Import 'proc-macro-hack' rust crate version 0.5.12
Bug: b/151760391
Test: m crosvm.experimental
Change-Id: I70ccc8c3a5640eab38ce5bcfea97feedad7e972d
diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json
new file mode 100644
index 0000000..8216174
--- /dev/null
+++ b/.cargo_vcs_info.json
@@ -0,0 +1,5 @@
+{
+ "git": {
+ "sha1": "d29a20e44207f915f42e6d1668d2864b0152e5a8"
+ }
+}
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a9d37c5
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+target
+Cargo.lock
diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..c8253df
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1,19 @@
+// This file is generated by cargo2android.py.
+
+rust_proc_macro {
+ name: "libproc_macro_hack",
+ crate_name: "proc_macro_hack",
+ srcs: ["src/lib.rs"],
+ edition: "2018",
+ rlibs: [
+ "libproc_macro2",
+ "libquote",
+ "libsyn",
+ ],
+}
+
+// dependent_library ["feature_list"]
+// proc-macro2-1.0.9 "default,proc-macro"
+// quote-1.0.3 "default,proc-macro"
+// syn-1.0.16 "clone-impls,default,derive,parsing,printing,proc-macro,quote"
+// unicode-xid-0.2.0 "default"
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..0096538
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,40 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+edition = "2018"
+name = "proc-macro-hack"
+version = "0.5.12"
+authors = ["David Tolnay <[email protected]>"]
+description = "Procedural macros in expression position"
+readme = "README.md"
+categories = ["development-tools::procedural-macro-helpers"]
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/dtolnay/proc-macro-hack"
+
+[lib]
+proc-macro = true
+[dependencies.proc-macro2]
+version = "1.0"
+
+[dependencies.quote]
+version = "1.0"
+
+[dependencies.syn]
+version = "1.0.5"
+[dev-dependencies.demo-hack]
+version = "0.0.5"
+
+[dev-dependencies.demo-hack-impl]
+version = "0.0.5"
+[badges.travis-ci]
+repository = "dtolnay/proc-macro-hack"
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
new file mode 100644
index 0000000..ddc7286
--- /dev/null
+++ b/Cargo.toml.orig
@@ -0,0 +1,28 @@
+[package]
+name = "proc-macro-hack"
+version = "0.5.12"
+authors = ["David Tolnay <[email protected]>"]
+edition = "2018"
+license = "MIT OR Apache-2.0"
+description = "Procedural macros in expression position"
+repository = "https://github.com/dtolnay/proc-macro-hack"
+categories = ["development-tools::procedural-macro-helpers"]
+readme = "README.md"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = "1.0.5"
+
+[dev-dependencies]
+demo-hack = { version = "0.0.5", path = "demo-hack" }
+demo-hack-impl = { version = "0.0.5", path = "demo-hack-impl" }
+
+[badges]
+travis-ci = { repository = "dtolnay/proc-macro-hack" }
+
+[workspace]
+members = ["demo-hack", "demo-hack-impl", "example", "nested"]
diff --git a/LICENSE b/LICENSE
new file mode 120000
index 0000000..6b579aa
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1 @@
+LICENSE-APACHE
\ No newline at end of file
diff --git a/LICENSE-APACHE b/LICENSE-APACHE
new file mode 100644
index 0000000..16fe87b
--- /dev/null
+++ b/LICENSE-APACHE
@@ -0,0 +1,201 @@
+ Apache License
+ Version 2.0, January 2004
+ http://www.apache.org/licenses/
+
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diff --git a/LICENSE-MIT b/LICENSE-MIT
new file mode 100644
index 0000000..f2675cd
--- /dev/null
+++ b/LICENSE-MIT
@@ -0,0 +1,25 @@
+Copyright (c) 2018 David Tolnay
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
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+the Software, and to permit persons to whom the Software
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+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
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+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/METADATA b/METADATA
new file mode 100644
index 0000000..f5a6faa
--- /dev/null
+++ b/METADATA
@@ -0,0 +1,17 @@
+name: "proc-macro-hack"
+description:
+ "Procedural macros in expression position"
+
+third_party {
+ url {
+ type: HOMEPAGE
+ value: "https://crates.io/crates/proc-macro-hack"
+ }
+ url {
+ type: GIT
+ value: "https://github.com/dtolnay/proc-macro-hack"
+ }
+ version: "0.5.12"
+ last_upgrade_date { year: 2020 month: 3 day: 19 }
+ license_type: NOTICE
+}
diff --git a/MODULE_LICENSE_APACHE2 b/MODULE_LICENSE_APACHE2
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/MODULE_LICENSE_APACHE2
diff --git a/NOTICE b/NOTICE
new file mode 120000
index 0000000..7a694c9
--- /dev/null
+++ b/NOTICE
@@ -0,0 +1 @@
+LICENSE
\ No newline at end of file
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..7984e6d
--- /dev/null
+++ b/README.md
@@ -0,0 +1,142 @@
+Procedural macros in expression position
+========================================
+
+[](https://travis-ci.org/dtolnay/proc-macro-hack)
+[](https://crates.io/crates/proc-macro-hack)
+
+As of Rust 1.30, the language supports user-defined function-like procedural
+macros. However these can only be invoked in item position, not in
+statements or expressions.
