jsonpath_rust/parser/
model.rs

use serde_json::Value;

use crate::path::JsonLike;

use super::errors::JsonPathParserError;
use super::parse_json_path;
use std::fmt::{Display, Formatter};
use std::{convert::TryFrom, str::FromStr};

/// The basic structures for parsing json paths.
/// The common logic of the structures pursues to correspond the internal parsing structure.
///
/// usually it's created by using [`FromStr`] or [`TryFrom<&str>`]
#[derive(Debug, Clone)]
pub enum JsonPath<T = Value> {
    /// The $ operator
    Root,
    /// Field represents key
    Field(String),
    /// The whole chain of the path.
    Chain(Vec<JsonPath<T>>),
    /// The .. operator
    Descent(String),
    /// The ..* operator
    DescentW,
    /// The indexes for array
    Index(JsonPathIndex<T>),
    /// The @ operator
    Current(Box<JsonPath<T>>),
    /// The * operator
    Wildcard,
    /// The item uses to define the unresolved state
    Empty,
    /// Functions that can calculate some expressions
    Fn(Function),
}

impl<T: Display> Display for JsonPath<T> {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        let str = match self {
            JsonPath::Root => "$".to_string(),
            JsonPath::Field(e) => format!(".'{}'", e),
            JsonPath::Chain(elems) => elems.iter().map(ToString::to_string).collect::<String>(),
            JsonPath::Descent(e) => {
                format!("..{}", e)
            }
            JsonPath::DescentW => "..*".to_string(),
            JsonPath::Index(e) => e.to_string(),
            JsonPath::Current(e) => format!("@{}", e),
            JsonPath::Wildcard => "[*]".to_string(),
            JsonPath::Empty => "".to_string(),
            JsonPath::Fn(e) => format!(".{}", e),
        };
        write!(f, "{}", str)
    }
}

impl<T> TryFrom<&str> for JsonPath<T>
where
    T: JsonLike,
{
    type Error = JsonPathParserError;

    /// Parses a string into a [JsonPath].
    ///
    /// # Errors
    ///
    /// Returns a variant of [JsonPathParserError] if the parsing operation failed.
    fn try_from(value: &str) -> Result<Self, Self::Error> {
        parse_json_path(value)
    }
}

impl<T> FromStr for JsonPath<T>
where
    T: JsonLike,
{
    type Err = JsonPathParserError;

    /// Parses a string into a [JsonPath].
    ///
    /// # Errors
    ///
    /// Returns a variant of [JsonPathParserError] if the parsing operation failed.
    fn from_str(value: &str) -> Result<Self, Self::Err> {
        parse_json_path(value)
    }
}

#[derive(Debug, PartialEq, Clone)]
pub enum Function {
    /// length()
    Length,
}

impl Display for Function {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        let str = match self {
            Function::Length => "length()".to_string(),
        };
        write!(f, "{}", str)
    }
}

#[derive(Debug, Clone)]
pub enum JsonPathIndex<T> {
    /// A single element in array
    Single(T),
    /// Union represents a several indexes
    UnionIndex(Vec<T>),
    /// Union represents a several keys
    UnionKeys(Vec<String>),
    /// DEfault slice where the items are start/end/step respectively
    Slice(i32, i32, usize),
    /// Filter ?()
    Filter(FilterExpression<T>),
}

impl<T: Display> Display for JsonPathIndex<T> {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        let str = match self {
            JsonPathIndex::Single(e) => format!("[{}]", e),
            JsonPathIndex::UnionIndex(elems) => {
                format!(
                    "[{}]",
                    elems
                        .iter()
                        .map(ToString::to_string)
                        .collect::<Vec<_>>()
                        .join(",")
                )
            }
            JsonPathIndex::UnionKeys(elems) => {
                format!(
                    "[{}]",
                    elems
                        .iter()
                        .map(|el| format!("'{}'", el))
                        .collect::<Vec<_>>()
                        .join(",")
                )
            }
            JsonPathIndex::Slice(s, e, st) => {
                format!("[{}:{}:{}]", s, e, st)
            }
            JsonPathIndex::Filter(filter) => format!("[?({})]", filter),
        };
        write!(f, "{}", str)
    }
}

#[derive(Debug, Clone, PartialEq)]
pub enum FilterExpression<T> {
    /// a single expression like a > 2
    Atom(Operand<T>, FilterSign, Operand<T>),
    /// and with &&
    And(Box<FilterExpression<T>>, Box<FilterExpression<T>>),
    /// or with ||
    Or(Box<FilterExpression<T>>, Box<FilterExpression<T>>),
    /// not with !
    Not(Box<FilterExpression<T>>),
}

impl<T: Display> Display for FilterExpression<T> {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        let str = match self {
            FilterExpression::Atom(left, sign, right) => {
                format!("{} {} {}", left, sign, right)
            }
            FilterExpression::And(left, right) => {
                format!("{} && {}", left, right)
            }
            FilterExpression::Or(left, right) => {
                format!("{} || {}", left, right)
            }
            FilterExpression::Not(expr) => {
                format!("!{}", expr)
            }
        };
        write!(f, "{}", str)
    }
}

impl<T> FilterExpression<T> {
    pub fn exists(op: Operand<T>) -> Self {
        FilterExpression::Atom(
            op,
            FilterSign::Exists,
            Operand::Dynamic(Box::new(JsonPath::Empty)),
        )
    }
}

