Add audiounit-rust backend (#511)

CMakeLists.txt

@@ -45,6 +45,9 @@ if (BUILD_RUST_LIBS)
   if(EXISTS "${PROJECT_SOURCE_DIR}/src/cubeb-pulse-rs")
     set(USE_PULSE_RUST 1)
   endif()
+  if(EXISTS "${PROJECT_SOURCE_DIR}/src/cubeb-coreaudio-rs")
+    set(USE_AUDIOUNIT_RUST 1)
+  endif()
 endif()
 
 # On OS/2, visibility attribute is not supported.
@@ -248,6 +251,24 @@ if(USE_PULSE_RUST)
     optimized "${CMAKE_SOURCE_DIR}/src/cubeb-pulse-rs/target/release/libcubeb_pulse.a")
 endif()
 
+if(USE_AUDIOUNIT_RUST)
+  include(ExternalProject)
+  set_directory_properties(PROPERTIES EP_PREFIX ${CMAKE_BINARY_DIR}/rust)
+  ExternalProject_Add(
+    cubeb_coreaudio_rs
+    DOWNLOAD_COMMAND ""
+    CONFIGURE_COMMAND ""
+    BUILD_COMMAND cargo build COMMAND cargo build --release
+    BINARY_DIR "${CMAKE_SOURCE_DIR}/src/cubeb-coreaudio-rs"
+    INSTALL_COMMAND ""
+    LOG_BUILD ON)
+  add_dependencies(cubeb cubeb_coreaudio_rs)
+  target_compile_definitions(cubeb PRIVATE USE_AUDIOUNIT_RUST)
+  target_link_libraries(cubeb PRIVATE
+    debug "${CMAKE_SOURCE_DIR}/src/cubeb-coreaudio-rs/target/debug/libcubeb_coreaudio.a"
+    optimized "${CMAKE_SOURCE_DIR}/src/cubeb-coreaudio-rs/target/release/libcubeb_coreaudio.a")
+endif()
+
 find_package(Doxygen)
 if(DOXYGEN_FOUND)
   configure_file(${CMAKE_CURRENT_SOURCE_DIR}/docs/Doxyfile.in ${CMAKE_CURRENT_BINARY_DIR}/docs/Doxyfile @ONLY)

src/cubeb.c

@@ -42,6 +42,9 @@ int alsa_init(cubeb ** context, char const * context_name);
 #if defined(USE_AUDIOUNIT)
 int audiounit_init(cubeb ** context, char const * context_name);
 #endif
+#if defined(USE_AUDIOUNIT_RUST)
+int audiounit_rust_init(cubeb ** contet, char const * context_name);
+#endif
 #if defined(USE_WINMM)
 int winmm_init(cubeb ** context, char const * context_name);
 #endif
@@ -135,6 +138,10 @@ cubeb_init(cubeb ** context, char const * context_name, char const * backend_nam
     } else if (!strcmp(backend_name, "audiounit")) {
 #if defined(USE_AUDIOUNIT)
       init_oneshot = audiounit_init;
+#endif
+    } else if (!strcmp(backend_name, "audiounit-rust")) {
+#if defined(USE_AUDIOUNIT_RUST)
+      init_oneshot = audiounit_rust_init;
 #endif
     } else if (!strcmp(backend_name, "wasapi")) {
 #if defined(USE_WASAPI)
@@ -186,6 +193,9 @@ cubeb_init(cubeb ** context, char const * context_name, char const * backend_nam
 #if defined(USE_AUDIOUNIT)
     audiounit_init,
 #endif
+#if defined(USE_AUDIOUNIT_RUST)
+    audiounit_rust_init,
+#endif
 #if defined(USE_WASAPI)
     wasapi_init,
 #endif