+
+This crate implements an alternative type of procedural macro that can be
+invoked in statement or expression position.
+
+This approach works with any stable or nightly Rust version 1.31+.
+
+## Defining procedural macros
+
+Two crates are required to define a procedural macro.
+
+### The implementation crate
+
+This crate must contain nothing but procedural macros. Private helper
+functions and private modules are fine but nothing can be public.
+
+[> example of an implementation crate][demo-hack-impl]
+
+Just like you would use a #\[proc_macro\] attribute to define a natively
+supported procedural macro, use proc-macro-hack's #\[proc_macro_hack\]
+attribute to define a procedural macro that works in expression position.
+The function signature is the same as for ordinary function-like procedural
+macros.
+
+```rust
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+use proc_macro_hack::proc_macro_hack;
+use quote::quote;
+use syn::{parse_macro_input, Expr};
+
+#[proc_macro_hack]
+pub fn add_one(input: TokenStream) -> TokenStream {
+ let expr = parse_macro_input!(input as Expr);
+ TokenStream::from(quote! {
+ 1 + (#expr)
+ })
+}
+```
+
+### The declaration crate
+
+This crate is allowed to contain other public things if you need, for
+example traits or functions or ordinary macros.
+
+[> example of a declaration crate][demo-hack]
+
+Within the declaration crate there needs to be a re-export of your
+procedural macro from the implementation crate. The re-export also carries a
+\#\[proc_macro_hack\] attribute.
+
+```rust
+use proc_macro_hack::proc_macro_hack;
+
+/// Add one to an expression.
+///
+/// (Documentation goes here on the re-export, not in the other crate.)
+#[proc_macro_hack]
+pub use demo_hack_impl::add_one;
+```
+
+Both crates depend on `proc-macro-hack`:
+
+```toml
+[dependencies]
+proc-macro-hack = "0.5"
+```
+
+Additionally, your implementation crate (but not your declaration crate) is
+a proc macro crate:
+
+```toml
+[lib]
+proc-macro = true
+```
+
+## Using procedural macros
+
+Users of your crate depend on your declaration crate (not your
+implementation crate), then use your procedural macros as usual.
+
+[> example of a downstream crate][example]
+
+```rust
+use demo_hack::add_one;
+
+fn main() {
+ let two = 2;
+ let nine = add_one!(two) + add_one!(2 + 3);
+ println!("nine = {}", nine);
+}
+```
+
+[demo-hack-impl]: https://github.com/dtolnay/proc-macro-hack/tree/master/demo-hack-impl
+[demo-hack]: https://github.com/dtolnay/proc-macro-hack/tree/master/demo-hack
+[example]: https://github.com/dtolnay/proc-macro-hack/tree/master/example
+
+## Limitations
+
+- Only proc macros in expression position are supported. Proc macros in pattern
+ position ([#20]) are not supported.
+
+- By default, nested invocations are not supported i.e. the code emitted by a
+ proc-macro-hack macro invocation cannot contain recursive calls to the same
+ proc-macro-hack macro nor calls to any other proc-macro-hack macros. Use
+ [`proc-macro-nested`] if you require support for nested invocations.
+
+- By default, hygiene is structured such that the expanded code can't refer to
+ local variables other than those passed by name somewhere in the macro input.
