AppFlowy/frontend/rust-lib/flowy-document/src/services/doc/revision/cache/cache.rs

use crate::{
    errors::FlowyError,
    services::doc::revision::cache::{
        disk::{Persistence, RevisionDiskCache},
        memory::{RevisionMemoryCache, RevisionMemoryCacheDelegate},
    },
    sql_tables::{RevisionChangeset, RevisionTableState},
};

use flowy_collaboration::entities::revision::{Revision, RevisionRange, RevisionState};
use flowy_database::ConnectionPool;
use flowy_error::{internal_error, FlowyResult};

use std::sync::{
    atomic::{AtomicI64, Ordering::SeqCst},
    Arc,
};
use tokio::task::spawn_blocking;

pub struct RevisionCache {
    doc_id: String,
    disk_cache: Arc<dyn RevisionDiskCache<Error = FlowyError>>,
    memory_cache: Arc<RevisionMemoryCache>,
    latest_rev_id: AtomicI64,
}

impl RevisionCache {
    pub fn new(user_id: &str, doc_id: &str, pool: Arc<ConnectionPool>) -> RevisionCache {
        let disk_cache = Arc::new(Persistence::new(user_id, pool));
        let memory_cache = Arc::new(RevisionMemoryCache::new(doc_id, Arc::new(disk_cache.clone())));
        let doc_id = doc_id.to_owned();
        Self {
            doc_id,
            disk_cache,
            memory_cache,
            latest_rev_id: AtomicI64::new(0),
        }
    }

    pub async fn add(
        &self,
        revision: Revision,
        state: RevisionState,
        write_to_disk: bool,
    ) -> FlowyResult<RevisionRecord> {
        if self.memory_cache.contains(&revision.rev_id) {
            return Err(FlowyError::internal().context(format!("Duplicate remote revision id: {}", revision.rev_id)));
        }
        let rev_id = revision.rev_id;
        let record = RevisionRecord {
            revision,
            state,
            write_to_disk,
        };
        self.memory_cache.add(&record).await;
        self.set_latest_rev_id(rev_id);
        Ok(record)
    }

    pub async fn ack(&self, rev_id: i64) { self.memory_cache.ack(&rev_id).await; }

    pub async fn get(&self, rev_id: i64) -> Option<RevisionRecord> {
        match self.memory_cache.get(&rev_id).await {
            None => match self.disk_cache.read_revision_records(&self.doc_id, Some(vec![rev_id])) {
                Ok(mut records) => {
                    if records.is_empty() {
                        tracing::warn!("Can't find revision in {} with rev_id: {}", &self.doc_id, rev_id);
                    }
                    assert_eq!(records.len(), 1);
                    records.pop()
                },
                Err(e) => {
                    tracing::error!("{}", e);
                    None
                },
            },
            Some(revision) => Some(revision),
        }
    }

    pub fn batch_get(&self, doc_id: &str) -> FlowyResult<Vec<RevisionRecord>> {
        self.disk_cache.read_revision_records(doc_id, None)
    }

    pub async fn latest_revision(&self) -> Revision {
        let rev_id = self.latest_rev_id.load(SeqCst);
        self.get(rev_id).await.unwrap().revision
    }

    pub async fn revisions_in_range(&self, range: RevisionRange) -> FlowyResult<Vec<Revision>> {
        let mut records = self.memory_cache.get_with_range(&range).await?;
        let range_len = range.len() as usize;
        if records.len() != range_len {
            let disk_cache = self.disk_cache.clone();
            let doc_id = self.doc_id.clone();
            records = spawn_blocking(move || disk_cache.read_revision_records_with_range(&doc_id, &range))
                .await
                .map_err(internal_error)??;

            if records.len() != range_len {
                log::error!("Revisions len is not equal to range required");
            }
        }
        Ok(records
            .into_iter()
            .map(|record| record.revision)
            .collect::<Vec<Revision>>())
    }

    #[tracing::instrument(level = "debug", skip(self, doc_id, revisions))]
    pub fn reset_document(&self, doc_id: &str, revisions: Vec<Revision>) -> FlowyResult<()> {
        let disk_cache = self.disk_cache.clone();
        let conn = disk_cache.db_pool().get().map_err(internal_error)?;
        let records = revisions
            .into_iter()
            .map(|revision| RevisionRecord {
                revision,
                state: RevisionState::Local,
                write_to_disk: true,
            })
            .collect::<Vec<_>>();

        conn.immediate_transaction::<_, FlowyError, _>(|| {
            let _ = disk_cache.delete_revision_records(doc_id, None, &*conn)?;
            let _ = disk_cache.write_revision_records(records, &*conn)?;
            Ok(())
        })
    }

    #[inline]
    fn set_latest_rev_id(&self, rev_id: i64) {
        let _ = self.latest_rev_id.fetch_update(SeqCst, SeqCst, |_e| Some(rev_id));
    }
}

impl RevisionMemoryCacheDelegate for Arc<Persistence> {
    fn checkpoint_tick(&self, mut records: Vec<RevisionRecord>) -> FlowyResult<()> {
        let conn = &*self.pool.get().map_err(internal_error)?;
        records.retain(|record| record.write_to_disk);
        if !records.is_empty() {
            let _ = self.write_revision_records(records, &conn)?;
        }
        Ok(())
    }

    fn receive_ack(&self, doc_id: &str, rev_id: i64) {
        let changeset = RevisionChangeset {
            doc_id: doc_id.to_string(),
            rev_id: rev_id.into(),
            state: RevisionTableState::Ack,
        };
        match self.update_revision_record(vec![changeset]) {
            Ok(_) => {},
            Err(e) => tracing::error!("{}", e),
        }
    }
}

#[derive(Clone)]
pub struct RevisionRecord {
    pub revision: Revision,
    pub state: RevisionState,
    pub write_to_disk: bool,
}

impl RevisionRecord {
    pub fn ack(&mut self) { self.state = RevisionState::Ack; }
}