Add CMake build system

.github/workflows/macos.yml

@@ -24,3 +24,28 @@ jobs:
     - name: Build Manual makefile
       working-directory: mac
       run: make -f Makefile-manual
+
+  build-cmake:
+
+    runs-on: macos-latest
+
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        path: hidapisrc
+    - name: Configure CMake
+      run: |
+        rm -rf build install
+        cmake -B build/shared -S hidapisrc -DCMAKE_INSTALL_PREFIX=install/shared
+        cmake -B build/framework -S hidapisrc -DCMAKE_INSTALL_PREFIX=install/framework -DCMAKE_FRAMEWORK=ON
+    - name: Build CMake Shared
+      working-directory: build/shared
+      run: make install
+    - name: Build CMake Framework
+      working-directory: build/framework
+      run: make install
+    - name: Check artifacts
+      uses: andstor/file-existence-action@v1
+      with:
+        files: "install/shared/lib/libhidapi.dylib, install/shared/include/hidapi/hidapi.h, install/framework/lib/hidapi.framework/hidapi, install/framework/lib/hidapi.framework/Headers/hidapi.h"
+        allow_failure: true

BUILD.autotools.md

@@ -0,0 +1,106 @@
+# Building HIDAPI using Autotools
+
+To be able to use Autotools to build HIDAPI, it has to be [installed](#installing-autotools)/available in the system.
+
+Make sure you've checked [prerequisites](BUILD.md#prerequisites) and installed all required dependencies.
+
+## Installing Autotools
+
+HIDAPI uses few specific tools/packages from Autotools: `autoconf`, `automake`, `libtool`.
+
+On different platforms or package managers, those could be named a bit differently or packaged together.
+You'll have to check the documentation/package list for your specific package manager.
+
+### Linux
+
+On Ubuntu the tools are available via APT:
+
+```sh
+sudo apt install autoconf automake libtool
+```
+
+### FreeBSD
+
+FreeBSD Autotools can be installed as:
+
+```sh
+pkg_add -r autotools
+```
+
+Additionally, on FreeBSD you will need to install GNU make:
+```sh
+pkg_add -r gmake
+```
+
+## Building HIDAPI with Autotools
+
+A simple command list, to build HIDAPI with Autotools as a _shared library_ and install in into your system:
+
+```sh
+./bootstrap # this prepares the configure script
+./configure
+make # build the library
+make install # as root, or using sudo, this will install hidapi into your system
+```
+
+`./configure` can take several arguments which control the build. A few commonly used options:
+```sh
+	--enable-testgui
+		# Enable the build of Foxit-based Test GUI. This requires Fox toolkit to
+		# be installed/available. See README.md#test-gui for remarks.
+
+	--prefix=/usr
+		# Specify where you want the output headers and libraries to
+		# be installed. The example above will put the headers in
+		# /usr/include and the binaries in /usr/lib. The default is to
+		# install into /usr/local which is fine on most systems.
+
+	--disable-shared
+		# By default, both shared and static libraries are going to be built/installed.
+		# This option disables shared library build, if only static library is required.
+```
+
+
+## Cross Compiling
+
+This section talks about cross compiling HIDAPI for Linux using Autotools.
+This is useful for using HIDAPI on embedded Linux targets. These
+instructions assume the most raw kind of embedded Linux build, where all
+prerequisites will need to be built first. This process will of course vary
+based on your embedded Linux build system if you are using one, such as
+OpenEmbedded or Buildroot.
+
+For the purpose of this section, it will be assumed that the following
+environment variables are exported.
+```sh
+$ export STAGING=$HOME/out
+$ export HOST=arm-linux
+```
+
+`STAGING` and `HOST` can be modified to suit your setup.
+
+### Prerequisites
+
+Depending on what backend you want to cross-compile, you also need to prepare the dependencies:
+`libusb` for libusb HIDAPI backend, or `libudev` for hidraw HIDAPI backend.
+
+An example of cross-compiling `libusb`. From `libusb` source directory, run:
+```sh
+./configure --host=$HOST --prefix=$STAGING
+make
+make install
+```
+
+An example of cross-comping `libudev` is not covered by this section.
+Check `libudev`'s documentation for details.
