src/ETag.cc

   1 /*
   2  * Copyright (C) 1996-2020 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #include "squid.h"
  10 #include "ETag.h"
  11
  12 #include <cstring>
  13
  14 /*
  15  * Note: ETag is not an http "field" like, for example HttpHdrRange. ETag is a
  16  * field-value that maybe used in many http fields.
  17  */
  18
  19 /// whether etag strings match
  20 static bool
  21 etagStringsMatch(const ETag &tag1, const ETag &tag2)
  22 {
  23     return !strcmp(tag1.str, tag2.str);
  24 }
  25
  26 /* parses a string as weak or strong entity-tag; returns true on success */
  27 /* note: we do not duplicate "str"! */
  28 int
  29 etagParseInit(ETag * etag, const char *str)
  30 {
  31     int len;
  32     assert(etag && str);
  33     etag->str = NULL;
  34     etag->weak = !strncmp(str, "W/", 2);
  35
  36     if (etag->weak)
  37         str += 2;
  38
  39     /* check format (quoted-string) */
  40     len = strlen(str);
  41
  42     if (len >= 2 && str[0] == '"' && str[len - 1] == '"')
  43         etag->str = str;
  44
  45     return etag->str != NULL;
  46 }
  47
  48 bool
  49 etagIsStrongEqual(const ETag &tag1, const ETag &tag2)
  50 {
  51     return !tag1.weak && !tag2.weak && etagStringsMatch(tag1, tag2);
  52 }
  53
  54 bool
  55 etagIsWeakEqual(const ETag &tag1, const ETag &tag2)
  56 {
  57     return etagStringsMatch(tag1, tag2);
  58 }
  59