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use crate::{
MemoryPolicy, NodeRef, Traversal, Traverser, Tree, TreeVariant, pinned_storage::PinnedStorage,
};
use core::marker::PhantomData;
use serde::{Deserialize, Serialize, de::Visitor, ser::SerializeSeq};
// Serialize
impl<V, M, P> Serialize for Tree<V, M, P>
where
V: TreeVariant,
M: MemoryPolicy,
P: PinnedStorage,
P::PinnedVec<V>: Default,
V::Item: Serialize,
{
/// Serializes the tree into linearized [`DepthFirstSequence`].
///
/// [`DepthFirstSequence`]: crate::DepthFirstSequence
///
/// # Examples
///
/// ```
/// use orx_tree::*;
///
/// let tree = BinaryTree::<i32>::empty();
/// let json = serde_json::to_string(&tree).unwrap();
/// assert_eq!(json, "[]");
///
/// let tree = DynTree::new(10);
/// let json = serde_json::to_string(&tree).unwrap();
/// assert_eq!(json, "[[0,10]]");
///
/// // 0
/// // ╱ ╲
/// // ╱ ╲
/// // 1 2
/// // ╱ ╱ ╲
/// // 3 4 5
/// // | |
/// // 6 7
/// let mut tree = DaryTree::<4, _>::new(0);
/// let [id1, id2] = tree.root_mut().push_children([1, 2]);
/// let id3 = tree.node_mut(id1).push_child(3);
/// tree.node_mut(id3).push_child(6);
/// let [_, id5] = tree.node_mut(id2).push_children([4, 5]);
/// tree.node_mut(id5).push_child(7);
///
/// let json = serde_json::to_string(&tree).unwrap();
/// assert_eq!(json, "[[0,0],[1,1],[2,3],[3,6],[1,2],[2,4],[2,5],[3,7]]");
/// ```
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
let mut seq = serializer.serialize_seq(Some(self.len()))?;
if let Some(root) = self.get_root() {
let mut t = Traversal.dfs().with_depth();
for x in root.walk_with(&mut t) {
seq.serialize_element(&x)?;
}
}
seq.end()
}
}
// Deserialize
/// Tree deserializer using the linear DepthFirstSequence representation of a tree.
struct TreeDeserializer<V, M, P>
where
V: TreeVariant,
M: MemoryPolicy,
P: PinnedStorage,
P::PinnedVec<V>: Default,
{
phantom: PhantomData<(V, M, P)>,
}
impl<'de, V, M, P> Visitor<'de> for TreeDeserializer<V, M, P>
where
V: TreeVariant,
M: MemoryPolicy,
P: PinnedStorage,
P::PinnedVec<V>: Default,
V::Item: Deserialize<'de>,
{
type Value = Tree<V, M, P>;
fn expecting(&self, formatter: &mut core::fmt::Formatter) -> core::fmt::Result {
formatter.write_str("Expecting a DepthFirstSequence which contains (depth, value) pairs in depth-first order. Following is an example valid sequence of (depth, value) pairs: [[0, 0], [1, 1], [2, 3], [3, 6], [1, 2], [2, 4], [2, 5], [3, 7]].")
}
#[allow(clippy::unwrap_in_result)]
fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
where
A: serde::de::SeqAccess<'de>,
{
let err = |x| Err(serde::de::Error::custom(x));
use alloc::format;
let mut tree = Tree::default();
if let Some(x) = seq.next_element()? {
let (depth, value): (usize, V::Item) = x;
if depth != 0 {
return err(format!(
"First element of DepthFirstSequence (root of the tree) must have depth 0; however, received a depth of {depth}. Following is an example valid sequence of (depth, value) pairs: [[0, 0], [1, 1], [2, 3], [3, 6], [1, 2], [2, 4], [2, 5], [3, 7]].",
));
}
tree.push_root(value);
let mut current_depth = depth;
let mut dst = tree.root_mut();
while let Some((depth, value)) = seq.next_element::<(usize, V::Item)>()? {
match depth > current_depth {
true => {
if depth > current_depth + 1 {
return err(format!(
"Let d1 and d2 be two consecutive depths in the depth-first sequence. Then, (i) d2=d1+1, (ii) d2=d1 or (iii) d2<d1 are valid cases. However, received the invalid case where d2>d1+1 (d1={current_depth}, d2={depth}). Please see DepthFirstSequenceError documentation for details. Following is an example valid sequence of (depth, value) pairs: [[0, 0], [1, 1], [2, 3], [3, 6], [1, 2], [2, 4], [2, 5], [3, 7]].",
));
}
}
false => {
let num_parent_moves = current_depth - depth + 1;
for _ in 0..num_parent_moves {
dst = dst.into_parent_mut().expect("in bounds");
}
}
}
let position = dst.num_children();
dst.push_child(value);
dst = dst.into_child_mut(position).expect("child exists");
current_depth = depth;
}
}
Ok(tree)
}
}
impl<'de, V, M, P> Deserialize<'de> for Tree<V, M, P>
where
V: TreeVariant,
M: MemoryPolicy,
P: PinnedStorage,
P::PinnedVec<V>: Default,
V::Item: Deserialize<'de>,
{
/// Deserializes the tree from linearized [`DepthFirstSequence`].
///
/// [`DepthFirstSequence`]: crate::DepthFirstSequence
///
/// # Examples
///
/// ```
/// use orx_tree::*;
///
/// let json = "[]";
/// let result: Result<DaryTree<4, i32>, _> = serde_json::from_str(json);
/// let tree = result.unwrap();
/// assert!(tree.is_empty());
///
/// let json = "[[0,10]]";
/// let result: Result<DynTree<i32>, _> = serde_json::from_str(json);
/// let tree = result.unwrap();
/// assert_eq!(tree.len(), 1);
/// assert_eq!(tree.root().data(), &10);
///
/// // 0
/// // ╱ ╲
/// // ╱ ╲
/// // 1 2
/// // ╱ ╱ ╲
/// // 3 4 5
/// // | |
/// // 6 7
/// let json = "[[0, 0], [1, 1], [2, 3], [3, 6], [1, 2], [2, 4], [2, 5], [3, 7]]";
/// let result: Result<BinaryTree<i32>, _> = serde_json::from_str(json);
/// let tree = result.unwrap();
/// let bfs_values: Vec<_> = tree.root().walk::<Bfs>().copied().collect();
/// assert_eq!(bfs_values, [0, 1, 2, 3, 4, 5, 6, 7]);
///
/// // errors
///
/// // A. First element of DepthFirstSequence (root of the tree) must have depth 0;
/// // however, received a depth of 1.
/// let json = "[[1,10]]";
/// let result: Result<DynTree<i32>, _> = serde_json::from_str(json);
/// assert!(result.is_err());
///
/// // B. Let d1 and d2 be two consecutive depths in the depth-first sequence.
/// // Then, (i) d2=d1+1, (ii) d2=d1 or (iii) d2<d1 are valid cases.
/// // However, received the invalid case where d2>d1+1 (d1=1, d2=3).
/// let json = "[[0, 0], [1, 1], [3, 6], [1, 2], [2, 4], [2, 5], [3, 7]]";
/// let result: Result<BinaryTree<i32>, _> = serde_json::from_str(json);
/// assert!(result.is_err());
/// ```
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
deserializer.deserialize_seq(TreeDeserializer {
phantom: PhantomData,
})
}
}