use core::ops::Bound;
use std::borrow::BorrowMut;
use std::marker::PhantomPinned;
use std::pin::Pin;
use std::ptr::NonNull;
use std::sync::{Arc, Mutex, MutexGuard};
use rusqlite::{params, Connection, Rows, Statement, Transaction};
use crate::{
Db, Error, IDb, ITx, ITxFn, Result, TxError, TxFnResult, TxOpError, TxOpResult, TxResult,
TxValueIter, Value, ValueIter,
};
pub use rusqlite;
impl From<rusqlite::Error> for Error {
fn from(e: rusqlite::Error) -> Error {
Error(format!("Sqlite: {}", e).into())
}
}
impl From<rusqlite::Error> for TxOpError {
fn from(e: rusqlite::Error) -> TxOpError {
TxOpError(e.into())
}
}
pub struct SqliteDb(Mutex<SqliteDbInner>);
struct SqliteDbInner {
db: Connection,
trees: Vec<String>,
}
impl SqliteDb {
pub fn init(db: rusqlite::Connection) -> Db {
let s = Self(Mutex::new(SqliteDbInner {
db,
trees: Vec::new(),
}));
Db(Arc::new(s))
}
}
impl SqliteDbInner {
fn get_tree(&self, i: usize) -> Result<&'_ str> {
self.trees
.get(i)
.map(String::as_str)
.ok_or_else(|| Error("invalid tree id".into()))
}
fn internal_get(&self, tree: &str, key: &[u8]) -> Result<Option<Value>> {
let mut stmt = self
.db
.prepare(&format!("SELECT v FROM {} WHERE k = ?1", tree))?;
let mut res_iter = stmt.query([key])?;
match res_iter.next()? {
None => Ok(None),
Some(v) => Ok(Some(v.get::<_, Vec<u8>>(0)?)),
}
}
}
impl IDb for SqliteDb {
fn engine(&self) -> String {
format!("sqlite3 v{} (using rusqlite crate)", rusqlite::version())
}
fn open_tree(&self, name: &str) -> Result<usize> {
let name = format!("tree_{}", name.replace(':', "_COLON_"));
let mut this = self.0.lock().unwrap();
if let Some(i) = this.trees.iter().position(|x| x == &name) {
Ok(i)
} else {
trace!("create table {}", name);
this.db.execute(
&format!(
"CREATE TABLE IF NOT EXISTS {} (
k BLOB PRIMARY KEY,
v BLOB
)",
name
),
[],
)?;
trace!("table created: {}, unlocking", name);
let i = this.trees.len();
this.trees.push(name.to_string());
Ok(i)
}
}
fn list_trees(&self) -> Result<Vec<String>> {
let mut trees = vec![];
trace!("list_trees: lock db");
let this = self.0.lock().unwrap();
trace!("list_trees: lock acquired");
let mut stmt = this.db.prepare(
"SELECT name FROM sqlite_schema WHERE type = 'table' AND name LIKE 'tree_%'",
)?;
let mut rows = stmt.query([])?;
while let Some(row) = rows.next()? {
let name = row.get::<_, String>(0)?;
let name = name.replace("_COLON_", ":");
let name = name.strip_prefix("tree_").unwrap().to_string();
trees.push(name);
}
Ok(trees)
}
fn get(&self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
trace!("get {}: lock db", tree);
let this = self.0.lock().unwrap();
trace!("get {}: lock acquired", tree);
let tree = this.get_tree(tree)?;
this.internal_get(tree, key)
}
fn len(&self, tree: usize) -> Result<usize> {
trace!("len {}: lock db", tree);
let this = self.0.lock().unwrap();
trace!("len {}: lock acquired", tree);
let tree = this.get_tree(tree)?;
let mut stmt = this.db.prepare(&format!("SELECT COUNT(*) FROM {}", tree))?;
let mut res_iter = stmt.query([])?;
match res_iter.next()? {
None => Ok(0),
Some(v) => Ok(v.get::<_, usize>(0)?),
}
}
fn fast_len(&self, tree: usize) -> Result<Option<usize>> {
Ok(Some(self.len(tree)?))
