UniFFI C++ Bindging Integration

CMakeLists.txt

@@ -269,6 +269,10 @@ endif()
 message(STATUS \"[run_cargo.cmake] CFG=\${CFG}  CARGO=\${CARGO}  PROTOC=\${PROTOC_PATH}\")
 set(ENV{PROTOC} \"\${PROTOC_PATH}\")
 
+if(DEFINED CARGO_TARGET_DIR AND NOT CARGO_TARGET_DIR STREQUAL \"\")
+  set(ENV{CARGO_TARGET_DIR} \"\${CARGO_TARGET_DIR}\")
+endif()
+
 if(DEFINED GCC_LIB_DIR AND NOT GCC_LIB_DIR STREQUAL \"\")
   set(ENV{RUSTFLAGS} \"-L \${GCC_LIB_DIR} \$ENV{RUSTFLAGS}\")
   set(ENV{LD_LIBRARY_PATH} \"\${GCC_LIB_DIR}:\$ENV{LD_LIBRARY_PATH}\")
@@ -368,6 +372,8 @@ add_custom_target(build_rust_ffi
   DEPENDS "${RUST_LIB_DEBUG}" "${RUST_LIB_RELEASE}"
 )
 
+include(uniffi_cpp)
+
 # Note: protozero_plugin.o removal is no longer needed since we use dynamic libraries on Unix
 
 add_library(livekit SHARED
@@ -466,6 +472,7 @@ target_link_libraries(livekit
   PRIVATE
     spdlog::spdlog
     nlohmann_json::nlohmann_json
+    livekit_uniffi_cpp
     livekit_ffi
     ${LIVEKIT_PROTOBUF_TARGET}
 )

cmake/uniffi_cpp.cmake

@@ -0,0 +1,122 @@
+# Copyright 2026 LiveKit, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set(LIVEKIT_UNIFFI_CPP_GENERATED_DIR "${LIVEKIT_BINARY_DIR}/generated/uniffi")
+set(LIVEKIT_UNIFFI_CPP_SOURCE
+    "${LIVEKIT_UNIFFI_CPP_GENERATED_DIR}/livekit_ffi.cpp")
+set(LIVEKIT_UNIFFI_CPP_HEADER
+    "${LIVEKIT_UNIFFI_CPP_GENERATED_DIR}/livekit_ffi.hpp")
+set(LIVEKIT_UNIFFI_CPP_SCAFFOLDING_HEADER
+    "${LIVEKIT_UNIFFI_CPP_GENERATED_DIR}/livekit_ffi_scaffolding.hpp")
+
+# Release Linux builds strip the UniFFI metadata symbols, so generate from a
+# separate unstripped Debug library there. PE and Mach-O retain the metadata,
+# allowing Windows and macOS to reuse the livekit-ffi library already built for
+# the selected CMake configuration.
+if(UNIX AND NOT APPLE)
+  set(LIVEKIT_UNIFFI_METADATA_TARGET_DIR
+      "${RUST_ROOT}/target/uniffi-cpp-metadata")
+  set(LIVEKIT_UNIFFI_METADATA_LIBRARY
+      "${LIVEKIT_UNIFFI_METADATA_TARGET_DIR}/debug/liblivekit_ffi.so")
+endif()
+
+file(GLOB_RECURSE LIVEKIT_UNIFFI_RUST_SOURCES CONFIGURE_DEPENDS
+  "${RUST_ROOT}/livekit-ffi/src/*.rs"
+  "${RUST_ROOT}/livekit-ffi/Cargo.toml"
+)
+list(APPEND LIVEKIT_UNIFFI_RUST_SOURCES
+  "${RUST_ROOT}/Cargo.toml"
+  "${RUST_ROOT}/Cargo.lock"
+  "${RUST_ROOT}/rust-toolchain.toml"
+)
+
+file(GLOB_RECURSE LIVEKIT_UNIFFI_BINDGEN_SOURCES CONFIGURE_DEPENDS
+  "${RUST_ROOT}/tools/bindgens/src/*.rs"
+  "${RUST_ROOT}/tools/bindgens/Cargo.toml"
+)
+
+if(UNIX AND NOT APPLE)
+  add_custom_command(
+    OUTPUT "${LIVEKIT_UNIFFI_METADATA_LIBRARY}"
+    COMMAND "${CMAKE_COMMAND}"
+            -DCFG=Debug
+            -DRUST_ROOT=${RUST_ROOT}
+            -DCARGO=${CARGO_EXECUTABLE}
+            -DPROTOC_PATH=${Protobuf_PROTOC_EXECUTABLE}
+            -DGCC_LIB_DIR=${GCC_LIB_DIR}
+            -DCARGO_TARGET_DIR=${LIVEKIT_UNIFFI_METADATA_TARGET_DIR}
+            -P "${RUN_CARGO_SCRIPT}"
+    WORKING_DIRECTORY "${RUST_ROOT}"
+    DEPENDS ${LIVEKIT_UNIFFI_RUST_SOURCES}
+    COMMENT "Building unstripped livekit-ffi metadata library"
+    VERBATIM
+  )
+  add_custom_target(build_livekit_ffi_metadata
+    DEPENDS "${LIVEKIT_UNIFFI_METADATA_LIBRARY}")
+else()
+  set(LIVEKIT_UNIFFI_METADATA_LIBRARY "$<TARGET_FILE:livekit_ffi>")
+  add_custom_target(build_livekit_ffi_metadata)
+endif()
+
+# Keep Cargo invocations serialized on fresh runners, and ensure the selected
+# livekit-ffi library exists before it is inspected on Windows and macOS.
+add_dependencies(build_livekit_ffi_metadata build_rust_ffi)
+
+add_custom_command(
+  OUTPUT
+    "${LIVEKIT_UNIFFI_CPP_SOURCE}"
+    "${LIVEKIT_UNIFFI_CPP_HEADER}"
+    "${LIVEKIT_UNIFFI_CPP_SCAFFOLDING_HEADER}"
+  COMMAND "${CMAKE_COMMAND}" -E make_directory
+          "${LIVEKIT_UNIFFI_CPP_GENERATED_DIR}"
+  COMMAND "${CMAKE_COMMAND}" -E env
+          "CARGO_TARGET_DIR=${RUST_ROOT}/target/bindgens"
+          "CARGO_ENCODED_RUSTFLAGS="
+          "RUSTFLAGS="
+          "${CARGO_EXECUTABLE}" run --locked
+          --package bindgens
+          --bin uniffi-bindgen-cpp
+          --
+          --library "${LIVEKIT_UNIFFI_METADATA_LIBRARY}"
+          --out-dir "${LIVEKIT_UNIFFI_CPP_GENERATED_DIR}"
+  WORKING_DIRECTORY "${RUST_ROOT}"
+  DEPENDS
+    build_livekit_ffi_metadata
+    ${LIVEKIT_UNIFFI_RUST_SOURCES}
+    ${LIVEKIT_UNIFFI_BINDGEN_SOURCES}
+  COMMENT "Generating UniFFI C++ bindings"
+  VERBATIM
+)
+add_custom_target(generate_livekit_ffi_uniffi_cpp
+  DEPENDS
+    "${LIVEKIT_UNIFFI_CPP_SOURCE}"
+    "${LIVEKIT_UNIFFI_CPP_HEADER}"
+    "${LIVEKIT_UNIFFI_CPP_SCAFFOLDING_HEADER}"
+)
+
+set_source_files_properties(
+  "${LIVEKIT_UNIFFI_CPP_SOURCE}"
+  "${LIVEKIT_UNIFFI_CPP_HEADER}"
+  "${LIVEKIT_UNIFFI_CPP_SCAFFOLDING_HEADER}"
+  PROPERTIES GENERATED TRUE
+)
+
+add_library(livekit_uniffi_cpp OBJECT
+  "${LIVEKIT_UNIFFI_CPP_SOURCE}"
+)
+add_dependencies(livekit_uniffi_cpp generate_livekit_ffi_uniffi_cpp)
+target_include_directories(livekit_uniffi_cpp
+  PUBLIC "${LIVEKIT_UNIFFI_CPP_GENERATED_DIR}"
+)
+target_link_libraries(livekit_uniffi_cpp PRIVATE livekit_ffi)

src/tests/CMakeLists.txt

@@ -89,6 +89,8 @@ if(UNIT_TEST_SOURCES)
   target_link_libraries(livekit_unit_tests
     PRIVATE
       livekit
+      livekit_uniffi_cpp
+      livekit_ffi
       spdlog::spdlog
       ${LIVEKIT_PROTOBUF_TARGET}
       GTest::gtest_main

src/tests/unit/test_uniffi.cpp

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2026 LiveKit, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+
+#include <livekit_ffi.hpp>
+
+namespace livekit {
+namespace {
+
+TEST(UniFfiTest, BuildVersion) {
+  const auto version = livekit_ffi::build_version();
+  std::cout << "build_version: " << version << std::endl;
+  EXPECT_FALSE(version.empty());
+  EXPECT_NE(version, "unknown");
+}
+
+} // namespace
+} // namespace livekit