Enable consistent clang format for the project

1. Add a .clang-format which is basically 2 spaces, allman braces,
   embedded namespaces.
2. Reformat the entire codebase with
   find src -iname "*.cpp" -o -iname "*.h" -o -iname "*.mm" | xargs clang-format -i
3. add a cmake code checks target which currently just checkes that
   the code remains clang formatted
4. Add a github action which runs that code check target on ubuntu on a PR

.clang-format

@@ -0,0 +1,19 @@
+---
+UseTab: Never
+---
+Language: Cpp
+IndentWidth: 2
+AlignAfterOpenBracket: Align
+BreakBeforeBraces: Allman
+ColumnLimit: 120
+SortIncludes: false
+NamespaceIndentation: All
+---
+Language: ObjC
+IndentWidth: 2
+AlignAfterOpenBracket: Align
+BreakBeforeBraces: Allman
+ColumnLimit: 120
+SortIncludes: false
+NamespaceIndentation: All
+...

.github/workflows/code-checks.yml

@@ -0,0 +1,21 @@
+name: Clap Wrapper Format and Code Checks
+on: [pull_request]
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  build-code-checks:
+    name: code-checks
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          submodules: recursive
+      - name: Run Code Checks
+        run: |
+          cmake -Bbuild -DCLAP_WRAPPER_CODE_CHECKS_ONLY=TRUE
+          cmake --build build --target clap-wrapper-code-checks

CMakeLists.txt

@@ -55,7 +55,11 @@ set(CMAKE_VISIBILITY_INLINES_HIDDEN ON)
 # defines functions relative to this, so needs a cache
 # variable with the source dir
 set(CLAP_WRAPPER_CMAKE_CURRENT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR} CACHE STRING "Clap Wrapper Source Location")
-include(cmake/enable_sdks.cmake)
+if (DEFINED CLAP_WRAPPER_CODE_CHECKS_ONLY)
+	message(STATUS "clap-wrapper: code checks only; skipping enable sdks")
+else()
+	include(cmake/enable_sdks.cmake)
+endif()
 
 # automatically build the wrapper only if this is the top level project
 set(skipbuild FALSE)
@@ -64,6 +68,9 @@ if (NOT PROJECT_IS_TOP_LEVEL)
 		set(skipbuild TRUE)
 	endif()
 endif()
+if (DEFINED CLAP_WRAPPER_CODE_CHECKS_ONLY)
+	set(skipbuild ${CLAP_WRAPPER_CODE_CHECKS_ONLY})
+endif()
 
 if (${skipbuild})
 	message(STATUS "clap-wrapper: Skipping clap wrapper target ejection")
@@ -106,3 +113,23 @@ else()
 		endif()
 	endif()
 endif()
+
+
+add_custom_target(clap-wrapper-code-checks)
+
+# Clang Format checks
+find_program(CLANG_FORMAT_EXE NAMES clang-format-12 clang-format)
+set(CLANG_FORMAT_DIRS src)
+set(CLANG_FORMAT_EXTS cpp h)
+foreach(dir ${CLANG_FORMAT_DIRS})
+	foreach(ext ${CLANG_FORMAT_EXTS})
+		list(APPEND CLANG_FORMAT_GLOBS "':(glob)${dir}/**/*.${ext}'")
+	endforeach()
+endforeach()
+add_custom_command(TARGET clap-wrapper-code-checks
+		POST_BUILD
+		WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+		COMMAND ${CMAKE_COMMAND} -E echo About to check clang-format using ${CLANG_FORMAT_EXE}
+		COMMAND git ls-files -- ${CLANG_FORMAT_GLOBS} | xargs ${CLANG_FORMAT_EXE} --dry-run --Werror
+		)
+# }}}