serialize.cc

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#include "serialize.hh"
 
#include "Base64.hh"
#include "HexDump.hh"
#include "XMLElement.hh"
#include "XMLException.hh"
#include "DeltaBlock.hh"
#include "MemBuffer.hh"
#include "FileOperations.hh"
#include "Version.hh"
#include "Date.hh"
#include "narrow.hh"
#include "one_of.hh"
#include "stl.hh"
#include "build-info.hh"
 
#include <bit>
#include "cstdiop.hh" // for dup()
#include <cstdint>
#include <cstring>
#include <iostream>
#include <limits>
 
using std::string;
using std::string_view;
 
namespace openmsx {
 
template<typename Derived>
void ArchiveBase<Derived>::attribute(const char* name, const char* value)
{
        string valueStr(value);
        self().attribute(name, valueStr);
}
template class ArchiveBase<MemOutputArchive>;
template class ArchiveBase<XmlOutputArchive>;
 
 
unsigned OutputArchiveBase2::generateID1(const void* p)
{
        #ifdef linux
        assert("Can't serialize ID of object located on the stack" &&
               !addressOnStack(p));
        #endif
        ++lastId;
        assert(!polyIdMap.contains(p));
        polyIdMap.emplace_noDuplicateCheck(p, lastId);
        return lastId;
}
unsigned OutputArchiveBase2::generateID2(
        const void* p, const std::type_info& typeInfo)
{
        #ifdef linux
        assert("Can't serialize ID of object located on the stack" &&
               !addressOnStack(p));
        #endif
        ++lastId;
        auto key = std::pair(p, std::type_index(typeInfo));
        assert(!idMap.contains(key));
        idMap.emplace_noDuplicateCheck(key, lastId);
        return lastId;
}
 
unsigned OutputArchiveBase2::getID1(const void* p)
{
        const auto* v = lookup(polyIdMap, p);
        return v ? *v : 0;
}
unsigned OutputArchiveBase2::getID2(
        const void* p, const std::type_info& typeInfo)
{
        const auto* v = lookup(idMap, std::pair(p, std::type_index(typeInfo)));
        return v ? *v : 0;
}
 
 
template<typename Derived>
void OutputArchiveBase<Derived>::serialize_blob(
        const char* tag, std::span<const uint8_t> data, bool /*diff*/)
{
        string encoding;
        string tmp;
        if (false) {
                // useful for debugging
                encoding = "hex";
                tmp = HexDump::encode(data);
        } else if (false) {
                encoding = "base64";
                tmp = Base64::encode(data);
        } else {
                encoding = "gz-base64";
                // TODO check for overflow?
                auto len = data.size();
                auto dstLen = uLongf(len + len / 1000 + 12 + 1); // worst-case
                MemBuffer<uint8_t> buf(dstLen);
                if (compress2(buf.data(), &dstLen,
                              std::bit_cast<const Bytef*>(data.data()),
                              uLong(len), 9)
                    != Z_OK) {
                        throw MSXException("Error while compressing blob.");
                }
                tmp = Base64::encode(buf.first(dstLen));
        }
        this->self().beginTag(tag);
        this->self().attribute("encoding", encoding);
        Saver<string> saver;
        saver(this->self(), tmp, false);
        this->self().endTag(tag);
}
 
template class OutputArchiveBase<MemOutputArchive>;
template class OutputArchiveBase<XmlOutputArchive>;
 
 
void* InputArchiveBase2::getPointer(unsigned id)
{
        auto* v = lookup(idMap, id);
        return v ? *v : nullptr;
}
 
void InputArchiveBase2::addPointer(unsigned id, const void* p)
{
        assert(!idMap.contains(id));
        idMap.emplace_noDuplicateCheck(id, const_cast<void*>(p));
}
 
unsigned InputArchiveBase2::getId(const void* ptr) const
{
        for (const auto& [id, pt] : idMap) {
                if (pt == ptr) return id;
        }
        return 0;
}
 
template<typename Derived>
void InputArchiveBase<Derived>::serialize_blob(
        const char* tag, std::span<uint8_t> data, bool /*diff*/)
{
        this->self().beginTag(tag);
        string encoding;
        this->self().attribute("encoding", encoding);
 
