json_value.h

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2012, 2013 Ripple Labs Inc.
 
    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.
 
    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
 
#ifndef RIPPLE_JSON_JSON_VALUE_H_INCLUDED
#define RIPPLE_JSON_JSON_VALUE_H_INCLUDED
 
#include <xrpl/basics/Number.h>
#include <xrpl/json/json_forwards.h>
 
#include <cstring>
#include <map>
#include <string>
#include <utility>
#include <vector>
 
namespace Json {
 
enum ValueType {
    nullValue = 0,  
    intValue,       
    uintValue,      
    realValue,      
    stringValue,    
    booleanValue,   
    arrayValue,     
    objectValue     
};
 
class StaticString
{
public:
    constexpr explicit StaticString(char const* czstring) : str_(czstring)
    {
    }
 
    constexpr
    operator char const*() const
    {
        return str_;
    }
 
    constexpr char const*
    c_str() const
    {
        return str_;
    }
 
private:
    char const* str_;
};
 
inline bool
operator==(StaticString x, StaticString y)
{
    return strcmp(x.c_str(), y.c_str()) == 0;
}
 
inline bool
operator!=(StaticString x, StaticString y)
{
    return !(x == y);
}
 
inline bool
operator==(std::string const& x, StaticString y)
{
    return strcmp(x.c_str(), y.c_str()) == 0;
}
 
inline bool
operator!=(std::string const& x, StaticString y)
{
    return !(x == y);
}
 
inline bool
operator==(StaticString x, std::string const& y)
{
    return y == x;
}
 
inline bool
operator!=(StaticString x, std::string const& y)
{
    return !(y == x);
}
 
class Value
{
    friend class ValueIteratorBase;
 
public:
    using Members = std::vector<std::string>;
    using iterator = ValueIterator;
    using const_iterator = ValueConstIterator;
    using UInt = Json::UInt;
    using Int = Json::Int;
    using ArrayIndex = UInt;
 
    static Value const null;
    static Int const minInt;
    static Int const maxInt;
    static UInt const maxUInt;
 
private:
    class CZString
    {
    public:
        enum DuplicationPolicy {
            noDuplication = 0,
            duplicate,
            duplicateOnCopy
        };
        CZString(int index);
        CZString(char const* cstr, DuplicationPolicy allocate);
        CZString(CZString const& other);
        ~CZString();
        CZString&
        operator=(CZString const& other) = delete;
        bool
        operator<(CZString const& other) const;
        bool
        operator==(CZString const& other) const;
        int
        index() const;
        char const*
        c_str() const;
        bool
        isStaticString() const;
 
    private:
        char const* cstr_;
        int index_;
    };
 
public:
    using ObjectValues = std::map<CZString, Value>;
 
public:
    Value(ValueType type = nullValue);
    Value(Int value);
    Value(UInt value);
    Value(double value);
    Value(char const* value);
    Value(ripple::Number const& value);
    Value(StaticString const& value);
    Value(std::string const& value);
    Value(bool value);
    Value(Value const& other);
    ~Value();
 
    Value&
    operator=(Value const& other);
    Value&
    operator=(Value&& other);
 
    Value(Value&& other) noexcept;
 
    void
    swap(Value& other) noexcept;
 
    ValueType
    type() const;
 
    char const*
    asCString() const;
    std::string
    asString() const;
    Int
    asInt() const;
    UInt
    asUInt() const;
    double
    asDouble() const;
    bool
    asBool() const;
 
    // TODO: What is the "empty()" method this docstring mentions?
    bool
    isNull() const;
    bool
    isBool() const;
    bool
    isInt() const;
    bool
    isUInt() const;
    bool
    isIntegral() const;
    bool
    isDouble() const;
    bool
    isNumeric() const;
    bool
    isString() const;
    bool
    isArray() const;
    bool
    isArrayOrNull() const;
    bool
    isObject() const;
    bool
    isObjectOrNull() const;
 
    bool
    isConvertibleTo(ValueType other) const;
 
    UInt
    size() const;
 
    explicit
    operator bool() const;
 
    void
    clear();
 
    Value&
    operator[](UInt index);
    Value const&
    operator[](UInt index) const;
    Value
    get(UInt index, Value const& defaultValue) const;
    bool
    isValidIndex(UInt index) const;
    Value&
    append(Value const& value);
    Value&
    append(Value&& value);
 
    Value&
    operator[](char const* key);
    Value const&
    operator[](char const* key) const;
    Value&
    operator[](std::string const& key);
    Value const&
    operator[](std::string const& key) const;
    Value&
    operator[](StaticString const& key);
    Value const&
    operator[](StaticString const& key) const;
 
    Value
    get(char const* key, Value const& defaultValue) const;
    Value
    get(std::string const& key, Value const& defaultValue) const;
 