+
+### Building HIDAPI
+
+Build HIDAPI:
+```sh
+PKG_CONFIG_DIR= \
+PKG_CONFIG_LIBDIR=$STAGING/lib/pkgconfig:$STAGING/share/pkgconfig \
+PKG_CONFIG_SYSROOT_DIR=$STAGING \
+./configure --host=$HOST --prefix=$STAGING
+# make / make install - same as for a regular build
+```

BUILD.cmake.md

@@ -0,0 +1,221 @@
+# Building HIDAPI using CMake
+
+To build HIDAPI with CMake, it has to be [installed](#installing-cmake)/available in the system.
+
+Make sure you've checked [prerequisites](BUILD.md#prerequisites) and installed all required dependencies.
+
+HIDAPI CMake build system allows you to build HIDAPI in two generally different ways:
+1) As a [standalone package/library](#standalone-package-build);
+2) As [part of a larger CMake project](#hidapi-as-a-subdirectory).
+
+**TL;DR**: if you're experienced developer and have been working with CMake projects or have been written some of your own -
+most of this document may not be of interest for you; just check variables names, its default values and the target names.
+
+## Installing CMake
+
+CMake can be installed either using your system's package manager,
+or by downloading an installer/prebuilt version from the [official website](https://cmake.org/download/).
+
+On most \*nix systems, the prefered way to install CMake is via package manager,
+e.g. `sudo apt install cmake`.
+
+On Windows CMake could be provided by your development environment (e.g. by Visual Studio Installer or MinGW installer),
+or you may install it system-wise using the installer from the official website.
+
+On macOS CMake may be installed by Homebrew/MacPorts or using the installer from the official website.
+
+## Standalone package build
+
+To build HIDAPI as a standalone package, you follow [general steps](https://cmake.org/runningcmake/) of building any CMake project.
+
+An example of building HIDAPI with CMake:
+```sh
+cd <build dir>
+# configure the build
+cmake <HIDAPI source dir>
+# build it!
+cmake --build .
+# install library; by default installs into /usr/local/
+cmake --build . --target install
+# NOTE: you need to run install command as root, to be able to install into /usr/local/
+```
+Such invocation will use the default (as per CMake magic) compiler/build environment available in your system.
+
+You may pass some additional CMake variables to control the build configuration as `-D<CMake Variable>=value`.
+E.g.:
+```sh
+# install command now would install things into /usr
+cmake <HIDAPI source dir> -DCMAKE_INSTALL_PREFIX=/usr
+```
+
+<details>
+  <summary>Using a specific CMake generator</summary>
+
+An example of using `Ninja` as a CMake generator:
+
+```sh
+cd <build dir>
+# configure the build
+cmake -GNinja <HIDAPI source dir>
+# we know, that CMake has generated build files for Ninja,
+# so we can use `ninja` directly, instead of `cmake --build .`
+ninja
+# install library
+ninja install
+```
+
+`-G` here specifies a native build system CMake would generate build files for.
+Check [CMake Documentation](https://cmake.org/cmake/help/latest/manual/cmake-generators.7.html) for a list of available generators (system-specific).
+
+</details><br>
+
+Some of the [standard](https://cmake.org/cmake/help/latest/manual/cmake-variables.7.html) CMake variables you may want to use to configure a build:
+
+- [`CMAKE_INSTALL_PREFIX`](https://cmake.org/cmake/help/latest/variable/CMAKE_INSTALL_PREFIX.html) - prefix where `install` target would install the library(ies);
+- [`CMAKE_BUILD_TYPE`](https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html) - standard possible values: `Debug`, `Release`, `RelWithDebInfo`, `MinSizeRel`; Defaults to `Release` for HIDAPI, if not specified;
+- [`BUILD_SHARED_LIBS`](https://cmake.org/cmake/help/latest/variable/BUILD_SHARED_LIBS.html) - when set to TRUE, HIDAPI is built as a shared library, otherwise build statically; Defaults to `TRUE` for HIDAPI, if not specified;
+
+<details>
+  <summary>macOS-specific variables</summary>
+
+  - [`CMAKE_FRAMEWORK`](https://cmake.org/cmake/help/latest/variable/CMAKE_FRAMEWORK.html) - (since CMake 3.15) when set to TRUE, HIDAPI is built as a framework library, otherwise build as a regular static/shared library; Defaults to `FALSE` for HIDAPI, if not specified;
+  - [`CMAKE_OSX_DEPLOYMENT_TARGET`](https://cmake.org/cmake/help/latest/variable/CMAKE_OSX_DEPLOYMENT_TARGET.html) - minimum version of the target platform (e.g. macOS or iOS) on which the target binaries are to be deployed; defaults to a maximum supported target platform by currently used XCode/Toolchain;
+
+</details><br>
+
+HIDAPI-specific CMake variables:
+
+- `HIDAPI_BUILD_HIDTEST` - when set to TRUE, build a small test application `hidtest`;
+
+<details>
+  <summary>Linux-specific variables</summary>
+
+  - `HIDAPI_WITH_HIDRAW` - when set to TRUE, build HIDRAW-based implementation of HIDAPI (`hidapi-hidraw`), otherwise don't build it; defaults to TRUE;
+  - `HIDAPI_WITH_LIBUSB` - when set to TRUE, build LIBUSB-based implementation of HIDAPI (`hidapi-libusb`), otherwise don't build it; defaults to TRUE;
+
+  **NOTE**: at least one of `HIDAPI_WITH_HIDRAW` or `HIDAPI_WITH_LIBUSB` has to be set to TRUE.
