Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 368 insertions, 0 deletions

diff --git a/third_party/rust/smart-default/src/body_impl.rs b/third_party/rust/smart-default/src/body_impl.rs
new file mode 100755
index 0000000000..a40b11f562
--- /dev/null
+++ b/third_party/rust/smart-default/src/body_impl.rs
@@ -0,0 +1,130 @@
+use proc_macro2::TokenStream;
+
+use syn::DeriveInput;
+use syn::spanned::Spanned;
+use syn::parse::Error;
+use quote::quote;
+
+use default_attr::{DefaultAttr, ConversionStrategy};
+use util::find_only;
+
+pub fn impl_my_derive(input: &DeriveInput) -> Result<TokenStream, Error> {
+    let name = &input.ident;
+    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
+
+    let (default_expr, doc) = match input.data {
+        syn::Data::Struct(ref body) => {
+            let (body_assignment, doc) = default_body_tt(&body.fields)?;
+            (quote! {
+                #name #body_assignment
+            }, format!("Return `{}{}`", name, doc))
+        }
+        syn::Data::Enum(ref body) => {
+            let default_variant = find_only(body.variants.iter(), |variant| {
+                if let Some(meta) = DefaultAttr::find_in_attributes(&variant.attrs)? {
+                    if meta.code.is_none() {
+                        Ok(true)
+                    } else {
+                        Err(Error::new(meta.code.span(), "Attribute #[default] on variants should have no value"))
+                    }
+                } else {
+                    Ok(false)
+                }
+            })?.ok_or_else(|| Error::new(input.span(), "No default variant"))?;
+            let default_variant_name = &default_variant.ident;
+            let (body_assignment, doc) = default_body_tt(&default_variant.fields)?;
+            (quote! {
+                #name :: #default_variant_name #body_assignment
+            }, format!("Return `{}::{}{}`", name, default_variant_name, doc))
+        }
+        syn::Data::Union(_) => {
+            panic!()
+        }
+    };
+    Ok(quote! {
+        #[automatically_derived]
+        impl #impl_generics Default for #name #ty_generics #where_clause {
+            #[doc = #doc]
+            fn default() -> Self {
+                #default_expr
+            }
+        }
+    })
+}
+
+/// Return a token-tree for the default "body" - the part after the name that contains the values.
+/// That is, the `{ ... }` part for structs, the `(...)` part for tuples, and nothing for units.
+fn default_body_tt(body: &syn::Fields) -> Result<(TokenStream, String), Error> {
+    let mut doc = String::new();
+    use std::fmt::Write;
+    let body_tt = match body {
+        &syn::Fields::Named(ref fields) => {
+            doc.push_str(" {");
+            let result = {
+                let field_assignments = fields.named.iter().map(|field| {
+                    let field_name = field.ident.as_ref();
+                    let (default_value, default_doc) = field_default_expr_and_doc(field)?;
+                    write!(&mut doc, "\n    {}: {},", field_name.expect("field value in struct is empty"), default_doc).unwrap();
+                    // let default_value = default_value.into_token_stream();
+                    Ok(quote! { #field_name : #default_value })
+                }).collect::<Result<Vec<_>, Error>>()?;
+                quote!{
+                    {
+                        #( #field_assignments ),*
+                    }
+                }
+            };
+            if (&mut doc).ends_with(",") {
+                doc.pop();
+                doc.push('\n');
+            };
+            doc.push('}');
+            result
+        }
+        &syn::Fields::Unnamed(ref fields) => {
+            doc.push('(');
+            let result = {
+                let field_assignments = fields.unnamed.iter().map(|field| {
+                    let (default_value, default_doc) = field_default_expr_and_doc(field)?;
+                    write!(&mut doc, "{}, ", default_doc).unwrap();
+                    Ok(default_value)
+                }).collect::<Result<Vec<TokenStream>, Error>>()?;
+                quote! {
+                    (
+                        #( #field_assignments ),*
+                    )
+                }
+            };
+            if (&mut doc).ends_with(", ") {
+                doc.pop();
+                doc.pop();
+            };
+            doc.push(')');
+            result
+        }
+        &syn::Fields::Unit => quote!{},
+    };
+    Ok((body_tt, doc))
+}
+
+/// Return a default expression for a field based on it's `#[default = "..."]` attribute. Panic
+/// if there is more than one, of if there is a `#[default]` attribute without value.