        string_view tmp = this->self().loadStr();
        this->self().endTag(tag);
 
        if (encoding == "gz-base64") {
                auto buf = Base64::decode(tmp);
                auto dstLen = uLongf(data.size()); // TODO check for overflow?
                if ((uncompress(std::bit_cast<Bytef*>(data.data()), &dstLen,
                                std::bit_cast<const Bytef*>(buf.data()), uLong(buf.size()))
                     != Z_OK) ||
                    (dstLen != data.size())) {
                        throw MSXException("Error while decompressing blob.");
                }
        } else if (encoding == one_of("hex", "base64")) {
                bool ok = (encoding == "hex")
                        ? HexDump::decode_inplace(tmp, data)
                        : Base64 ::decode_inplace(tmp, data);
                if (!ok) {
                        throw XMLException(
                                "Length of decoded blob different from "
                                "expected value (", data.size(), ')');
                }
        } else {
                throw XMLException("Unsupported encoding \"", encoding, "\" for blob");
        }
}
 
template class InputArchiveBase<MemInputArchive>;
template class InputArchiveBase<XmlInputArchive>;
 
 
void MemOutputArchive::save(std::string_view s)
{
        auto size = s.size();
        auto buf = buffer.allocate(sizeof(size) + size);
        memcpy(buf.data(), &size, sizeof(size));
        ranges::copy(s, subspan(buf, sizeof(size)));
}
 
 
void MemInputArchive::load(std::string& s)
{
        size_t length;
        load(length);
        s.resize(length);
        if (length) {
                buffer.read(s.data(), length);
        }
}
 
string_view MemInputArchive::loadStr()
{
        size_t length;
        load(length);
        const uint8_t* p = buffer.getCurrentPos();
        buffer.skip(length);
        return {std::bit_cast<const char*>(p), length};
}
 
 
// Too small inputs don't compress very well (often the compressed size is even
// bigger than the input). It also takes a relatively long time (because often
// compression has a relatively large setup time). I choose this value
// semi-arbitrary. I only made it >= 52 so that the (incompressible) RP5C01
// registers won't be compressed.
static constexpr size_t SMALL_SIZE = 64;
void MemOutputArchive::serialize_blob(const char* /*tag*/, std::span<const uint8_t> data,
                                      bool diff)
{
        // Delta-compress in-memory blobs, see DeltaBlock.hh for more details.
        if (data.size() > SMALL_SIZE) {
                auto deltaBlockIdx = unsigned(deltaBlocks.size());
                save(deltaBlockIdx); // see comment below in MemInputArchive
                deltaBlocks.push_back(diff
                        ? lastDeltaBlocks.createNew(data.data(), data)
                        : lastDeltaBlocks.createNullDiff(data.data(), data));
        } else {
                auto buf = buffer.allocate(data.size());
                ranges::copy(data, buf);
        }
}
 
void MemInputArchive::serialize_blob(const char* /*tag*/, std::span<uint8_t> data,
                                     bool /*diff*/)
{
        if (data.size() > SMALL_SIZE) {
                // Usually blobs are saved in the same order as they are loaded
                // (via the serialize_blob() methods in respectively
                // MemOutputArchive and MemInputArchive). In that case keeping
                // track of the deltaBlockIdx in the savestate itself is
                // redundant (it will simply be an increasing value). However
                // in rare cases, via the {begin,end,skip)Section() methods, it
                // is possible that certain blobs are stored in the savestate,
                // but skipped while loading. That's why we do need the index.
                unsigned deltaBlockIdx; load(deltaBlockIdx);
                deltaBlocks[deltaBlockIdx]->apply(data);
        } else {
                ranges::copy(std::span{buffer.getCurrentPos(), data.size()}, data);
                buffer.skip(data.size());
        }
}
 
