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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 09:06:44 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 09:06:44 +0000 |
commit | ed5640d8b587fbcfed7dd7967f3de04b37a76f26 (patch) | |
tree | 7a5f7c6c9d02226d7471cb3cc8fbbf631b415303 /tools/source/misc/json_writer.cxx | |
parent | Initial commit. (diff) | |
download | libreoffice-upstream.tar.xz libreoffice-upstream.zip |
Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/source/misc/json_writer.cxx')
-rw-r--r-- | tools/source/misc/json_writer.cxx | 482 |
1 files changed, 482 insertions, 0 deletions
diff --git a/tools/source/misc/json_writer.cxx b/tools/source/misc/json_writer.cxx new file mode 100644 index 000000000..3d78f82e0 --- /dev/null +++ b/tools/source/misc/json_writer.cxx @@ -0,0 +1,482 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +#include <tools/json_writer.hxx> +#include <stdio.h> +#include <cstring> +#include <rtl/math.hxx> + +namespace tools +{ +/** These buffers are short-lived, so rather waste some space and avoid the cost of + * repeated calls into the allocator */ +constexpr int DEFAULT_BUFFER_SIZE = 2048; + +JsonWriter::JsonWriter() + : mpBuffer(static_cast<char*>(malloc(DEFAULT_BUFFER_SIZE))) + , mPos(mpBuffer) + , mSpaceAllocated(DEFAULT_BUFFER_SIZE) + , mStartNodeCount(0) + , mbFirstFieldInNode(true) +{ + *mPos = '{'; + ++mPos; + *mPos = ' '; + ++mPos; + + addValidationMark(); +} + +JsonWriter::~JsonWriter() +{ + assert(!mpBuffer && "forgot to extract data?"); + free(mpBuffer); +} + +ScopedJsonWriterNode JsonWriter::startNode(const char* pNodeName) +{ + auto len = strlen(pNodeName); + ensureSpace(len + 8); + + addCommaBeforeField(); + + *mPos = '"'; + ++mPos; + memcpy(mPos, pNodeName, len); + mPos += len; + memcpy(mPos, "\": { ", 5); + mPos += 5; + mStartNodeCount++; + mbFirstFieldInNode = true; + + validate(); + + return ScopedJsonWriterNode(*this); +} + +void JsonWriter::endNode() +{ + assert(mStartNodeCount && "mismatched StartNode/EndNode somewhere"); + --mStartNodeCount; + ensureSpace(1); + *mPos = '}'; + ++mPos; + mbFirstFieldInNode = false; + + validate(); +} + +ScopedJsonWriterArray JsonWriter::startArray(const char* pNodeName) +{ + auto len = strlen(pNodeName); + ensureSpace(len + 8); + + addCommaBeforeField(); + + *mPos = '"'; + ++mPos; + memcpy(mPos, pNodeName, len); + mPos += len; + memcpy(mPos, "\": [ ", 5); + mPos += 5; + mStartNodeCount++; + mbFirstFieldInNode = true; + + validate(); + + return ScopedJsonWriterArray(*this); +} + +void JsonWriter::endArray() +{ + assert(mStartNodeCount && "mismatched StartNode/EndNode somewhere"); + --mStartNodeCount; + ensureSpace(1); + *mPos = ']'; + ++mPos; + mbFirstFieldInNode = false; + + validate(); +} + +ScopedJsonWriterStruct JsonWriter::startStruct() +{ + ensureSpace(6); + + addCommaBeforeField(); + + *mPos = '{'; + ++mPos; + *mPos = ' '; + ++mPos; + mStartNodeCount++; + mbFirstFieldInNode = true; + + validate(); + + return ScopedJsonWriterStruct(*this); +} + +void JsonWriter::endStruct() +{ + assert(mStartNodeCount && "mismatched StartNode/EndNode somewhere"); + --mStartNodeCount; + ensureSpace(1); + *mPos = '}'; + ++mPos; + mbFirstFieldInNode = false; + + validate(); +} + +static char getEscapementChar(char ch) +{ + switch (ch) + { + case '\b': + return 'b'; + case '\t': + return 't'; + case '\n': + return 'n'; + case '\f': + return 'f'; + case '\r': + return 'r'; + default: + return ch; + } +} + +static bool writeEscapedSequence(sal_uInt32 ch, char*& pos) +{ + switch (ch) + { + case '\b': + case '\t': + case '\n': + case '\f': + case '\r': + case '"': + case '/': + case '\\': + *pos++ = '\\'; + *pos++ = getEscapementChar(ch); + return true; + // Special processing of U+2028 and U+2029, which are valid JSON, but invalid JavaScript + // Write them in escaped '\u2028' or '\u2029' form + case 0x2028: + case 0x2029: + *pos++ = '\\'; + *pos++ = 'u'; + *pos++ = '2'; + *pos++ = '0'; + *pos++ = '2'; + *pos++ = ch == 0x2028 ? '8' : '9'; + return true; + default: + return false; + } +} + +void JsonWriter::writeEscapedOUString(const OUString& rPropVal) +{ + // Convert from UTF-16 to UTF-8 and perform escaping + sal_Int32 i = 0; + while (i < rPropVal.getLength()) + { + sal_uInt32 ch = rPropVal.iterateCodePoints(&i); + if (writeEscapedSequence(ch, mPos)) + continue; + if (ch <= 0x7F) + { + *mPos = static_cast<char>(ch); + ++mPos; + } + else if (ch <= 0x7FF) + { + *mPos = 0xC0 | (ch >> 6); /* 110xxxxx */ + ++mPos; + *mPos = 0x80 | (ch & 0x3F); /* 10xxxxxx */ + ++mPos; + } + else if (ch <= 0xFFFF) + { + *mPos = 0xE0 | (ch >> 12); /* 1110xxxx */ + ++mPos; + *mPos = 0x80 | ((ch >> 6) & 0x3F); /* 10xxxxxx */ + ++mPos; + *mPos = 0x80 | (ch & 0x3F); /* 10xxxxxx */ + ++mPos; + } + else + { + *mPos = 0xF0 | (ch >> 18); /* 11110xxx */ + ++mPos; + *mPos = 0x80 | ((ch >> 12) & 0x3F); /* 10xxxxxx */ + ++mPos; + *mPos = 0x80 | ((ch >> 6) & 0x3F); /* 10xxxxxx */ + ++mPos; + *mPos = 0x80 | (ch & 0x3F); /* 10xxxxxx */ + ++mPos; + } + } + + validate(); +} + +void JsonWriter::put(const char* pPropName, const OUString& rPropVal) +{ + auto nPropNameLength = strlen(pPropName); + // But values can be any UTF-8, + // if the string only contains of 0x2028, it will be expanded 6 times (see writeEscapedSequence) + auto nWorstCasePropValLength = rPropVal.getLength() * 6; + ensureSpace(nPropNameLength + nWorstCasePropValLength + 8); + + addCommaBeforeField(); + + *mPos = '"'; + ++mPos; + memcpy(mPos, pPropName, nPropNameLength); + mPos += nPropNameLength; + memcpy(mPos, "\": \"", 4); + mPos += 4; + + writeEscapedOUString(rPropVal); + + *mPos = '"'; + ++mPos; + + validate(); +} + +void JsonWriter::put(const char* pPropName, std::string_view rPropVal) +{ + // we assume property names are ascii + auto nPropNameLength = strlen(pPropName); + // escaping can double the length + auto nWorstCasePropValLength = rPropVal.size() * 2; + ensureSpace(nPropNameLength + nWorstCasePropValLength + 8); + + addCommaBeforeField(); + + *mPos = '"'; + ++mPos; + memcpy(mPos, pPropName, nPropNameLength); + mPos += nPropNameLength; + memcpy(mPos, "\": \"", 4); + mPos += 4; + + // copy and perform escaping + for (size_t i = 0; i < rPropVal.size(); ++i) + { + char ch = rPropVal[i]; + switch (ch) + { + case '\b': + case '\t': + case '\n': + case '\f': + case '\r': + case '"': + case '/': + case '\\': + writeEscapedSequence(ch, mPos); + break; + case '\xE2': // Special processing of U+2028 and U+2029 + if (i + 2 < rPropVal.size() && rPropVal[i + 1] == '\x80' + && (rPropVal[i + 2] == '\xA8' || rPropVal[i + 2] == '\xA9')) + { + writeEscapedSequence(rPropVal[i + 2] == '\xA8' ? 