+ If your macro must refer to *local* variables that don't get named in the
+ macro input, use `#[proc_macro_hack(fake_call_site)]` on the re-export in your
+ declaration crate. *Most macros won't need this.*
+
+[#10]: https://github.com/dtolnay/proc-macro-hack/issues/10
+[#20]: https://github.com/dtolnay/proc-macro-hack/issues/20
+[`proc-macro-nested`]: https://docs.rs/proc-macro-nested
+
+<br>
+
+#### License
+
+<sup>
+Licensed under either of <a href="LICENSE-APACHE">Apache License, Version
+2.0</a> or <a href="LICENSE-MIT">MIT license</a> at your option.
+</sup>
+
+<br>
+
+<sub>
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in this hack by you, as defined in the Apache-2.0 license, shall
+be dual licensed as above, without any additional terms or conditions.
+</sub>
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..e9b80e6
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,657 @@
+//! As of Rust 1.30, the language supports user-defined function-like procedural
+//! macros. However these can only be invoked in item position, not in
+//! statements or expressions.
+//!
+//! This crate implements an alternative type of procedural macro that can be
+//! invoked in statement or expression position.
+//!
+//! # Defining procedural macros
+//!
+//! Two crates are required to define a procedural macro.
+//!
+//! ## The implementation crate
+//!
+//! This crate must contain nothing but procedural macros. Private helper
+//! functions and private modules are fine but nothing can be public.
+//!
+//! [> example of an implementation crate][demo-hack-impl]
+//!
+//! Just like you would use a #\[proc_macro\] attribute to define a natively
+//! supported procedural macro, use proc-macro-hack's #\[proc_macro_hack\]
+//! attribute to define a procedural macro that works in expression position.
+//! The function signature is the same as for ordinary function-like procedural
+//! macros.
+//!
+//! ```
+//! extern crate proc_macro;
+//!
+//! use proc_macro::TokenStream;
+//! use proc_macro_hack::proc_macro_hack;
+//! use quote::quote;
+//! use syn::{parse_macro_input, Expr};
+//!
+//! # const IGNORE: &str = stringify! {
+//! #[proc_macro_hack]
+//! # };
+//! pub fn add_one(input: TokenStream) -> TokenStream {
+//! let expr = parse_macro_input!(input as Expr);
+//! TokenStream::from(quote! {
+//! 1 + (#expr)
+//! })
+//! }
+//! #
+//! # fn main() {}
+//! ```
+//!
+//! ## The declaration crate
+//!
+//! This crate is allowed to contain other public things if you need, for
+//! example traits or functions or ordinary macros.
+//!
+//! [> example of a declaration crate][demo-hack]
+//!
+//! Within the declaration crate there needs to be a re-export of your
+//! procedural macro from the implementation crate. The re-export also carries a
+//! \#\[proc_macro_hack\] attribute.
+//!
+//! ```
+//! use proc_macro_hack::proc_macro_hack;
+//!
+//! /// Add one to an expression.
+//! ///
+//! /// (Documentation goes here on the re-export, not in the other crate.)
+//! #[proc_macro_hack]
+//! pub use demo_hack_impl::add_one;
+//! #
+//! # fn main() {}
+//! ```
+//!
+//! Both crates depend on `proc-macro-hack`:
+//!
+//! ```toml
+//! [dependencies]
+//! proc-macro-hack = "0.5"
+//! ```
+//!
+//! Additionally, your implementation crate (but not your declaration crate) is
+//! a proc macro crate:
+//!
+//! ```toml
+//! [lib]
+//! proc-macro = true
+//! ```
+//!
+//! # Using procedural macros
+//!
+//! Users of your crate depend on your declaration crate (not your
+//! implementation crate), then use your procedural macros as usual.
+//!
+//! [> example of a downstream crate][example]
+//!
+//! ```
+//! use demo_hack::add_one;
+//!
+//! fn main() {
+//! let two = 2;
+//! let nine = add_one!(two) + add_one!(2 + 3);
+//! println!("nine = {}", nine);
+//! }
+//! ```
+//!
+//! [demo-hack-impl]: https://github.com/dtolnay/proc-macro-hack/tree/master/demo-hack-impl
+//! [demo-hack]: https://github.com/dtolnay/proc-macro-hack/tree/master/demo-hack
+//! [example]: https://github.com/dtolnay/proc-macro-hack/tree/master/example
+//!
+//! # Limitations
+//!
