libcruft-util/json/tree.cpp

/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Copyright 2010-2018 Danny Robson <danny@nerdcruft.net>
 */


#include "tree.hpp"

#include "except.hpp"
#include "flat.hpp"

#include "../debug.hpp"
#include "../io.hpp"
#include "../iterator.hpp"
#include "../maths.hpp"
#include "../stream.hpp"

#include "preprocessor.hpp"

#include <algorithm>
#include <cstdlib>
#include <iomanip>


///////////////////////////////////////////////////////////////////////////////
using json::tree::node;
using json::tree::object;
using json::tree::array;
using json::tree::string;
using json::tree::number;
using json::tree::boolean;
using json::tree::null;


///////////////////////////////////////////////////////////////////////////////
namespace util {
    bool
    is_integer (const json::tree::number &node)
    {
        using R = json::tree::number::repr_t;

        switch (node.repr ()) {
        case R::REAL:
               return is_integer (node.real ());

        case R::SINT:
        case R::UINT:
               return true;
        }

        unreachable ();
    }


    //-----------------------------------------------------------------------------
    bool
    is_integer (const json::tree::node &node)
    {
        return node.is_number () && is_integer (node.as_number ());
    }
}

///////////////////////////////////////////////////////////////////////////////
template <typename T>
static
typename std::vector<json::flat::item<T>>::const_iterator
parse (typename std::vector<json::flat::item<T>>::const_iterator first,
       typename std::vector<json::flat::item<T>>::const_iterator last,
       std::unique_ptr<json::tree::node> &output);


//-----------------------------------------------------------------------------
template <typename T>
static
typename std::vector<json::flat::item<T>>::const_iterator
parse (typename std::vector<json::flat::item<T>>::const_iterator first,
       typename std::vector<json::flat::item<T>>::const_iterator last,
       json::tree::array &parent)
{
    for (auto cursor = first; cursor != last; ) {
        if (cursor->tag == json::flat::type::ARRAY_END)
            return cursor + 1;

        std::unique_ptr<json::tree::node> value;
        cursor = ::parse<T> (cursor, last, value);
        parent.insert (std::move (value));
    }

    unreachable ();
}


//-----------------------------------------------------------------------------
template <typename T>
static
typename std::vector<json::flat::item<T>>::const_iterator
parse (typename std::vector<json::flat::item<T>>::const_iterator first,
       typename std::vector<json::flat::item<T>>::const_iterator last,
       json::tree::object &parent)
{
    for (auto cursor = first; cursor != last; ) {
        if (cursor->tag == json::flat::type::OBJECT_END)
            return cursor + 1;

        CHECK_EQ (cursor->tag, json::flat::type::STRING);

        std::string key (cursor->first + 1, cursor->last - 1);
        ++cursor;

        std::unique_ptr<json::tree::node> val;
        cursor = ::parse<T> (cursor, last, val);

        parent.insert (key, std::move (val));
    }

    unreachable ();
}


//-----------------------------------------------------------------------------
template <typename T>
static
typename std::vector<json::flat::item<T>>::const_iterator
parse (typename std::vector<json::flat::item<T>>::const_iterator first,
       typename std::vector<json::flat::item<T>>::const_iterator last,
       std::unique_ptr<json::tree::node> &output)
{
    CHECK (first != last);
    CHECK (output.get () == nullptr);

    using F = json::flat::type;

    switch (first->tag) {
        case F::NUL:
            output.reset (new json::tree::null ());
            return first + 1;

        case F::BOOLEAN:
            CHECK (*first->first == 't' || *first->first == 'f');
            output.reset (new json::tree::boolean (*first->first == 't'));
            return first + 1;

        case F::STRING:
            CHECK_NEQ (&*first->first, &*first->last);
            output.reset (new json::tree::string (first->first + 1, first->last - 1));
            return first + 1;

        case F::INTEGER: {
            T start = first->first;
            bool negative = *start == '-';
            if (negative)
                ++start;

