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/json/json_forwards.h>
#include <cstring>
#include <map>
#include <string>
#include <vector>
 
namespace Json {
 
enum ValueType {
    nullValue = 0,  
    intValue,       
    uintValue,      
    realValue,      
    stringValue,    
    booleanValue,   
    arrayValue,     
    objectValue     
};
 
class StaticString
{
public:
    constexpr explicit StaticString(const char* czstring) : str_(czstring)
    {
    }
 
    constexpr
    operator const char*() const
    {
        return str_;
    }
 
    constexpr const char*
    c_str() const
    {
        return str_;
    }
 
private:
    const char* 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 const Value null;
    static const Int minInt;
    static const Int maxInt;
    static const UInt maxUInt;
 
private:
    class CZString
    {
    public:
        enum DuplicationPolicy {
            noDuplication = 0,
            duplicate,
            duplicateOnCopy
        };
        CZString(int index);
        CZString(const char* cstr, DuplicationPolicy allocate);
        CZString(const CZString& other);
        ~CZString();
        CZString&
        operator=(const CZString& other) = delete;
        bool
        operator<(const CZString& other) const;
        bool
        operator==(const CZString& other) const;
        int
        index() const;
        const char*
        c_str() const;
        bool
        isStaticString() const;
 
    private:
        const char* 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(const char* value);
    Value(const StaticString& value);
    Value(std::string const& value);
    Value(bool value);
    Value(const Value& other);
    ~Value();
 
    Value&
    operator=(Value const& other);
    Value&
    operator=(Value&& other);
 
    Value(Value&& other) noexcept;
 
    void
    swap(Value& other) noexcept;
 
    ValueType
    type() const;
 
    const char*
    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);
    const Value&
    operator[](UInt index) const;
    Value
    get(UInt index, const Value& defaultValue) const;
    bool
    isValidIndex(UInt index) const;
    Value&
    append(const Value& value);
    Value&
    append(Value&& value);
 
    Value&
    operator[](const char* key);
    const Value&
    operator[](const char* key) const;
    Value&
    operator[](std::string const& key);
    const Value&
    operator[](std::string const& key) const;
    Value&
    operator[](const StaticString& key);
 
    Value
    get(const char* key, const Value& defaultValue) const;
    Value
    get(std::string const& key, const Value& defaultValue) const;
 
    Value
    removeMember(const char* key);
    Value
    removeMember(std::string const& key);
 
    bool
    isMember(const char* 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==(const Value&, const Value&);
    friend bool
    operator<(const Value&, const Value&);
 
private:
    Value&
    resolveReference(const char* 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.
};
 
bool
operator==(const Value&, const Value&);
 
inline bool
operator!=(const Value& x, const Value& y)
{
    return !(x == y);
}
 
bool
operator<(const Value&, const Value&);
 
inline bool
operator<=(const Value& x, const Value& y)
{
    return !(y < x);
}
 
inline bool
operator>(const Value& x, const Value& y)
{
    return y < x;
}
 
inline bool
operator>=(const Value& x, const Value& y)
{
    return !(x < y);
}
 
class ValueAllocator
{
public:
    enum { unknown = (unsigned)-1 };
 
    virtual ~ValueAllocator() = default;
 
    virtual char*
    makeMemberName(const char* memberName) = 0;
    virtual void
    releaseMemberName(char* memberName) = 0;
    virtual char*
    duplicateStringValue(const char* 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(const Value::ObjectValues::iterator& current);
 
    bool
    operator==(const SelfType& other) const
    {
        return isEqual(other);
    }
 
    bool
    operator!=(const SelfType& other) const
    {
        return !isEqual(other);
    }
 
    Value
    key() const;
 
    UInt
    index() const;
 
    const char*
    memberName() const;
 
protected:
    Value&
    deref() const;
 
    void
    increment();
 
    void
    decrement();
 
    difference_type
    computeDistance(const SelfType& other) const;
 
    bool
    isEqual(const SelfType& other) const;
 
    void
    copy(const SelfType& 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 = const Value&;
    using pointer = const Value*;
    using SelfType = ValueConstIterator;
 
    ValueConstIterator() = default;
 
private:
    explicit ValueConstIterator(const Value::ObjectValues::iterator& current);
 
public:
    SelfType&
    operator=(const ValueIteratorBase& 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(const ValueConstIterator& other);
    ValueIterator(const ValueIterator& other);
 
private:
    explicit ValueIterator(const Value::ObjectValues::iterator& current);
 
public:
    SelfType&
    operator=(const SelfType& 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