iris-chat-protocol 0.3.6

#[cfg(test)]
thread_local! {
    static CHECKPOINT_PENDING_SERIALIZED_ITEMS: std::cell::Cell<usize> = const { std::cell::Cell::new(0) };
}

type PendingGroupMessage = nostr_double_ratchet::wire::ParsedGroupSenderKeyMessageEvent;
type CachedPendingRecord = Arc<Mutex<Option<Arc<crate::StorageCheckpointBody>>>>;

struct SerializedPendingGroupMessages {
    json: Box<serde_json::value::RawValue>,
    records: Vec<CheckpointRecord>,
}

impl SerializedPendingGroupMessages {
    fn new(json: Box<serde_json::value::RawValue>) -> Self {
        let records = checkpoint_records_with_cached_pending(json.get(), 1, None);
        Self { json, records }
    }
}

// Immutable checkpoint clones share both ciphertexts and their JSON. Mutation
// detaches both generations, so rollback can restore its original cache.
#[derive(Clone, Default)]
struct PendingGroupMessages {
    values: Arc<Vec<PendingGroupMessage>>,
    serialized: Arc<std::sync::Mutex<Option<Arc<SerializedPendingGroupMessages>>>>,
    records: Arc<Vec<CachedPendingRecord>>,
}

impl std::fmt::Debug for PendingGroupMessages {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("PendingGroupMessages")
            .field("len", &self.values.len())
            .finish()
    }
}

impl PartialEq for PendingGroupMessages {
    fn eq(&self, other: &Self) -> bool {
        self.values == other.values
    }
}

impl Eq for PendingGroupMessages {}

impl std::ops::Deref for PendingGroupMessages {
    type Target = [PendingGroupMessage];
    fn deref(&self) -> &Self::Target {
        &self.values
    }
}

impl<'a> IntoIterator for &'a PendingGroupMessages {
    type Item = &'a PendingGroupMessage;
    type IntoIter = std::slice::Iter<'a, PendingGroupMessage>;
    fn into_iter(self) -> Self::IntoIter {
        self.values.iter()
    }
}

impl From<Vec<PendingGroupMessage>> for PendingGroupMessages {
    fn from(values: Vec<PendingGroupMessage>) -> Self {
        let records = Arc::new((0..values.len()).map(|_| Arc::default()).collect());
        Self {
            values: Arc::new(values),
            serialized: Arc::default(),
            records,
        }
    }
}

impl PendingGroupMessages {
    fn changed(&mut self) -> &mut Vec<PendingGroupMessage> {
        self.serialized = Arc::default();
        Arc::make_mut(&mut self.values)
    }

    fn push(&mut self, value: PendingGroupMessage) {
        Arc::make_mut(&mut self.records).push(Arc::default());
        self.changed().push(value);
    }
    fn insert(&mut self, index: usize, value: PendingGroupMessage) {
        Arc::make_mut(&mut self.records).insert(index, Arc::default());
        self.changed().insert(index, value);
    }
    fn remove(&mut self, index: usize) -> PendingGroupMessage {
        Arc::make_mut(&mut self.records).remove(index);
        self.changed().remove(index)
    }

    #[cfg(test)]
    fn pop(&mut self) -> Option<PendingGroupMessage> {
        Arc::make_mut(&mut self.records).pop();
        self.changed().pop()
    }

    fn retain(&mut self, mut keep: impl FnMut(&PendingGroupMessage) -> bool) {
        // Do not detach/serialize the queue for the common no-op ACK/prune.
        let Some(first_removed) = self.values.iter().position(|value| !keep(value)) else {
            return;
        };
        let mut index = 0;
        let mut retained = Vec::with_capacity(self.values.len());
        self.changed().retain(|value| {
            let current = index;
            index += 1;
            let keep = current < first_removed || (current > first_removed && keep(value));
            retained.push(keep);
            keep
        });
        let mut index = 0;
        Arc::make_mut(&mut self.records).retain(|_| {
            let keep = retained[index];
            index += 1;
            keep
        });
    }

    fn record_bodies(&self) -> Result<Vec<Arc<crate::StorageCheckpointBody>>, serde_json::Error> {
        self.values
            .iter()
            .zip(self.records.iter())
            .map(|(value, cache)| {
                let mut cache = cache.lock().unwrap_or_else(|poison| poison.into_inner());
                if let Some(body) = cache.as_ref() {
                    return Ok(body.clone());
                }
                let json = serde_json::value::to_raw_value(value)?.into();
                let body = Arc::new(crate::StorageCheckpointBody::new(json));
                #[cfg(test)]
                CHECKPOINT_PENDING_SERIALIZED_ITEMS.with(|count| count.set(count.get() + 1));
                *cache = Some(body.clone());
                Ok(body)
            })
            .collect()
    }

    fn serialized(&self) -> Result<Arc<SerializedPendingGroupMessages>, serde_json::Error> {
        let mut cached = self
            .serialized
            .lock()
            .unwrap_or_else(|poison| poison.into_inner());
        if let Some(value) = cached.as_ref() {
            return Ok(value.clone());
        }
        let records = self.record_bodies()?;
        let borrowed = records.iter().map(AsRef::as_ref).collect::<Vec<_>>();
        let json = serde_json::value::to_raw_value(&borrowed)?;
        let value = Arc::new(SerializedPendingGroupMessages::new(json));
        *cached = Some(value.clone());
        Ok(value)
    }
}

#[cfg(test)]
impl std::ops::IndexMut<usize> for PendingGroupMessages {
    fn index_mut(&mut self, index: usize) -> &mut Self::Output {
        Arc::make_mut(&mut self.records)[index] = Arc::default();
        &mut self.changed()[index]
    }
}

#[cfg(test)]
impl std::ops::Index<usize> for PendingGroupMessages {
    type Output = PendingGroupMessage;
    fn index(&self, index: usize) -> &Self::Output {
        &self.values[index]
    }
}

impl Serialize for PendingGroupMessages {
    fn serialize<S: serde::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
        let cached = self.serialized().map_err(serde::ser::Error::custom)?;
        cached.json.serialize(serializer)
    }
}

impl<'de> Deserialize<'de> for PendingGroupMessages {
    fn deserialize<D: serde::Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
        let values = Vec::deserialize(deserializer)?;
        let result = Self::from(values);
        // Compact once during restore: retaining old padding here would move
        // its absolute checkpoint boundaries when an earlier field grows.
        result.record_bodies().map_err(serde::de::Error::custom)?;
        Ok(result)
    }
}