+fn field_default_expr_and_doc(field: &syn::Field) -> Result<(TokenStream, String), Error> {
+    if let Some(default_attr) = DefaultAttr::find_in_attributes(&field.attrs)? {
+        let conversion_strategy = default_attr.conversion_strategy();
+        let field_value = default_attr.code.ok_or_else(|| {
+            Error::new(field.span(), "Expected #[default = ...] or #[default(...)]")})?;
+
+        let field_value = match conversion_strategy {
+            ConversionStrategy::NoConversion => field_value,
+            ConversionStrategy::Into => quote!((#field_value).into()),
+        };
+
+        let field_doc = format!("{}", field_value);
+        Ok((field_value, field_doc))
+    } else {
+        Ok((quote! {
+            Default::default()
+        }, "Default::default()".to_owned()))
+    }
+}
diff --git a/third_party/rust/smart-default/src/default_attr.rs b/third_party/rust/smart-default/src/default_attr.rs
new file mode 100755
index 0000000000..c429b23bb9
--- /dev/null
+++ b/third_party/rust/smart-default/src/default_attr.rs
@@ -0,0 +1,125 @@
+use proc_macro2::TokenStream;
+use syn::parse::Error;
+use syn::spanned::Spanned;
+use quote::ToTokens;
+
+use util::{find_only, single_value};
+
+#[derive(Debug, Clone, Copy)]
+pub enum ConversionStrategy {
+    NoConversion,
+    Into,
+}
+
+pub struct DefaultAttr {
+    pub code: Option<TokenStream>,
+    conversion_strategy: Option<ConversionStrategy>,
+}
+
+impl DefaultAttr {
+    pub fn find_in_attributes(attrs: &[syn::Attribute]) -> Result<Option<Self>, Error> {
+        if let Some(default_attr) = find_only(attrs.iter(), |attr| is_default_attr(attr))? {
+            match default_attr.parse_meta() {
+                Ok(syn::Meta::Path(_)) => Ok(Some(Self {
+                    code: None,
+                    conversion_strategy: None,
+                })),
+                Ok(syn::Meta::List(meta)) => {
+                    if let Some(field_value) = parse_code_hack(&meta)? { // #[default(_code = "...")]
+                        Ok(Some(Self {
+                            code: Some(field_value.into_token_stream()),
+                            conversion_strategy: Some(ConversionStrategy::NoConversion),
+                        }))
+                    } else if let Some(field_value) = single_value(meta.nested.iter()) { // #[default(...)]
+                        Ok(Some(Self {
+                            code: Some(field_value.into_token_stream()),
+                            conversion_strategy: None,
+                        }))
+                    } else {
+                        return Err(Error::new(
+                                if meta.nested.is_empty() {
+                                    meta.span()
+                                } else {
+                                    meta.nested.span()
+                                },
+                                "Expected signle value in #[default(...)]"));
+                    }
+                }
+                Ok(syn::Meta::NameValue(meta)) => {
+                    Ok(Some(Self {
+                        code: Some(meta.lit.into_token_stream()),
+                        conversion_strategy: None,
+                    }))
+                }
+                Err(error) => {
+                    if let syn::Expr::Paren(as_parens) = syn::parse(default_attr.tokens.clone().into())? {
+                        Ok(Some(Self {
+                            code: Some(as_parens.expr.into_token_stream()),
+                            conversion_strategy: None,
+                        }))
+                    } else {
+                        Err(error)
+                    }
+                }
+            }
+        } else {
+            Ok(None)
+        }
+    }
+
+    pub fn conversion_strategy(&self) -> ConversionStrategy {
+        if let Some(conversion_strategy) = self.conversion_strategy {
+            // Conversion strategy already set
+            return conversion_strategy;
+        }
+        let code = if let Some(code) = &self.code {
+            code
+        } else {
+            // #[default] - so no conversion (`Default::default()` already has the correct type)
+            return ConversionStrategy::NoConversion;
+        };
+        match syn::parse::<syn::Lit>(code.clone().into()) {
+            Ok(syn::Lit::Str(_)) | Ok(syn::Lit::ByteStr(_))=> {
+                // A string literal - so we need a conversion in case we need to make it a `String`
+                return ConversionStrategy::Into;
+            },
+            _ => {},
+        }
+        // Not handled by one of the rules, so we don't convert it to avoid causing trouble
+        ConversionStrategy::NoConversion
+    }
+}
+
+fn is_default_attr(attr: &syn::Attribute) -> Result<bool, Error> {
+    let path = &attr.path;
+    if path.leading_colon.is_some() {
+        return Ok(false);
+    }
+    let segment = if let Some(segment) = single_value(path.segments.iter()) {
+        segment
+    } else {
+        return Ok(false);
+    };
+
+    if let syn::PathArguments::None = segment.arguments {
+    } else {
+        return Ok(false);
+    }
+
+    Ok(segment.ident.to_string() == "default")
+}
+
+fn parse_code_hack(meta: &syn::MetaList) -> Result<Option<TokenStream>, Error> {
+    for meta in meta.nested.iter() {
+        if let syn::NestedMeta::Meta(syn::Meta::NameValue(meta)) = meta {
+            if !meta.path.is_ident("_code") {
+                continue;
+            }
+            if let syn::Lit::Str(lit) = &meta.lit {
+                use std::str::FromStr;
+                return Ok(Some(TokenStream::from_str(&lit.value())?));
+            }
+        };
+    }
+    Ok(None)
+}
diff --git a/third_party/rust/smart-default/src/lib.rs b/third_party/rust/smart-default/src/lib.rs
new file mode 100755
index 0000000000..650883226c
--- /dev/null
+++ b/third_party/rust/smart-default/src/lib.rs
@@ -0,0 +1,84 @@
+extern crate proc_macro;
+extern crate proc_macro2;
+extern crate syn;
+
+extern crate quote;
+
+use syn::{parse_macro_input, DeriveInput};
+
+mod body_impl;
+mod default_attr;
+mod util;
+
+/// # Smart Default
+///
+/// This crate provides a custom derive for `SmartDefault`. `SmartDefault` is not a real type -
+/// deriving it will actually `impl Default`. The difference from regular `#[derive(Default)]` is
+/// that `#[derive(SmartDefault)]` allows you to use `#[default = "..."]` attributes to customize
+/// the `::default()` method and to support `struct`s that don't have `Default` for all their
+/// fields - and even `enum`s!