+
+</details><br>
+
+To see all most-useful CMake variables available for HIDAPI, one of the most convenient ways is too use [`cmake-gui`](https://cmake.org/cmake/help/latest/manual/cmake-gui.1.html) tool ([example](https://cmake.org/runningcmake/)).
+
+_NOTE_: HIDAPI packages built by CMake can be used with `pkg-config`, as if built with [Autotools](BUILD.autotools.md).
+
+### MSVC and Ninja
+It is possible to build a CMake project (including HIDAPI) using MSVC compiler and Ninja (for medium and larger projects it is so much faster than msbuild).
+
+For that:
+1) Open cmd.exe;
+2) Setup MSVC build environment variables, e.g.: `vcvarsall.bat x64`, where:
+	- `vcvarsall.bat` is an environment setup script of your MSVC toolchain installation;<br>For MSVC 2019 Community edition it is located at: `C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\`;
+	- `x64` -a target architecture to build;
+3) Follow general build steps, and use `Ninja` as a generator.
+
+### Using HIDAPI in a CMake project
+
+When HIDAPI is used as a standalone package (either installed into the system or built manually and installed elsewhere), the simplest way to use it is as showed in the example:
+
+```cmake
+project(my_application)
+
+add_executable(my_application main.c)
+
+find_package(hidapi REQUIRED)
+target_link_libraries(my_application PRIVATE hidapi::hidapi)
+```
+
+If HIDAPI isn't installed in your system, or `find_package` cannot find HIDAPI by default for any other reasons,
+the recommended way manually specify which HIDAPI package to use is via `hidapi_ROOT` CMake variable, e.g.:
+`-Dhidapi_ROOT=<path to HIDAPI installation prefix>`.
+
+_NOTE_: usage of `hidapi_ROOT` is only possible (and recommended) with CMake 3.12 and higher. For older versions of CMake you'd need to specify [`CMAKE_PREFIX_PATH`](https://cmake.org/cmake/help/latest/variable/CMAKE_PREFIX_PATH.html#variable:CMAKE_PREFIX_PATH) instead.
+
+Check with [`find_package`](https://cmake.org/cmake/help/latest/command/find_package.html) documentation if you need more details.
+
+Available CMake targets after successful `find_package(hidapi)`:
+- `hidapi::hidapi` - indented to be used in most cases;
+- `hidapi::include` - if you need only to include `<hidapi.h>` but not link against the library;
+- `hidapi::winapi` - same as `hidapi::hidapi` on Windows; available only on Windows;
+- `hidapi::darwin` - same as `hidapi::hidapi` on macOS; available only on macOS;
+- `hidapi::libusb` - available when libusb backend is used/available;
+- `hidapi::hidraw` - available when hidraw backend is used/available on Linux;
+
+**NOTE**: on Linux often both `hidapi::libusb` and `hidapi::hidraw` backends are available; in that case `hidapi::hidapi` is an alias for **`hidapi::hidraw`**. The motivation is that `hidraw` backend is a native Linux kernel implementation of HID protocol, and supports various HID devices (USB, Bluetooth, I2C, etc.). If `hidraw` backend isn't built at all (`hidapi::libusb` is the only target) - `hidapi::hidapi` is an alias for `hidapi::libusb`.
