use cargo workspace

This reduces the build time a little bit.

CMakeLists.txt

@@ -125,9 +125,9 @@ find_package(Qt${QT_VERSION_MAJOR} COMPONENTS Core Gui REQUIRED)
 
 if(CMAKE_BUILD_TYPE STREQUAL "Release")
     set(CARGO_BUILD_TYPE "--release")
-    set(CARGO_TARGET_DIR "target/release")
+    set(CARGO_BUILD_TYPE_DIR "release")
 else()
-    set(CARGO_TARGET_DIR "target/debug")
+    set(CARGO_BUILD_TYPE_DIR "debug")
 endif()
 
 # FIXME: cxx's build.rs fails without this.
@@ -136,24 +136,25 @@ if(APPLE)
     set(ENV{SDKROOT} ${CMAKE_OSX_SYSROOT})
 endif()
 
-message(STATUS "Building C++ code generator")
+message(STATUS "Building C++ code generator and generating C++ library")
+set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS cxx-qt-lib)
 set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS cxx-qt-cli)
 set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS cxx-qt-gen)
 set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS cxx-qt-build)
-execute_process(
-    COMMAND ${CMAKE_COMMAND} -E env "SDKROOT=${CMAKE_OSX_SYSROOT}" cargo build ${CARGO_BUILD_TYPE}
-    WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/cxx-qt-cli"
-)
-set(CXXQTBRIDGE_EXECUTABLE "${CMAKE_CURRENT_SOURCE_DIR}/cxx-qt-cli/${CARGO_TARGET_DIR}/cxxqtbridge${EXE_SUFFIX}")
-
-message(STATUS "Generating cxxqt C++ library")
-# Regenerate C++ library whenever any files in cxx-qt-lib change
-set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS cxx-qt-lib)
+set(CARGO_TARGET_DIR "${CMAKE_BINARY_DIR}/cargo")
 set(CXXQT_CPP_LIB_GENERATED_DIR "${CMAKE_CURRENT_BINARY_DIR}/cxx-qt-cpplib")
 execute_process(
-    COMMAND ${CMAKE_COMMAND} -E env "CXX_QT_LIB_OUT_DIR=${CXXQT_CPP_LIB_GENERATED_DIR}" cargo build ${CARGO_BUILD_TYPE}
-    WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/cxx-qt-lib"
+    COMMAND ${CMAKE_COMMAND} -E env
+        "CARGO_TARGET_DIR=${CARGO_TARGET_DIR}"
+        "SDKROOT=${CMAKE_OSX_SYSROOT}"
+        "CXX_QT_LIB_OUT_DIR=${CXXQT_CPP_LIB_GENERATED_DIR}"
+        cargo build ${CARGO_BUILD_TYPE}
+        --manifest-path "${CMAKE_CURRENT_SOURCE_DIR}/Cargo.toml"
+        --package cxx-qt-cli
+        --package cxx-qt-lib
 )
+set(CXXQTBRIDGE_EXECUTABLE "${CARGO_TARGET_DIR}/${CARGO_BUILD_TYPE_DIR}/cxxqtbridge${EXE_SUFFIX}")
+
 add_subdirectory(${CXXQT_CPP_LIB_GENERATED_DIR})
 
 # This is extremely hacky, but such is CMake. The find_package calls

Cargo.toml

@@ -0,0 +1,22 @@
+# SPDX-FileCopyrightText: 2021 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+# SPDX-FileContributor: Be Wilson <[email protected]>
+#
+# SPDX-License-Identifier: MIT OR Apache-2.0
+
+[workspace]
+members = [
+    "cxx-qt",
+    "cxx-qt-build",
+    "cxx-qt-cli",
+    "cxx-qt-gen",
+
+    "examples/demo_threading",
+    "examples/qml_extension_plugin/core",
+    "examples/qml_features",
+    "examples/qml_minimal",
+    "examples/qml_with_threaded_logic",
+
+    "tests/basic_cxx_only",
+    "tests/basic_cxx_qt",
+    "tests/qt_types_standalone",
+]

cxx-qt-lib/CxxQt.cmake

@@ -50,6 +50,12 @@ function(cxx_qt_create_target)
     if(APPLE)
         set(ENV{SDKROOT} ${CMAKE_OSX_SYSROOT})
     endif()
-    corrosion_import_crate(MANIFEST_PATH ${CXXQT_MANIFEST_PATH})
+
+    # corrosion_import_crate cannot be called multiple times within
+    # one project.
+    list(GET CXXQT_CRATES 0 CORROSION_TARGET)
+    if(NOT TARGET ${CORROSION_TARGET})
+        corrosion_import_crate(MANIFEST_PATH ${CXXQT_MANIFEST_PATH})
+    endif()
     target_link_libraries(${CXXQT_TARGET} INTERFACE ${CXXQT_CRATES})
 endfunction()

tests/basic_cxx_only/CMakeLists.txt

@@ -39,7 +39,6 @@ target_include_directories(${APP_NAME} PRIVATE
     "${CXXQTBRIDGE_OUTPUT_DIR}/include"
 )
 
-corrosion_import_crate(MANIFEST_PATH Cargo.toml)
 target_link_libraries(${APP_NAME} PRIVATE basic-cxx-only)
 
 target_include_directories(${APP_NAME} PRIVATE include)