+//! - Only proc macros in expression position are supported. Proc macros in
+//! pattern position ([#20]) are not supported.
+//!
+//! - By default, nested invocations are not supported i.e. the code emitted by
+//! a proc-macro-hack macro invocation cannot contain recursive calls to the
+//! same proc-macro-hack macro nor calls to any other proc-macro-hack macros.
+//! Use [`proc-macro-nested`] if you require support for nested invocations.
+//!
+//! - By default, hygiene is structured such that the expanded code can't refer
+//! to local variables other than those passed by name somewhere in the macro
+//! input. If your macro must refer to *local* variables that don't get named
+//! in the macro input, use `#[proc_macro_hack(fake_call_site)]` on the
+//! re-export in your declaration crate. *Most macros won't need this.*
+//!
+//! [#10]: https://github.com/dtolnay/proc-macro-hack/issues/10
+//! [#20]: https://github.com/dtolnay/proc-macro-hack/issues/20
+//! [`proc-macro-nested`]: https://docs.rs/proc-macro-nested
+
+#![recursion_limit = "512"]
+#![cfg_attr(feature = "cargo-clippy", allow(renamed_and_removed_lints))]
+#![cfg_attr(feature = "cargo-clippy", allow(needless_pass_by_value))]
+
+extern crate proc_macro;
+
+use proc_macro2::{Span, TokenStream, TokenTree};
+use quote::{format_ident, quote, ToTokens};
+use std::fmt::Write;
+use syn::ext::IdentExt;
+use syn::parse::{Parse, ParseStream, Result};
+use syn::{braced, bracketed, parenthesized, parse_macro_input, token, Ident, LitInt, Token};
+
+type Visibility = Option<Token![pub]>;
+
+enum Input {
+ Export(Export),
+ Define(Define),
+}
+
+// pub use demo_hack_impl::{m1, m2 as qrst};
+struct Export {
+ attrs: TokenStream,
+ vis: Visibility,
+ from: Ident,
+ macros: Vec<Macro>,
+}
+
+// pub fn m1(input: TokenStream) -> TokenStream { ... }
+struct Define {
+ attrs: TokenStream,
+ name: Ident,
+ body: TokenStream,
+}
+
+struct Macro {
+ name: Ident,
+ export_as: Ident,
+}
+
+impl Parse for Input {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let ahead = input.fork();
+ parse_attributes(&ahead)?;
+ ahead.parse::<Visibility>()?;
+
+ if ahead.peek(Token![use]) {
+ input.parse().map(Input::Export)
+ } else if ahead.peek(Token![fn]) {
+ input.parse().map(Input::Define)
+ } else {
+ Err(input.error("unexpected input to #[proc_macro_hack]"))
+ }
+ }
+}
+
+impl Parse for Export {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let attrs = input.call(parse_attributes)?;
+ let vis: Visibility = input.parse()?;
+ input.parse::<Token![use]>()?;
+ input.parse::<Option<Token![::]>>()?;
+ let from: Ident = input.parse()?;
+ input.parse::<Token![::]>()?;
+
+ let mut macros = Vec::new();
+ if input.peek(token::Brace) {
+ let content;
+ braced!(content in input);
+ loop {
+ macros.push(content.parse()?);
+ if content.is_empty() {
+ break;
+ }
+ content.parse::<Token![,]>()?;
+ if content.is_empty() {
+ break;
+ }
+ }
+ } else {
+ macros.push(input.parse()?);
+ }
+
+ input.parse::<Token![;]>()?;
+ Ok(Export {
+ attrs,
+ vis,
+ from,
+ macros,
+ })
+ }
+}
+
+impl Parse for Define {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let attrs = input.call(parse_attributes)?;
+ let vis: Visibility = input.parse()?;
+ if vis.is_none() {
+ return Err(input.error("functions tagged with `#[proc_macro_hack]` must be `pub`"));
+ }
+
+ input.parse::<Token![fn]>()?;
+ let name: Ident = input.parse()?;
+ let body: TokenStream = input.parse()?;
+ Ok(Define { attrs, name, body })
+ }
+}
+
+impl Parse for Macro {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let name: Ident = input.parse()?;
+ let renamed: Option<Token![as]> = input.parse()?;
+ let export_as = if renamed.is_some() {
+ input.parse()?
