visions-vtt/servilo/src/datumbazo.rs

use rusqlite::{params, Connection};
use std::{
    ops::{Deref, DerefMut},
    path::PathBuf,
    sync::{Arc, Mutex},
};

pub struct ManagedConnection<'a> {
    pool: &'a Datumbazo,
    konekto: Option<Connection>,
}

#[derive(Clone)]
pub struct Datumbazo {
    dosierindiko: PathBuf,
    pool: Arc<Mutex<Vec<Connection>>>,
}

impl Datumbazo {
    pub fn kreu(dosierindiko: PathBuf) -> Result<Datumbazo, anyhow::Error> {
        let mut konekto = Connection::open(dosierindiko.clone())?;

        let tx = konekto.transaction()?;
        let versio: i32 = tx.pragma_query_value(None, "user_version", |r| r.get(0))?;
        println!("versio: {}", versio);
        if versio == 0 {
            tx.execute_batch(
                "CREATE TABLE uzantoj (id string primary key, nomo text);
        CREATE TABLE rajtoj (uzanto string, rajto string, foreign key(uzanto) references uzanto(id));
        CREATE TABLE sesioj (id string primary key not null, uzanto string, foreign key(uzanto) references uzantoj(id));
        PRAGMA user_version = 1;",
        )?;
        }
        let versio: i32 = tx.pragma_query_value(None, "user_version", |r| r.get(0))?;
        println!("versio: {}", versio);

        tx.commit()?;

        Ok(Datumbazo {
            dosierindiko,
            pool: Arc::new(Mutex::new(vec![konekto])),
        })
    }

    pub fn konektu<'a>(&'a self) -> Result<ManagedConnection<'a>, anyhow::Error> {
        let mut pool = self.pool.lock().unwrap();
        match pool.pop() {
            Some(konekto) => Ok(ManagedConnection {
                pool: &self,
                konekto: Some(konekto),
            }),
            None => {
                let konekto = Connection::open(self.dosierindiko.clone())?;
                Ok(ManagedConnection {
                    pool: &self,
                    konekto: Some(konekto),
                })
            }
        }
    }

    pub fn revenu(&self, konekto: Connection) {
        let mut pool = self.pool.lock().unwrap();
        pool.push(konekto);
    }
}

impl Deref for ManagedConnection<'_> {
    type Target = Connection;

    fn deref(&self) -> &Connection {
        self.konekto.as_ref().unwrap()
    }
}

impl DerefMut for ManagedConnection<'_> {
    fn deref_mut(&mut self) -> &mut Connection {
        self.konekto.as_mut().unwrap()
    }
}

impl Drop for ManagedConnection<'_> {
    fn drop(&mut self) {
        self.pool.revenu(self.konekto.take().unwrap());
    }
}

#[cfg(test)]
mod test {
    use super::*;
    use tempfile::NamedTempFile;

    #[test]
    fn povas_krei_uzanton() {
        let vojo = NamedTempFile::new().unwrap().into_temp_path();
        let datumbazo = Datumbazo::kreu(vojo.to_path_buf()).unwrap();
        let mut konekto = datumbazo.konektu().unwrap();
        let tr = konekto.transaction().unwrap();
        tr.execute(
            "INSERT INTO uzantoj VALUES(?, ?)",
            params![1, String::from("mia-uzantnomo")],
        )
        .unwrap();
        tr.commit().unwrap();

        let konekto = datumbazo.konektu().unwrap();
        let id: Option<u32> = konekto
            .query_row(
                "SELECT id FROM uzantoj WHERE nomo = ?",
                [String::from("mia-uzantnomo")],
                |row| row.get("id"),
            )
            .unwrap();
        assert_eq!(id, Some(1));
    }
}