            T finish = start;
            uintmax_t v = 0;
            while (isdigit (*finish))
                v *= 10, v += *finish - '0', ++finish;

            if (finish == start || finish > first->last)
                throw json::parse_error ("invalid integer");

            if (negative)
                output.reset (new json::tree::number (-intmax_t(v)));
            else
                output.reset (new json::tree::number (v));

            return first + 1;
        }

        case F::REAL: {
            std::string str (first->first, first->last);
            output.reset (new json::tree::number (std::atof (str.c_str())));
            return first + 1;
        }

        case F::ARRAY_BEGIN: {
            auto value = std::make_unique<json::tree::array> ();
            auto cursor = ::parse<T> (first + 1, last, *value);
            output = std::move (value);
            return cursor;
        }

        case F::OBJECT_BEGIN: {
            auto value = std::make_unique<json::tree::object> ();
            auto cursor = ::parse<T> (first + 1, last, *value);
            output = std::move (value);
            return cursor;
        }

        case F::UNKNOWN:
        case F::OBJECT_END:
        case F::ARRAY_END:
            unreachable ();
    }

    unreachable ();
}


///////////////////////////////////////////////////////////////////////////////
template <typename T>
std::unique_ptr<json::tree::node>
json::tree::parse (const util::view<T> &src)
{
    std::unique_ptr<json::tree::node> output;
    auto data = json::flat::parse (src);
    auto end  = ::parse<T> (data.cbegin (), data.cend (), output);

    CHECK (end == data.cend ());
    (void)end;

    return output;
}

#define INSTANTIATE(KLASS)          \
template                            \
std::unique_ptr<json::tree::node>   \
json::tree::parse (const util::view<KLASS>&);

MAP0(INSTANTIATE,
    std::string::iterator,
    std::string::const_iterator,
    const char*,
    char *
);

#undef INSTANTIATE


//-----------------------------------------------------------------------------
std::unique_ptr<json::tree::node>
json::tree::parse (const std::experimental::filesystem::path &src)
{
    const util::mapped_file data (src);
    return parse (util::view{data}.cast<const char*> ());
}


///////////////////////////////////////////////////////////////////////////////
void
json::tree::write (const json::tree::node &node, std::ostream &os)
{
    node.write (os);
}


///////////////////////////////////////////////////////////////////////////////
// Type conversion

const json::tree::object&
json::tree::node::as_object  (void) const&
    { throw json::type_error ("node is not an object"); }


//-----------------------------------------------------------------------------
const json::tree::array&
json::tree::node::as_array   (void) const&
    { throw json::type_error ("node is not an array"); }


//-----------------------------------------------------------------------------
const json::tree::string&
json::tree::node::as_string  (void) const&
    { throw json::type_error ("node is not a string"); }


//-----------------------------------------------------------------------------
const json::tree::number&
json::tree::node::as_number  (void) const&
    { throw json::type_error ("node is not a number"); }


//-----------------------------------------------------------------------------
const json::tree::boolean&
json::tree::node::as_boolean (void) const&
    { throw json::type_error ("node is not a boolean"); }


//-----------------------------------------------------------------------------
const json::tree::null&
json::tree::node::as_null (void) const&
    { throw json::type_error ("node is not a null"); }


///////////////////////////////////////////////////////////////////////////////
json::tree::object&
json::tree::node::as_object  (void)&
{ throw json::type_error ("node is not an object"); }


//-----------------------------------------------------------------------------
json::tree::array&
json::tree::node::as_array   (void)&
    { throw json::type_error ("node is not an array"); }


//-----------------------------------------------------------------------------
json::tree::string&
json::tree::node::as_string  (void)&
    { throw json::type_error ("node is not a string"); }


//-----------------------------------------------------------------------------
json::tree::number&
json::tree::node::as_number  (void)&
    { throw json::type_error ("node is not a number"); }


//-----------------------------------------------------------------------------
json::tree::boolean&
json::tree::node::as_boolean (void)&
    { throw json::type_error ("node is not a boolean"); }


