Adds re-exporting macros and crate renaming support;

Cargo.toml

@@ -11,17 +11,21 @@ edition = "2018"
 license = "Zlib OR Apache-2.0 OR MIT"
 exclude = ["/pedantic.bat"]
 
+[workspace]
+members = ["derive"]
+
 [features]
 # Note: Yeah these names are non-standard, we'll fix it in v2 some day maybe
 extern_crate_alloc = []
 extern_crate_std = ["extern_crate_alloc"]
 zeroable_maybe_uninit = []
 derive = ["bytemuck_derive"]
+proc-macro-crate = ["bytemuck_derive/proc-macro-crate"]
 
 [dependencies]
 # use the upper line for testing against bytemuck_derive changes, if any
-#bytemuck_derive = { version = "1.0.1-alpha.0", path = "derive", optional = true }
-bytemuck_derive = { version = "1", optional = true }
+bytemuck_derive = { version = "1.0.2-alpha.0", path = "derive", optional = true }
+# bytemuck_derive = { version = "1", optional = true }
 
 [package.metadata.docs.rs]
 all-features = true

derive/Cargo.toml

@@ -18,6 +18,7 @@ proc-macro = true
 syn = "1"
 quote = "1"
 proc-macro2 = "1"
+proc-macro-crate = { version = "1", optional = true }
 
 [dev-dependencies]
 bytemuck = "1.2"

derive/src/lib.rs

@@ -177,3 +177,25 @@ fn derive_marker_trait_inner<Trait: Derivable>(
     }
   })
 }
+
+#[test]
+fn test_derive_output() {
+  let input = quote!(
+    #[repr(C)]
+    #[derive(Copy, Clone, Contiguous)]
+    struct Foo {
+      bar: u32,
+    }
+  );
+  let input = syn::parse_str::<DeriveInput>(&input.to_string()[..])
+    .expect("syntax error");
+  let result = derive_marker_trait::<Pod>(input);
+
+  #[cfg(not(feature = "proc-macro-crate"))]
+  assert!(dbg!(result.to_string())
+    .contains("unsafe impl bytemuck :: Pod for Foo { }"));
+
+  #[cfg(feature = "proc-macro-crate")]
+  assert!(dbg!(result.to_string())
+    .contains("unsafe impl :: bytemuck :: Pod for Foo { }"));
+}

derive/src/traits.rs

@@ -26,7 +26,8 @@ pub struct Pod;
 
 impl Derivable for Pod {
   fn ident() -> TokenStream {
-    quote!(::bytemuck::Pod)
+    let bytemuck_name = get_bytemuck_crate_name();
+    quote!(#bytemuck_name::Pod)
   }
 
   fn struct_asserts(input: &DeriveInput) -> Result<TokenStream, &'static str> {
@@ -60,7 +61,8 @@ pub struct Zeroable;
 
 impl Derivable for Zeroable {
   fn ident() -> TokenStream {
-    quote!(::bytemuck::Zeroable)
+    let bytemuck_name = get_bytemuck_crate_name();
+    quote!(#bytemuck_name::Zeroable)
   }
 
   fn struct_asserts(input: &DeriveInput) -> Result<TokenStream, &'static str> {
@@ -90,7 +92,8 @@ impl TransparentWrapper {
 
 impl Derivable for TransparentWrapper {
   fn ident() -> TokenStream {
-    quote!(::bytemuck::TransparentWrapper)
+    let bytemuck_name = get_bytemuck_crate_name();
+    quote!(#bytemuck_name::TransparentWrapper)
   }
 
   fn generic_params(input: &DeriveInput) -> Result<TokenStream, &'static str> {
@@ -326,3 +329,34 @@ fn parse_int_expr(expr: &Expr) -> Result<i64, &'static str> {
     _ => Err("Not an integer expression"),
   }
 }
+
+#[cfg(not(feature = "proc-macro-crate"))]
+fn get_bytemuck_crate_name() -> TokenStream {
+  use proc_macro2::Span;
+  quote_spanned!(Span::mixed_site() => bytemuck)
+}
+
+#[cfg(feature = "proc-macro-crate")]
+fn get_bytemuck_crate_name() -> TokenStream {
+  use proc_macro2::Span;
+  use proc_macro_crate::{crate_name, FoundCrate};
+
+  // check for bytemuck in Cargo.toml
+  let crate_name = crate_name("bytemuck");
+  match crate_name {
+    // if found
+    Ok(found_name) => match found_name {
+      // if macro is being used inside bytemuck codebase
+      FoundCrate::Itself => quote!(crate),
+      // if found in toml (possibly renamed)
+      FoundCrate::Name(name) => {
+        let ident = Ident::new(&name, Span::call_site());
+        quote!(::#ident)
+      }
+    },
+    // if not found
+    Err(_) => {
+      quote_spanned!(Span::mixed_site() => bytemuck)
+    }
+  }
+}