Merge pull request #11 from eigerco/new-main

changes

CHANGELOG.md

@@ -28,11 +28,10 @@
     be used to avoid this and use the specified value.
 
 - Crates can now use proc-macros without UDL files to export their interface.  See the "Procedural Macros: Attributes and Derives" manual section for details.
+
 - [Custom Types](https://mozilla.github.io/uniffi-rs/proc_macro/index.html#the-unifficustomtype-derive) are now supported for proc-macros, including a very
   low-friction way of exposing types implementing the new-type idiom.
 - Proc-macros: Added support for ByRef arguments
-- Proc-macros: Implemented custom type conversion error handling (https://mozilla.github.io/uniffi-rs/udl/custom_types.html#error-handling-during-conversion)
-- Error types must now implement `Error + Send + Sync + 'static`.
 
 ### What's Fixed
 

Cargo.toml

@@ -6,8 +6,8 @@ members = [
   "uniffi_macros",
   "uniffi_meta",
   "uniffi_testing",
-  "uniffi_udl",
   "uniffi_docs",
+  "uniffi_udl",
   "uniffi",
   "weedle2",
 
@@ -23,16 +23,15 @@ members = [
   "examples/todolist",
   "examples/traits",
 
-  "fixtures/benchmarks",
-  "fixtures/coverall",
-  "fixtures/callbacks",
-
   "fixtures/ext-types/guid",
   "fixtures/ext-types/http-headermap",
   "fixtures/ext-types/uniffi-one",
   "fixtures/ext-types/lib",
   "fixtures/ext-types/proc-macro-lib",
 
+  "fixtures/benchmarks",
+  "fixtures/coverall",
+  "fixtures/callbacks",
   "fixtures/foreign-executor",
   "fixtures/keywords/kotlin",
   "fixtures/keywords/rust",

docs/manual/src/proc_macro/index.md

@@ -91,45 +91,13 @@ trait MyTrait {
 
 ```
 
+Most UniFFI [builtin types](../udl/builtin_types.md) can be used as parameter and return types.
+When a type is not supported, you will get a clear compiler error about it.
 
-All owned [builtin types](../udl/builtin_types.md) and user-defined types can be used as arguments
-and return types.
-
-Arguments and receivers can also be references to these types, for example:
-
-```rust
-// Input data types as references
-#[uniffi::export]
-fn process_data(a: &MyRecord, b: &MyEnum, c: Option<&MyRecord>) {
-    ...
-}
-
-#[uniffi::export]
-impl Foo {
-  // Methods can take a `&self`, which will be borrowed from `Arc<Self>`
-  fn some_method(&self) {
-    ...
-  }
-}
-
-// Input foo as an Arc and bar as a reference
-fn call_both(foo: Arc<Foo>, bar: &Foo) {
-  foo.some_method();
-  bar.some_method();
-}
-```
-
-The one restriction is that the reference must be visible in the function signature.  This wouldn't
-work:
-
-```rust
-type MyFooRef = &'static Foo;
-
-// ERROR: UniFFI won't recognize that the `foo` argument is a reference.
-#[uniffi::export]
-fn do_something(foo: MyFooRef) {
-}
-```
+User-defined types are also supported in a limited manner: records (structs with named fields,
+`dictionary` in UDL) and enums can be used when the corresponding derive macro is used at
+their definition. Opaque objects (`interface` in UDL) can always be used regardless of whether they
+are defined in UDL and / or via derive macro; they just need to be put inside an `Arc` as always.
 
 ## The `uniffi::Record` derive
 
@@ -218,6 +186,19 @@ impl Foo {
 }
 ```
 
+Exported functions can input object arguments as either an `Arc<>` or reference.
+```rust
+// Input foo as an Arc and bar as a reference
+fn call_both(foo: Arc<Foo>, bar: &Foo) {
+  foo.method_a();
+  bar.method_rba();
+```
+
+There are a couple limitations when using references for arguments:
+  - They can only be used with objects and trait interfaces
+  - The reference must be visible in the function signature.
+    If you have a type alias `type MyFooRef<'a> = &'a Foo`, then `fn do_something(foo: MyFooRef<'_>)` would not work.
+
 ## The `uniffi::custom_type` and `uniffi::custom_newtype` macros
 
 There are 2 macros available which allow procmacros to support "custom types" as described in the

fixtures/coverall/src/lib.rs

@@ -54,9 +54,7 @@ fn throw_flat_macro_error() -> Result<(), CoverallFlatMacroError> {
     Err(CoverallFlatMacroError::TooManyVariants { num: 88 })
 }
 
-#[derive(Debug, thiserror::Error)]
 pub enum CoverallRichErrorNoVariantData {
-    #[error("TooManyPlainVariants")]
     TooManyPlainVariants,
 }
 

fixtures/futures/Cargo.toml

@@ -16,7 +16,6 @@ path = "src/bin.rs"
 
 [dependencies]
 uniffi = { path = "../../uniffi", version = "0.24", features = ["tokio", "cli"] }
-thiserror = "1.0"
 tokio = { version = "1.24.1", features = ["time", "sync"] }
 once_cell = "1.18.0"
 

fixtures/futures/src/lib.rs

@@ -101,9 +101,8 @@ pub async fn sleep(ms: u16) -> bool {
 }
 
 // Our error.
-#[derive(thiserror::Error, uniffi::Error, Debug)]
+#[derive(uniffi::Error, Debug)]
 pub enum MyError {
-    #[error("Foo")]
     Foo,
 }
 
@@ -284,9 +283,8 @@ pub struct SharedResourceOptions {
 }
 
 // Our error.
-#[derive(thiserror::Error, uniffi::Error, Debug)]
+#[derive(uniffi::Error, Debug)]
 pub enum AsyncError {
-    #[error("Timeout")]
     Timeout,
 }
 

fixtures/metadata/Cargo.toml

@@ -9,7 +9,6 @@ publish = false
 name = "uniffi_fixture_metadata"
 
 [dependencies]
-thiserror = "1.0"
 uniffi = { path = "../../uniffi", version = "0.24" }
 uniffi_meta = { path = "../../uniffi_meta" }
 uniffi_core = { path = "../../uniffi_core" }