liquid-value 0.19.1

use std::fmt;
use std::slice;

use itertools;

use super::ScalarCow;

/// Path to a value in an `Object`.
///
/// There is guaranteed always at least one element.
#[derive(Clone, Debug, PartialEq)]
pub struct Path<'s>(Vec<ScalarCow<'s>>);

impl<'s> Path<'s> {
    /// Create a `Value` reference.
    pub fn with_index<I: Into<ScalarCow<'s>>>(value: I) -> Self {
        let indexes = vec![value.into()];
        Path(indexes)
    }

    /// Append an index.
    pub fn push<I: Into<ScalarCow<'s>>>(&mut self, value: I) {
        self.0.push(value.into());
    }

    /// Reserves capacity for at least `additional` more elements to be inserted
    /// in the given `Path`. The `Path` may reserve more space to avoid
    /// frequent reallocations. After calling `reserve`, capacity will be
    /// greater than or equal to `self.len() + additional`. Does nothing if
    /// capacity is already sufficient.
    pub fn reserve(&mut self, additional: usize) {
        self.0.reserve(additional);
    }

    /// Access the `Value` reference.
    pub fn iter(&self) -> PathIter<'_, '_> {
        PathIter(self.0.iter())
    }

    /// Extracts a slice containing the entire vector.
    #[inline]
    pub fn as_slice(&self) -> &[ScalarCow<'s>] {
        self.0.as_slice()
    }
}

impl<'s> Extend<ScalarCow<'s>> for Path<'s> {
    fn extend<T: IntoIterator<Item = ScalarCow<'s>>>(&mut self, iter: T) {
        self.0.extend(iter);
    }
}

impl<'s> ::std::ops::Deref for Path<'s> {
    type Target = [ScalarCow<'s>];

    #[inline]
    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

impl<'s> ::std::borrow::Borrow<[ScalarCow<'s>]> for Path<'s> {
    #[inline]
    fn borrow(&self) -> &[ScalarCow<'s>] {
        self
    }
}

impl<'s> AsRef<[ScalarCow<'s>]> for Path<'s> {
    #[inline]
    fn as_ref(&self) -> &[ScalarCow<'s>] {
        self
    }
}

impl<'s> fmt::Display for Path<'s> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let data = itertools::join(self.iter().map(ScalarCow::render), ".");
        write!(f, "{}", data)
    }
}

/// Iterate over indexes in a `Value`'s `Path`.
#[derive(Debug)]
pub struct PathIter<'i, 's: 'i>(slice::Iter<'i, ScalarCow<'s>>);

impl<'i, 's: 'i> Iterator for PathIter<'i, 's> {
    type Item = &'i ScalarCow<'s>;

    #[inline]
    fn next(&mut self) -> Option<&'i ScalarCow<'s>> {
        self.0.next()
    }

    #[inline]
    fn size_hint(&self) -> (usize, Option<usize>) {
        self.0.size_hint()
    }

    #[inline]
    fn count(self) -> usize {
        self.0.count()
    }
}

impl<'i, 's: 'i> ExactSizeIterator for PathIter<'i, 's> {
    #[inline]
    fn len(&self) -> usize {
        self.0.len()
    }
}

/// Path to a value in an `Object`.
pub type PathRef<'p, 's> = &'p [ScalarCow<'s>];