    Value
    removeMember(char const* key);
    Value
    removeMember(std::string const& key);
 
    bool
    isMember(char const* key) const;
    bool
    isMember(std::string const& key) const;
 
    Members
    getMemberNames() const;
 
    std::string
    toStyledString() const;
 
    const_iterator
    begin() const;
    const_iterator
    end() const;
 
    iterator
    begin();
    iterator
    end();
 
    friend bool
    operator==(Value const&, Value const&);
    friend bool
    operator<(Value const&, Value const&);
 
private:
    Value&
    resolveReference(char const* key, bool isStatic);
 
private:
    union ValueHolder
    {
        Int int_;
        UInt uint_;
        double real_;
        bool bool_;
        char* string_;
        ObjectValues* map_{nullptr};
    } value_;
    ValueType type_ : 8;
    int allocated_ : 1;  // Notes: if declared as bool, bitfield is useless.
};
 
inline Value
to_json(ripple::Number const& number)
{
    return to_string(number);
}
 
bool
operator==(Value const&, Value const&);
 
inline bool
operator!=(Value const& x, Value const& y)
{
    return !(x == y);
}
 
bool
operator<(Value const&, Value const&);
 
inline bool
operator<=(Value const& x, Value const& y)
{
    return !(y < x);
}
 
inline bool
operator>(Value const& x, Value const& y)
{
    return y < x;
}
 
inline bool
operator>=(Value const& x, Value const& y)
{
    return !(x < y);
}
 
class ValueAllocator
{
public:
    enum { unknown = (unsigned)-1 };
 
    virtual ~ValueAllocator() = default;
 
    virtual char*
    makeMemberName(char const* memberName) = 0;
    virtual void
    releaseMemberName(char* memberName) = 0;
    virtual char*
    duplicateStringValue(char const* value, unsigned int length = unknown) = 0;
    virtual void
    releaseStringValue(char* value) = 0;
};
 
class ValueIteratorBase
{
public:
    using size_t = unsigned int;
    using difference_type = int;
    using SelfType = ValueIteratorBase;
 
    ValueIteratorBase();
 
    explicit ValueIteratorBase(Value::ObjectValues::iterator const& current);
 
    bool
    operator==(SelfType const& other) const
    {
        return isEqual(other);
    }
 
    bool
    operator!=(SelfType const& other) const
    {
        return !isEqual(other);
    }
 
    Value
    key() const;
 
    UInt
    index() const;
 
    char const*
    memberName() const;
 
protected:
    Value&
    deref() const;
 
    void
    increment();
 
    void
    decrement();
 
    difference_type
    computeDistance(SelfType const& other) const;
 
    bool
    isEqual(SelfType const& other) const;
 
    void
    copy(SelfType const& other);
 
private:
    Value::ObjectValues::iterator current_;
    // Indicates that iterator is for a null value.
    bool isNull_;
};
 
class ValueConstIterator : public ValueIteratorBase
{
    friend class Value;
 
public:
    using size_t = unsigned int;
    using difference_type = int;
    using reference = Value const&;
    using pointer = Value const*;
    using SelfType = ValueConstIterator;
 
    ValueConstIterator() = default;
 
private:
    explicit ValueConstIterator(Value::ObjectValues::iterator const& current);
 
public:
    SelfType&
    operator=(ValueIteratorBase const& other);
 
    SelfType
    operator++(int)
    {
        SelfType temp(*this);
        ++*this;
        return temp;
    }
 
    SelfType
    operator--(int)
    {
        SelfType temp(*this);
        --*this;
        return temp;
    }
 
    SelfType&
    operator--()
    {
        decrement();
        return *this;
    }
 
    SelfType&
    operator++()
    {
        increment();
        return *this;
    }
 
    reference
    operator*() const
    {
        return deref();
    }
};
 
class ValueIterator : public ValueIteratorBase
{
    friend class Value;
 
public:
    using size_t = unsigned int;
    using difference_type = int;
    using reference = Value&;
    using pointer = Value*;
    using SelfType = ValueIterator;
 
    ValueIterator() = default;
    ValueIterator(ValueConstIterator const& other);
    ValueIterator(ValueIterator const& other);
 
private:
    explicit ValueIterator(Value::ObjectValues::iterator const& current);
 
public:
    SelfType&
    operator=(SelfType const& other);
 
    SelfType
    operator++(int)
    {
        SelfType temp(*this);
        ++*this;
        return temp;
    }
 
    SelfType
    operator--(int)
    {
        SelfType temp(*this);
        --*this;
        return temp;
    }
 
    SelfType&
    operator--()
    {
        decrement();
        return *this;
    }
 
    SelfType&
    operator++()
    {
        increment();
        return *this;
    }
 
    reference
    operator*() const
    {
        return deref();
    }
};
 
}  // namespace Json
 
#endif  // CPPTL_JSON_H_INCLUDED