1 files changed, 486 insertions, 0 deletions
diff --git a/third_party/rust/wast/src/component/func.rs b/third_party/rust/wast/src/component/func.rs
new file mode 100644
index 0000000000..24cbb3eb67
--- /dev/null
+++ b/third_party/rust/wast/src/component/func.rs
@@ -0,0 +1,486 @@
+use crate::component::*;
+use crate::kw;
+use crate::parser::{Parse, Parser, Result};
+use crate::token::{Id, Index, LParen, NameAnnotation, Span};
+
+/// A declared core function.
+///
+/// This is a member of both the core alias and canon sections.
+#[derive(Debug)]
+pub struct CoreFunc<'a> {
+    /// Where this `core func` was defined.
+    pub span: Span,
+    /// An identifier that this function is resolved with (optionally) for name
+    /// resolution.
+    pub id: Option<Id<'a>>,
+    /// An optional name for this function stored in the custom `name` section.
+    pub name: Option<NameAnnotation<'a>>,
+    /// The kind of core function.
+    pub kind: CoreFuncKind<'a>,
+}
+
+impl<'a> Parse<'a> for CoreFunc<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let span = parser.parse::<kw::core>()?.0;
+        parser.parse::<kw::func>()?;
+        let id = parser.parse()?;
+        let name = parser.parse()?;
+        let kind = parser.parse()?;
+
+        Ok(Self {
+            span,
+            id,
+            name,
+            kind,
+        })
+    }
+}
+
+/// Represents the kind of core functions.
+#[derive(Debug)]
+#[allow(missing_docs)]
+pub enum CoreFuncKind<'a> {
+    /// The core function is defined in terms of lowering a component function.
+    ///
+    /// The core function is actually a member of the canon section.
+    Lower(CanonLower<'a>),
+    /// The core function is defined in terms of aliasing a module instance export.
+    ///
+    /// The core function is actually a member of the core alias section.
+    Alias(InlineExportAlias<'a, true>),
+    ResourceNew(CanonResourceNew<'a>),
+    ResourceDrop(CanonResourceDrop<'a>),
+    ResourceRep(CanonResourceRep<'a>),
+}
+
+impl<'a> Parse<'a> for CoreFuncKind<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parens(|parser| {
+            let mut l = parser.lookahead1();
+            if l.peek::<kw::canon>()? {
+                parser.parse::<kw::canon>()?;
+            } else if l.peek::<kw::alias>()? {
+                return Ok(Self::Alias(parser.parse()?));
+            } else {
+                return Err(l.error());
+            }
+            let mut l = parser.lookahead1();
+            if l.peek::<kw::lower>()? {
+                Ok(CoreFuncKind::Lower(parser.parse()?))
+            } else if l.peek::<kw::resource_new>()? {
+                Ok(CoreFuncKind::ResourceNew(parser.parse()?))
+            } else if l.peek::<kw::resource_drop>()? {
+                Ok(CoreFuncKind::ResourceDrop(parser.parse()?))
+            } else if l.peek::<kw::resource_rep>()? {
+                Ok(CoreFuncKind::ResourceRep(parser.parse()?))
+            } else {
+                Err(l.error())
+            }
+        })
+    }
+}
+
+/// A declared component function.
+///
+/// This may be a member of the import, alias, or canon sections.
+#[derive(Debug)]
+pub struct Func<'a> {
+    /// Where this `func` was defined.
+    pub span: Span,
+    /// An identifier that this function is resolved with (optionally) for name
+    /// resolution.
+    pub id: Option<Id<'a>>,
+    /// An optional name for this function stored in the custom `name` section.
+    pub name: Option<NameAnnotation<'a>>,
+    /// If present, inline export annotations which indicate names this
+    /// definition should be exported under.
+    pub exports: InlineExport<'a>,
+    /// The kind of function.
