Cleaner error management (less error-prone api)

4 files changed, 113 insertions, 76 deletions

diff --git a/src/db/lib.rs b/src/db/lib.rs
index a7b6197c..a4da4086 100644
--- a/src/db/lib.rs
+++ b/src/db/lib.rs
@@ -34,6 +34,9 @@ pub struct Error(pub Cow<'static, str>);
 
 pub type Result<T> = std::result::Result<T, Error>;
 
+pub struct TxOpError(pub(crate) Error);
+pub type TxOpResult<T> = std::result::Result<T, TxOpError>;
+
 #[derive(Debug)]
 pub enum TxError<E> {
 	Abort(E),
@@ -41,9 +44,17 @@ pub enum TxError<E> {
 }
 pub type TxResult<R, E> = std::result::Result<R, TxError<E>>;
 
-impl<E> From<Error> for TxError<E> {
-	fn from(e: Error) -> TxError<E> {
-		TxError::Db(e)
+impl<E> From<TxOpError> for TxError<E> {
+	fn from(e: TxOpError) -> TxError<E> {
+		TxError::Db(e.0)
+	}
+}
+
+pub fn unabort<R, E>(res: TxResult<R, E>) -> TxOpResult<std::result::Result<R, E>> {
+	match res {
+		Ok(v) => Ok(Ok(v)),
+		Err(TxError::Abort(e)) => Ok(Err(e)),
+		Err(TxError::Db(e)) => Err(TxOpError(e)),
 	}
 }
 
@@ -117,19 +128,19 @@ impl Db {
 
 			let tx_res = self.transaction(|mut tx| {
 				let mut i = 0;
-				for item in ex_tree.iter()? {
-					let (k, v) = item?;
+				for item in ex_tree.iter().map_err(TxError::Abort)? {
+					let (k, v) = item.map_err(TxError::Abort)?;
 					tx.insert(&tree, k, v)?;
 					i += 1;
 					if i % 1000 == 0 {
 						println!("{}: imported {}", name, i);
 					}
 				}
-				Ok::<_, TxError<()>>(i)
+				tx.commit(i)
 			});
 			let total = match tx_res {
 				Err(TxError::Db(e)) => return Err(e),
-				Err(TxError::Abort(_)) => unreachable!(),
+				Err(TxError::Abort(e)) => return Err(e),
 				Ok(x) => x,
 			};
 
@@ -215,11 +226,11 @@ impl Tree {
 #[allow(clippy::len_without_is_empty)]
 impl<'a> Transaction<'a> {
 	#[inline]
-	pub fn get<T: AsRef<[u8]>>(&self, tree: &Tree, key: T) -> Result<Option<Value>> {
+	pub fn get<T: AsRef<[u8]>>(&self, tree: &Tree, key: T) -> TxOpResult<Option<Value>> {
 		self.0.get(tree.1, key.as_ref())
 	}
 	#[inline]
-	pub fn len(&self, tree: &Tree) -> Result<usize> {
+	pub fn len(&self, tree: &Tree) -> TxOpResult<usize> {
 		self.0.len(tree.1)
 	}
 
@@ -230,26 +241,26 @@ impl<'a> Transaction<'a> {
 		tree: &Tree,
 		key: T,
 		value: U,
-	) -> Result<Option<Value>> {
+	) -> TxOpResult<Option<Value>> {
 		self.0.insert(tree.1, key.as_ref(), value.as_ref())
 	}
 	/// Returns the old value if there was one
 	#[inline]
-	pub fn remove<T: AsRef<[u8]>>(&mut self, tree: &Tree, key: T) -> Result<Option<Value>> {
+	pub fn remove<T: AsRef<[u8]>>(&mut self, tree: &Tree, key: T) -> TxOpResult<Option<Value>> {
 		self.0.remove(tree.1, key.as_ref())
 	}
 
 	#[inline]
-	pub fn iter(&self, tree: &Tree) -> Result<ValueIter<'_>> {
+	pub fn iter(&self, tree: &Tree) -> TxOpResult<ValueIter<'_>> {
 		self.0.iter(tree.1)
 	}
 	#[inline]
-	pub fn iter_rev(&self, tree: &Tree) -> Result<ValueIter<'_>> {
+	pub fn iter_rev(&self, tree: &Tree) -> TxOpResult<ValueIter<'_>> {
 		self.0.iter_rev(tree.1)
 	}
 
 	#[inline]
-	pub fn range<K, R>(&self, tree: &Tree, range: R) -> Result<ValueIter<'_>>
+	pub fn range<K, R>(&self, tree: &Tree, range: R) -> TxOpResult<ValueIter<'_>>
 	where
 		K: AsRef<[u8]>,
 		R: RangeBounds<K>,
@@ -259,7 +270,7 @@ impl<'a> Transaction<'a> {
 		self.0.range(tree.1, get_bound(sb), get_bound(eb))
 	}
 	#[inline]
-	pub fn range_rev<K, R>(&self, tree: &Tree, range: R) -> Result<ValueIter<'_>>
+	pub fn range_rev<K, R>(&self, tree: &Tree, range: R) -> TxOpResult<ValueIter<'_>>
 	where
 		K: AsRef<[u8]>,
 		R: RangeBounds<K>,
@@ -314,27 +325,27 @@ pub(crate) trait IDb: Send + Sync {
 }
 
 pub(crate) trait ITx {
-	fn get(&self, tree: usize, key: &[u8]) -> Result<Option<Value>>;
-	fn len(&self, tree: usize) -> Result<usize>;
+	fn get(&self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>>;
+	fn len(&self, tree: usize) -> TxOpResult<usize>;
 
-	fn insert(&mut self, tree: usize, key: &[u8], value: &[u8]) -> Result<Option<Value>>;
-	fn remove(&mut self, tree: usize, key: &[u8]) -> Result<Option<Value>>;
+	fn insert(&mut self, tree: usize, key: &[u8], value: &[u8]) -> TxOpResult<Option<Value>>;
+	fn remove(&mut self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>>;
 
-	fn iter(&self, tree: usize) -> Result<ValueIter<'_>>;
-	fn iter_rev(&self, tree: usize) -> Result<ValueIter<'_>>;
+	fn iter(&self, tree: usize) -> TxOpResult<ValueIter<'_>>;
+	fn iter_rev(&self, tree: usize) -> TxOpResult<ValueIter<'_>>;
 
 	fn range<'r>(
 		&self,
 		tree: usize,
 		low: Bound<&'r [u8]>,
 		high: Bound<&'r [u8]>,
-	) -> Result<ValueIter<'_>>;
+	) -> TxOpResult<ValueIter<'_>>;
 	fn range_rev<'r>(
 		&self,
 		tree: usize,
 		low: Bound<&'r [u8]>,
 		high: Bound<&'r [u8]>,
-	) -> Result<ValueIter<'_>>;
+	) -> TxOpResult<ValueIter<'_>>;
 }
 
 pub(crate) trait ITxFn {
diff --git a/src/db/lmdb_adapter.rs b/src/db/lmdb_adapter.rs
index 9e4306c8..d1efd216 100644
--- a/src/db/lmdb_adapter.rs
+++ b/src/db/lmdb_adapter.rs
@@ -8,7 +8,10 @@ use std::sync::{Arc, RwLock};
 use heed::types::ByteSlice;
 use heed::{BytesDecode, Env, RoTxn, RwTxn, UntypedDatabase as Database};
 
-use crate::{Db, Error, IDb, ITx, ITxFn, Result, TxError, TxFnResult, TxResult, Value, ValueIter};
+use crate::{
+	Db, Error, IDb, ITx, ITxFn, Result, TxError, TxFnResult, TxOpError, TxOpResult, TxResult,
+	Value, ValueIter,
+};
 
 pub use heed;
 
@@ -20,9 +23,9 @@ impl From<heed::Error> for Error {
 	}
 }
 
-impl<T> From<heed::Error> for TxError<T> {
-	fn from(e: heed::Error) -> TxError<T> {
-		TxError::Db(e.into())
+impl From<heed::Error> for TxOpError {
+	fn from(e: heed::Error) -> TxOpError {
+		TxOpError(e.into())
 	}
 }
 
@@ -171,21 +174,25 @@ impl IDb for LmdbDb {
 		let trees = self.trees.read().unwrap();
 		let mut tx = LmdbTx {
 			trees: &trees.0[..],
-			tx: self.db.write_txn()?,
+			tx: self
+				.db
+				.write_txn()
+				.map_err(Error::from)
+				.map_err(TxError::Db)?,
 		};
 
 		let res = f.try_on(&mut tx);
 		match res {
 			TxFnResult::Ok => {
-				tx.tx.commit()?;
+				tx.tx.commit().map_err(Error::from).map_err(TxError::Db)?;
 				Ok(())
 			}
 			TxFnResult::Abort => {
-				tx.tx.abort()?;
+				tx.tx.abort().map_err(Error::from).map_err(TxError::Db)?;
 				Err(TxError::Abort(()))
 			}
 			TxFnResult::DbErr => {
-				tx.tx.abort()?;
+				tx.tx.abort().map_err(Error::from).map_err(TxError::Db)?;
 				Err(TxError::Db(Error(
 					"(this message will be discarded)".into(),
 				)))
@@ -202,44 +209,44 @@ struct LmdbTx<'a, 'db> {
 }
 
 impl<'a, 'db> LmdbTx<'a, 'db> {
-	fn get_tree(&self, i: usize) -> Result<&Database> {
+	fn get_tree(&self, i: usize) -> TxOpResult<&Database> {
 		self.trees.get(i).ok_or_else(|| {
-			Error(
+			TxOpError(Error(
 				"invalid tree id (it might have been openned after the transaction started)".into(),
-			)
+			))
 		})
 	}
 }
 
 impl<'a, 'db> ITx for LmdbTx<'a, 'db> {
-	fn get(&self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
+	fn get(&self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>> {
 		let tree = self.get_tree(tree)?;
 		match tree.get(&self.tx, key)? {
 			Some(v) => Ok(Some(v.to_vec())),
 			None => Ok(None),
 		}
 	}
-	fn len(&self, _tree: usize) -> Result<usize> {
+	fn len(&self, _tree: usize) -> TxOpResult<usize> {
 		unimplemented!(".len() in transaction not supported with LMDB backend")
 	}
 
-	fn insert(&mut self, tree: usize, key: &[u8], value: &[u8]) -> Result<Option<Value>> {
+	fn insert(&mut self, tree: usize, key: &[u8], value: &[u8]) -> TxOpResult<Option<Value>> {
 		let tree = *self.get_tree(tree)?;
 		let old_val = tree.get(&self.tx, key)?.map(Vec::from);
 		tree.put(&mut self.tx, key, value)?;
 		Ok(old_val)
 	}
-	fn remove(&mut self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
+	fn remove(&mut self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>> {
 		let tree = *self.get_tree(tree)?;
 		let old_val = tree.get(&self.tx, key)?.map(Vec::from);
 		tree.delete(&mut self.tx, key)?;
 		Ok(old_val)
 	}
 
-	fn iter(&self, _tree: usize) -> Result<ValueIter<'_>> {
+	fn iter(&self, _tree: usize) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!("Iterators in transactions not supported with LMDB backend");
 	}
-	fn iter_rev(&self, _tree: usize) -> Result<ValueIter<'_>> {
+	fn iter_rev(&self, _tree: usize) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!("Iterators in transactions not supported with LMDB backend");
 	}
 
@@ -248,7 +255,7 @@ impl<'a, 'db> ITx for LmdbTx<'a, 'db> {
 		_tree: usize,
 		_low: Bound<&'r [u8]>,
 		_high: Bound<&'r [u8]>,
-	) -> Result<ValueIter<'_>> {
+	) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!("Iterators in transactions not supported with LMDB backend");
 	}
 	fn range_rev<'r>(
@@ -256,7 +263,7 @@ impl<'a, 'db> ITx for LmdbTx<'a, 'db> {
 		_tree: usize,
 		_low: Bound<&'r [u8]>,
 		_high: Bound<&'r [u8]>,
-	) -> Result<ValueIter<'_>> {
+	) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!("Iterators in transactions not supported with LMDB backend");
 	}
 }
diff --git a/src/db/sled_adapter.rs b/src/db/sled_adapter.rs
index b07401c9..d0d9e9c0 100644
--- a/src/db/sled_adapter.rs
+++ b/src/db/sled_adapter.rs
@@ -9,7 +9,10 @@ use sled::transaction::{
 	UnabortableTransactionError,
 };
 
