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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
//! # Enum definitions for a `ComponentInterface`.
//!
//! This module converts enum definition from UDL into structures that can be
//! added to a `ComponentInterface`. A declaration in the UDL like this:
//!
//! ```
//! # let ci = uniffi_bindgen::interface::ComponentInterface::from_webidl(r##"
//! # namespace example {};
//! enum Example {
//! "one",
//! "two"
//! };
//! # "##, "crate_name")?;
//! # Ok::<(), anyhow::Error>(())
//! ```
//!
//! Will result in a [`Enum`] member being added to the resulting [`crate::ComponentInterface`]:
//!
//! ```
//! # let ci = uniffi_bindgen::interface::ComponentInterface::from_webidl(r##"
//! # namespace example {};
//! # enum Example {
//! # "one",
//! # "two"
//! # };
//! # "##, "crate_name")?;
//! let e = ci.get_enum_definition("Example").unwrap();
//! assert_eq!(e.name(), "Example");
//! assert_eq!(e.variants().len(), 2);
//! assert_eq!(e.variants()[0].name(), "one");
//! assert_eq!(e.variants()[1].name(), "two");
//! # Ok::<(), anyhow::Error>(())
//! ```
//!
//! Like in Rust, UniFFI enums can contain associated data, but this needs to be
//! declared with a different syntax in order to work within the restrictions of
//! WebIDL. A declaration like this:
//!
//! ```
//! # let ci = uniffi_bindgen::interface::ComponentInterface::from_webidl(r##"
//! # namespace example {};
//! [Enum]
//! interface Example {
//! Zero();
//! One(u32 first);
//! Two(u32 first, string second);
//! };
//! # "##, "crate_name")?;
//! # Ok::<(), anyhow::Error>(())
//! ```
//!
//! Will result in an [`Enum`] member whose variants have associated fields:
//!
//! ```
//! # let ci = uniffi_bindgen::interface::ComponentInterface::from_webidl(r##"
//! # namespace example {};
//! # [Enum]
//! # interface ExampleWithData {
//! # Zero();
//! # One(u32 first);
//! # Two(u32 first, string second);
//! # };
//! # "##, "crate_name")?;
//! let e = ci.get_enum_definition("ExampleWithData").unwrap();
//! assert_eq!(e.name(), "ExampleWithData");
//! assert_eq!(e.variants().len(), 3);
//! assert_eq!(e.variants()[0].name(), "Zero");
//! assert_eq!(e.variants()[0].fields().len(), 0);
//! assert_eq!(e.variants()[1].name(), "One");
//! assert_eq!(e.variants()[1].fields().len(), 1);
//! assert_eq!(e.variants()[1].fields()[0].name(), "first");
//! # Ok::<(), anyhow::Error>(())
//! ```
//!
//! # Enums are also used to represent error definitions for a `ComponentInterface`.
//!
//! ```
//! # let ci = uniffi_bindgen::interface::ComponentInterface::from_webidl(r##"
//! # namespace example {};
//! [Error]
//! enum Example {
//! "one",
//! "two"
//! };
//! # "##, "crate_name")?;
//! # Ok::<(), anyhow::Error>(())
//! ```
//!
//! Will result in an [`Enum`] member with fieldless variants being added to the resulting [`crate::ComponentInterface`]:
//!
//! ```
//! # let ci = uniffi_bindgen::interface::ComponentInterface::from_webidl(r##"
//! # namespace example {
//! # [Throws=Example] void func();
//! # };
//! # [Error]
//! # enum Example {
//! # "one",
//! # "two"
//! # };
//! # "##, "crate_name")?;
//! let err = ci.get_enum_definition("Example").unwrap();
//! assert_eq!(err.name(), "Example");
//! assert_eq!(err.variants().len(), 2);
//! assert_eq!(err.variants()[0].name(), "one");
//! assert_eq!(err.variants()[1].name(), "two");
//! assert_eq!(err.is_flat(), true);
//! assert!(ci.is_name_used_as_error(&err.name()));
//! # Ok::<(), anyhow::Error>(())
//! ```
//!
//! A declaration in the UDL like this:
//!
//! ```
//! # let ci = uniffi_bindgen::interface::ComponentInterface::from_webidl(r##"
//! # namespace example {};
//! [Error]
//! interface Example {
//! one(i16 code);
//! two(string reason);
//! three(i32 x, i32 y);
//! };
//! # "##, "crate_name")?;
//! # Ok::<(), anyhow::Error>(())
//! ```
//!