}
fn insert(&self, tree: usize, key: &[u8], value: &[u8]) -> Result<Option<Value>> {
trace!("insert {}: lock db", tree);
let this = self.0.lock().unwrap();
trace!("insert {}: lock acquired", tree);
let tree = this.get_tree(tree)?;
let old_val = this.internal_get(tree, key)?;
let sql = match &old_val {
Some(_) => format!("UPDATE {} SET v = ?2 WHERE k = ?1", tree),
None => format!("INSERT INTO {} (k, v) VALUES (?1, ?2)", tree),
};
let n = this.db.execute(&sql, params![key, value])?;
assert_eq!(n, 1);
Ok(old_val)
}
fn remove(&self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
trace!("remove {}: lock db", tree);
let this = self.0.lock().unwrap();
trace!("remove {}: lock acquired", tree);
let tree = this.get_tree(tree)?;
let old_val = this.internal_get(tree, key)?;
if old_val.is_some() {
let n = this
.db
.execute(&format!("DELETE FROM {} WHERE k = ?1", tree), params![key])?;
assert_eq!(n, 1);
}
Ok(old_val)
}
fn clear(&self, tree: usize) -> Result<()> {
trace!("clear {}: lock db", tree);
let this = self.0.lock().unwrap();
trace!("clear {}: lock acquired", tree);
let tree = this.get_tree(tree)?;
this.db.execute(&format!("DELETE FROM {}", tree), [])?;
Ok(())
}
fn iter(&self, tree: usize) -> Result<ValueIter<'_>> {
trace!("iter {}: lock db", tree);
let this = self.0.lock().unwrap();
trace!("iter {}: lock acquired", tree);
let tree = this.get_tree(tree)?;
let sql = format!("SELECT k, v FROM {} ORDER BY k ASC", tree);
DbValueIterator::make(this, &sql, [])
}
fn iter_rev(&self, tree: usize) -> Result<ValueIter<'_>> {
trace!("iter_rev {}: lock db", tree);
let this = self.0.lock().unwrap();
trace!("iter_rev {}: lock acquired", tree);
let tree = this.get_tree(tree)?;
let sql = format!("SELECT k, v FROM {} ORDER BY k DESC", tree);
DbValueIterator::make(this, &sql, [])
}
fn range<'r>(
&self,
tree: usize,
low: Bound<&'r [u8]>,
high: Bound<&'r [u8]>,
) -> Result<ValueIter<'_>> {
trace!("range {}: lock db", tree);
let this = self.0.lock().unwrap();
trace!("range {}: lock acquired", tree);
let tree = this.get_tree(tree)?;
let (bounds_sql, params) = bounds_sql(low, high);
let sql = format!("SELECT k, v FROM {} {} ORDER BY k ASC", tree, bounds_sql);
let params = params
.iter()
.map(|x| x as &dyn rusqlite::ToSql)
.collect::<Vec<_>>();
DbValueIterator::make::<&[&dyn rusqlite::ToSql]>(this, &sql, params.as_ref())
}
fn range_rev<'r>(
&self,
tree: usize,
low: Bound<&'r [u8]>,
high: Bound<&'r [u8]>,
) -> Result<ValueIter<'_>> {
trace!("range_rev {}: lock db", tree);
let this = self.0.lock().unwrap();
trace!("range_rev {}: lock acquired", tree);
let tree = this.get_tree(tree)?;
let (bounds_sql, params) = bounds_sql(low, high);
let sql = format!("SELECT k, v FROM {} {} ORDER BY k DESC", tree, bounds_sql);
let params = params
.iter()
.map(|x| x as &dyn rusqlite::ToSql)
.collect::<Vec<_>>();
DbValueIterator::make::<&[&dyn rusqlite::ToSql]>(this, &sql, params.as_ref())
}
fn transaction(&self, f: &dyn ITxFn) -> TxResult<(), ()> {
trace!("transaction: lock db");
let mut this = self.0.lock().unwrap();
trace!("transaction: lock acquired");
let this_mut_ref: &mut SqliteDbInner = this.borrow_mut();
let mut tx = SqliteTx {
tx: this_mut_ref
.db
.transaction()
.map_err(Error::from)
.map_err(TxError::Db)?,
trees: &this_mut_ref.trees,
};
let res = match f.try_on(&mut tx) {
TxFnResult::Ok => {
tx.tx.commit().map_err(Error::from).map_err(TxError::Db)?;
Ok(())
}
TxFnResult::Abort => {
tx.tx.rollback().map_err(Error::from).map_err(TxError::Db)?;
Err(TxError::Abort(()))
}
TxFnResult::DbErr => {
tx.tx.rollback().map_err(Error::from).map_err(TxError::Db)?;
Err(TxError::Db(Error(
"(this message will be discarded)".into(),
)))
}
};
trace!("transaction done");
res
}
}
struct SqliteTx<'a> {
tx: Transaction<'a>,
trees: &'a [String],
}
impl<'a> SqliteTx<'a> {
fn get_tree(&self, i: usize) -> TxOpResult<&'_ str> {
self.trees.get(i).map(String::as_ref).ok_or_else(|| {
TxOpError(Error(
"invalid tree id (it might have been openned after the transaction started)".into(),
))
})
}
fn internal_get(&self, tree: &str, key: &[u8]) -> TxOpResult<Option<Value>> {
let mut stmt = self
.tx
.prepare(&format!("SELECT v FROM {} WHERE k = ?1", tree))?;
let mut res_iter = stmt.query([key])?;
match res_iter.next()? {
None => Ok(None),
Some(v) => Ok(Some(v.get::<_, Vec<u8>>(0)?)),
}
}
}
impl<'a> ITx for SqliteTx<'a> {
fn get(&self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>> {
let tree = self.get_tree(tree)?;
self.internal_get(tree, key)
}
fn len(&self, tree: usize) -> TxOpResult<usize> {
let tree = self.get_tree(tree)?;
let mut stmt = self.tx.prepare(&format!("SELECT COUNT(*) FROM {}", tree))?;
let mut res_iter = stmt.query([])?;
match res_iter.next()? {
None => Ok(0),
Some(v) => Ok(v.get::<_, usize>(0)?),
}
}
fn insert(&mut self, tree: usize, key: &[u8], value: &[u8]) -> TxOpResult<Option<Value>> {
let tree = self.get_tree(tree)?;
let old_val = self.internal_get(tree, key)?;
let sql = match &old_val {
Some(_) => format!("UPDATE {} SET v = ?2 WHERE k = ?1", tree),
None => format!("INSERT INTO {} (k, v) VALUES (?1, ?2)", tree),
};
let n = self.tx.execute(&sql, params![key, value])?;
assert_eq!(n, 1);
Ok(old_val)
}
fn remove(&mut self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>> {
let tree = self.get_tree(tree)?;
let old_val = self.internal_get(tree, key)?;
if old_val.is_some() {
let n = self
.tx
.execute(&format!("DELETE FROM {} WHERE k = ?1", tree), params![key])?;
assert_eq!(n, 1);
}
Ok(old_val)
}
fn iter(&self, _tree: usize) -> TxOpResult<TxValueIter<'_>> {
unimplemented!();
}
fn iter_rev(&self, _tree: usize) -> TxOpResult<TxValueIter<'_>> {
unimplemented!();
}
fn range<'r>(
&self,
_tree: usize,
_low: Bound<&'r [u8]>,
_high: Bound<&'r [u8]>,
) -> TxOpResult<TxValueIter<'_>> {
unimplemented!();
}
fn range_rev<'r>(
&self,
_tree: usize,
_low: Bound<&'r [u8]>,
_high: Bound<&'r [u8]>,
) -> TxOpResult<TxValueIter<'_>> {
unimplemented!();
}
}
struct DbValueIterator<'a> {
db: MutexGuard<'a, SqliteDbInner>,
stmt: Option<Statement<'a>>,
iter: Option<Rows<'a>>,
_pin: PhantomPinned,
}
impl<'a> DbValueIterator<'a> {
fn make<P: rusqlite::Params>(
db: MutexGuard<'a, SqliteDbInner>,
sql: &str,
args: P,
) -> Result<ValueIter<'a>> {
let res = DbValueIterator {
db,
stmt: None,
iter: None,
_pin: PhantomPinned,
};
let mut boxed = Box::pin(res);
trace!("make iterator with sql: {}", sql);
unsafe {
let db = NonNull::from(&boxed.db);
let stmt = db.as_ref().db.prepare(sql)?;
let mut_ref: Pin<&mut DbValueIterator<'a>> = Pin::as_mut(&mut boxed);
Pin::get_unchecked_mut(mut_ref).stmt = Some(stmt);
let mut stmt = NonNull::from(&boxed.stmt);
let iter = stmt.as_mut().as_mut().unwrap().query(args)?;
let mut_ref: Pin<&mut DbValueIterator<'a>> = Pin::as_mut(&mut boxed);
Pin::get_unchecked_mut(mut_ref).iter = Some(iter);
}
Ok(Box::new(DbValueIteratorPin(boxed)))
}
}
impl<'a> Drop for DbValueIterator<'a> {
fn drop(&mut self) {
trace!("drop iter");
drop(self.iter.take());
drop(self.stmt.take());
}
}
struct DbValueIteratorPin<'a>(Pin<Box<DbValueIterator<'a>>>);
impl<'a> Iterator for DbValueIteratorPin<'a> {
type Item = Result<(Value, Value)>;
fn next(&mut self) -> Option<Self::Item> {
let next = unsafe {
let mut_ref: Pin<&mut DbValueIterator<'a>> = Pin::as_mut(&mut self.0);
Pin::get_unchecked_mut(mut_ref).iter.as_mut()?.next()
};
let row = match next {
Err(e) => return Some(Err(e.into())),
Ok(None) => return None,
Ok(Some(r)) => r,
};
let k = match row.get::<_, Vec<u8>>(0) {
Err(e) => return Some(Err(e.into())),
Ok(x) => x,
};
let v = match row.get::<_, Vec<u8>>(1) {
Err(e) => return Some(Err(e.into())),
Ok(y) => y,
};
Some(Ok((k, v)))
}
}
fn bounds_sql<'r>(low: Bound<&'r [u8]>, high: Bound<&'r [u8]>) -> (String, Vec<Vec<u8>>) {
let mut sql = String::new();
let mut params: Vec<Vec<u8>> = vec![];
match low {
Bound::Included(b) => {
sql.push_str(" WHERE k >= ?1");
params.push(b.to_vec());
}
Bound::Excluded(b) => {
sql.push_str(" WHERE k > ?1");
params.push(b.to_vec());
}
Bound::Unbounded => (),
};
match high {
Bound::Included(b) => {
if !params.is_empty() {
sql.push_str(" AND k <= ?2");
} else {
sql.push_str(" WHERE k <= ?1");
}
params.push(b.to_vec());
}
Bound::Excluded(b) => {
if !params.is_empty() {
sql.push_str(" AND k < ?2");
} else {
sql.push_str(" WHERE k < ?1");
}
params.push(b.to_vec());
}
Bound::Unbounded => (),
}
(sql, params)
}