We need to enable the c_api by default (#416)

Remove a collection of unneccesarily complex CMake logic.

Major change is that we explicitly opt-in to building the C API bindings by default since it is a hard requirement for our python bindings, and the project has numerous conditions to disable it.

Authors:
  - Robert Maynard (https://github.com/robertmaynard)

Approvers:
  - Ben Frederickson (https://github.com/benfred)

URL: #416

cpp/CMakeLists.txt

@@ -53,8 +53,7 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 option(BUILD_SHARED_LIBS "Build cuvs shared libraries" ON)
 option(BUILD_TESTS "Build cuvs unit-tests" ON)
-option(BUILD_C_LIBRARY "Build cuVS C API library" OFF)
-option(BUILD_C_TESTS "Build cuVS C API tests" OFF)
+option(BUILD_C_LIBRARY "Build cuVS C API library" ON)
 option(BUILD_CUVS_BENCH "Build cuVS ann benchmarks" OFF)
 option(BUILD_CAGRA_HNSWLIB "Build CAGRA+hnswlib interface" ON)
 option(BUILD_MG_ALGOS "Build with multi-GPU support" ON)
@@ -72,21 +71,12 @@ option(DISABLE_OPENMP "Disable OpenMP" OFF)
 option(CUVS_NVTX "Enable nvtx markers" OFF)
 option(CUVS_RAFT_CLONE_ON_PIN "Explicitly clone RAFT branch when pinned to non-feature branch" ON)
 
-if((BUILD_TESTS OR BUILD_C_LIBRARY) AND NOT BUILD_CPU_ONLY)
-
-endif()
-
 if(BUILD_CPU_ONLY)
   set(BUILD_SHARED_LIBS OFF)
   set(BUILD_TESTS OFF)
   set(BUILD_C_LIBRARY OFF)
-endif()
-
-if(NOT BUILD_C_LIBRARY)
-  set(BUILD_C_TESTS OFF)
-endif()
-
-if(NOT BUILD_SHARED_LIBS)
+  set(BUILD_CAGRA_HNSWLIB OFF)
+elseif(NOT BUILD_SHARED_LIBS)
   set(BUILD_TESTS OFF)
   set(BUILD_C_LIBRARY OFF)
   set(BUILD_CAGRA_HNSWLIB OFF)
@@ -771,7 +761,7 @@ endif()
 # ##################################################################################################
 # * build test executable ----------------------------------------------------
 
-if(BUILD_TESTS OR BUILD_C_TESTS)
+if(BUILD_TESTS)
   add_subdirectory(internal)
   add_subdirectory(test)
 endif()

cpp/test/CMakeLists.txt

@@ -215,7 +215,9 @@ if(BUILD_TESTS)
   )
 endif()
 
-if(BUILD_C_TESTS)
+if(TARGET cuvs::c_api)
+  enable_language(C)
+
   ConfigureTest(NAME INTEROP_TEST PATH core/interop.cu C_LIB)
   ConfigureTest(
     NAME DISTANCE_C_TEST PATH distance/run_pairwise_distance_c.c distance/pairwise_distance_c.cu
@@ -239,19 +241,37 @@ if(BUILD_C_TESTS)
     target_link_libraries(NEIGHBORS_HNSW_TEST PRIVATE hnswlib::hnswlib)
     target_compile_definitions(NEIGHBORS_HNSW_TEST PUBLIC CUVS_BUILD_CAGRA_HNSWLIB)
   endif()
-endif()
 
-# ##################################################################################################
-# Install tests ####################################################################################
-# ##################################################################################################
-rapids_test_install_relocatable(INSTALL_COMPONENT_SET testing DESTINATION bin/gtests/libcuvs)
-
-if(BUILD_C_TESTS)
-  enable_language(C)
 
   add_executable(cuvs_c_test core/c_api.c)
   target_link_libraries(cuvs_c_test PUBLIC cuvs::c_api)
 
   add_executable(cuvs_c_neighbors_test neighbors/c_api.c)
   target_link_libraries(cuvs_c_neighbors_test PUBLIC cuvs::c_api)
+
+  set_target_properties(
+    cuvs_c_test cuvs_c_neighbors_test
+    PROPERTIES RUNTIME_OUTPUT_DIRECTORY "$<BUILD_INTERFACE:${CUVS_BINARY_DIR}/gtests>"
+               INSTALL_RPATH "\$ORIGIN/../../../lib"
+  )
+
+  rapids_test_add(
+    NAME cuvs_c_test
+    COMMAND cuvs_c_test
+    GPUS 1
+    PERCENT 100
+    INSTALL_COMPONENT_SET testing
+  )
+  rapids_test_add(
+    NAME cuvs_c_neighbors_test
+    COMMAND cuvs_c_neighbors_test
+    GPUS 1
+    PERCENT 100
+    INSTALL_COMPONENT_SET testing
+  )
 endif()
+
+# ##################################################################################################
+# Install tests ####################################################################################
+# ##################################################################################################
+rapids_test_install_relocatable(INSTALL_COMPONENT_SET testing DESTINATION bin/gtests/libcuvs)