//! Will result in an [`Enum`] member with variants that have fields being added to the resulting [`crate::ComponentInterface`]:
//!
//! ```
//! # let ci = uniffi_bindgen::interface::ComponentInterface::from_webidl(r##"
//! # namespace example {
//! # [Throws=Example] void func();
//! # };
//! # [Error]
//! # interface Example {
//! # one();
//! # two(string reason);
//! # three(i32 x, i32 y);
//! # };
//! # "##, "crate_name")?;
//! let err = ci.get_enum_definition("Example").unwrap();
//! assert_eq!(err.name(), "Example");
//! assert_eq!(err.variants().len(), 3);
//! assert_eq!(err.variants()[0].name(), "one");
//! assert_eq!(err.variants()[1].name(), "two");
//! assert_eq!(err.variants()[2].name(), "three");
//! assert_eq!(err.variants()[0].fields().len(), 0);
//! assert_eq!(err.variants()[1].fields().len(), 1);
//! assert_eq!(err.variants()[1].fields()[0].name(), "reason");
//! assert_eq!(err.variants()[2].fields().len(), 2);
//! assert_eq!(err.variants()[2].fields()[0].name(), "x");
//! assert_eq!(err.variants()[2].fields()[1].name(), "y");
//! assert_eq!(err.is_flat(), false);
//! assert!(ci.is_name_used_as_error(err.name()));
//! # Ok::<(), anyhow::Error>(())
//! ```
use anyhow::Result;
use uniffi_meta::{Checksum, EnumShape};
use super::record::Field;
use super::{AsType, Literal, Type, TypeIterator};
/// Represents an enum with named variants, each of which may have named
/// and typed fields.
///
/// Enums are passed across the FFI by serializing to a bytebuffer, with a
/// i32 indicating the variant followed by the serialization of each field.
#[derive(Debug, Clone, PartialEq, Eq, Checksum)]
pub struct Enum {
pub(super) name: String,
pub(super) module_path: String,
pub(super) discr_type: Option<Type>,
pub(super) variants: Vec<Variant>,
pub(super) shape: EnumShape,
pub(super) non_exhaustive: bool,
#[checksum_ignore]
pub(super) docstring: Option<String>,
}
impl Enum {
pub fn name(&self) -> &str {
&self.name
}
pub fn rename(&mut self, name: String) {
self.name = name;
}
pub fn variants(&self) -> &[Variant] {
&self.variants
}
// Get the literal value to use for the specified variant's discriminant.
// Follows Rust's rules when mixing specified and unspecified values; please
// file a bug if you find a case where it does not.
// However, it *does not* attempt to handle error cases - either cases where
// a discriminant is not unique, or where a discriminant would overflow the
// repr. The intention is that the Rust compiler itself will fail to build
// in those cases, so by the time this get's run we can be confident these
// error cases can't exist.
pub fn variant_discr(&self, variant_index: usize) -> Result<Literal> {
if variant_index >= self.variants.len() {
anyhow::bail!("Invalid variant index {variant_index}");
}
let mut next = 0;
let mut this;
let mut this_lit = Literal::new_uint(0);
for v in self.variants().iter().take(variant_index + 1) {
(this, this_lit) = match v.discr {
None => (
next,
if (next as i64) < 0 {
Literal::new_int(next as i64)
} else {
Literal::new_uint(next)
},
),
Some(Literal::UInt(v, _, _)) => (v, Literal::new_uint(v)),
// in-practice, Literal::Int == a negative number.
Some(Literal::Int(v, _, _)) => (v as u64, Literal::new_int(v)),
_ => anyhow::bail!("Invalid literal type {v:?}"),
};
next = this.wrapping_add(1);
}
Ok(this_lit)
}
pub fn variant_discr_type(&self) -> &Option<Type> {
&self.discr_type
}
pub fn is_flat(&self) -> bool {
match self.shape {
EnumShape::Error { flat } => flat,
EnumShape::Enum => self.variants.iter().all(|v| v.fields.is_empty()),
}
}
pub fn is_non_exhaustive(&self) -> bool {
self.non_exhaustive
}
pub fn iter_types(&self) -> TypeIterator<'_> {
Box::new(self.variants.iter().flat_map(Variant::iter_types))
}
pub fn docstring(&self) -> Option<&str> {
self.docstring.as_deref()
}
}
impl TryFrom<uniffi_meta::EnumMetadata> for Enum {
type Error = anyhow::Error;
fn try_from(meta: uniffi_meta::EnumMetadata) -> Result<Self> {
Ok(Self {
name: meta.name,
module_path: meta.module_path,
discr_type: meta.discr_type,
variants: meta
.variants
.into_iter()
.map(TryInto::try_into)
.collect::<Result<_>>()?,
shape: meta.shape,
non_exhaustive: meta.non_exhaustive,
docstring: meta.docstring.clone(),
})
}
}
impl AsType for Enum {
fn as_type(&self) -> Type {
Type::Enum {
name: self.name.clone(),
module_path: self.module_path.clone(),
}
}
}
/// Represents an individual variant in an Enum.
