fixity 0.0.1

Storage for structured and unstructured data backed by an immutable storage engine
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use {
    crate::{
        core::{
            cache::{CacheRead, CacheWrite},
            primitive::{appendlog::LogContainer, AppendLog},
        },
        Addr, Error,
    },
    chrono::Utc,
};
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[cfg_attr(
    feature = "borsh",
    derive(borsh::BorshSerialize, borsh::BorshDeserialize)
)]
#[derive(Debug, Clone)]
pub struct CommitNode {
    pub timestamp: i64,
    pub content: Addr,
}
pub struct CommitLog<'s, C> {
    log: AppendLog<'s, C>,
}
impl<'s, C> CommitLog<'s, C> {
    pub fn new(storage: &'s C, addr: Option<Addr>) -> Self {
        let log = AppendLog::new(storage, addr);
        Self { log }
    }
}
impl<'s, C> CommitLog<'s, C>
where
    C: CacheRead,
{
    pub async fn first_container(&self) -> Result<Option<LogContainer<'_, CommitNode>>, Error> {
        let container = self.log.first_container::<CommitNode>().await?;
        Ok(container.map(|LogContainer { node, addr }| LogContainer {
            addr,
            node: node.inner,
        }))
    }
    pub async fn first(&self) -> Result<Option<CommitNode>, Error> {
        let container = self.first_container().await?;
        Ok(container.map(|LogContainer { node, .. }| node))
    }
}
impl<'s, C> CommitLog<'s, C>
where
    C: CacheRead + CacheWrite,
{
    pub async fn append(&mut self, content: Addr) -> Result<Addr, Error> {
        let container = self.first_container().await?;
        if let Some(LogContainer {
            addr: old_addr,
            node:
                CommitNode {
                    content: old_content,
                    ..
                },
        }) = container
        {
            if content == old_content {
                return Ok(old_addr.clone());
            }
        }
        self.log
            .append(CommitNode {
                timestamp: Utc::now().timestamp(),
                content,
            })
            .await
    }
}