1 files changed, 166 insertions, 0 deletions
diff --git a/include/tools/json_writer.hxx b/include/tools/json_writer.hxx
new file mode 100644
index 000000000..700e82b9a
--- /dev/null
+++ b/include/tools/json_writer.hxx
@@ -0,0 +1,166 @@
+/* -*- 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/.
+ */
+#pragma once
+
+#include <sal/config.h>
+
+#include <tools/toolsdllapi.h>
+#include <rtl/string.hxx>
+#include <rtl/ustring.hxx>
+#include <sal/types.h>
+
+#include <string>
+#include <string_view>
+#include <utility>
+
+/** Simple JSON encoder designed specifically for LibreOfficeKit purposes.
+ *
+ * (1) Minimal allocations/re-allocations/copying
+ * (2) Small/simple JSON documents
+ * (3) ascii property names
+ */
+namespace tools
+{
+class ScopedJsonWriterNode;
+class ScopedJsonWriterArray;
+class ScopedJsonWriterStruct;
+
+class TOOLS_DLLPUBLIC JsonWriter
+{
+    friend class ScopedJsonWriterNode;
+    friend class ScopedJsonWriterArray;
+    friend class ScopedJsonWriterStruct;
+
+    char* mpBuffer;
+    char* mPos;
+    int mSpaceAllocated;
+    int mStartNodeCount;
+    bool mbFirstFieldInNode;
+
+public:
+    JsonWriter();
+    ~JsonWriter();
+
+    [[nodiscard]] ScopedJsonWriterNode startNode(const char*);
+    [[nodiscard]] ScopedJsonWriterArray startArray(const char*);
+    [[nodiscard]] ScopedJsonWriterStruct startStruct();
+
+    void put(const char* pPropName, const OUString& rPropValue);
+    // Assumes utf-8 property value encoding
+    void put(const char* pPropName, std::string_view rPropValue);
+    void put(const char* pPropName, const char* pPropVal)
+    {
+        put(pPropName, std::string_view(pPropVal));
+    }
+
+    void put(const char* pPropName, sal_uInt16 nPropVal) { put(pPropName, sal_Int64(nPropVal)); }
+    void put(const char* pPropName, sal_Int16 nPropVal) { put(pPropName, sal_Int64(nPropVal)); }
+    void put(const char* pPropName, sal_Int32 nPropVal) { put(pPropName, sal_Int64(nPropVal)); }
+    void put(const char* pPropName, sal_uInt32 nPropVal) { put(pPropName, sal_Int64(nPropVal)); }
+    void put(const char* pPropName, sal_Int64);
+    void put(const char* pPropName, bool);
+    void put(const char* pPropName, double);
+
+    void putSimpleValue(const OUString& rPropValue);
+
+    /// This assumes that this data belongs at this point in the stream, and is valid, and properly encoded
+    void putRaw(std::string_view);
+
+    /** Hands ownership of the underlying storage buffer to the caller,
+     * after this no more document modifications may be written. */
+    char* extractData() { return extractDataImpl().first; }
+    OString extractAsOString();
+    std::string extractAsStdString();
+
+    /** returns true if the current JSON data matches the string */
+    bool isDataEquals(const std::string&) const;
+
+private:
+    void endNode();
+    void endArray();
+    void endStruct();
+    void addCommaBeforeField();
+    void writeEscapedOUString(const OUString& rPropVal);
+    std::pair<char*, int> extractDataImpl();
+    void ensureSpace(int noMoreBytesRequired);
+
+    // overflow validation in debug mode
+    static constexpr unsigned char JSON_WRITER_DEBUG_MARKER = 0xde;
+
+    inline void addValidationMark()
+    {
+#ifndef NDEBUG
+        *(mpBuffer + mSpaceAllocated - 1) = JSON_WRITER_DEBUG_MARKER;
+#endif
+    }
+
+    inline void validate()
+    {
+#ifndef NDEBUG
+        unsigned char c = *(mpBuffer + mSpaceAllocated - 1);
+        assert(c == JSON_WRITER_DEBUG_MARKER);
+#endif
+    }
+};
+
+/**
+ * Auto-closes the node.
+ */
+class ScopedJsonWriterNode
+{
+    friend class JsonWriter;
+
+    JsonWriter& mrWriter;
+
+    ScopedJsonWriterNode(JsonWriter& rWriter)
+        : mrWriter(rWriter)
+    {
+    }
+
+public:
+    ~ScopedJsonWriterNode() { mrWriter.endNode(); }
+};
+
+/**
+ * Auto-closes the node.
+ */
+class ScopedJsonWriterArray
+{
+    friend class JsonWriter;
+
+    JsonWriter& mrWriter;
+
+    ScopedJsonWriterArray(JsonWriter& rWriter)
+        : mrWriter(rWriter)
+    {
+    }
+
+public:
+    ~ScopedJsonWriterArray() { mrWriter.endArray(); }
+};
+
+/**
+ * Auto-closes the node.
+ */
+class ScopedJsonWriterStruct
+{
+    friend class JsonWriter;
+
+    JsonWriter& mrWriter;
+
+    ScopedJsonWriterStruct(JsonWriter& rWriter)
+        : mrWriter(rWriter)
+    {
+    }
+
+public:
+    ~ScopedJsonWriterStruct() { mrWriter.endStruct(); }
+};
+};
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */