backend: impl From<heed::Error> for RuntimeError

database/src/backend/heed/error.rs

@@ -0,0 +1,61 @@
+//! Conversion from `heed::Error` -> `cuprate_database::RuntimeError`.
+
+//---------------------------------------------------------------------------------------------------- Import
+use std::borrow::Cow;
+
+//---------------------------------------------------------------------------------------------------- Error
+impl From<heed::Error> for crate::RuntimeError {
+    fn from(error: heed::Error) -> Self {
+        use heed::Error as E1;
+        use heed::MdbError as E2;
+
+        match error {
+            // I/O errors.
+            E1::Io(io_error) => Self::Io(io_error),
+
+            // LMDB errors.
+            E1::Mdb(mdb_error) => match mdb_error {
+                E2::KeyExist => Self::KeyExists,
+                E2::NotFound => Self::KeyNotFound,
+                E2::VersionMismatch => Self::VersionMismatch,
+                E2::MapFull => Self::MapFull,
+                E2::ReadersFull => Self::ReadersFull,
+                E2::PageFull => Self::PageFull,
+                E2::Other(c_int) => {
+                    Self::Unknown(Cow::Owned(format!("heed::Error::Other({c_int})")))
+                }
+                E2::DbsFull
+                | E2::PageNotFound
+                | E2::Corrupted
+                | E2::Panic
+                | E2::Invalid
+                | E2::TlsFull
+                | E2::TxnFull
+                | E2::CursorFull
+                | E2::MapResized
+                | E2::Incompatible
+                | E2::BadRslot
+                | E2::BadTxn
+                | E2::BadValSize
+                | E2::BadDbi
+                | E2::Problem => Self::Unknown(Cow::from(std::any::type_name_of_val(&mdb_error))),
+            },
+
+            // Database is shutting down.
+            E1::DatabaseClosing => Self::ShuttingDown,
+
+            // TODO: these will never occur once correct?
+            // TODO: (de)serialization is infallible?
+            E1::InvalidDatabaseTyping
+            | E1::BadOpenOptions { .. }
+            | E1::Encoding(_)
+            | E1::Decoding(_) => unreachable!(),
+        }
+    }
+}
+
+//---------------------------------------------------------------------------------------------------- Tests
+#[cfg(test)]
+mod test {
+    // use super::*;
+}

database/src/backend/heed/mod.rs

@@ -3,6 +3,8 @@
 mod env;
 pub use env::ConcreteEnv;
 
+mod error;
+
 mod database;
 
 mod serde;

database/src/error.rs

@@ -4,8 +4,6 @@
 //---------------------------------------------------------------------------------------------------- Import
 use std::{borrow::Cow, fmt::Debug};
 
-use crate::constants::DATABASE_BACKEND;
-
 //---------------------------------------------------------------------------------------------------- InitError
 /// Database errors that occur during initialization.
 ///
@@ -45,18 +43,12 @@ pub enum InitError {
 #[derive(thiserror::Error, Debug)]
 pub enum RuntimeError {
     /// The given key already existed in the database.
-    ///
+    #[error("key already existed")]
-    /// The string inside is the output of
+    KeyExists,
-    /// [`std::any::type_name`] on the key type.
-    #[error("key of type `{0}` already existed")]
-    KeyExists(&'static str),
 
     /// The given key did not exist in the database.
-    ///
+    #[error("key/value pair was not found")]
-    /// The string inside is the output of
+    KeyNotFound,
-    /// [`std::any::type_name`] on the key type.
-    #[error("key/value pair was not found: {0}")]
-    KeyNotFound(&'static str),
 
     /// The database environment has reached
     /// maximum memory map size, it must be
@@ -76,21 +68,21 @@ pub enum RuntimeError {
     #[error("I/O error: {0}")]
     Io(#[from] std::io::Error),
 
+    /// The database is currently in the process
+    /// of shutting down and cannot respond.
+    #[error("database is shutting down")]
+    ShuttingDown,
+
     /// The expected database version was not the version found.
-    #[error("database version mismatch: expected {expected}, found {found}")]
+    #[error("database version mismatch")]
-    VersionMismatch {
+    VersionMismatch,
-        /// The expected database version.
-        expected: &'static str,
-        /// The database version found.
-        found: &'static str,
-    },
 
     /// The database has reached maximum parallel readers.
     ///
     /// TODO: this can be used for retry logic in reader threads,
     /// although, does this error ever actually occur in practice?
     #[error("database maximum parallel readers reached")]
-    MaxReaders,
+    ReadersFull,
 
     // TODO: this could be removed once we have all errors figured out.
     /// An unknown error occurred.