CMake Infrastructure Start (#814)

* Add the start of some cmake infrastructure.

* Add cmake based tests build.

* Fix compile errors in the tests.

* Add readme for the cmake.

* Remove extra "-c" option.

cmake/README.md

@@ -0,0 +1,3 @@
+# CMake Infrastructure
+
+Currently the CMake infrastructure is a work in progress. Some features work, many features do not. The official build infrastructure still uses the manually managed GNU Makefiles at this time. Users are recommended to use the manually managed GNU Makefiles for "stable" development.

cmake/spiffs.cmake

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+# Find SPIFFS
+
+if(DEFINED ENV{SPIFFSPATH})
+set(SPIFFSPATH $ENV{SPIFFSPATH})
+else()
+find_path(
+    SPIFFSPATH
+        src/
+    HINTS
+        /opt/spiffs
+        /opt/spiffs/default
+)
+endif()
+
+# SPIFFS
+if(${TARGET_SPIFFS})
+add_library(spiffs
+    ${SPIFFSPATH}/src/spiffs_cache.c
+    ${SPIFFSPATH}/src/spiffs_check.c
+    ${SPIFFSPATH}/src/spiffs_gc.c
+    ${SPIFFSPATH}/src/spiffs_hydrogen.c
+    ${SPIFFSPATH}/src/spiffs_nucleus.c
+    ${OPENMRNPATH}/src/freertos_drivers/spiffs/SPIFFS.cxx
+)
+target_include_directories(spiffs
+    PUBLIC
+        ${SPIFFSPATH}/src
+        ${OPENMRNPATH}/src/frertos_drivers/spiffs
+)
+target_compile_options(spiffs
+    PUBLIC
+        -DNO_TEST
+)
+endif() # TARGET_SPIFFS

cmake/test_setup_epilogue.cmake

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+# This is a target file designed to run on a host system.
+
+# Treat the tests (*.cxxtest extension) as C++ language files.
+set_source_files_properties(${TESTS} PROPERTIES LANGUAGE CXX)
+
+if(${COVERAGE})
+# Setup gcov target.
+add_custom_target(TARGET_GCOV ALL
+    DEPENDS gcovr/coverage.html
+)
+endif()
+
+# Build an executable for each test file.
+foreach(testsourcefile ${TESTS})
+    get_filename_component(testname ${testsourcefile} NAME_WE)
+    add_executable(${testname} ${testsourcefile})
+    target_include_directories(${testname}
+        PUBLIC
+            $ENV{OPENMRNPATH}/src
+            $ENV{OPENMRNPATH}/include
+            $ENV{SXMLCPATH}/src
+            ${ROOT_DIR}
+    )
+    target_link_libraries(${testname}
+        GTest::gtest_main
+        GTest::gmock_main
+
+        -fPIC
+        -lgcov
+        -Wl,--start-group
+        openmrn
+        ${LINK_LIBS}
+        -Wl,--end-group
+        -lavahi-client
+        -lavahi-common
+    )
+    add_custom_command(TARGET ${testname}
+        POST_BUILD
+        COMMAND ./${testname}
+        # Forces the coverage report to be regenerated if tests are run.
+        COMMAND rm -rf gcovr
+    )
+    if(${COVERAGE})
+    add_dependencies(TARGET_GCOV ${testname})
+    endif()
+endforeach(testsourcefile ${TESTS})
+
+if(${COVERAGE})
+# Generate the HTML coverage report
+add_custom_command(OUTPUT gcovr/coverage.html
+    COMMAND mkdir -p gcovr
+    COMMAND gcovr --html-details gcovr/coverage.html --exclude=_deps.* -r ${GCOV_SOURCE_DIR} .
+    VERBATIM
+)
+endif()

cmake/test_setup_prologue.cmake

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+# This is a target file designed to run on a host system.
+
+# Default coverage option to off.
+option(COVERAGE "COVERAGE" OFF)
+
+# Enable the required language standards.
+set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+set(CMAKE_C_STANDARD 99)
+set(CMAKE_C_STANDARD_REQUIRED ON)
+set(CMAKE_C_EXTENSIONS OFF)
+
+if(NOT DEFINED GTEST_TAG)
+set(GTEST_TAG v1.15.2)
+endif()
+message(STATUS "Using GoogleTest tag: ${GTEST_TAG}")
+
+# Get a copy of GoogleTest.
+include(FetchContent)
+FetchContent_Declare(
+    googletest
+    URL https://github.com/google/googletest/archive/refs/tags/${GTEST_TAG}.zip
+)
+
+# On Windows: Prevent overriding the parent project's compiler/linker settings.
+set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+FetchContent_MakeAvailable(googletest)
+
+# This magic is required in order to properly add the "-x" option for the
+# *.cxxtest file extension.
+set(CMAKE_CXX_COMPILE_OBJECT
+    "<CMAKE_CXX_COMPILER> -MD -MF [email protected] <DEFINES> <INCLUDES> <FLAGS> -o \
+    <OBJECT> -c -x c++ <SOURCE>"
+)
+
+# Compile flags.
+add_compile_options(
+    -fPIC -g -O0 -Wall -Werror -DGTEST -D_GNU_SOURCE
+    -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS
+    -Wno-attributes
+)
+if(${COVERAGE})
+# Compile flags for coverage.
+add_compile_options(--coverage)
+endif()
+
+# GTest and GMock includes.
+include_directories(${gtest_SOURCE_DIR}/include ${gmock_SOURCE_DIR}/include)
+
+# Add OpenMRN sources
+add_subdirectory(${OPENMRNPATH}/src openmrn)
+