+ } else {
+ name.clone()
+ };
+ Ok(Macro { name, export_as })
+ }
+}
+
+fn parse_attributes(input: ParseStream) -> Result<TokenStream> {
+ let mut attrs = TokenStream::new();
+ while input.peek(Token![#]) {
+ let pound: Token![#] = input.parse()?;
+ pound.to_tokens(&mut attrs);
+ let content;
+ let bracket_token = bracketed!(content in input);
+ let content: TokenStream = content.parse()?;
+ bracket_token.surround(&mut attrs, |tokens| content.to_tokens(tokens));
+ }
+ Ok(attrs)
+}
+
+#[proc_macro_attribute]
+pub fn proc_macro_hack(
+ args: proc_macro::TokenStream,
+ input: proc_macro::TokenStream,
+) -> proc_macro::TokenStream {
+ proc_macro::TokenStream::from(match parse_macro_input!(input) {
+ Input::Export(export) => {
+ let args = parse_macro_input!(args as ExportArgs);
+ expand_export(export, args)
+ }
+ Input::Define(define) => {
+ parse_macro_input!(args as DefineArgs);
+ expand_define(define)
+ }
+ })
+}
+
+mod kw {
+ syn::custom_keyword!(derive);
+ syn::custom_keyword!(fake_call_site);
+ syn::custom_keyword!(internal_macro_calls);
+ syn::custom_keyword!(support_nested);
+}
+
+struct ExportArgs {
+ support_nested: bool,
+ internal_macro_calls: u16,
+ fake_call_site: bool,
+}
+
+impl Parse for ExportArgs {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let mut args = ExportArgs {
+ support_nested: false,
+ internal_macro_calls: 0,
+ fake_call_site: false,
+ };
+
+ while !input.is_empty() {
+ let ahead = input.lookahead1();
+ if ahead.peek(kw::support_nested) {
+ input.parse::<kw::support_nested>()?;
+ args.support_nested = true;
+ } else if ahead.peek(kw::internal_macro_calls) {
+ input.parse::<kw::internal_macro_calls>()?;
+ input.parse::<Token![=]>()?;
+ let calls = input.parse::<LitInt>()?.base10_parse()?;
+ args.internal_macro_calls = calls;
+ } else if ahead.peek(kw::fake_call_site) {
+ input.parse::<kw::fake_call_site>()?;
+ args.fake_call_site = true;
+ } else {
+ return Err(ahead.error());
+ }
+ if input.is_empty() {
+ break;
+ }
+ input.parse::<Token![,]>()?;
+ }
+
+ Ok(args)
+ }
+}
+
+struct DefineArgs;
+
+impl Parse for DefineArgs {
+ fn parse(_input: ParseStream) -> Result<Self> {
+ Ok(DefineArgs)
+ }
+}
+
+struct EnumHack {
+ token_stream: TokenStream,
+}
+
+impl Parse for EnumHack {
+ fn parse(input: ParseStream) -> Result<Self> {
+ input.parse::<Token![enum]>()?;
+ input.parse::<Ident>()?;
+
+ let braces;
+ braced!(braces in input);
+ braces.parse::<Ident>()?;
+ braces.parse::<Token![=]>()?;
+
+ let parens;
+ parenthesized!(parens in braces);
+ parens.parse::<Ident>()?;
+ parens.parse::<Token![!]>()?;
+
+ let inner;
+ braced!(inner in parens);
+ let token_stream: TokenStream = inner.parse()?;
+
+ parens.parse::<Token![,]>()?;
+ parens.parse::<TokenTree>()?;
+ braces.parse::<Token![.]>()?;
+ braces.parse::<TokenTree>()?;
+ braces.parse::<Token![,]>()?;
+
+ Ok(EnumHack { token_stream })
+ }
+}
+
+#[doc(hidden)]
+#[proc_macro_derive(ProcMacroHack)]
+pub fn enum_hack(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+ let inner = parse_macro_input!(input as EnumHack);
+ proc_macro::TokenStream::from(inner.token_stream)
+}
+
+struct FakeCallSite {
+ derive: Ident,
+ rest: TokenStream,
+}
+
+impl Parse for FakeCallSite {
+ fn parse(input: ParseStream) -> Result<Self> {
+ input.parse::<Token![#]>()?;