///
/// Each variant has a name and zero or more fields.
#[derive(Debug, Clone, Default, PartialEq, Eq, Checksum)]
pub struct Variant {
pub(super) name: String,
pub(super) discr: Option<Literal>,
pub(super) fields: Vec<Field>,
#[checksum_ignore]
pub(super) docstring: Option<String>,
}
impl Variant {
pub fn name(&self) -> &str {
&self.name
}
pub fn rename(&mut self, new_name: String) {
self.name = new_name;
}
pub fn fields(&self) -> &[Field] {
&self.fields
}
pub fn has_fields(&self) -> bool {
!self.fields.is_empty()
}
pub fn has_nameless_fields(&self) -> bool {
self.fields.iter().any(|f| f.name.is_empty())
}
pub fn docstring(&self) -> Option<&str> {
self.docstring.as_deref()
}
pub fn iter_types(&self) -> TypeIterator<'_> {
Box::new(self.fields.iter().flat_map(Field::iter_types))
}
}
impl TryFrom<uniffi_meta::VariantMetadata> for Variant {
type Error = anyhow::Error;
fn try_from(meta: uniffi_meta::VariantMetadata) -> Result<Self> {
Ok(Self {
name: meta.name,
discr: meta.discr,
fields: meta
.fields
.into_iter()
.map(TryInto::try_into)
.collect::<Result<_>>()?,
docstring: meta.docstring.clone(),
})
}
}
#[cfg(test)]
mod test {
use super::super::{ComponentInterface, FfiType};
use super::*;
#[test]
fn test_duplicate_variants() {
const UDL: &str = r#"
namespace test{};
// Weird, but currently allowed!
// We should probably disallow this...
enum Testing { "one", "two", "one" };
"#;
let ci = ComponentInterface::from_webidl(UDL, "crate_name").unwrap();
assert_eq!(ci.enum_definitions().count(), 1);
assert_eq!(
ci.get_enum_definition("Testing").unwrap().variants().len(),
3
);
}
#[test]
fn test_associated_data() {
const UDL: &str = r#"
namespace test {
void takes_an_enum(TestEnum e);
void takes_an_enum_with_data(TestEnumWithData ed);
TestEnum returns_an_enum();
TestEnumWithData returns_an_enum_with_data();
};
enum TestEnum { "one", "two" };
[Enum]
interface TestEnumWithData {
Zero();
One(u32 first);
Two(u32 first, string second);
};
[Enum]
interface TestEnumWithoutData {
One();
Two();
};
"#;
let ci = ComponentInterface::from_webidl(UDL, "crate_name").unwrap();
assert_eq!(ci.enum_definitions().count(), 3);
assert_eq!(ci.function_definitions().len(), 4);
// The "flat" enum with no associated data.
let e = ci.get_enum_definition("TestEnum").unwrap();
assert!(e.is_flat());
assert_eq!(e.variants().len(), 2);
assert_eq!(
e.variants().iter().map(|v| v.name()).collect::<Vec<_>>(),
vec!["one", "two"]
);
assert_eq!(e.variants()[0].fields().len(), 0);
assert_eq!(e.variants()[1].fields().len(), 0);
// The enum with associated data.
let ed = ci.get_enum_definition("TestEnumWithData").unwrap();
assert!(!ed.is_flat());
assert_eq!(ed.shape, EnumShape::Enum);
assert_eq!(ed.variants().len(), 3);
assert_eq!(
ed.variants().iter().map(|v| v.name()).collect::<Vec<_>>(),
vec!["Zero", "One", "Two"]
);
assert_eq!(ed.variants()[0].fields().len(), 0);
assert_eq!(
ed.variants()[1]
.fields()
.iter()
.map(|f| f.name())
.collect::<Vec<_>>(),
vec!["first"]
);
assert_eq!(
ed.variants()[1]
.fields()
.iter()
.map(|f| f.as_type())
.collect::<Vec<_>>(),
vec![Type::UInt32]
);
assert_eq!(
ed.variants()[2]
.fields()
.iter()
.map(|f| f.name())
.collect::<Vec<_>>(),
vec!["first", "second"]
);
assert_eq!(
ed.variants()[2]
.fields()
.iter()
.map(|f| f.as_type())
.collect::<Vec<_>>(),
vec![Type::UInt32, Type::String]
);
// The enum declared via interface, but with no associated data.
