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use std::{fmt, fmt::Write, slice::Iter};
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct JSONPointer(Vec<PathChunk>);
impl JSONPointer {
#[must_use]
pub fn into_vec(self) -> Vec<String> {
self.0
.into_iter()
.map(|item| match item {
PathChunk::Property(value) => value,
PathChunk::Index(idx) => idx.to_string(),
PathChunk::Keyword(keyword) => keyword.to_string(),
})
.collect()
}
#[must_use]
pub fn iter(&self) -> Iter<'_, PathChunk> {
self.0.iter()
}
#[inline]
pub fn last(&self) -> Option<&PathChunk> {
self.0.last()
}
pub(crate) fn clone_with(&self, chunk: impl Into<PathChunk>) -> Self {
let mut new = self.clone();
new.0.push(chunk.into());
new
}
pub(crate) fn extend_with(&self, chunks: &[PathChunk]) -> Self {
let mut new = self.clone();
new.0.extend_from_slice(chunks);
new
}
pub(crate) fn as_slice(&self) -> &[PathChunk] {
&self.0
}
}
impl Default for JSONPointer {
fn default() -> Self {
JSONPointer(Vec::new())
}
}
impl fmt::Display for JSONPointer {
fn fmt(&self, mut f: &mut fmt::Formatter<'_>) -> fmt::Result {
if !self.0.is_empty() {
for chunk in &self.0 {
f.write_char('/')?;
match chunk {
PathChunk::Property(value) => {
for ch in value.chars() {
match ch {
'/' => f.write_str("~1")?,
'~' => f.write_str("~0")?,
_ => f.write_char(ch)?,
}
}
}
PathChunk::Index(idx) => itoa::fmt(&mut f, *idx)?,
PathChunk::Keyword(keyword) => f.write_str(keyword)?,
}
}
}
Ok(())
}
}
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum PathChunk {
Property(String),
Index(usize),
Keyword(&'static str),
}
#[derive(Debug, Clone)]
pub(crate) struct InstancePath<'a> {
pub(crate) chunk: Option<PathChunk>,
pub(crate) parent: Option<&'a InstancePath<'a>>,
}
impl<'a> InstancePath<'a> {
pub(crate) const fn new() -> Self {
InstancePath {
chunk: None,
parent: None,
}
}
pub(crate) fn push(&'a self, chunk: impl Into<PathChunk>) -> Self {
InstancePath {
chunk: Some(chunk.into()),
parent: Some(self),
}
}
pub(crate) fn to_vec(&'a self) -> Vec<PathChunk> {
let mut result = Vec::with_capacity(6);
let mut current = self;
if let Some(chunk) = ¤t.chunk {
result.push(chunk.clone())
}
while let Some(next) = current.parent {
current = next;
if let Some(chunk) = ¤t.chunk {
result.push(chunk.clone())
}
}
result.reverse();
result
}
}
impl IntoIterator for JSONPointer {
type Item = PathChunk;
type IntoIter = <Vec<PathChunk> as IntoIterator>::IntoIter;
fn into_iter(self) -> Self::IntoIter {
self.0.into_iter()
}
}
impl<'a> IntoIterator for &'a JSONPointer {
type Item = &'a PathChunk;
type IntoIter = Iter<'a, PathChunk>;
fn into_iter(self) -> Self::IntoIter {
self.0.iter()
}
}
impl From<String> for PathChunk {
#[inline]
fn from(value: String) -> Self {
PathChunk::Property(value)
}
}
impl From<&'static str> for PathChunk {
#[inline]
fn from(value: &'static str) -> Self {
PathChunk::Keyword(value)
}
}
impl From<usize> for PathChunk {
#[inline]
fn from(value: usize) -> Self {
PathChunk::Index(value)
}
}
impl<'a> From<&'a InstancePath<'a>> for JSONPointer {
#[inline]
fn from(path: &'a InstancePath<'a>) -> Self {
JSONPointer(path.to_vec())
}
}
impl From<InstancePath<'_>> for JSONPointer {
#[inline]
fn from(path: InstancePath<'_>) -> Self {
JSONPointer(path.to_vec())
}
}
impl From<&[&str]> for JSONPointer {
#[inline]
fn from(path: &[&str]) -> Self {
JSONPointer(
path.iter()
.map(|item| PathChunk::Property((*item).to_string()))
.collect(),
)
}
}
impl From<&[PathChunk]> for JSONPointer {
#[inline]
fn from(path: &[PathChunk]) -> Self {
JSONPointer(path.to_vec())
}
}
#[cfg(test)]
mod tests {
use super::JSONPointer;
use serde_json::json;
#[test]
fn json_pointer_to_string() {
let chunks = ["/", "~"];
let pointer = JSONPointer::from(&chunks[..]).to_string();
assert_eq!(pointer, "/~1/~0");
let data = json!({"/": {"~": 42}});
assert_eq!(data.pointer(&pointer), Some(&json!(42)))
}
}