+ let attr;
+ bracketed!(attr in input);
+ attr.parse::<kw::derive>()?;
+ let path;
+ parenthesized!(path in attr);
+ Ok(FakeCallSite {
+ derive: path.parse()?,
+ rest: input.parse()?,
+ })
+ }
+}
+
+#[doc(hidden)]
+#[proc_macro_attribute]
+pub fn fake_call_site(
+ args: proc_macro::TokenStream,
+ input: proc_macro::TokenStream,
+) -> proc_macro::TokenStream {
+ let args = TokenStream::from(args);
+ let span = match args.into_iter().next() {
+ Some(token) => token.span(),
+ None => return input,
+ };
+
+ let input = parse_macro_input!(input as FakeCallSite);
+ let mut derive = input.derive;
+ derive.set_span(span);
+ let rest = input.rest;
+
+ let expanded = quote! {
+ #[derive(#derive)]
+ #rest
+ };
+
+ proc_macro::TokenStream::from(expanded)
+}
+
+fn expand_export(export: Export, args: ExportArgs) -> TokenStream {
+ let dummy = dummy_name_for_export(&export);
+
+ let attrs = export.attrs;
+ let vis = export.vis;
+ let macro_export = match vis {
+ Some(_) => quote!(#[macro_export]),
+ None => quote!(),
+ };
+ let crate_prefix = vis.map(|_| quote!($crate::));
+ let enum_variant = if args.support_nested {
+ if args.internal_macro_calls == 0 {
+ quote!(Nested)
+ } else {
+ format_ident!("Nested{}", args.internal_macro_calls).to_token_stream()
+ }
+ } else {
+ quote!(Value)
+ };
+
+ let from = export.from;
+ let rules = export
+ .macros
+ .into_iter()
+ .map(|Macro { name, export_as }| {
+ let actual_name = actual_proc_macro_name(&name);
+ let dispatch = dispatch_macro_name(&name);
+ let call_site = call_site_macro_name(&name);
+
+ let export_dispatch = if args.support_nested {
+ quote! {
+ #[doc(hidden)]
+ #vis use proc_macro_nested::dispatch as #dispatch;
+ }
+ } else {
+ quote!()
+ };
+
+ let proc_macro_call = if args.support_nested {
+ let extra_bangs = (0..args.internal_macro_calls).map(|_| quote!(!));
+ quote! {
+ #crate_prefix #dispatch! { ($($proc_macro)*) #(#extra_bangs)* }
+ }
+ } else {
+ quote! {
+ proc_macro_call!()
+ }
+ };
+
+ let export_call_site = if args.fake_call_site {
+ quote! {
+ #[doc(hidden)]
+ #vis use proc_macro_hack::fake_call_site as #call_site;
+ }
+ } else {
+ quote!()
+ };
+
+ let do_derive = if !args.fake_call_site {
+ quote! {
+ #[derive(#crate_prefix #actual_name)]
+ }
+ } else if crate_prefix.is_some() {
+ quote! {
+ use #crate_prefix #actual_name;
+ #[#crate_prefix #call_site ($($proc_macro)*)]
+ #[derive(#actual_name)]
+ }
+ } else {
+ quote! {
+ #[#call_site ($($proc_macro)*)]
+ #[derive(#actual_name)]
+ }
+ };
+
+ quote! {
+ #[doc(hidden)]
+ #vis use #from::#actual_name;
+
+ #export_dispatch
+ #export_call_site
+
+ #attrs
+ #macro_export
+ macro_rules! #export_as {
+ ($($proc_macro:tt)*) => {{
+ #do_derive
+ enum ProcMacroHack {
+ #enum_variant = (stringify! { $($proc_macro)* }, 0).1,
+ }
+ #proc_macro_call
+ }};
+ }
+ }
+ })
+ .collect();
+
+ wrap_in_enum_hack(dummy, rules)
+}
+
+fn expand_define(define: Define) -> TokenStream {
+ let attrs = define.attrs;
+ let name = define.name;
+ let dummy = actual_proc_macro_name(&name);
+ let body = define.body;
+
+ quote! {
+ mod #dummy {
+ extern crate proc_macro;
+ pub use self::proc_macro::*;
+ }
+
+ #attrs
+ #[proc_macro_derive(#dummy)]
+ pub fn #dummy(input: #dummy::TokenStream) -> #dummy::TokenStream {
+ use std::iter::FromIterator;
