACTOR_man_extract_method (struct EXTRACTOR_ExtractContext *ec)
 {
   const size_t xlen = strlen (".TH ");
   size_t pos;
   size_t xsize;
   size_t end;
   void *data;
   ssize_t size;
   char *buf;
 
   if (0 >= (size = ec->read (ec->cls, &data, MAX_READ)))
     return;
   buf = data;
   pos = 0;
   if (size < xlen)
     return;
   /* find actual beginning of the man page (.TH);
      abort if we find non-printable characters */
   while ( (pos < size - xlen) &&
           ( (0 != strncmp (".TH ",
                            &buf[pos],
                            xlen)) ||
             ( (0 != pos) &&
               (buf[pos - 1] != '\n') ) ) )
   {
     if ( (! isgraph ((unsigned char) buf[pos])) &&
          (! isspace ((unsigned char) buf[pos])) )
       return;
     pos++;
   }
   if (0 != strncmp (".TH ", &buf[pos], xlen))
     return;
 
   /* find end of ".TH"-line */
   xsize = pos;
   while ( (xsize < size) && ('\n' != buf[xsize]) )
     xsize++;
   /* limit processing to ".TH" line */
   size = xsize;
 
   /* skip over ".TH" */
   pos += xlen;
 
   /* first token is the title */
   end = pos;
   find_end_of_token (&end, buf, size);
   if (end > size)
     return;
   if (end > pos)
   {
     ADD (EXTRACTOR_METATYPE_TITLE, stndup (&buf[pos], end - pos));
     pos = end + 1;
   }
   if (pos >= size)
     return;
 
   /* next token is the section */
   end = pos;
   find_end_of_token (&end, buf, size);
   if (end > size)
     return;
   if ('\"' == buf[pos])
     pos++;
   if ((end - pos >= 1) && (end - pos <= 4))
   {
     switch (buf[pos])
     {
     case '1':
       ADD (EXTRACTOR_METATYPE_SECTION,
            strdup (_ ("Commands")));
       break;
     case '2':
       ADD (EXTRACTOR_METATYPE_SECTION,
            strdup (_ ("System calls")));
       break;
     case '3':
       ADD (EXTRACTOR_METATYPE_SECTION,
            strdup (_ ("Library calls")));
       break;
     case '4':
       ADD (EXTRACTOR_METATYPE_SECTION,
            strdup (_ ("Special files")));
       break;
     case '5':
       ADD (EXTRACTOR_METATYPE_SECTION,
            strdup (_ ("File formats and conventions")));
       break;
     case '6':
       ADD (EXTRACTOR_METATYPE_SECTION,
            strdup (_ ("Games")));
       break;
     case '7':
       ADD (EXTRACTOR_METATYPE_SECTION,
            strdup (_ ("Conventions and miscellaneous")));
       break;
     case '8':
       ADD (EXTRACTOR_METATYPE_SECTION,
            strdup (_ ("System management commands")));
       break;
     case '9':
       ADD (EXTRACTOR_METATYPE_SECTION,
            strdup (_ ("Kernel routines")));
       break;
     default:
       ADD (EXTRACTOR_METATYPE_SECTION,
            stndup (&buf[pos], 1));
     }
     pos = end + 1;
   }
   end = pos;
 
   /* next token is the modification date */
   find_end_of_token (&end, buf, size);
   if (end > size)
     return;
   if (end > pos)
   {
     ADD (EXTRACTOR_METATYPE_MODIFICATION_DATE, stndup (&buf[pos], end - pos));
     pos = end + 1;
   }
 
   /* next token is the source of the man page */
   end = pos;
   find_end_of_token (&end, buf, size);
   if (end > size)
     return;
   if (end > pos)
   {
     ADD (EXTRACTOR_METATYPE_SOURCE,
          stndup (&buf[pos], end - pos));
     pos = end + 1;
   }
 
   /* last token is the title of the book the man page belongs to */
   end = pos;
   find_end_of_token (&end, buf, size);
   if (end > size)
     return;
   if (end > pos)
   {
     ADD (EXTRACTOR_METATYPE_BOOK_TITLE,
          stndup (&buf[pos], end - pos));
     pos = end + 1;
   }
 }
 
 
 /* end of man_extractor.c */