+    pub kind: FuncKind<'a>,
+}
+
+impl<'a> Parse<'a> for Func<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let span = parser.parse::<kw::func>()?.0;
+        let id = parser.parse()?;
+        let name = parser.parse()?;
+        let exports = parser.parse()?;
+        let kind = parser.parse()?;
+
+        Ok(Self {
+            span,
+            id,
+            name,
+            exports,
+            kind,
+        })
+    }
+}
+
+/// Represents the kind of component functions.
+#[derive(Debug)]
+pub enum FuncKind<'a> {
+    /// A function which is actually defined as an import, such as:
+    ///
+    /// ```text
+    /// (func (import "foo") (param string))
+    /// ```
+    Import {
+        /// The import name of this import.
+        import: InlineImport<'a>,
+        /// The type that this function will have.
+        ty: ComponentTypeUse<'a, ComponentFunctionType<'a>>,
+    },
+    /// The function is defined in terms of lifting a core function.
+    ///
+    /// The function is actually a member of the canon section.
+    Lift {
+        /// The lifted function's type.
+        ty: ComponentTypeUse<'a, ComponentFunctionType<'a>>,
+        /// Information relating to the lifting of the core function.
+        info: CanonLift<'a>,
+    },
+    /// The function is defined in terms of aliasing a component instance export.
+    ///
+    /// The function is actually a member of the alias section.
+    Alias(InlineExportAlias<'a, false>),
+}
+
+impl<'a> Parse<'a> for FuncKind<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        if let Some(import) = parser.parse()? {
+            Ok(Self::Import {
+                import,
+                ty: parser.parse()?,
+            })
+        } else if parser.peek::<LParen>()? && parser.peek2::<kw::alias>()? {
+            parser.parens(|parser| Ok(Self::Alias(parser.parse()?)))
+        } else {
+            Ok(Self::Lift {
+                ty: parser.parse()?,
+                info: parser.parens(|parser| {
+                    parser.parse::<kw::canon>()?;
+                    parser.parse()
+                })?,
+            })
+        }
+    }
+}
+
+/// A WebAssembly canonical function to be inserted into a component.
+///
+/// This is a member of the canonical section.
+#[derive(Debug)]
+pub struct CanonicalFunc<'a> {
+    /// Where this `func` was defined.
+    pub span: Span,
+    /// An identifier that this function is resolved with (optionally) for name
+    /// resolution.
+    pub id: Option<Id<'a>>,
+    /// An optional name for this function stored in the custom `name` section.
+    pub name: Option<NameAnnotation<'a>>,
+    /// What kind of function this is, be it a lowered or lifted function.
+    pub kind: CanonicalFuncKind<'a>,
+}
+
+impl<'a> Parse<'a> for CanonicalFunc<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let span = parser.parse::<kw::canon>()?.0;
+
+        if parser.peek::<kw::lift>()? {
+            let info = parser.parse()?;
+            let (id, name, ty) = parser.parens(|parser| {
+                parser.parse::<kw::func>()?;
+                let id = parser.parse()?;
+                let name = parser.parse()?;
+                let ty = parser.parse()?;
+                Ok((id, name, ty))
+            })?;
+
+            Ok(Self {
+                span,
+                id,
+                name,
+                kind: CanonicalFuncKind::Lift { info, ty },
+            })
+        } else if parser.peek::<kw::lower>()? {
+            Self::parse_core_func(span, parser, CanonicalFuncKind::Lower)
+        } else if parser.peek::<kw::resource_new>()? {
+            Self::parse_core_func(span, parser, CanonicalFuncKind::ResourceNew)
+        } else if parser.peek::<kw::resource_drop>()? {
+            Self::parse_core_func(span, parser, CanonicalFuncKind::ResourceDrop)
+        } else if parser.peek::<kw::resource_rep>()? {
+            Self::parse_core_func(span, parser, CanonicalFuncKind::ResourceRep)
+        } else {
+            Err(parser.error("expected `canon lift` or `canon lower`"))
+        }
+    }
+}
+
+impl<'a> CanonicalFunc<'a> {
+    fn parse_core_func<T>(
+        span: Span,
+        parser: Parser<'a>,
+        variant: fn(T) -> CanonicalFuncKind<'a>,
+    ) -> Result<Self>
+    where
+        T: Parse<'a>,
+    {
+        let info = parser.parse()?;
+        let (id, name) = parser.parens(|parser| {
+            parser.parse::<kw::core>()?;
+            parser.parse::<kw::func>()?;
+            let id = parser.parse()?;
+            let name = parser.parse()?;
+            Ok((id, name))
+        })?;
+
+        Ok(Self {
+            span,
+            id,
+            name,
+            kind: variant(info),
+        })
+    }
+}
+
+/// Possible ways to define a canonical function in the text format.
