Add macro to get rustc version. (#62)

Add macro to query git-describe. (#62)

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/info/version.rs

@@ -9,6 +9,7 @@ use std::sync::OnceLock;
 
 static BRANDING: &str = "Tuwunel";
 static SEMANTIC: &str = env!("CARGO_PKG_VERSION");
+tuwunel_macros::git_describe!();
 
 static VERSION: OnceLock<String> = OnceLock::new();
 static USER_AGENT: OnceLock<String> = OnceLock::new();

src/macros/git.rs

@@ -0,0 +1,64 @@
+use std::process::Command;
+
+use proc_macro::TokenStream;
+use quote::quote;
+
+pub(super) fn semantic(_args: TokenStream) -> TokenStream {
+	static ARGS: &[&str] = &["describe", "--tags", "--abbrev=1"];
+
+	let output = git(ARGS);
+	let output = output
+		.strip_prefix('v')
+		.map(str::to_string)
+		.unwrap_or(output);
+
+	let output = output
+		.rsplit_once('-')
+		.map(|(s, _)| s)
+		.map(str::to_string)
+		.unwrap_or(output);
+
+	let ret = quote! {
+		static GIT_SEMANTIC: &'static str = #output;
+	};
+
+	ret.into()
+}
+
+pub(super) fn commit(_args: TokenStream) -> TokenStream {
+	static ARGS: &[&str] = &["describe", "--always", "--dirty", "--abbrev=10"];
+
+	let output = git(ARGS);
+	let ret = quote! {
+		static GIT_COMMIT: &'static str = #output;
+	};
+
+	ret.into()
+}
+
+pub(super) fn describe(_args: TokenStream) -> TokenStream {
+	static ARGS: &[&str] =
+		&["describe", "--dirty", "--tags", "--always", "--broken", "--abbrev=10"];
+
+	let output = git(ARGS);
+	let ret = quote! {
+		static GIT_DESCRIBE: &'static str = #output;
+	};
+
+	ret.into()
+}
+
+fn git(args: &[&str]) -> String {
+	Command::new("git")
+		.args(args)
+		.output()
+		.map(|output| {
+			str::from_utf8(&output.stdout)
+				.map(str::trim)
+				.map(String::from)
+				.ok()
+		})
+		.ok()
+		.flatten()
+		.unwrap_or_default()
+}

src/macros/mod.rs

@@ -4,6 +4,7 @@ mod admin;
 mod cargo;
 mod config;
 mod debug;
+mod git;
 mod implement;
 mod refutable;
 mod rustc;
@@ -41,6 +42,9 @@ pub fn recursion_depth(args: TokenStream, input: TokenStream) -> TokenStream {
 #[proc_macro]
 pub fn rustc_flags_capture(args: TokenStream) -> TokenStream { rustc::flags_capture(args) }
 
+#[proc_macro]
+pub fn rustc_version(args: TokenStream) -> TokenStream { rustc::version(args) }
+
 #[proc_macro_attribute]
 pub fn refutable(args: TokenStream, input: TokenStream) -> TokenStream {
 	attribute_macro::<ItemFn, _>(args, input, refutable::refutable)
@@ -56,6 +60,15 @@ pub fn config_example_generator(args: TokenStream, input: TokenStream) -> TokenS
 	attribute_macro::<ItemStruct, _>(args, input, config::example_generator)
 }
 
+#[proc_macro]
+pub fn git_semantic(args: TokenStream) -> TokenStream { git::semantic(args) }
+
+#[proc_macro]
+pub fn git_commit(args: TokenStream) -> TokenStream { git::commit(args) }
+
+#[proc_macro]
+pub fn git_describe(args: TokenStream) -> TokenStream { git::describe(args) }
+
 fn attribute_macro<I, F>(args: TokenStream, input: TokenStream, func: F) -> TokenStream
 where
 	F: Fn(I, &[Meta]) -> Result<TokenStream>,

src/macros/rustc.rs

@@ -1,3 +1,5 @@
+use std::process::Command;
+
 use proc_macro::TokenStream;
 use quote::quote;
 
@@ -27,3 +29,32 @@ pub(super) fn flags_capture(args: TokenStream) -> TokenStream {
 
 	ret.into()
 }
+
+pub(super) fn version(args: TokenStream) -> TokenStream {
+	let Some(_) = get_crate_name() else {
+		return args;
+	};
+
+	let rustc_path = std::env::args()
+		.next()
+		.expect("Path to rustc executable");
+
+	let version = Command::new(rustc_path)
+		.args(["-V"])
+		.output()
+		.map(|output| {
+			str::from_utf8(&output.stdout)
+				.map(str::trim)
+				.map(String::from)
+				.ok()
+		})
+		.ok()
+		.flatten()
+		.unwrap_or_default();
+
+	let ret = quote! {
+		static RUSTC_VERSION: &'static str = #version;
+	};
+
+	ret.into()
+}