 
XmlOutputArchive::XmlOutputArchive(zstring_view filename_)
        : filename(filename_)
        , writer(*this)
{
        {
                auto f = FileOperations::openFile(filename, "wb");
                if (!f) error();
                int duped_fd = dup(fileno(f.get()));
                if (duped_fd == -1) error();
                file = gzdopen(duped_fd, "wb9");
                if (!file) {
                        ::close(duped_fd);
                        error();
                }
                // on scope-exit 'f' is closed, and 'file'
                // uses the dup()'ed file descriptor.
        }
 
        static constexpr std::string_view header =
                "<?xml version=\"1.0\" ?>\n"
                "<!DOCTYPE openmsx-serialize SYSTEM 'openmsx-serialize.dtd'>\n";
        write(header);
 
        writer.begin("serial");
        writer.attribute("openmsx_version", Version::full());
        writer.attribute("date_time", Date::toString(time(nullptr)));
        writer.attribute("platform", TARGET_PLATFORM);
}
 
void XmlOutputArchive::close()
{
        if (!file) return; // already closed
 
        writer.end("serial");
 
        if (gzclose(file) != Z_OK) {
                error();
        }
        file = nullptr;
}
 
XmlOutputArchive::~XmlOutputArchive()
{
        try {
                close();
        } catch (...) {
                // Eat exception. Explicitly call close() if you want to handle errors.
        }
}
 
void XmlOutputArchive::write(std::span<const char> buf)
{
        if ((gzwrite(file, buf.data(), unsigned(buf.size())) == 0) && !buf.empty()) {
                error();
        }
}
 
void XmlOutputArchive::write1(char c)
{
        if (gzputc(file, c) == -1) {
                error();
        }
}
 
void XmlOutputArchive::check(bool condition) const
{
        assert(condition); (void)condition;
}
 
void XmlOutputArchive::error()
{
        if (file) {
                gzclose(file);
                file = nullptr;
        }
        throw XMLException("could not write \"", filename, '"');
}
 
void XmlOutputArchive::saveChar(char c)
{
        writer.data(std::string_view(&c, 1));
}
void XmlOutputArchive::save(std::string_view str)
{
        writer.data(str);
}
void XmlOutputArchive::save(bool b)
{
        writer.data(b ? "true" : "false");
}
void XmlOutputArchive::save(unsigned char b)
{
        save(unsigned(b));
}
void XmlOutputArchive::save(signed char c)
{
        save(int(c));
}
void XmlOutputArchive::save(char c)
{
        save(int(c));
}
void XmlOutputArchive::save(int i)
{
        saveImpl(i);
}
void XmlOutputArchive::save(unsigned u)
{
        saveImpl(u);
}
void XmlOutputArchive::save(unsigned long long ull)
{
        saveImpl(ull);
}
 
void XmlOutputArchive::attribute(const char* name, std::string_view str)
{
        writer.attribute(name, str);
}
void XmlOutputArchive::attribute(const char* name, int i)
{
        attributeImpl(name, i);
}
void XmlOutputArchive::attribute(const char* name, unsigned u)
{
        attributeImpl(name, u);
}
 
void XmlOutputArchive::beginTag(const char* tag)
{
        writer.begin(tag);
}
void XmlOutputArchive::endTag(const char* tag)
{
        writer.end(tag);
}
 
 
XmlInputArchive::XmlInputArchive(const string& filename)
{
        xmlDoc.load(filename, "openmsx-serialize.dtd");
        const auto* root = xmlDoc.getRoot();
        elems.emplace_back(root, root->getFirstChild());
}
 
string_view XmlInputArchive::loadStr() const
{
        if (currentElement()->hasChildren()) {
                throw XMLException("No child tags expected for primitive type");
        }
        return currentElement()->getData();
}
void XmlInputArchive::load(string& t) const
{
        t = loadStr();
}
void XmlInputArchive::loadChar(char& c) const
{
        std::string str;
        load(str);
        std::istringstream is(str);
        is >> c;
}
void XmlInputArchive::load(bool& b) const
{
        string_view s = loadStr();
        if (s == one_of("true", "1")) {
                b = true;
        } else if (s == one_of("false", "0")) {
                b = false;
        } else {
                throw XMLException("Bad value found for boolean: ", s);
        }
}
 