+#[derive(Debug)]
+#[allow(missing_docs)]
+pub enum CanonicalFuncKind<'a> {
+    /// A canonical function that is defined in terms of lifting a core function.
+    Lift {
+        /// The lifted function's type.
+        ty: ComponentTypeUse<'a, ComponentFunctionType<'a>>,
+        /// Information relating to the lifting of the core function.
+        info: CanonLift<'a>,
+    },
+    /// A canonical function that is defined in terms of lowering a component function.
+    Lower(CanonLower<'a>),
+
+    ResourceNew(CanonResourceNew<'a>),
+    ResourceDrop(CanonResourceDrop<'a>),
+    ResourceRep(CanonResourceRep<'a>),
+}
+
+/// Information relating to lifting a core function.
+#[derive(Debug)]
+pub struct CanonLift<'a> {
+    /// The core function being lifted.
+    pub func: CoreItemRef<'a, kw::func>,
+    /// The canonical options for the lifting.
+    pub opts: Vec<CanonOpt<'a>>,
+}
+
+impl<'a> Parse<'a> for CanonLift<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::lift>()?;
+
+        Ok(Self {
+            func: parser.parens(|parser| {
+                parser.parse::<kw::core>()?;
+                parser.parse()
+            })?,
+            opts: parser.parse()?,
+        })
+    }
+}
+
+impl Default for CanonLift<'_> {
+    fn default() -> Self {
+        let span = Span::from_offset(0);
+        Self {
+            func: CoreItemRef {
+                kind: kw::func(span),
+                idx: Index::Num(0, span),
+                export_name: None,
+            },
+            opts: Vec::new(),
+        }
+    }
+}
+
+/// Information relating to lowering a component function.
+#[derive(Debug)]
+pub struct CanonLower<'a> {
+    /// The function being lowered.
+    pub func: ItemRef<'a, kw::func>,
+    /// The canonical options for the lowering.
+    pub opts: Vec<CanonOpt<'a>>,
+}
+
+impl<'a> Parse<'a> for CanonLower<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::lower>()?;
+
+        Ok(Self {
+            func: parser.parens(|parser| parser.parse())?,
+            opts: parser.parse()?,
+        })
+    }
+}
+
+impl Default for CanonLower<'_> {
+    fn default() -> Self {
+        let span = Span::from_offset(0);
+        Self {
+            func: ItemRef {
+                kind: kw::func(span),
+                idx: Index::Num(0, span),
+                export_names: Vec::new(),
+            },
+            opts: Vec::new(),
+        }
+    }
+}
+
+/// Information relating to the `resource.new` intrinsic.
+#[derive(Debug)]
+pub struct CanonResourceNew<'a> {
+    /// The resource type that this intrinsic creates an owned reference to.
+    pub ty: Index<'a>,
+}
+
+impl<'a> Parse<'a> for CanonResourceNew<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::resource_new>()?;
+
+        Ok(Self {
+            ty: parser.parse()?,
+        })
+    }
+}
+
+impl Default for CanonResourceNew<'_> {
+    fn default() -> Self {
+        CanonResourceNew {
+            ty: Index::Num(0, Span::from_offset(0)),
+        }
+    }
+}
+
+/// Information relating to the `resource.drop` intrinsic.
+#[derive(Debug)]
+pub struct CanonResourceDrop<'a> {
+    /// The resource type that this intrinsic is dropping.