+
+ let mut iter = input.into_iter();
+ iter.next().unwrap(); // `enum`
+ iter.next().unwrap(); // `ProcMacroHack`
+
+ let mut braces = match iter.next().unwrap() {
+ #dummy::TokenTree::Group(group) => group.stream().into_iter(),
+ _ => unimplemented!(),
+ };
+ let variant = braces.next().unwrap(); // `Value` or `Nested`
+ let varname = variant.to_string();
+ let support_nested = varname.starts_with("Nested");
+ braces.next().unwrap(); // `=`
+
+ let mut parens = match braces.next().unwrap() {
+ #dummy::TokenTree::Group(group) => group.stream().into_iter(),
+ _ => unimplemented!(),
+ };
+ parens.next().unwrap(); // `stringify`
+ parens.next().unwrap(); // `!`
+
+ let inner = match parens.next().unwrap() {
+ #dummy::TokenTree::Group(group) => group.stream(),
+ _ => unimplemented!(),
+ };
+
+ let output: #dummy::TokenStream = #name(inner.clone());
+
+ fn count_bangs(input: #dummy::TokenStream) -> usize {
+ let mut count = 0;
+ for token in input {
+ match token {
+ #dummy::TokenTree::Punct(punct) => {
+ if punct.as_char() == '!' {
+ count += 1;
+ }
+ }
+ #dummy::TokenTree::Group(group) => {
+ count += count_bangs(group.stream());
+ }
+ _ => {}
+ }
+ }
+ count
+ }
+
+ // macro_rules! proc_macro_call {
+ // () => { #output }
+ // }
+ #dummy::TokenStream::from_iter(vec![
+ #dummy::TokenTree::Ident(
+ #dummy::Ident::new("macro_rules", #dummy::Span::call_site()),
+ ),
+ #dummy::TokenTree::Punct(
+ #dummy::Punct::new('!', #dummy::Spacing::Alone),
+ ),
+ #dummy::TokenTree::Ident(
+ #dummy::Ident::new(
+ &if support_nested {
+ let extra_bangs = if varname == "Nested" {
+ 0
+ } else {
+ varname["Nested".len()..].parse().unwrap()
+ };
+ format!("proc_macro_call_{}", extra_bangs + count_bangs(inner))
+ } else {
+ String::from("proc_macro_call")
+ },
+ #dummy::Span::call_site(),
+ ),
+ ),
+ #dummy::TokenTree::Group(
+ #dummy::Group::new(#dummy::Delimiter::Brace, #dummy::TokenStream::from_iter(vec![
+ #dummy::TokenTree::Group(
+ #dummy::Group::new(#dummy::Delimiter::Parenthesis, #dummy::TokenStream::new()),
+ ),
+ #dummy::TokenTree::Punct(
+ #dummy::Punct::new('=', #dummy::Spacing::Joint),
+ ),
+ #dummy::TokenTree::Punct(
+ #dummy::Punct::new('>', #dummy::Spacing::Alone),
+ ),
+ #dummy::TokenTree::Group(
+ #dummy::Group::new(#dummy::Delimiter::Brace, output),
+ ),
+ ])),
+ ),
+ ])
+ }
+
+ fn #name #body
+ }
+}
+
+fn actual_proc_macro_name(conceptual: &Ident) -> Ident {
+ format_ident!("proc_macro_hack_{}", conceptual)
+}
+
+fn dispatch_macro_name(conceptual: &Ident) -> Ident {
+ format_ident!("proc_macro_call_{}", conceptual)
+}
+
+fn call_site_macro_name(conceptual: &Ident) -> Ident {
+ format_ident!("proc_macro_fake_call_site_{}", conceptual)
+}
+
+fn dummy_name_for_export(export: &Export) -> String {
+ let mut dummy = String::new();
+ let from = export.from.unraw().to_string();
+ write!(dummy, "_{}{}", from.len(), from).unwrap();
+ for m in &export.macros {
+ let name = m.name.unraw().to_string();
+ write!(dummy, "_{}{}", name.len(), name).unwrap();
+ }
+ dummy
+}
+
+fn wrap_in_enum_hack(dummy: String, inner: TokenStream) -> TokenStream {
+ let dummy = Ident::new(&dummy, Span::call_site());
+ quote! {
+ #[derive(proc_macro_hack::ProcMacroHack)]
+ enum #dummy {
+ Value = (stringify! { #inner }, 0).1,
+ }
+ }
+}