// This function parses a number from a string. It's similar to the generic
// templatized XmlInputArchive::load() method, but _much_ faster. It does
// have some limitations though:
//  - it can't handle leading whitespace
//  - it can't handle extra characters at the end of the string
//  - it can only handle one base (only decimal, not octal or hexadecimal)
//  - it doesn't understand a leading '+' sign
//  - it doesn't detect overflow or underflow (The generic implementation sets
//    a 'bad' flag on the stream and clips the result to the min/max allowed
//    value. Though this 'bad' flag was ignored by the openMSX code).
// This routine is only used to parse strings we've written ourselves (and the
// savestate/replay XML files are not meant to be manually edited). So the
// above limitations don't really matter. And we can use the speed gain.
template<std::integral T> static inline void fastAtoi(string_view str, T& t)
{
        t = 0;
        bool neg = false;
        size_t i = 0;
        size_t l = str.size();
 
        if constexpr (std::numeric_limits<T>::is_signed) {
                if (l == 0) return;
                if (str[0] == '-') {
                        neg = true;
                        i = 1;
                }
        }
        for (; i < l; ++i) {
                unsigned d = str[i] - '0';
                if (d > 9) [[unlikely]] {
                        throw XMLException("Invalid integer: ", str);
                }
                t = 10 * t + d;
        }
        if constexpr (std::numeric_limits<T>::is_signed) {
                if (neg) t = -t;
        } else {
                assert(!neg); (void)neg;
        }
}
void XmlInputArchive::load(int& i) const
{
        string_view str = loadStr();
        fastAtoi(str, i);
}
void XmlInputArchive::load(unsigned& u) const
{
        string_view str = loadStr();
        try {
                fastAtoi(str, u);
        } catch (XMLException&) {
                // One reason could be that the type of a member was corrected
                // from 'int' to 'unsigned'. In that case loading an old
                // savestate (that contains a negative value) might fail. So try
                // again parsing as an 'int'.
                int i;
                fastAtoi(str, i);
                u = narrow_cast<unsigned>(i);
        }
}
void XmlInputArchive::load(unsigned long long& ull) const
{
        string_view str = loadStr();
        fastAtoi(str, ull);
}
void XmlInputArchive::load(unsigned char& b) const
{
        unsigned u;
        load(u);
        b = narrow_cast<unsigned char>(u);
}
void XmlInputArchive::load(signed char& c) const
{
        int i;
        load(i);
        c = narrow_cast<signed char>(i);
}
void XmlInputArchive::load(char& c) const
{
        int i;
        load(i);
        c = narrow_cast<char>(i);
}
 
void XmlInputArchive::beginTag(const char* tag)
{
        const auto* child = currentElement()->findChild(tag, elems.back().second);
        if (!child) {
                string path;
                for (const auto& [e, _] : elems) {
                        strAppend(path, e->getName(), '/');
                }
                throw XMLException("No child tag \"", tag,
                                   "\" found at location \"", path, '\"');
        }
        elems.emplace_back(child, child->getFirstChild());
}
void XmlInputArchive::endTag(const char* tag)
{
        const auto& elem = *currentElement();
        if (elem.getName() != tag) {
                throw XMLException("End tag \"", elem.getName(),
                                   "\" not equal to begin tag \"", tag, "\"");
        }
        auto& elem2 = const_cast<XMLElement&>(elem);
        elem2.clearName(); // mark this elem for later beginTag() calls
        elems.pop_back();
}
 
void XmlInputArchive::attribute(const char* name, string& t) const
{
        const auto* attr = currentElement()->findAttribute(name);
        if (!attr) {
                throw XMLException("Missing attribute \"", name, "\".");
        }
        t = attr->getValue();
}
void XmlInputArchive::attribute(const char* name, int& i) const
{
        attributeImpl(name, i);
}
void XmlInputArchive::attribute(const char* name, unsigned& u) const
{
        attributeImpl(name, u);
}
bool XmlInputArchive::hasAttribute(const char* name) const
{
        return currentElement()->findAttribute(name);
}
int XmlInputArchive::countChildren() const
{
        return int(currentElement()->numChildren());
}
 
} // namespace openmsx