office-gobmx/include/tools/json_writer.hxx
Szymon Kłos 496fcccfa6 jsonwriter: ensure correct number of bytes is available
In some functions author forgot that addCommaBeforeField()
can add additional two characters.

I didn't change cases where more bytes than needed are requested.

Additional change is that in debug mode there is a marker at the
end of allocated buffer - we check that after every write to
detect overflow. No need to request more space for a marker as
we always allocate "needed size * 2".

Change-Id: I28066797b0ba833e408b0a731abc01b7fd989da3
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/126535
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129163
Tested-by: Jenkins
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
2022-01-31 17:01:33 +01:00

166 lines
4.3 KiB
C++

/* -*- 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: */