sirenia: Refactor ScopedData to use BorrowMut<Storage>.
This increases the flexibility of manatee-runtime::ScopedData so the
storage implementation can be shared between different ScopedData or
also used for read_raw and write_raw while a ScopedData exists.
BUG=b:173598376
TEST=cargo test
Change-Id: I771437f76ac4df06979f81cefe93d9ece315c63d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/2600260
Tested-by: Allen Webb <allenwebb@google.com>
Reviewed-by: Nicole Anderson-Au <nvaa@google.com>
Commit-Queue: Allen Webb <allenwebb@google.com>
diff --git a/sirenia/manatee-runtime/src/lib.rs b/sirenia/manatee-runtime/src/lib.rs
index 46198e7..9976f14 100644
--- a/sirenia/manatee-runtime/src/lib.rs
+++ b/sirenia/manatee-runtime/src/lib.rs
@@ -7,6 +7,7 @@
use std::borrow::{Borrow, BorrowMut};
use std::collections::HashMap;
use std::fmt::{self, Debug, Display};
+use std::marker::PhantomData;
use libsirenia::storage::{self, Storable, Storage};
@@ -33,26 +34,27 @@
pub type Result<T> = std::result::Result<T, storage::Error>;
/// Represents some scoped data temporarily loaded from the backing store.
-pub struct ScopedData<'a, S: Storable, T: Storage> {
+pub struct ScopedData<S: Storable, T: Storage, R: BorrowMut<T>> {
identifier: String,
data: S,
- storage: &'a mut T,
+ storage: R,
+ storage_phantom: PhantomData<*const T>,
}
-impl<'a, S: Storable, T: Storage> AsRef<S> for ScopedData<'a, S, T> {
+impl<S: Storable, T: Storage, R: BorrowMut<T>> AsRef<S> for ScopedData<S, T, R> {
fn as_ref(&self) -> &S {
self.borrow()
}
}
-impl<'a, S: Storable, T: Storage> AsMut<S> for ScopedData<'a, S, T> {
+impl<S: Storable, T: Storage, R: BorrowMut<T>> AsMut<S> for ScopedData<S, T, R> {
fn as_mut(&mut self) -> &mut S {
self.borrow_mut()
}
}
/// Borrows the data read-only.
-impl<'a, S: Storable, T: Storage> Borrow<S> for ScopedData<'a, S, T> {
+impl<S: Storable, T: Storage, R: BorrowMut<T>> Borrow<S> for ScopedData<S, T, R> {
fn borrow(&self) -> &S {
&self.data
}
@@ -60,13 +62,13 @@
/// Borrows a mutable reference to the data (the ScopedData must be
/// constructed read-write).
-impl<'a, S: Storable, T: Storage> BorrowMut<S> for ScopedData<'a, S, T> {
+impl<S: Storable, T: Storage, R: BorrowMut<T>> BorrowMut<S> for ScopedData<S, T, R> {
fn borrow_mut(&mut self) -> &mut S {
&mut self.data
}
}
-impl<'a, S: Storable, T: Storage> Drop for ScopedData<'a, S, T> {
+impl<S: Storable, T: Storage, R: BorrowMut<T>> Drop for ScopedData<S, T, R> {
fn drop(&mut self) {
// TODO: Figure out how we want to handle errors on storing.
// We might want to log failures, but not necessarily crash. This will
@@ -76,24 +78,26 @@
// One option would be set a callback. We could provide some standard
// callbacks like unwrap and log.
self.storage
+ .borrow_mut()
.write_data(&self.identifier, &self.data)
.unwrap();
}
}
/// Reads the data into itself then writes back on a flush.
-impl<'a, S: Storable, T: Storage> ScopedData<'a, S, T> {
+impl<S: Storable, T: Storage, R: BorrowMut<T>> ScopedData<S, T, R> {
/// Creates and returns a new scoped data. Attempts to read the value of
/// the id from the backing store and uses the passed in closure to
/// determine the default value if the id is not found.
