The Tor Browser: xpcom/glue/nsID.cpp@97036ab72558

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

     1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

     2 /* This Source Code Form is subject to the terms of the Mozilla Public

     3  * License, v. 2.0. If a copy of the MPL was not distributed with this

     4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     6 #include "nsID.h"

     7 #include "prprf.h"

     8 #include "nsMemory.h"

    10 /**

    11  * Multiplies the_int_var with 16 (0x10) and adds the value of the

    12  * hexadecimal digit the_char. If it fails it returns false from

    13  * the function it's used in.

    14  */

    16 #define ADD_HEX_CHAR_TO_INT_OR_RETURN_FALSE(the_char, the_int_var) \

    17     the_int_var = (the_int_var << 4) + the_char; \

    18     if(the_char >= '0' && the_char <= '9') the_int_var -= '0'; \

    19     else if(the_char >= 'a' && the_char <= 'f') the_int_var -= 'a'-10; \

    20     else if(the_char >= 'A' && the_char <= 'F') the_int_var -= 'A'-10; \

    21     else return false

    24 /**

    25  * Parses number_of_chars characters from the char_pointer pointer and

    26  * puts the number in the dest_variable. The pointer is moved to point

    27  * at the first character after the parsed ones. If it fails it returns

    28  * false from the function the macro is used in.

    29  */

    31 #define PARSE_CHARS_TO_NUM(char_pointer, dest_variable, number_of_chars) \

    32   do { int32_t _i=number_of_chars; \

    33   dest_variable = 0; \

    34   while(_i) { \

    35     ADD_HEX_CHAR_TO_INT_OR_RETURN_FALSE(*char_pointer, dest_variable); \

    36     char_pointer++; \

    37     _i--; \

    38   } } while(0)

    41 /**

    42  * Parses a hyphen from the char_pointer string. If there is no hyphen there

    43  * the function returns false from the function it's used in. The

    44  * char_pointer is advanced one step.

    45  */

    47  #define PARSE_HYPHEN(char_pointer)   if(*(char_pointer++) != '-') return false

    49 /*

    50  * Turns a {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx} string into

    51  * an nsID. It can also handle the old format without the { and }.

    52  */

    54 bool nsID::Parse(const char *aIDStr)

    55 {

    56   /* Optimized for speed */

    57   if(!aIDStr) {

    58     return false;

    59   }

    61   bool expectFormat1 = (aIDStr[0] == '{');

    62   if(expectFormat1) aIDStr++;

    64   PARSE_CHARS_TO_NUM(aIDStr, m0, 8);

    65   PARSE_HYPHEN(aIDStr);

    66   PARSE_CHARS_TO_NUM(aIDStr, m1, 4);

    67   PARSE_HYPHEN(aIDStr);

    68   PARSE_CHARS_TO_NUM(aIDStr, m2, 4);

    69   PARSE_HYPHEN(aIDStr);

    70   int i;

    71   for(i=0; i<2; i++)

    72     PARSE_CHARS_TO_NUM(aIDStr, m3[i], 2);

    73   PARSE_HYPHEN(aIDStr);

    74   while(i < 8) {

    75     PARSE_CHARS_TO_NUM(aIDStr, m3[i], 2);

    76     i++;

    77   }

    79   return expectFormat1 ? *aIDStr == '}' : true;

    80 }

    82 #ifndef XPCOM_GLUE_AVOID_NSPR

    84 static const char gIDFormat[] =

    85   "{%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x}";

    87 /*

    88  * Returns an allocated string in {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}

    89  * format. The string is allocated with NS_Alloc and should be freed by

    90  * the caller.

    91  */

    93 char *nsID::ToString() const

    94 {

    95   char *res = (char*)NS_Alloc(NSID_LENGTH);

    97   if (res != nullptr) {

    98     PR_snprintf(res, NSID_LENGTH, gIDFormat,

    99                 m0, (uint32_t) m1, (uint32_t) m2,

   100                 (uint32_t) m3[0], (uint32_t) m3[1], (uint32_t) m3[2],

   101                 (uint32_t) m3[3], (uint32_t) m3[4], (uint32_t) m3[5],

   102                 (uint32_t) m3[6], (uint32_t) m3[7]);

   103   }

   104   return res;

   105 }

   107 void nsID::ToProvidedString(char (&dest)[NSID_LENGTH]) const

   108 {

   109   PR_snprintf(dest, NSID_LENGTH, gIDFormat,

   110               m0, (uint32_t) m1, (uint32_t) m2,

   111               (uint32_t) m3[0], (uint32_t) m3[1], (uint32_t) m3[2],

   112               (uint32_t) m3[3], (uint32_t) m3[4], (uint32_t) m3[5],

   113               (uint32_t) m3[6], (uint32_t) m3[7]);

   114 }

   116 #endif // XPCOM_GLUE_AVOID_NSPR

The Tor Browser / file revision

xpcom/glue/nsID.cpp@97036ab72558

xpcom/glue/nsID.cpp