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//! Serialize a database.
use std::convert::TryInto;
use std::marker::PhantomData;
use std::ops::Deref;
use std::ptr::NonNull;
use crate::error::error_from_handle;
use crate::ffi;
use crate::{Connection, DatabaseName, Result};
/// Shared (SQLITE_SERIALIZE_NOCOPY) serialized database
pub struct SharedData<'conn> {
phantom: PhantomData<&'conn Connection>,
ptr: NonNull<u8>,
sz: usize,
}
/// Owned serialized database
pub struct OwnedData {
ptr: NonNull<u8>,
sz: usize,
}
impl OwnedData {
/// # Safety
///
/// Caller must be certain that `ptr` is allocated by `sqlite3_malloc`.
pub unsafe fn from_raw_nonnull(ptr: NonNull<u8>, sz: usize) -> Self {
Self { ptr, sz }
}
fn into_raw(self) -> (*mut u8, usize) {
let raw = (self.ptr.as_ptr(), self.sz);
std::mem::forget(self);
raw
}
}
impl Drop for OwnedData {
fn drop(&mut self) {
unsafe {
ffi::sqlite3_free(self.ptr.as_ptr().cast());
}
}
}
/// Serialized database
pub enum Data<'conn> {
/// Shared (SQLITE_SERIALIZE_NOCOPY) serialized database
Shared(SharedData<'conn>),
/// Owned serialized database
Owned(OwnedData),
}
impl<'conn> Deref for Data<'conn> {
type Target = [u8];
fn deref(&self) -> &[u8] {
let (ptr, sz) = match self {
Data::Owned(OwnedData { ptr, sz }) => (ptr.as_ptr(), *sz),
Data::Shared(SharedData { ptr, sz, .. }) => (ptr.as_ptr(), *sz),
};
unsafe { std::slice::from_raw_parts(ptr, sz) }
}
}
impl Connection {
/// Serialize a database.
pub fn serialize(&self, schema: DatabaseName) -> Result<Data> {
let schema = schema.as_cstring()?;
let mut sz = 0;
let mut ptr: *mut u8 = unsafe {
ffi::sqlite3_serialize(
self.handle(),
schema.as_ptr(),
&mut sz,
ffi::SQLITE_SERIALIZE_NOCOPY,
)
};
Ok(if ptr.is_null() {
ptr = unsafe { ffi::sqlite3_serialize(self.handle(), schema.as_ptr(), &mut sz, 0) };
if ptr.is_null() {
return Err(unsafe { error_from_handle(self.handle(), ffi::SQLITE_NOMEM) });
}
Data::Owned(OwnedData {
ptr: NonNull::new(ptr).unwrap(),
sz: sz.try_into().unwrap(),
})
} else {
// shared buffer
Data::Shared(SharedData {
ptr: NonNull::new(ptr).unwrap(),
sz: sz.try_into().unwrap(),
phantom: PhantomData,
})
})
}
/// Deserialize a database.
pub fn deserialize(
&mut self,
schema: DatabaseName<'_>,
data: OwnedData,
read_only: bool,
) -> Result<()> {
let schema = schema.as_cstring()?;
let (data, sz) = data.into_raw();
let sz = sz.try_into().unwrap();
let flags = if read_only {
ffi::SQLITE_DESERIALIZE_FREEONCLOSE | ffi::SQLITE_DESERIALIZE_READONLY
} else {
ffi::SQLITE_DESERIALIZE_FREEONCLOSE | ffi::SQLITE_DESERIALIZE_RESIZEABLE
};
let rc = unsafe {
ffi::sqlite3_deserialize(self.handle(), schema.as_ptr(), data, sz, sz, flags)
};
if rc != ffi::SQLITE_OK {
// TODO sqlite3_free(data) ?
return Err(unsafe { error_from_handle(self.handle(), rc) });
}
/* TODO
if let Some(mxSize) = mxSize {
unsafe {
ffi::sqlite3_file_control(
self.handle(),
schema.as_ptr(),
ffi::SQLITE_FCNTL_SIZE_LIMIT,
&mut mxSize,
)
};
}*/
Ok(())
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::{Connection, DatabaseName, Result};
#[test]
fn serialize() -> Result<()> {
let db = Connection::open_in_memory()?;
db.execute_batch("CREATE TABLE x AS SELECT 'data'")?;
let data = db.serialize(DatabaseName::Main)?;
let Data::Owned(data) = data else {
panic!("expected OwnedData")
};
assert!(data.sz > 0);
Ok(())
}
#[test]
fn deserialize() -> Result<()> {
let src = Connection::open_in_memory()?;
src.execute_batch("CREATE TABLE x AS SELECT 'data'")?;
let data = src.serialize(DatabaseName::Main)?;
let Data::Owned(data) = data else {
panic!("expected OwnedData")
};
let mut dst = Connection::open_in_memory()?;
dst.deserialize(DatabaseName::Main, data, false)?;
dst.execute("DELETE FROM x", [])?;
Ok(())
}
}