let ewd = ci.get_enum_definition("TestEnumWithoutData").unwrap();
assert_eq!(ewd.variants().len(), 2);
assert_eq!(
ewd.variants().iter().map(|v| v.name()).collect::<Vec<_>>(),
vec!["One", "Two"]
);
assert_eq!(ewd.variants()[0].fields().len(), 0);
assert_eq!(ewd.variants()[1].fields().len(), 0);
assert!(ewd.is_flat());
assert_eq!(ewd.shape, EnumShape::Enum);
// Flat enums pass over the FFI as bytebuffers.
// (It might be nice to optimize these to pass as plain integers, but that's
// difficult atop the current factoring of `ComponentInterface` and friends).
let farg = ci.get_function_definition("takes_an_enum").unwrap();
assert_eq!(
farg.arguments()[0].as_type(),
Type::Enum {
name: "TestEnum".into(),
module_path: "crate_name".into()
}
);
assert_eq!(
farg.ffi_func().arguments()[0].type_(),
FfiType::RustBuffer(None)
);
let fret = ci.get_function_definition("returns_an_enum").unwrap();
assert!(
matches!(fret.return_type(), Some(Type::Enum { name, .. }) if name == "TestEnum" && !ci.is_name_used_as_error(name))
);
assert!(matches!(
fret.ffi_func().return_type(),
Some(FfiType::RustBuffer(None))
));
// Enums with associated data pass over the FFI as bytebuffers.
let farg = ci
.get_function_definition("takes_an_enum_with_data")
.unwrap();
assert_eq!(
farg.arguments()[0].as_type(),
Type::Enum {
name: "TestEnumWithData".into(),
module_path: "crate_name".into()
}
);
assert_eq!(
farg.ffi_func().arguments()[0].type_(),
FfiType::RustBuffer(None)
);
let fret = ci
.get_function_definition("returns_an_enum_with_data")
.unwrap();
assert!(
matches!(fret.return_type(), Some(Type::Enum { name, .. }) if name == "TestEnumWithData" && !ci.is_name_used_as_error(name))
);
assert!(matches!(
fret.ffi_func().return_type(),
Some(FfiType::RustBuffer(None))
));
}
// Tests for [Error], which are represented as `Enum`
#[test]
fn test_variants() {
const UDL: &str = r#"
namespace test{
[Throws=Testing]
void func();
};
[Error]
enum Testing { "one", "two", "three" };
"#;
let ci = ComponentInterface::from_webidl(UDL, "crate_name").unwrap();
assert_eq!(ci.enum_definitions().count(), 1);
let error = ci.get_enum_definition("Testing").unwrap();
assert_eq!(
error
.variants()
.iter()
.map(|v| v.name())
.collect::<Vec<&str>>(),
vec!("one", "two", "three")
);
assert!(error.is_flat());
assert!(ci.is_name_used_as_error(&error.name));
}
#[test]
fn test_duplicate_error_variants() {
const UDL: &str = r#"
namespace test{};
// Weird, but currently allowed!
// We should probably disallow this...
