164 lines
6.1 KiB
C++
164 lines
6.1 KiB
C++
/*
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* Copyright (C) 2010-2018 Apple Inc. All rights reserved.
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* Copyright (C) 2012 Google Inc. All rights reserved.
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* Copyright (C) 2017 Yusuke Suzuki <utatane.tea@gmail.com>. All rights reserved.
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* Copyright (C) 2017 Mozilla Foundation. All rights reserved.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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#include "config.h"
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#include <wtf/text/StringBuilder.h>
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#include <wtf/text/StringBuilderInternals.h>
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#include <wtf/text/WTFString.h>
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namespace WTF {
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// This table driven escaping is ported from SpiderMonkey.
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static const constexpr LChar escapedFormsForJSON[0x100] = {
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'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u',
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'b', 't', 'n', 'u', 'f', 'r', 'u', 'u',
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'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u',
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'u', 'u', 'u', 'u', 'u', 'u', 'u', 'u',
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0, 0, '\"', 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, '\\', 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0,
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};
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template<typename OutputCharacterType, typename InputCharacterType>
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ALWAYS_INLINE static void appendQuotedJSONStringInternal(OutputCharacterType*& output, const InputCharacterType* input, unsigned length)
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{
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for (auto* end = input + length; input != end; ++input) {
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auto character = *input;
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if (LIKELY(character <= 0xFF)) {
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auto escaped = escapedFormsForJSON[character];
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if (LIKELY(!escaped)) {
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*output++ = character;
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continue;
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}
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*output++ = '\\';
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*output++ = escaped;
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if (UNLIKELY(escaped == 'u')) {
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*output++ = '0';
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*output++ = '0';
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*output++ = upperNibbleToLowercaseASCIIHexDigit(character);
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*output++ = lowerNibbleToLowercaseASCIIHexDigit(character);
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}
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continue;
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}
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if (LIKELY(!U16_IS_SURROGATE(character))) {
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*output++ = character;
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continue;
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}
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auto next = input + 1;
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bool isValidSurrogatePair = U16_IS_SURROGATE_LEAD(character) && next != end && U16_IS_TRAIL(*next);
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if (isValidSurrogatePair) {
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*output++ = character;
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*output++ = *next;
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++input;
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continue;
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}
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uint8_t upper = static_cast<uint32_t>(character) >> 8;
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uint8_t lower = static_cast<uint8_t>(character);
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*output++ = '\\';
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*output++ = 'u';
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*output++ = upperNibbleToLowercaseASCIIHexDigit(upper);
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*output++ = lowerNibbleToLowercaseASCIIHexDigit(upper);
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*output++ = upperNibbleToLowercaseASCIIHexDigit(lower);
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*output++ = lowerNibbleToLowercaseASCIIHexDigit(lower);
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continue;
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}
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}
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void StringBuilder::appendQuotedJSONString(const String& string)
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{
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if (hasOverflowed())
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return;
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// Make sure we have enough buffer space to append this string for worst case without reallocating.
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// The 2 is for the '"' quotes on each end.
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// The 6 is the worst case for a single code unit that could be encoded as \uNNNN.
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CheckedUint32 stringLength = string.length();
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auto maximumCapacityRequired = m_length + 2 + stringLength * 6;
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if (maximumCapacityRequired.hasOverflowed()) {
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didOverflow();
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return;
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}
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// We need to check maximum length before calling roundUpPowerOfTwo because that function returns 0 for values in the range [2^31, 2^32-2].
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// FIXME: Instead, roundUpToPowerOfTwo should be fixed to do something more useful in those cases, perhaps using checked or saturated arithmetic.
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// https://bugs.webkit.org/show_bug.cgi?id=176086
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auto allocationSize = maximumCapacityRequired.value();
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if (allocationSize > String::MaxLength) {
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didOverflow();
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return;
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}
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allocationSize = roundUpToPowerOfTwo(allocationSize);
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if (allocationSize > String::MaxLength) {
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didOverflow();
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return;
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}
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// FIXME: Consider switching to extendBufferForAppending/shrink instead to share more code with the rest of StringBuilder.
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if (is8Bit() && !string.is8Bit())
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allocateBuffer<UChar>(characters<LChar>(), allocationSize);
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else
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reserveCapacity(allocationSize);
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if (UNLIKELY(hasOverflowed()))
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return;
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if (m_buffer->is8Bit()) {
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auto characters = const_cast<LChar*>(m_buffer->characters<LChar>());
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auto output = characters + m_length;
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*output++ = '"';
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appendQuotedJSONStringInternal(output, string.characters8(), string.length());
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*output++ = '"';
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m_length = output - characters;
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} else {
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auto characters = const_cast<UChar*>(m_buffer->characters<UChar>());
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auto output = characters + m_length;
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*output++ = '"';
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if (string.is8Bit())
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appendQuotedJSONStringInternal(output, string.characters8(), string.length());
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else
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appendQuotedJSONStringInternal(output, string.characters16(), string.length());
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*output++ = '"';
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m_length = output - characters;
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}
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ASSERT(m_buffer->length() >= m_length);
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}
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} // namespace WTF
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