-use crate::{Db, Error, IDb, ITx, ITxFn, Result, TxError, TxFnResult, TxResult, Value, ValueIter};
+use crate::{
+	Db, Error, IDb, ITx, ITxFn, Result, TxError, TxFnResult, TxOpError, TxOpResult, TxResult,
+	Value, ValueIter,
+};
 
 pub use sled;
 
@@ -21,6 +24,12 @@ impl From<sled::Error> for Error {
 	}
 }
 
+impl From<sled::Error> for TxOpError {
+	fn from(e: sled::Error) -> TxOpError {
+		TxOpError(e.into())
+	}
+}
+
 // -- db
 
 pub struct SledDb {
@@ -177,51 +186,54 @@ struct SledTx<'a> {
 }
 
 impl<'a> SledTx<'a> {
-	fn get_tree(&self, i: usize) -> Result<&TransactionalTree> {
+	fn get_tree(&self, i: usize) -> TxOpResult<&TransactionalTree> {
 		self.trees.get(i).ok_or_else(|| {
-			Error(
+			TxOpError(Error(
 				"invalid tree id (it might have been openned after the transaction started)".into(),
-			)
+			))
 		})
 	}
 
-	fn save_error<R>(&self, v: std::result::Result<R, UnabortableTransactionError>) -> Result<R> {
+	fn save_error<R>(
+		&self,
+		v: std::result::Result<R, UnabortableTransactionError>,
+	) -> TxOpResult<R> {
 		match v {
 			Ok(x) => Ok(x),
 			Err(e) => {
 				let txt = format!("{}", e);
 				self.err.set(Some(e));
-				Err(Error(txt.into()))
+				Err(TxOpError(Error(txt.into())))
 			}
 		}
 	}
 }
 
 impl<'a> ITx for SledTx<'a> {
-	fn get(&self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
+	fn get(&self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>> {
 		let tree = self.get_tree(tree)?;
 		let tmp = self.save_error(tree.get(key))?;
 		Ok(tmp.map(|x| x.to_vec()))
 	}
-	fn len(&self, _tree: usize) -> Result<usize> {
+	fn len(&self, _tree: usize) -> TxOpResult<usize> {
 		unimplemented!(".len() in transaction not supported with Sled backend")
 	}
 
-	fn insert(&mut self, tree: usize, key: &[u8], value: &[u8]) -> Result<Option<Value>> {
+	fn insert(&mut self, tree: usize, key: &[u8], value: &[u8]) -> TxOpResult<Option<Value>> {
 		let tree = self.get_tree(tree)?;
 		let old_val = self.save_error(tree.insert(key, value))?;
 		Ok(old_val.map(|x| x.to_vec()))
 	}
-	fn remove(&mut self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
+	fn remove(&mut self, tree: usize, key: &[u8]) -> TxOpResult<Option<Value>> {
 		let tree = self.get_tree(tree)?;
 		let old_val = self.save_error(tree.remove(key))?;
 		Ok(old_val.map(|x| x.to_vec()))
 	}
 
-	fn iter(&self, _tree: usize) -> Result<ValueIter<'_>> {
+	fn iter(&self, _tree: usize) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!("Iterators in transactions not supported with Sled backend");
 	}
-	fn iter_rev(&self, _tree: usize) -> Result<ValueIter<'_>> {
+	fn iter_rev(&self, _tree: usize) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!("Iterators in transactions not supported with Sled backend");
 	}
 
@@ -230,7 +242,7 @@ impl<'a> ITx for SledTx<'a> {
 		_tree: usize,
 		_low: Bound<&'r [u8]>,
 		_high: Bound<&'r [u8]>,
-	) -> Result<ValueIter<'_>> {
+	) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!("Iterators in transactions not supported with Sled backend");
 	}
 	fn range_rev<'r>(
@@ -238,7 +250,7 @@ impl<'a> ITx for SledTx<'a> {
 		_tree: usize,
 		_low: Bound<&'r [u8]>,
 		_high: Bound<&'r [u8]>,
-	) -> Result<ValueIter<'_>> {
+	) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!("Iterators in transactions not supported with Sled backend");
 	}
 }
diff --git a/src/db/sqlite_adapter.rs b/src/db/sqlite_adapter.rs
index b23885bd..8d6bd714 100644
--- a/src/db/sqlite_adapter.rs
+++ b/src/db/sqlite_adapter.rs
@@ -10,7 +10,10 @@ use log::trace;
 
 use rusqlite::{params, Connection, Rows, Statement, Transaction};
 