0x2028 : 0x2029, mPos); + i += 2; + break; + } + [[fallthrough]]; + default: + *mPos = ch; + ++mPos; + break; + } + } + + *mPos = '"'; + ++mPos; + + validate(); +} + +void JsonWriter::put(const char* pPropName, sal_Int64 nPropVal) +{ + auto nPropNameLength = strlen(pPropName); + auto nWorstCasePropValLength = 32; + ensureSpace(nPropNameLength + nWorstCasePropValLength + 8); + + addCommaBeforeField(); + + *mPos = '"'; + ++mPos; + memcpy(mPos, pPropName, nPropNameLength); + mPos += nPropNameLength; + memcpy(mPos, "\": ", 3); + mPos += 3; + + // clang-format off + SAL_WNODEPRECATED_DECLARATIONS_PUSH // sprintf (macOS 13 SDK) + mPos += sprintf(mPos, "%" SAL_PRIdINT64, nPropVal); + SAL_WNODEPRECATED_DECLARATIONS_POP + // clang-format on + + validate(); +} + +void JsonWriter::put(const char* pPropName, double fPropVal) +{ + OString sPropVal = rtl::math::doubleToString(fPropVal, rtl_math_StringFormat_F, 12, '.'); + auto nPropNameLength = strlen(pPropName); + ensureSpace(nPropNameLength + sPropVal.getLength() + 8); + + addCommaBeforeField(); + + *mPos = '"'; + ++mPos; + memcpy(mPos, pPropName, nPropNameLength); + mPos += nPropNameLength; + memcpy(mPos, "\": ", 3); + mPos += 3; + + memcpy(mPos, sPropVal.getStr(), sPropVal.getLength()); + mPos += sPropVal.getLength(); + + validate(); +} + +void JsonWriter::put(const char* pPropName, bool nPropVal) +{ + auto nPropNameLength = strlen(pPropName); + ensureSpace(nPropNameLength + 5 + 8); + + addCommaBeforeField(); + + *mPos = '"'; + ++mPos; + memcpy(mPos, pPropName, nPropNameLength); + mPos += nPropNameLength; + memcpy(mPos, "\": ", 3); + mPos += 3; + + const char* pVal; + if (nPropVal) + pVal = "true"; + else + pVal = "false"; + memcpy(mPos, pVal, strlen(pVal)); + mPos += strlen(pVal); + + validate(); +} + +void JsonWriter::putSimpleValue(const OUString& rPropVal) +{ + auto nWorstCasePropValLength = rPropVal.getLength() * 3; + ensureSpace(nWorstCasePropValLength + 4); + + addCommaBeforeField(); + + *mPos = '"'; + ++mPos; + + writeEscapedOUString(rPropVal); + + *mPos = '"'; + ++mPos; + + validate(); +} + +void JsonWriter::putRaw(std::string_view rRawBuf) +{ + ensureSpace(rRawBuf.size() + 2); + + addCommaBeforeField(); + + memcpy(mPos, rRawBuf.data(), rRawBuf.size()); + mPos += rRawBuf.size(); + + validate(); +} + +void JsonWriter::addCommaBeforeField() +{ + if (mbFirstFieldInNode) + mbFirstFieldInNode = false; + else + { + *mPos = ','; + ++mPos; + *mPos = ' '; + ++mPos; + } +} + +void JsonWriter::ensureSpace(int noMoreBytesRequired) +{ + assert(mpBuffer && "already extracted data"); + int currentUsed = mPos - mpBuffer; + if (currentUsed + noMoreBytesRequired >= mSpaceAllocated) + { + auto newSize = (currentUsed + noMoreBytesRequired) * 2; + mpBuffer = static_cast<char*>(realloc(mpBuffer, newSize)); + mPos = mpBuffer + currentUsed; + mSpaceAllocated = newSize; + + addValidationMark(); + } +} + +/** Hands ownership of the underlying storage buffer to the caller, + * after this no more document modifications may be written. */ +std::pair<char*, int> JsonWriter::extractDataImpl() +{ + assert(mStartNodeCount == 0 && "did not close all nodes"); + assert(mpBuffer && "data already extracted"); + ensureSpace(2); + // add closing brace + *mPos = '}'; + ++mPos; + // null-terminate + *mPos = 0; + const int sz = mPos - mpBuffer; + mPos = nullptr; + return { std::exchange(mpBuffer, nullptr), sz }; +} + +OString JsonWriter::extractAsOString() +{ + auto[pChar, sz] = extractDataImpl(); + OString ret(pChar, sz); + free(pChar); + return ret; +} + +std::string JsonWriter::extractAsStdString() +{ + auto[pChar, sz] = extractDataImpl(); + std::string ret(pChar, sz); + free(pChar); + return ret; +} + +bool JsonWriter::isDataEquals(const std::string& s) const +{ + return s.length() == static_cast<size_t>(mPos - mpBuffer) + && memcmp(s.data(), mpBuffer, s.length()) == 0; +} + +} // namespace tools +/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ |