cbindgen: Automatically detect package name.

Store the package name of the rust target as a property,
so that the user does not need to specify it.
If I'm not missing anything, then this should also
allow us to remove the `CARGO_PACKAGE` parameter
completely (in a future update).

RELEASES.md

@@ -27,6 +27,9 @@
 - `corrosion_experimental_cbindgen()` now forwards the Rust target-triple (e.g. `aarch64-unknown-linux-gnu`)
   to cbindgen via the `TARGET` environment variable. The `hostbuild` property is considered. [#507]
 - Detect msvc linker flags coming from `--print=native-static-libs` and put them into `INTERFACE_LINK_OPTIONS` instead of `INTERFACE_LINK_LIBRARIES` [#511]
+- `corrosion_experimental_cbindgen()` will now correctly use the package name, instead of assuming that 
+  the package and crate name are identical.
+
 
 [issue #501]: https://github.com/corrosion-rs/corrosion/issues/501
 [#459]: https://github.com/corrosion-rs/corrosion/pull/459

cmake/Corrosion.cmake

@@ -1498,8 +1498,8 @@ ANCHOR: corrosion_cbindgen
 ```cmake
 corrosion_cbindgen(
         TARGET <imported_target_name>
-        CARGO_PACKAGE <cargo_package_name>
         HEADER_NAME <output_header_name>
+        [CARGO_PACKAGE <cargo_package_name>]
         [MANIFEST_DIRECTORY <package_manifest_directory>]
         [CBINDGEN_VERSION <version>]
         [FLAGS <flag1> ... <flagN>]
@@ -1517,8 +1517,8 @@ between multiple invocations of this function.
               `rlib`, you must additionally specify `MANIFEST_DIRECTORY`.
 
 * **CARGO_PACKAGE**: The name of the Rust cargo package that contains the library target. Note, that `cbindgen`
-                     expects this package name using the `--crate` parameter. If not specified, the **TARGET**
-                     will be used instead.
+                     expects this package name using the `--crate` parameter. If not specified, the **package** name
+                     of the imported **TARGET** will be used, which should be correct.
 
 * **MANIFEST_DIRECTORY**: Directory of the package defining the library crate bindings should be generated for.
     If you want to avoid specifying `MANIFEST_DIRECTORY` you could add a `staticlib` target to your package
@@ -1587,12 +1587,18 @@ function(corrosion_experimental_cbindgen)
 
     unset(rust_cargo_package)
     if(NOT DEFINED CCN_CARGO_PACKAGE)
-        message(STATUS "Using rust_target ${rust_target} as crate for cbindgen")
-        set(rust_cargo_package "${rust_target}")
+        get_target_property(rust_cargo_package "${rust_target}" COR_CARGO_PACKAGE_NAME )
+        if(NOT rust_cargo_package)
+            message(FATAL_ERROR "Could not determine cargo package name for cbindgen. "
+                                "You may want to explicitly pass the package name via the "
+                                "CARGO_PACKAGE argument to corrosion_experimental_cbindgen."
+            )
+        endif()
     else()
-        message(STATUS "Using crate ${CCN_CARGO_PACKAGE} as crate for cbindgen")
         set(rust_cargo_package "${CCN_CARGO_PACKAGE}")
     endif()
+    message(STATUS "Using package ${rust_cargo_package} as crate for cbindgen")
+
 
     set(output_header_name "${CCN_HEADER_NAME}")
 

cmake/CorrosionGenerator.cmake

@@ -156,6 +156,7 @@ function(_generator_add_package_targets)
                 )
             endif()
             list(APPEND corrosion_targets ${target_name})
+            set_property(TARGET "${target_name}" PROPERTY COR_CARGO_PACKAGE_NAME "${package_name}" )
         # Note: "bin" is mutually exclusive with "staticlib/cdylib", since `bin`s are seperate crates from libraries.
         elseif("bin" IN_LIST kinds)
             set(bin_byproduct "")
@@ -188,6 +189,7 @@ function(_generator_add_package_targets)
                 )
             endif()
             list(APPEND corrosion_targets ${target_name})
+            set_property(TARGET "${target_name}" PROPERTY COR_CARGO_PACKAGE_NAME "${package_name}" )
         else()
             # ignore other kinds (like examples, tests, build scripts, ...)
         endif()