-use crate::{Db, Error, IDb, ITx, ITxFn, Result, TxError, TxFnResult, TxResult, Value, ValueIter};
+use crate::{
+	Db, Error, IDb, ITx, ITxFn, Result, TxError, TxFnResult, TxOpError, TxOpResult, TxResult,
+	Value, ValueIter,
+};
 
 pub use rusqlite;
 
@@ -22,9 +25,9 @@ impl From<rusqlite::Error> for Error {
 	}
 }
 
-impl<T> From<rusqlite::Error> for TxError<T> {
-	fn from(e: rusqlite::Error) -> TxError<T> {
-		TxError::Db(e.into())
+impl From<rusqlite::Error> for TxOpError {
+	fn from(e: rusqlite::Error) -> TxOpError {
+		TxOpError(e.into())
 	}
 }
 
@@ -260,20 +263,24 @@ impl IDb for SqliteDb {
 		let this_mut_ref: &mut SqliteDbInner = this.borrow_mut();
 
 		let mut tx = SqliteTx {
-			tx: this_mut_ref.db.transaction()?,
+			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()?;
+				tx.tx.commit().map_err(Error::from).map_err(TxError::Db)?;
 				Ok(())
 			}
 			TxFnResult::Abort => {
-				tx.tx.rollback()?;
+				tx.tx.rollback().map_err(Error::from).map_err(TxError::Db)?;
 				Err(TxError::Abort(()))
 			}
 			TxFnResult::DbErr => {
-				tx.tx.rollback()?;
+				tx.tx.rollback().map_err(Error::from).map_err(TxError::Db)?;
 				Err(TxError::Db(Error(
 					"(this message will be discarded)".into(),
 				)))
@@ -293,15 +300,15 @@ struct SqliteTx<'a> {
 }
 
 impl<'a> SqliteTx<'a> {
-	fn get_tree(&self, i: usize) -> Result<&'_ str> {
+	fn get_tree(&self, i: usize) -> TxOpResult<&'_ str> {
 		self.trees.get(i).map(String::as_ref).ok_or_else(|| {
-			Error(
+			TxOpError(Error(
 				"invalid tree id (it might have been openned after the transaction started)".into(),
-			)
+			))
 		})
 	}
 
-	fn internal_get(&self, tree: &str, key: &[u8]) -> Result<Option<Value>> {
+	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))?;
@@ -314,11 +321,11 @@ impl<'a> SqliteTx<'a> {
 }
 
 impl<'a> ITx for SqliteTx<'a> {
-	fn get(&self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
+	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) -> Result<usize> {
+	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([])?;
@@ -328,7 +335,7 @@ impl<'a> ITx for SqliteTx<'a> {
 		}
 	}
 
-	fn insert(&mut self, tree: usize, key: &[u8], value: &[u8]) -> Result<Option<Value>> {
+	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)?;
 
@@ -351,7 +358,7 @@ impl<'a> ITx for SqliteTx<'a> {
 
 		Ok(old_val)
 	}
-	fn remove(&mut self, tree: usize, key: &[u8]) -> Result<Option<Value>> {
+	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)?;
 
@@ -365,10 +372,10 @@ impl<'a> ITx for SqliteTx<'a> {
 		Ok(old_val)
 	}
 
-	fn iter(&self, _tree: usize) -> Result<ValueIter<'_>> {
+	fn iter(&self, _tree: usize) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!();
 	}
-	fn iter_rev(&self, _tree: usize) -> Result<ValueIter<'_>> {
+	fn iter_rev(&self, _tree: usize) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!();
 	}
 
@@ -377,7 +384,7 @@ impl<'a> ITx for SqliteTx<'a> {
 		_tree: usize,
 		_low: Bound<&'r [u8]>,
 		_high: Bound<&'r [u8]>,
-	) -> Result<ValueIter<'_>> {
+	) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!();
 	}
 	fn range_rev<'r>(
@@ -385,7 +392,7 @@ impl<'a> ITx for SqliteTx<'a> {
 		_tree: usize,
 		_low: Bound<&'r [u8]>,
 		_high: Bound<&'r [u8]>,
-	) -> Result<ValueIter<'_>> {
+	) -> TxOpResult<ValueIter<'_>> {
 		unimplemented!();
 	}
 }