The Tor Browser: security/sandbox/chromium/base/strings/utf_string_conversion

security/sandbox/chromium/base/strings/utf_string_conversion_utils.cc@97036ab72558 (annotated)

security/sandbox/chromium/base/strings/utf_string_conversion_utils.cc

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

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.

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 #include "base/strings/utf_string_conversion_utils.h"
 #include "base/third_party/icu/icu_utf.h"
 namespace base {
 // ReadUnicodeCharacter --------------------------------------------------------
 bool ReadUnicodeCharacter(const char* src,
                           int32 src_len,
                           int32* char_index,
                           uint32* code_point_out) {
   // U8_NEXT expects to be able to use -1 to signal an error, so we must
   // use a signed type for code_point.  But this function returns false
   // on error anyway, so code_point_out is unsigned.
   int32 code_point;
   CBU8_NEXT(src, *char_index, src_len, code_point);
   *code_point_out = static_cast<uint32>(code_point);
   // The ICU macro above moves to the next char, we want to point to the last
   // char consumed.
   (*char_index)--;
   // Validate the decoded value.
   return IsValidCodepoint(code_point);
 }
 bool ReadUnicodeCharacter(const char16* src,
                           int32 src_len,
                           int32* char_index,
                           uint32* code_point) {
   if (CBU16_IS_SURROGATE(src[*char_index])) {
     if (!CBU16_IS_SURROGATE_LEAD(src[*char_index]) ||
         *char_index + 1 >= src_len ||
         !CBU16_IS_TRAIL(src[*char_index + 1])) {
       // Invalid surrogate pair.
       return false;
     }
     // Valid surrogate pair.
     *code_point = CBU16_GET_SUPPLEMENTARY(src[*char_index],
                                           src[*char_index + 1]);
     (*char_index)++;
   } else {
     // Not a surrogate, just one 16-bit word.
     *code_point = src[*char_index];
   }
   return IsValidCodepoint(*code_point);
 }
 #if defined(WCHAR_T_IS_UTF32)
 bool ReadUnicodeCharacter(const wchar_t* src,
                           int32 src_len,
                           int32* char_index,
                           uint32* code_point) {
   // Conversion is easy since the source is 32-bit.
   *code_point = src[*char_index];
   // Validate the value.
   return IsValidCodepoint(*code_point);
 }
 #endif  // defined(WCHAR_T_IS_UTF32)
 // WriteUnicodeCharacter -------------------------------------------------------
 size_t WriteUnicodeCharacter(uint32 code_point, std::string* output) {
   if (code_point <= 0x7f) {
     // Fast path the common case of one byte.
     output->push_back(code_point);
     return 1;
   }
   // CBU8_APPEND_UNSAFE can append up to 4 bytes.
   size_t char_offset = output->length();
   size_t original_char_offset = char_offset;
   output->resize(char_offset + CBU8_MAX_LENGTH);
   CBU8_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
   // CBU8_APPEND_UNSAFE will advance our pointer past the inserted character, so
   // it will represent the new length of the string.
   output->resize(char_offset);
   return char_offset - original_char_offset;
 }
 size_t WriteUnicodeCharacter(uint32 code_point, string16* output) {
   if (CBU16_LENGTH(code_point) == 1) {
     // Thie code point is in the Basic Multilingual Plane (BMP).
     output->push_back(static_cast<char16>(code_point));
     return 1;
   }
   // Non-BMP characters use a double-character encoding.
   size_t char_offset = output->length();
   output->resize(char_offset + CBU16_MAX_LENGTH);
   CBU16_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
   return CBU16_MAX_LENGTH;
 }
 // Generalized Unicode converter -----------------------------------------------
 template<typename CHAR>
 void PrepareForUTF8Output(const CHAR* src,
                           size_t src_len,
                           std::string* output) {
   output->clear();
   if (src_len == 0)
     return;
   if (src[0] < 0x80) {
     // Assume that the entire input will be ASCII.
     output->reserve(src_len);
   } else {
     // Assume that the entire input is non-ASCII and will have 3 bytes per char.
     output->reserve(src_len * 3);
   }
 }
 // Instantiate versions we know callers will need.
 template void PrepareForUTF8Output(const wchar_t*, size_t, std::string*);
 template void PrepareForUTF8Output(const char16*, size_t, std::string*);
 template<typename STRING>
 void PrepareForUTF16Or32Output(const char* src,
                                size_t src_len,
                                STRING* output) {
   output->clear();
   if (src_len == 0)
     return;
   if (static_cast<unsigned char>(src[0]) < 0x80) {
     // Assume the input is all ASCII, which means 1:1 correspondence.
     output->reserve(src_len);
   } else {
     // Otherwise assume that the UTF-8 sequences will have 2 bytes for each
     // character.
     output->reserve(src_len / 2);
   }
 }
 // Instantiate versions we know callers will need.
 template void PrepareForUTF16Or32Output(const char*, size_t, std::wstring*);
 template void PrepareForUTF16Or32Output(const char*, size_t, string16*);
 }  // namespace base

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security/sandbox/chromium/base/strings/utf_string_conversion_utils.cc@97036ab72558 (annotated)

security/sandbox/chromium/base/strings/utf_string_conversion_utils.cc