Use delayed error handling for Encodable
and Encoder
infallible.
There are two impls of the `Encoder` trait: `opaque::Encoder` and `opaque::FileEncoder`. The former encodes into memory and is infallible, the latter writes to file and is fallible. Currently, standard `Result`/`?`/`unwrap` error handling is used, but this is a bit verbose and has non-trivial cost, which is annoying given how rare failures are (especially in the infallible `opaque::Encoder` case). This commit changes how `Encoder` fallibility is handled. All the `emit_*` methods are now infallible. `opaque::Encoder` requires no great changes for this. `opaque::FileEncoder` now implements a delayed error handling strategy. If a failure occurs, it records this via the `res` field, and all subsequent encoding operations are skipped if `res` indicates an error has occurred. Once encoding is complete, the new `finish` method is called, which returns a `Result`. In other words, there is now a single `Result`-producing method instead of many of them. This has very little effect on how any file errors are reported if `opaque::FileEncoder` has any failures. Much of this commit is boring mechanical changes, removing `Result` return values and `?` or `unwrap` from expressions. The more interesting parts are as follows. - serialize.rs: The `Encoder` trait gains an `Ok` associated type. The `into_inner` method is changed into `finish`, which returns `Result<Vec<u8>, !>`. - opaque.rs: The `FileEncoder` adopts the delayed error handling strategy. Its `Ok` type is a `usize`, returning the number of bytes written, replacing previous uses of `FileEncoder::position`. - Various methods that take an encoder now consume it, rather than being passed a mutable reference, e.g. `serialize_query_result_cache`.
This commit is contained in:
parent
582b9cbc45
commit
1acbe7573d
45 changed files with 611 additions and 682 deletions
|
@ -842,7 +842,7 @@ impl<K: DepKind> DepGraph<K> {
|
|||
if let Some(data) = &self.data {
|
||||
data.current.encoder.steal().finish(profiler)
|
||||
} else {
|
||||
Ok(())
|
||||
Ok(0)
|
||||
}
|
||||
}
|
||||
|
||||
|
|
Loading…
Add table
Add a link
Reference in a new issue