//-----------------------------------------------------------------------------
json::tree::null&
json::tree::node::as_null (void)&
    { throw json::type_error ("node is not a null"); }


///////////////////////////////////////////////////////////////////////////////
bool
json::tree::node::as_bool (void) const
{
    return !!as_boolean ();
}


//-----------------------------------------------------------------------------
float
json::tree::node::as_float (void) const
{
    return static_cast<float> (as_number ().real ());
}


//-----------------------------------------------------------------------------
double
json::tree::node::as_double (void) const
{
    return as_number ().real ();
}


//-----------------------------------------------------------------------------
uintmax_t
json::tree::node::as_uint (void) const
{
    return as_number ().uint ();
}


//-----------------------------------------------------------------------------
intmax_t
json::tree::node::as_sint (void) const
{
    return as_number ().sint ();
}


//-----------------------------------------------------------------------------
const char*
json::tree::node::as_chars (void) const&
{
    return as_string ().native ().c_str ();
}


///////////////////////////////////////////////////////////////////////////////
namespace json::tree {
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wuseless-cast"
#endif
    template <>
    bool node::as (void) const
    {
        return as_bool ();
    }


//-----------------------------------------------------------------------------
    template <>
    float json::tree::node::as (void) const
    {
        return as_float ();
    }


//-----------------------------------------------------------------------------
    template <>
    double
    json::tree::node::as (void) const
    {
        return as_double ();
    }


//-----------------------------------------------------------------------------
    template <>
    uint32_t
    json::tree::node::as (void) const
    {
        return static_cast<uint32_t> (as_uint ());
    }


//-----------------------------------------------------------------------------
    template <>
    uint64_t
    json::tree::node::as (void) const
    {
        return static_cast<uint64_t> (as_uint ());
    }


//-----------------------------------------------------------------------------
    template <>
    int32_t
    json::tree::node::as (void) const
    {
        return static_cast<int32_t> (as_sint ());
    }


//-----------------------------------------------------------------------------
    template <>
    int64_t
    json::tree::node::as (void) const
    {
        return static_cast<int64_t> (as_sint ());
    }


    //-------------------------------------------------------------------------
    template <>
    const std::string&
    json::tree::node::as (void) const
    {
        return as_string ().native ();
    }
#if defined(__clang__)
#elif defined(__GNUC__)
#pragma GCC diagnostic pop
#endif
}


///////////////////////////////////////////////////////////////////////////////
// Global operatoers
bool
json::tree::node::operator!= (const node &rhs) const
    { return !(*this == rhs); }


//-----------------------------------------------------------------------------
bool json::tree::node::operator==(const char *rhs) const
{
    try {
        return as_string ().native () == rhs;
    } catch (const json::type_error&) {
        return false;
    }
}


//-----------------------------------------------------------------------------
json::tree::node&
json::tree::node::operator[] (const std::string &key)&
    { return as_object ()[key]; }


//-----------------------------------------------------------------------------
json::tree::node&
json::tree::node::operator[] (size_t idx)&
    { return as_array()[idx]; }


//-----------------------------------------------------------------------------
const json::tree::node&
json::tree::node::operator[] (const std::string &key) const&
    { return as_object ()[key]; }


//-----------------------------------------------------------------------------
const json::tree::node&
json::tree::node::operator[] (size_t idx) const&
    { return as_array()[idx]; }


///////////////////////////////////////////////////////////////////////////////
// Object
json::tree::object::~object ()
    { ; }