- pub fn new(storage: &'a mut T, identifier: &str, f: fn(&str) -> S) -> Result<Self> {
- match storage.read_data(identifier) {
+ pub fn new(mut storage: R, identifier: &str, f: fn(&str) -> S) -> Result<Self> {
+ match storage.borrow_mut().read_data(identifier) {
Ok(data) => {
let id = identifier.to_string();
Ok(ScopedData {
identifier: id,
data,
storage,
+ storage_phantom: PhantomData,
})
}
Err(storage::Error::IdNotFound(_)) => {
@@ -103,6 +107,7 @@
identifier: id,
data,
storage,
+ storage_phantom: PhantomData,
})
}
Err(e) => Err(e),
@@ -112,14 +117,22 @@
/// Write the data back out to the backing store.
pub fn flush(&mut self) -> Result<()> {
self.storage
+ .borrow_mut()
.write_data(&self.identifier, &self.data)
.unwrap();
Ok(())
}
}
+/// A helper type for when the storage implementation doesn't need to be shared. See ScopedData.
+pub type ExclusiveScopedData<'a, S, T> = ScopedData<S, T, &'a mut T>;
+
/// Represents an entire key value store for one identifier.
-pub type ScopedKeyValueStore<'a, S, T> = ScopedData<'a, HashMap<String, S>, T>;
+pub type ScopedKeyValueStore<S, T, R> = ScopedData<HashMap<String, S>, T, R>;
+
+/// A helper type for when the storage implementation doesn't need to be shared.
+/// See ScopedKeyValueStore.
+pub type ExclusiveScopedKeyValueStore<'a, S, T> = ScopedKeyValueStore<S, T, &'a mut T>;
#[cfg(test)]
mod tests {
@@ -203,8 +216,8 @@
#[test]
fn make_new_scoped_data() {
let (mut store, id, _s) = setup_test_case(/* write back */ false);
- let data: ScopedData<String, MockStorage> =
- ScopedData::<String, MockStorage>::new(&mut store, &id, callback_id_not_found).unwrap();
+ let data: ExclusiveScopedData<String, MockStorage> =
+ ScopedData::new(&mut store, &id, callback_id_not_found).unwrap();
let res: &String = data.borrow();
assert_eq!("Could not find id", res);
}
@@ -213,8 +226,8 @@
fn make_existing_scoped_data() {
let (mut store, id, s) = setup_test_case(/* write back */ true);
- let data: ScopedData<String, MockStorage> =
- ScopedData::<String, MockStorage>::new(&mut store, &id, callback_id_found).unwrap();
+ let data: ExclusiveScopedData<String, MockStorage> =
+ ScopedData::new(&mut store, &id, callback_id_found).unwrap();
let res: &String = data.borrow();
assert_eq!(&s, res);
}
@@ -224,8 +237,8 @@
let (mut store, id, mut s) = setup_test_case(/* write back */ true);
{
- let mut data: ScopedData<String, MockStorage> =
- ScopedData::<String, MockStorage>::new(&mut store, &id, callback_id_found).unwrap();
+ let mut data: ExclusiveScopedData<String, MockStorage> =
+ ScopedData::new(&mut store, &id, callback_id_found).unwrap();
let res: &mut String = data.borrow_mut();
res.push_str(" New");
}
@@ -239,8 +252,8 @@
let (mut store, id, mut s) = setup_test_case(/* write back */ true);
{
- let mut data: ScopedData<String, MockStorage> =
- ScopedData::<String, MockStorage>::new(&mut store, &id, callback_id_found).unwrap();
+ let mut data: ExclusiveScopedData<String, MockStorage> =
+ ScopedData::new(&mut store, &id, callback_id_found).unwrap();
let res: &mut String = data.borrow_mut();
res.push_str(" New");
data.flush().unwrap();
@@ -263,8 +276,8 @@
let fun = |_h: &str| panic!();
let key = "key";
let value = "value";
- let mut kvstore =
- ScopedKeyValueStore::<String, MockStorage>::new(&mut store, &id, fun).unwrap();
+ let mut kvstore: ExclusiveScopedKeyValueStore<String, MockStorage> =
+ ScopedKeyValueStore::new(&mut store, &id, fun).unwrap();
kvstore.as_mut().insert(key.to_string(), value.to_string());
assert!(kvstore.as_mut().contains_key(key));
}
