From e92536f300f4ece151bcab62bf3dc1fbd36c8c41 Mon Sep 17 00:00:00 2001
From: Richard Dodd <richard.o.dodd@gmail.com>
Date: Tue, 21 Aug 2018 13:47:00 +0100
Subject: [PATCH] Allow Vec as well as slice
---
crates/macro-support/src/parser.rs | 39 +++++++++++++++++++++++++++---
tests/wasm/variadic.rs | 2 +-
2 files changed, 37 insertions(+), 4 deletions(-)
diff --git a/crates/macro-support/src/parser.rs b/crates/macro-support/src/parser.rs
index dd52bc3c..97957f8f 100644
--- a/crates/macro-support/src/parser.rs
+++ b/crates/macro-support/src/parser.rs
@@ -1111,14 +1111,47 @@ fn assert_last_param_is_slice(decl: &syn::FnDecl) -> Result<(), Diagnostic> {
#[inline]
fn not_slice_error(tok: &dyn ToTokens) -> Diagnostic {
Diagnostic::span_error(tok, "for variadic extern functions, the last argument must be a \
- slice, to hold the arguments of unknown length")
+ slice or `::std::vec::Vec`, to hold the arguments of unknown length")
}
- let arg = decl.inputs.last().ok_or_else(|| not_slice_error(&decl))?;
+ /// Is this path `::std::vec::Vec`.
+ ///
+ /// I could add `Vec`, but this would break in wierd ways if the user does
+ /// `use SomethingElse as Vec;`.
+ #[inline]
+ fn path_is_vec(path: &syn::Path) -> bool {
+ #[inline]
+ fn is_path_segment(path: Option<&syn::PathSegment>,
+ name: Option<&str>,
+ plain: bool) -> bool {
+ match (path, name) {
+ (Some(ref path), Some(ref name)) =>
+ (path.arguments.is_empty() || ! plain) && path.ident == name,
+ (None, None) => true,
+ _ => false
+ }
+ }
+
+ let mut iter = (&path.segments).into_iter();
+ path.leading_colon.is_some()
+ && is_path_segment(iter.next(), Some("std"), true)
+ && is_path_segment(iter.next(), Some("vec"), true)
+ && is_path_segment(iter.next(), Some("Vec"), false)
+ && is_path_segment(iter.next(), None, true)
+ }
+
+ let arg = decl.inputs.last().ok_or_else(|| not_slice_error(&decl.inputs))?;
if let syn::FnArg::Captured(ref arg_cap) = arg.value() {
+ // check for slice reference
if let syn::Type::Reference(ref ref_ty) = arg_cap.ty {
if let syn::Type::Slice(_) = *ref_ty.elem {
- return Ok(())
+ return Ok(());
+ }
+ }
+ // check for `Vec`
+ if let syn::Type::Path(ref path) = arg_cap.ty {
+ if path_is_vec(&path.path) {
+ return Ok(());
}
}
}
diff --git a/tests/wasm/variadic.rs b/tests/wasm/variadic.rs
index b2219078..a26c0fdb 100644
--- a/tests/wasm/variadic.rs
+++ b/tests/wasm/variadic.rs
@@ -32,7 +32,7 @@ extern {
#[wasm_bindgen(variadic)]
fn variadic_concat_str(first: &str, second: &str, rest: &[&str]) -> String;
#[wasm_bindgen(variadic)]
- fn variadic_concat_string(first: String, second: String, rest: Vec<String>) -> String;
+ fn variadic_concat_string(first: String, second: String, rest: ::std::vec::Vec<String>) -> String;
}
// ints