//-----------------------------------------------------------------------------
std::unique_ptr<json::tree::node>
json::tree::object::clone (void) const
{
    auto obj = std::make_unique<json::tree::object> ();

    for (auto &i: *this)
        obj->insert (i.first, i.second->clone ());

    return std::move (obj);
}


//-----------------------------------------------------------------------------
bool
json::tree::object::operator== (const json::tree::object &rhs) const
{
    if (rhs.size () != size ())
        return false;

    for (auto const &[i,j]: util::zip (m_values, rhs.m_values)) {
        if (i.first != j.first)
            return false;

        if (*i.second != *j.second)
            return false;
    }

    return true;
}


//-----------------------------------------------------------------------------
void
json::tree::object::insert (const std::string &_key, std::unique_ptr<json::tree::node> &&value)
{
    m_values[_key] = move(value);
}


//-----------------------------------------------------------------------------
json::tree::node&
json::tree::object::operator[](const std::string &key)&
{
    auto value = m_values.find (key);
    if (value == m_values.end ())
        throw json::key_error (key);

    return *value->second;
}


//-----------------------------------------------------------------------------
const json::tree::node&
json::tree::object::operator[](const std::string &key) const&
{
    auto value = m_values.find (key);
    if (value == m_values.end ())
        throw json::key_error (key);

    return *value->second;
}


//-----------------------------------------------------------------------------
bool
json::tree::object::has (const std::string &key) const
{
    return m_values.find (key) != m_values.end ();
}


//-----------------------------------------------------------------------------
json::tree::object::const_iterator
json::tree::object::find (const std::string &key) const
{
    return m_values.find (key);
}


//-----------------------------------------------------------------------------
json::tree::object::const_iterator
json::tree::object::begin (void) const
    { return m_values.begin (); }


//-----------------------------------------------------------------------------
json::tree::object::const_iterator
json::tree::object::end (void) const
    { return m_values.end (); }


//-----------------------------------------------------------------------------
size_t
json::tree::object::size (void) const
{
    return m_values.size ();
}


//-----------------------------------------------------------------------------
void
json::tree::object::clear (void)
{
    m_values.clear ();
}


//-----------------------------------------------------------------------------
void
json::tree::object::erase (const std::string &key)
{
    auto pos = m_values.find (key);
    if (pos == m_values.end ())
        throw json::error ("erasing invalid key");

    m_values.erase (key);
}


//-----------------------------------------------------------------------------
std::ostream&
json::tree::object::write (std::ostream &os) const
{
    os << "{\n";
    {
        util::indenter raii(os);

        for (auto i = m_values.begin (); i != m_values.end ();) {
            os << '"' << i->first << "\" : " << *i->second;

            if (++i != m_values.end ())
                os << ",\n";
        }
    }

    os << "\n}";
    return os;
}


///////////////////////////////////////////////////////////////////////////////
// Array

json::tree::array::~array()
{
    m_values.clear ();
}


//-----------------------------------------------------------------------------
std::unique_ptr<json::tree::node>
json::tree::array::clone (void) const
{
    auto ret = std::make_unique<array> ();

    for (const auto &i: *this)
        ret->insert (i.clone ());

    return std::move (ret);
}


//-----------------------------------------------------------------------------
void
json::tree::array::insert (std::unique_ptr<json::tree::node> &&_value)
{
    m_values.push_back (move (_value));
}


//-----------------------------------------------------------------------------
bool
json::tree::array::operator==(const json::tree::array &rhs) const
{
    if (rhs.size () != size ())
        return false;

    for (auto const &[i,j]: util::zip (m_values, rhs.m_values))
        if (*i != *j)
            return false;

    return true;
}


//-----------------------------------------------------------------------------
bool
json::tree::array::operator== (const node &rhs) const
{
    return rhs == *this;
}


//-----------------------------------------------------------------------------
size_t
json::tree::array::size (void) const
{
    return m_values.size ();
}


//-----------------------------------------------------------------------------
json::tree::node&
json::tree::array::operator[] (size_t idx)&
{
    return *m_values[idx];
}


//-----------------------------------------------------------------------------
const json::tree::node&
json::tree::array::operator[] (size_t idx) const&
{
    return *m_values[idx];
}


//-----------------------------------------------------------------------------
json::tree::array::iterator
json::tree::array::begin (void)
{
    return iterator (m_values.begin ());
}



