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: */