Added support for CMake build system

Created CMakeLists.txt and updated .gitignore accordingly. Having
support for CMake enables liburing  to be added as a dependency via the
FetchContent interface, so that other projects build and link against
liburing on supported kernel versions even if no system installation is
present. This can be useful on HPC systems or other shared clusters
where the approval process for system-wide installation is slow. It also
makes it easier for users to test and compare more recent versions of
the library to an existing system installation.

Signed-off-by: Alecto Perez <[email protected]>

.gitignore

@@ -139,3 +139,6 @@ config-host.mak
 config.log
 
 liburing.pc
+
+/.ccls-cache/
+/build/

CMakeLists.txt

@@ -0,0 +1,90 @@
+cmake_minimum_required(VERSION 3.14)
+
+project("liburing")
+set(libname "uring")
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+############################
+## Add headers to library ##
+############################
+function(add_headers VAR dir)
+    set(headers ${${VAR}})
+    foreach (header ${ARGN})
+        set(headers ${headers} ${dir}/${header})
+    endforeach()
+    set(${VAR} ${headers} PARENT_SCOPE)
+endfunction()
+
+add_headers(
+    liburing_headers    # Variable name
+    src/include         # Directory to find headers
+    liburing.h
+    liburing/barrier.h
+    liburing/io_uring.h)
+
+file(GLOB liburing_sources src/*.c)
+# string(REPLACE ";" " " liburing_sources "${liburing_sources}")
+
+add_library("${libname}" ${liburing_sources} ${liburing_headers})
+
+target_include_directories(
+    "${libname}"
+    PUBLIC
+    $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/src/include/>
+    $<INSTALL_INTERFACE:include>)
+
+# If we're building this project directly (rather than as a dependency), we
+# have to build tests
+if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME)
+
+    # Run configure to generate config-host.h, if configure hasn't been run
+    if(NOT EXISTS "${PROJECT_SOURCE_DIR}/config-host.h")
+        execute_process(
+            COMMAND "${PROJECT_SOURCE_DIR}/configure"
+            WORKING_DIRECTORY "${PROJECT_SOURCE_DIR}")
+    endif()
+
+    include(CTest)
+
+    # Tests need to be linked against pthreads
+    set(THREADS_PREFER_PTHREAD_FLAG ON)
+    find_package(Threads REQUIRED)
+
+    set(liburing_test_flags
+        -include "${PROJECT_SOURCE_DIR}/config-host.h"
+        -g
+        -O2
+        -D_GNU_SOURCE
+        -D__SANE_USERSPACE_TYPES__
+        -Wall
+        -Wextra
+        -Wno-unused-parameter
+        -Wno-sign-compare
+        -Wstringop-overflow=0
+        -Warray-bounds=0)
+    file(GLOB liburing_tests "test/*.c")
+    # Remove the helpers.c, which doesn't contain a main
+    list(FILTER liburing_tests EXCLUDE REGEX "helpers.c")
+    foreach(test_file ${liburing_tests})
+
+        # Get the name of the target. This will be the file name, stripped of
+        # ".c" at the end.
+        get_filename_component(target ${test_file} NAME_WLE)
+
+        # Create an executable target for the test; add test/helpers.c as a source
+        add_executable(${target} ${test_file} test/helpers.c)
+
+        # Target liburing and pthreads
+        target_link_libraries(
+            ${target}
+            PRIVATE
+            ${libname}
+            Threads::Threads)
+
+        # Add additional compiler options and definitions
+        target_compile_options(${target} PRIVATE ${liburing_test_flags})
+
+        # Register the test with ctest
+        add_test(NAME "test-${target}" COMMAND "${target}")
+    endforeach()
+endif()