//-----------------------------------------------------------------------------
json::tree::array::iterator
json::tree::array::end (void)
{
    return iterator (m_values.end ());
}



//-----------------------------------------------------------------------------
json::tree::array::const_iterator
json::tree::array::begin (void) const
{
    return const_iterator (m_values.begin ());
}



//-----------------------------------------------------------------------------
json::tree::array::const_iterator
json::tree::array::end (void) const
{
    return const_iterator (m_values.end ());
}



//-----------------------------------------------------------------------------
json::tree::array::const_iterator
json::tree::array::cbegin (void) const
{
    return const_iterator (m_values.cbegin ());
}


//-----------------------------------------------------------------------------
json::tree::array::const_iterator
json::tree::array::cend (void) const
{
    return const_iterator (m_values.cend ());
}


//-----------------------------------------------------------------------------
std::ostream&
json::tree::array::write (std::ostream &os) const {
    os << "[\n";
    {
        util::indenter raii(os);

        for (auto i = m_values.begin (); i != m_values.end (); ++i) {
            (*i)->write (os);

            if (i != m_values.end () - 1)
                os << ",\n";
        }
    }
    os << "\n]";
    return os;
}


///////////////////////////////////////////////////////////////////////////////
// String

std::unique_ptr<json::tree::node>
json::tree::string::clone (void) const
{
    return std::make_unique<json::tree::string> (m_value);
}


//-----------------------------------------------------------------------------
std::ostream&
json::tree::string::write (std::ostream &os) const
{
    os << '"' << m_value << '"';
    return os;
}


//-----------------------------------------------------------------------------
bool
json::tree::string::operator== (const json::tree::string &rhs) const
    { return rhs.m_value == m_value; }


//-----------------------------------------------------------------------------
bool
json::tree::string::operator== (const char *rhs) const
    { return rhs == m_value; }


//-----------------------------------------------------------------------------
bool
json::tree::string::operator== (const std::string &rhs) const
    { return rhs == m_value; }

///////////////////////////////////////////////////////////////////////////////
// Number

std::unique_ptr<json::tree::node>
json::tree::number::clone (void) const
{
    switch (m_repr) {
    case REAL: return std::make_unique<json::tree::number> (m_value.r);
    case SINT: return std::make_unique<json::tree::number> (m_value.s);
    case UINT: return std::make_unique<json::tree::number> (m_value.u);
    }

    unreachable ();
}


//-----------------------------------------------------------------------------
std::ostream&
json::tree::number::write (std::ostream &os) const
{
    util::stream::scoped::precision p (os);

    switch (m_repr) {
    case REAL: return os << std::setprecision (std::numeric_limits<real_t>::digits10) << m_value.r;
    case SINT: return os << std::setprecision (std::numeric_limits<sint_t>::digits10) << m_value.s;
    case UINT: return os << std::setprecision (std::numeric_limits<uint_t>::digits10) << m_value.u;
    }

    unreachable ();
}


//-----------------------------------------------------------------------------
bool
json::tree::number::operator ==(const json::tree::number &rhs) const {
    if (repr () != rhs.repr ())
        return false;

    switch (repr ()) {
    case REAL: return util::almost_equal (real (), rhs.real ());
    case SINT: return util::almost_equal (sint (), rhs.sint ());
    case UINT: return util::almost_equal (uint (), rhs.uint ());
    }

    unreachable ();
}


///////////////////////////////////////////////////////////////////////////////
json::tree::number::real_t
json::tree::number::real (void) const
{
    switch (repr ()) {
    case REAL:
        return m_value.r;

    case UINT:
        if (uint_t (real_t (m_value.u)) != m_value.u)
            throw type_error ("number is not a real");
        return m_value.u;

    case SINT:
        if (sint_t (real_t (m_value.s)) != m_value.s)
            throw type_error ("number is not a real");
        return m_value.s;
    }

