c-api: Bring wasmtime-cpp into this repository

.github/workflows/main.yml

@@ -666,7 +666,7 @@ jobs:
     # Rust programs. Note that this only executes if the `determine` step told
     # us to test the capi which is off-by-default for PRs.
     - run: rustup target add wasm32-wasip2 # wasip2 target needed by example programs
-    - run: cmake -Sexamples -Bexamples/build -DBUILD_SHARED_LIBS=OFF
+    - run: cmake -Sexamples -Bexamples/build -DBUILD_SHARED_LIBS=OFF -DBUILD_TESTS=ON
     - run: cmake --build examples/build --config Debug
     - run: cmake -E env CTEST_OUTPUT_ON_FAILURE=1 cmake --build examples/build --config Debug --target RUN_TESTS
       if: runner.os == 'Windows'

crates/c-api/CMakeLists.txt

@@ -3,6 +3,7 @@ project(wasmtime C)
 
 set(WASMTIME_USER_CARGO_BUILD_OPTIONS "" CACHE STRING "Additional cargo flags (such as --features) to apply to the build command")
 option(BUILD_SHARED_LIBS "Build using shared libraries" OFF)
+option(BUILD_TESTS "Build tests" OFF)
 option(WASMTIME_ALWAYS_BUILD "If cmake should always invoke cargo to build wasmtime" ON)
 option(WASMTIME_FASTEST_RUNTIME "Set flags designed to optimize runtime performance" OFF)
 set(WASMTIME_TARGET "" CACHE STRING "Rust target to build for")
@@ -129,3 +130,46 @@ add_custom_target(headers-to-doc
       -DWASMTIME_HEADER_DST=${CMAKE_BINARY_DIR}/include
       -P ${CMAKE_CURRENT_SOURCE_DIR}/cmake/install-headers.cmake
   DEPENDS ${headers})
+
+if (NOT CMAKE_CXX_STANDARD)
+  message(STATUS "Cannot detect C++ Standard. Switching to C++17 by default !!")
+  set(CMAKE_CXX_STANDARD 17)
+endif()
+message(STATUS "CMAKE_CXX_STANDARD is ${CMAKE_CXX_STANDARD}")
+if (NOT CMAKE_CXX_STANDARD GREATER_EQUAL 17)
+  message(FATAL_ERROR "WASMTIME_CPP library does not support ${CMAKE_CXX_STANDARD}")
+endif()
+set(CMAKE_CXX_STANDARD_REQUIRED True)
+
+option(ENABLE_CODE_ANALYSIS "Run code analysis" OFF)
+message(STATUS "ENABLE_CODE_ANALYSIS       ${ENABLE_CODE_ANALYSIS}")
+
+if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+   add_compile_options (-fdiagnostics-color=always)
+elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+   add_compile_options (-fcolor-diagnostics)
+endif ()
+
+add_library(wasmtime-cpp INTERFACE)
+target_link_libraries(wasmtime-cpp INTERFACE wasmtime)
+if (MSVC)
+  target_compile_options(wasmtime-cpp INTERFACE /DWASM_API_EXTERN= /DWASI_API_EXTERN=)
+  target_link_libraries(wasmtime-cpp INTERFACE ws2_32 bcrypt advapi32 userenv ntdll shell32 ole32)
+else()
+  target_link_libraries(wasmtime-cpp INTERFACE stdc++ pthread)
+endif()
+
+target_include_directories(
+        wasmtime-cpp
+        INTERFACE
+        ${PROJECT_SOURCE_DIR}/include)
+
+if (BUILD_TESTS)
+  message(STATUS "Building tests")
+
+  enable_language(CXX)
+  set(INSTALL_GTEST OFF CACHE BOOL "" FORCE)
+
+  enable_testing()
+  add_subdirectory(tests)
+endif()

crates/c-api/README.md

@@ -38,6 +38,10 @@ These commands will produce the following files:
 
 * `artifacts/include/**.h`: Header files for working with Wasmtime.
 
+## Using in a C++ Project
+
+A header only C++ API is also offered as `wasmtime.hh`, which is built on top of the C API. Its located next to the C headers when you download a pre-built library, or when building from source. C++17 is required.
+
 ## Using in a Rust Project
 
 If you have a Rust crate that contains bindings to a C or C++ library that uses Wasmtime, you can link the Wasmtime C API using Cargo.

crates/c-api/doxygen.conf.in

@@ -893,7 +893,8 @@ INPUT_ENCODING         = UTF-8
 # *.py, *.pyw, *.f90, *.f95, *.f03, *.f08, *.f18, *.f, *.for, *.vhd, *.vhdl,
 # *.ucf, *.qsf and *.ice.
 
-FILE_PATTERNS          = *.h
+FILE_PATTERNS          = *.h \
+                         *.hh
 
 # The RECURSIVE tag can be used to specify whether or not subdirectories should
 # be searched for input files as well.
@@ -924,7 +925,7 @@ EXCLUDE_SYMLINKS       = NO
 # Note that the wildcards are matched against the file with absolute path, so to
 # exclude all test directories for example use the pattern */test/*
 
-EXCLUDE_PATTERNS       =
+EXCLUDE_PATTERNS       = */wasm.hh
 
 # The EXCLUDE_SYMBOLS tag can be used to specify one or more symbol names
 # (namespaces, classes, functions, etc.) that should be excluded from the
@@ -944,7 +945,11 @@ EXCLUDE_SYMBOLS        = assertions \
                          WASMTIME_CONFIG_PROP \
                          WASMTIME_POOLING_ALLOCATION_CONFIG_PROP \
                          own \
-                         wasm_*_enum
+                         wasm_*_enum \
+                         wasmtime::detail \
+                         CASE_KIND_PRINT_NAME \
+                         CASE_KIND_TO_C \
+                         CASE_C_TO_KIND
 
 # The EXAMPLE_PATH tag can be used to specify one or more files or directories
 # that contain example code fragments that are included (see the \include