+///
+/// # Examples
+///
+/// ```
+/// #[macro_use]
+/// extern crate smart_default;
+///
+/// # fn main() {
+/// #[derive(SmartDefault)]
+/// # #[derive(PartialEq)]
+/// # #[allow(dead_code)]
+/// enum Foo {
+///     Bar,
+///     #[default]
+///     Baz {
+///         #[default = 12]
+///         a: i32,
+///         b: i32,
+///         #[default(Some(Default::default()))]
+///         c: Option<i32>,
+///         #[default(_code = "vec![1, 2, 3]")]
+///         d: Vec<u32>,
+///         #[default = "four"]
+///         e: String,
+///     },
+///     Qux(i32),
+/// }
+///
+/// assert!(Foo::default() == Foo::Baz {
+///     a: 12,
+///     b: 0,
+///     c: Some(0),
+///     d: vec![1, 2, 3],
+///     e: "four".to_owned(),
+/// });
+/// # }
+/// ```
+///
+/// * `Baz` has the `#[default]` attribute. This means that the default `Foo` is a `Foo::Baz`. Only
+///   one variant may have a `#[default]` attribute, and that attribute must have no value.
+/// * `a` has a `#[default = 12]` attribute. This means that it's default value is `12`.
+/// * `b` has no `#[default = ...]` attribute. It's default value will `i32`'s default value
+///   instead - `0`.
+/// * `c` is an `Option<i32>`, and it's default is `Some(Default::default())`. Rust cannot (currently)
+///   parse `#[default = Some(Default::default())]` and therefore we have to use a special syntax:
+///   `#[default(Some(Default::default))]`
+/// * `d` has the `!` token in it, which cannot (currently) be parsed even with `#[default(...)]`,
+///   so we have to encode it as a string and mark it as `_code = `.
+/// * `e` is a `String`, so the string literal "four" is automatically converted to it. This
+///   automatic conversion **only** happens to string (or byte string) literals - and only if
+///   `_code` is not used.
+/// * Documentation for the `impl Default` section is generated automatically, specifying the
+///   default value returned from `::default()`.
+#[proc_macro_derive(SmartDefault, attributes(default))]
+pub fn derive_smart_default(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    match body_impl::impl_my_derive(&input) {
+        Ok(output) => {
+            output.into()
+        },
+        Err(error) =>{
+            error.to_compile_error().into()
+        }
+    }
+}
diff --git a/third_party/rust/smart-default/src/util.rs b/third_party/rust/smart-default/src/util.rs
new file mode 100755
index 0000000000..452ac91f95
--- /dev/null
+++ b/third_party/rust/smart-default/src/util.rs
@@ -0,0 +1,29 @@
+use syn::spanned::Spanned;
+use syn::parse::Error;
+
+/// Return the value that fulfills the predicate if there is one in the slice. Panic if there is
+/// more than one.
+pub fn find_only<T, F>(iter: impl Iterator<Item = T>, pred: F) -> Result<Option<T>, Error>
+where T: Spanned,
+      F: Fn(&T) -> Result<bool, Error>,
+{
+    let mut result = None;
+    for item in iter {
+        if pred(&item)? {
+            if result.is_some() {
+                return Err(Error::new(item.span(), "Multiple defaults"));
+            }
+            result = Some(item);
+        }
+    }
+    Ok(result)
+}
+
+pub fn single_value<T>(mut it: impl Iterator<Item = T>) -> Option<T> {
+    if let Some(result) = it.next() {
+        if it.next().is_none() {
+            return Some(result)
+        }
+    }
+    None
+}