    unreachable ();
}


//-----------------------------------------------------------------------------
json::tree::number::sint_t
json::tree::number::sint (void) const
{
    switch (repr ()) {
    case SINT:
        return m_value.s;

    case REAL:
        if (!::util::equal (real_t (sint_t (m_value.r)), m_value.r))
            throw type_error ("number is not a sint");
        return sint_t (m_value.r);

    case UINT:
        if (uint_t (sint_t (m_value.u)) != m_value.u)
            throw type_error ("number is not a sint");
        return m_value.s;
    }

    unreachable ();
}


//-----------------------------------------------------------------------------
json::tree::number::uint_t
json::tree::number::uint (void) const
{
    switch (repr ()) {
    case UINT:
        return m_value.u;

    case REAL:
        if (!::util::equal (real_t (uint_t (m_value.r)), m_value.r))
            throw type_error ("number is not a uint");
        return uint_t (m_value.r);

    case SINT:
        if (sint_t (uint_t (m_value.s)) != m_value.s)
            throw type_error ("number is not a uint");
        return m_value.s;
    }

    unreachable ();
}


///////////////////////////////////////////////////////////////////////////////
json::tree::number::operator json::tree::number::real_t (void) const
{
    return real ();
}


//-----------------------------------------------------------------------------
json::tree::number::operator json::tree::number::sint_t (void) const
{
    return sint ();
}


//-----------------------------------------------------------------------------
json::tree::number::operator json::tree::number::uint_t (void) const
{
    return uint ();
}


///////////////////////////////////////////////////////////////////////////////
// Boolean

std::unique_ptr<json::tree::node>
json::tree::boolean::clone (void) const
{
    return std::make_unique<json::tree::boolean> (m_value);
}


//-----------------------------------------------------------------------------
std::ostream&
json::tree::boolean::write (std::ostream &os) const
{
    os << (m_value ? "true" : "false");
    return os;
}


//-----------------------------------------------------------------------------
bool
json::tree::boolean::operator ==(const json::tree::boolean &rhs) const
    { return rhs.m_value == m_value; }


///////////////////////////////////////////////////////////////////////////////
// Null

std::unique_ptr<json::tree::node>
json::tree::null::clone (void) const
{
    return std::make_unique<json::tree::null> ();
}


//-----------------------------------------------------------------------------
std::ostream&
json::tree::null::write (std::ostream &os) const
{
    os << "null";
    return os;
}


//-----------------------------------------------------------------------------
std::ostream&
json::tree::operator<< (std::ostream &os, const json::tree::node &n)
    { return n.write (os); }


//-----------------------------------------------------------------------------
// to_json

namespace json::tree {
    template <>
    std::unique_ptr<node>
    io<bool>::serialise (const bool &b) {
        return std::unique_ptr<node> (new boolean (b));
    }

    template <>
    std::unique_ptr<node>
    io<std::nullptr_t>::serialise (const std::nullptr_t &) {
        return std::unique_ptr<node> (new null ());
    }

    template <>
    std::unique_ptr<node>
    io<std::string>::serialise (const std::string &s) {
        return std::unique_ptr<node> (new string (s));
    }

    template <>
    std::unique_ptr<node>
    io<int32_t>::serialise (const int32_t &i) {
        return std::unique_ptr<node> (new number (intmax_t {i}));
    }

    template <>
    std::unique_ptr<node>
    io<int64_t>::serialise (const int64_t &i) {
        return std::unique_ptr<node> (new number (intmax_t {i}));
    }

    template <>
    std::unique_ptr<node>
    io<uint32_t>::serialise (const uint32_t &i) {
        return std::unique_ptr<node> (new number (uintmax_t {i}));
    }

    template <>
    std::unique_ptr<node>
    io<uint64_t>::serialise (const uint64_t &i) {
        return std::unique_ptr<node> (new number (uintmax_t {i}));
    }

    template <>
    std::unique_ptr<node>
    io<float>::serialise (const float &f) {
        return std::unique_ptr<node> (new number (f));
    }
}