+    pub ty: Index<'a>,
+}
+
+impl<'a> Parse<'a> for CanonResourceDrop<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::resource_drop>()?;
+
+        Ok(Self {
+            ty: parser.parse()?,
+        })
+    }
+}
+
+impl Default for CanonResourceDrop<'_> {
+    fn default() -> Self {
+        CanonResourceDrop {
+            ty: Index::Num(0, Span::from_offset(0)),
+        }
+    }
+}
+
+/// Information relating to the `resource.rep` intrinsic.
+#[derive(Debug)]
+pub struct CanonResourceRep<'a> {
+    /// The resource type that this intrinsic is accessing.
+    pub ty: Index<'a>,
+}
+
+impl<'a> Parse<'a> for CanonResourceRep<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        parser.parse::<kw::resource_rep>()?;
+
+        Ok(Self {
+            ty: parser.parse()?,
+        })
+    }
+}
+
+impl Default for CanonResourceRep<'_> {
+    fn default() -> Self {
+        CanonResourceRep {
+            ty: Index::Num(0, Span::from_offset(0)),
+        }
+    }
+}
+
+#[derive(Debug)]
+/// Canonical ABI options.
+pub enum CanonOpt<'a> {
+    /// Encode strings as UTF-8.
+    StringUtf8,
+    /// Encode strings as UTF-16.
+    StringUtf16,
+    /// Encode strings as "compact UTF-16".
+    StringLatin1Utf16,
+    /// Use the specified memory for canonical ABI memory access.
+    Memory(CoreItemRef<'a, kw::memory>),
+    /// Use the specified reallocation function for memory allocations.
+    Realloc(CoreItemRef<'a, kw::func>),
+    /// Call the specified function after the lifted function has returned.
+    PostReturn(CoreItemRef<'a, kw::func>),
+}
+
+impl<'a> Parse<'a> for CanonOpt<'a> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut l = parser.lookahead1();
+        if l.peek::<kw::string_utf8>()? {
+            parser.parse::<kw::string_utf8>()?;
+            Ok(Self::StringUtf8)
+        } else if l.peek::<kw::string_utf16>()? {
+            parser.parse::<kw::string_utf16>()?;
+            Ok(Self::StringUtf16)
+        } else if l.peek::<kw::string_latin1_utf16>()? {
+            parser.parse::<kw::string_latin1_utf16>()?;
+            Ok(Self::StringLatin1Utf16)
+        } else if l.peek::<LParen>()? {
+            parser.parens(|parser| {
+                let mut l = parser.lookahead1();
+                if l.peek::<kw::memory>()? {
+                    let span = parser.parse::<kw::memory>()?.0;
+                    Ok(CanonOpt::Memory(parse_trailing_item_ref(
+                        kw::memory(span),
+                        parser,
+                    )?))
+                } else if l.peek::<kw::realloc>()? {
+                    parser.parse::<kw::realloc>()?;
+                    Ok(CanonOpt::Realloc(
+                        parser.parse::<IndexOrCoreRef<'_, _>>()?.0,
+                    ))
+                } else if l.peek::<kw::post_return>()? {
+                    parser.parse::<kw::post_return>()?;
+                    Ok(CanonOpt::PostReturn(
+                        parser.parse::<IndexOrCoreRef<'_, _>>()?.0,
+                    ))
+                } else {
+                    Err(l.error())
+                }
+            })
+        } else {
+            Err(l.error())
+        }
+    }
+}
+
+fn parse_trailing_item_ref<T>(kind: T, parser: Parser) -> Result<CoreItemRef<T>> {
+    Ok(CoreItemRef {
+        kind,
+        idx: parser.parse()?,
+        export_name: parser.parse()?,
+    })
+}
+
+impl<'a> Parse<'a> for Vec<CanonOpt<'a>> {
+    fn parse(parser: Parser<'a>) -> Result<Self> {
+        let mut funcs = Vec::new();
+        while !parser.is_empty() {
+            funcs.push(parser.parse()?);
+        }
+        Ok(funcs)
+    }
+}