/// Operand for filtering expressions
#[derive(Debug, Clone)]
pub enum Operand<T> {
    Static(T),
    Dynamic(Box<JsonPath<T>>),
}

impl<T: Display> Display for Operand<T> {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        let str = match self {
            Operand::Static(e) => e.to_string(),
            Operand::Dynamic(e) => e.to_string(),
        };
        write!(f, "{}", str)
    }
}

#[allow(dead_code)]
impl<T> Operand<T> {
    pub fn val(v: T) -> Self {
        Operand::Static(v)
    }
}

/// The operators for filtering functions
#[derive(Debug, Clone, PartialEq)]
pub enum FilterSign {
    Equal,
    Unequal,
    Less,
    Greater,
    LeOrEq,
    GrOrEq,
    Regex,
    In,
    Nin,
    Size,
    NoneOf,
    AnyOf,
    SubSetOf,
    Exists,
}

impl Display for FilterSign {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        let str = match self {
            FilterSign::Equal => "==",
            FilterSign::Unequal => "!=",
            FilterSign::Less => "<",
            FilterSign::Greater => ">",
            FilterSign::LeOrEq => "<=",
            FilterSign::GrOrEq => ">=",
            FilterSign::Regex => "~=",
            FilterSign::In => "in",
            FilterSign::Nin => "nin",
            FilterSign::Size => "size",
            FilterSign::NoneOf => "noneOf",
            FilterSign::AnyOf => "anyOf",
            FilterSign::SubSetOf => "subsetOf",
            FilterSign::Exists => "exists",
        };
        write!(f, "{}", str)
    }
}

impl FilterSign {
    pub fn new(key: &str) -> Self {
        match key {
            "==" => FilterSign::Equal,
            "!=" => FilterSign::Unequal,
            "<" => FilterSign::Less,
            ">" => FilterSign::Greater,
            "<=" => FilterSign::LeOrEq,
            ">=" => FilterSign::GrOrEq,
            "~=" => FilterSign::Regex,
            "in" => FilterSign::In,
            "nin" => FilterSign::Nin,
            "size" => FilterSign::Size,
            "noneOf" => FilterSign::NoneOf,
            "anyOf" => FilterSign::AnyOf,
            "subsetOf" => FilterSign::SubSetOf,
            _ => FilterSign::Exists,
        }
    }
}

impl<T> PartialEq for JsonPath<T>
where
    T: PartialEq,
{
    fn eq(&self, other: &Self) -> bool {
        match (self, other) {
            (JsonPath::Root, JsonPath::Root) => true,
            (JsonPath::Descent(k1), JsonPath::Descent(k2)) => k1 == k2,
            (JsonPath::DescentW, JsonPath::DescentW) => true,
            (JsonPath::Field(k1), JsonPath::Field(k2)) => k1 == k2,
            (JsonPath::Wildcard, JsonPath::Wildcard) => true,
            (JsonPath::Empty, JsonPath::Empty) => true,
            (JsonPath::Current(jp1), JsonPath::Current(jp2)) => jp1 == jp2,
            (JsonPath::Chain(ch1), JsonPath::Chain(ch2)) => ch1 == ch2,
            (JsonPath::Index(idx1), JsonPath::Index(idx2)) => idx1 == idx2,
            (JsonPath::Fn(fn1), JsonPath::Fn(fn2)) => fn2 == fn1,
            (_, _) => false,
        }
    }
}

impl<T> PartialEq for JsonPathIndex<T>
where
    T: PartialEq,
{
    fn eq(&self, other: &Self) -> bool {
        match (self, other) {
            (JsonPathIndex::Slice(s1, e1, st1), JsonPathIndex::Slice(s2, e2, st2)) => {
                s1 == s2 && e1 == e2 && st1 == st2
            }
            (JsonPathIndex::Single(el1), JsonPathIndex::Single(el2)) => el1 == el2,
            (JsonPathIndex::UnionIndex(elems1), JsonPathIndex::UnionIndex(elems2)) => {
                elems1 == elems2
            }
            (JsonPathIndex::UnionKeys(elems1), JsonPathIndex::UnionKeys(elems2)) => {
                elems1 == elems2
            }
            (JsonPathIndex::Filter(left), JsonPathIndex::Filter(right)) => left.eq(right),
            (_, _) => false,
        }
    }
}

impl<T> PartialEq for Operand<T>
where
    T: PartialEq,
{
    fn eq(&self, other: &Self) -> bool {
        match (self, other) {
            (Operand::Static(v1), Operand::Static(v2)) => v1 == v2,
            (Operand::Dynamic(jp1), Operand::Dynamic(jp2)) => jp1 == jp2,
            (_, _) => false,
        }
    }
}
jsonpath_rust/parser/model.rs

jsonpath_rust/parser/
model.rs