[Error]
enum Testing { "one", "two", "one" };
"#;
let ci = ComponentInterface::from_webidl(UDL, "crate_name").unwrap();
assert_eq!(ci.enum_definitions().count(), 1);
assert_eq!(
ci.get_enum_definition("Testing").unwrap().variants().len(),
3
);
}
#[test]
fn test_variant_data() {
const UDL: &str = r#"
namespace test{
[Throws=Testing]
void func();
};
[Error]
interface Testing {
One(string reason);
Two(u8 code);
};
"#;
let ci = ComponentInterface::from_webidl(UDL, "crate_name").unwrap();
assert_eq!(ci.enum_definitions().count(), 1);
let error: &Enum = ci.get_enum_definition("Testing").unwrap();
assert_eq!(
error
.variants()
.iter()
.map(|v| v.name())
.collect::<Vec<&str>>(),
vec!("One", "Two")
);
assert!(!error.is_flat());
assert!(ci.is_name_used_as_error(&error.name));
}
#[test]
fn test_enum_variant_named_error() {
const UDL: &str = r#"
namespace test{};
[Enum]
interface Testing {
Normal(string first);
Error(string first);
};
"#;
let ci = ComponentInterface::from_webidl(UDL, "crate_name").unwrap();
assert_eq!(ci.enum_definitions().count(), 1);
let testing: &Enum = ci.get_enum_definition("Testing").unwrap();
assert_eq!(
testing.variants()[0]
.fields()
.iter()
.map(|f| f.name())
.collect::<Vec<_>>(),
vec!["first"]
);
assert_eq!(
testing.variants()[0]
.fields()
.iter()
.map(|f| f.as_type())
.collect::<Vec<_>>(),
vec![Type::String]
);
assert_eq!(
testing.variants()[1]
.fields()
.iter()
.map(|f| f.name())
.collect::<Vec<_>>(),
vec!["first"]
);
assert_eq!(
testing.variants()[1]
.fields()
.iter()
.map(|f| f.as_type())
.collect::<Vec<_>>(),
vec![Type::String]
);
assert_eq!(
testing
.variants()
.iter()
.map(|v| v.name())
.collect::<Vec<_>>(),
vec!["Normal", "Error"]
);
}
fn variant(val: Option<u64>) -> Variant {
Variant {
name: "v".to_string(),
discr: val.map(Literal::new_uint),
fields: vec![],
docstring: None,
}
}
fn check_discrs(e: &mut Enum, vs: Vec<Variant>) -> Vec<u64> {
e.variants = vs;
(0..e.variants.len())
.map(|i| e.variant_discr(i).unwrap())
.map(|l| match l {
Literal::UInt(v, _, _) => v,
_ => unreachable!(),
})
.collect()
}
#[test]
fn test_variant_values() {
let mut e = Enum {
module_path: "test".to_string(),
name: "test".to_string(),
discr_type: None,
variants: vec![],
shape: EnumShape::Enum,
non_exhaustive: false,
docstring: None,
};
assert!(e.variant_discr(0).is_err());
// single values
assert_eq!(check_discrs(&mut e, vec![variant(None)]), vec![0]);
assert_eq!(check_discrs(&mut e, vec![variant(Some(3))]), vec![3]);
// no values
assert_eq!(
check_discrs(&mut e, vec![variant(None), variant(None)]),
vec![0, 1]
);
// values
assert_eq!(
check_discrs(&mut e, vec![variant(Some(1)), variant(Some(3))]),
vec![1, 3]
);
// mixed values
assert_eq!(
check_discrs(&mut e, vec![variant(None), variant(Some(3)), variant(None)]),
vec![0, 3, 4]
);
assert_eq!(
check_discrs(
&mut e,
vec![variant(Some(4)), variant(None), variant(Some(1))]
),
vec![4, 5, 1]
);
}
#[test]
fn test_docstring_enum() {
const UDL: &str = r#"
namespace test{};
/// informative docstring
enum Testing { "foo" };
"#;
let ci = ComponentInterface::from_webidl(UDL, "crate_name").unwrap();
assert_eq!(
ci.get_enum_definition("Testing")
.unwrap()
.docstring()
.unwrap(),
"informative docstring"
);
}
#[test]
fn test_docstring_enum_variant() {
const UDL: &str = r#"
namespace test{};
enum Testing {
/// informative docstring
"foo"
};
"#;
let ci = ComponentInterface::from_webidl(UDL, "crate_name").unwrap();
assert_eq!(
ci.get_enum_definition("Testing").unwrap().variants()[0]
.docstring()
.unwrap(),
"informative docstring"
);
}
#[test]
fn test_docstring_associated_enum() {
const UDL: &str = r#"
namespace test{};
/// informative docstring
[Enum]
interface Testing { };
"#;
let ci = ComponentInterface::from_webidl(UDL, "crate_name").unwrap();
assert_eq!(
ci.get_enum_definition("Testing")
.unwrap()
.docstring()
.unwrap(),
"informative docstring"
);
}
#[test]
fn test_docstring_associated_enum_variant() {
const UDL: &str = r#"
namespace test{};
[Enum]
interface Testing {
/// informative docstring
testing();
};
"#;
let ci = ComponentInterface::from_webidl(UDL, "crate_name").unwrap();
assert_eq!(
ci.get_enum_definition("Testing").unwrap().variants()[0]
.docstring()
.unwrap(),
"informative docstring"
);
}
}