+If you're developing a cross-platform application and you are sure you need to use `libusb` backend on Linux, the simple way to achieve this is:
+```cmake
+if(TARGET hidapi::libusb)
+    target_link_libraries(my_project PRIVATE hidapi::libusb)
+else()
+    target_link_libraries(my_project PRIVATE hidapi::hidapi)
+endif()
+```
+
+## HIDAPI as a subdirectory
+
+HIDAPI can be easily used as a subdirectory of a larger CMake project:
+```cmake
+# root CMakeLists.txt
+cmake_minimum_required(VERSION 3.4.3 FATAL_ERROR)
+
+add_subdirectory(hidapi)
+add_subdirectory(my_application)
+
+# my_application/CMakeLists.txt
+project(my_application)
+
+add_executable(my_application main.c)
+
+# NOTE: no `find_package` is required, since HIDAPI targets are already a part of the project tree
+target_link_libraries(my_application PRIVATE hidapi::hidapi)
+```
+Lets call this "larger project" a "host project".
+
+All of the variables described in [standalone build](#standalone-package-build) section can be used to control HIDAPI build in case of a subdirectory, e.g.:
+```cmake
+set(HIDAPI_WITH_LIBUSB FALSE) # surely will be used only on Linux
+set(BUILD_SHARED_LIBS FALSE) # HIDAPI as static library on all platforms
+add_subdirectory(hidapi)
+```
+
+There is two important differences in the behavior of HIDAPI CMake build system when CMake is built as standalone package vs subdirectory build:
+
+1) In _standalone build_ a number of standard and HIDAPI-specific variables are marked as _cache variables_ or _options_.
+This is done for convenience: when you're building HIDAPI as a standalone package and using tools like `cmake-gui` - those are highlighted as variables that can be changed and has some short description/documentation. E.g.:
+![an example of highlighted variables in cmake-gui](documentation/cmake-gui-highlights.png "cmake-gui highlighted variables")<br>
+E.g.2:<br>
+![an example of drop-down menu in cmake-gui](documentation/cmake-gui-drop-down.png "cmake-gui drop-down menu")<br>
+When HIDAPI is built as a _subdirectory_ - **_none of the variables are marked for cache or as options_** by HIDAPI.
+This is done to let the host project's developer decide what is important (what needs to be highlighted) and what's not.
+
+2) The default behavior/default value for some of the variables is a bit different:
+	- by default, none of HIDAPI targets are [installed](https://cmake.org/cmake/help/latest/command/install.html); if required, HIDAPI targets can be installed by host project _after_ including HIDAPI subdirectory (requires CMake 3.13 or later); **or**, the default installation can be enabled by setting `HIDAPI_INSTALL_TARGETS` variable _before_ including HIDAPI subdirectory.
+		HIDAPI uses [GNUInstallDirs](https://cmake.org/cmake/help/latest/module/GNUInstallDirs.html) to specify install locations. Variables like `CMAKE_INSTALL_LIBDIR` can be used to control HIDAPI's installation locations. E.g.:
+		```cmake
+		# enable the installation if you need it
+		set(HIDAPI_INSTALL_TARGETS ON)
+		# (optionally) change default installation locations if it makes sense for your target platform, etc.
+		set(CMAKE_INSTALL_LIBDIR "lib64")
+		add_subdirectory(hidapi)
+		```
+	- HIDAPI prints its version during the configuration when built as a standalone package; to enable this for subdirectory builds - set `HIDAPI_PRINT_VERSION` to TRUE before including HIDAPI;
+
+Available CMake targets after `add_subdirectory(hidapi)` _are the same as in case of [standalone build](#standalone-package-build)_, and a few additional ones:
+- `hidapi_include` - the interface library; `hidapi::hidapi` is an alias of it;
+- `hidapi_winapi` - library target on Windows; `hidapi::winapi` is an alias of it;
+- `hidapi_darwin` - library target on macOS; `hidapi::darwin` is an alias of it;
+- `hidapi_libusb` - library target for libusb backend; `hidapi::libusb` is an alias of it;
+- `hidapi_hidraw` - library target for hidraw backend; `hidapi::hidraw` is an alias of it;
+- `hidapi-libusb` - an alias of `hidapi_libusb` for compatibility with raw library name;
+- `hidapi-hidraw` - an alias of `hidapi_hidraw` for compatibility with raw library name;
+- `hidapi` - an alias of `hidapi_winapi` or `hidapi_darwin` on Windows or macOS respectfully.
+
+Advanced:
+- Why would I need additional targets described in this section above, if I already have alias targets compatible with `find_package`?
+	- an example:
+		```cmake
+		add_subdirectory(hidapi)
+		if(TARGET hidapi_libusb)
+			# see libusb/hid.c for usage of `NO_ICONV`
+			target_compile_definitions(hidapi_libusb PRIVATE NO_ICONV)
+		endif()
+		```