Implement device IO as a shared library

Provide make targets and build configuration to create a shared object
for other systems/applications to use to control keyboard LEDs without
 the need for instantiating the g810-led process.

Provide make targets for installing library and development files into
environments, such as the current system or package builders.

Currently preserves precious behavior of building g810-led binary as
statically linked. Provides an alternative build target of "bin-linked"
which will create a dynamically linked variant.

Signed-off-by: Kevin Pearson <pearson.kevin.m@gmail.com>

.gitignore

@@ -1,3 +1,4 @@
 g810-led.*
 bin/*
+lib/*
 .

CONTRIBUTORS.md

@@ -45,5 +45,8 @@
 * Add wireshark dump effects
 * Improve makefile
 
+## [pearsonk](https://github.com/pearsonk) :
+* Implement underlying device IO as a shared library
+
 ## [wextia](https://github.com/wextia) :
 * Fixed incorrect markdown formatting in README.md

INSTALL.md

@@ -38,6 +38,14 @@ Fedora :</br>
 `make` # for hidapi</br>
 `make LIB=libusb` # for libusb</br>
 `sudo make install`</br>
+`make install-lib` to install the libg810-led library.</br>
+`make install-dev` to install the libg810-led library and headers for development.</br>
+
+## Building the library :</br>
+The library is built by default when running the `make` (default target "all").</br>
+
+To specifically build the library as a standalone component: </br>
+`make lib`</br>
 
 ## Update :</br>
 Same as install, but your profile and reboot files are preserved.</br>

README.md

@@ -56,3 +56,13 @@ Linux led controller for Logitech G410, G610, G810 and G910 Keyboards.</br>
 ## Samples with pipe (for effects) :</br>
 `g810-led -pp < profilefile # Load a profile`</br>
 `echo -e "k w ff0000\nk a ff0000\nk s ff0000\nk d ff0000\nc" | g810-led -pp # Set multiple keys`</br>
+
+## Building and linking against the libg810-led library :</br>
+Include in implementing source files.</br>
+```cpp
+#include <g810-led/Keyboard.h>
+```
+To link, simply provide `-lg810-led` to the build flags.</br>
+
+To build the g810-led application as a dynamically-linked variant, run the target:</br>
+`make bin-linked`</br>

makefile

@@ -8,22 +8,46 @@ else
 	CPPFLAGS=-Dhidapi
 	LDFLAGS=-lhidapi-hidraw
 endif
-PROGN=g810-led
 SYSTEMDDIR?=/usr/lib/systemd
 
-.PHONY: all debug clean setup install uninstall
+prefix?=$(DESTDIR)/usr
+libdir?=$(prefix)/lib
+includedir?=$(prefix)/include
 
-all: bin/$(PROGN)
+# Program & versioning information
+PROGN=g810-led
+MAJOR=0
+MINOR=1
+MICRO=6
 
-bin/$(PROGN): src/main.cpp src/helpers/*.cpp src/helpers/*.h src/classes/*.cpp src/classes/*.h
+APPSRCS=src/main.cpp src/helpers/*.cpp src/helpers/*.h
+LIBSRCS=src/classes/*.cpp src/classes/*.h
+
+.PHONY: all debug clean setup install uninstall lib install-lib install-dev
+
+all: lib/lib$(PROGN).so bin/$(PROGN)
+
+bin/$(PROGN): $(APPSRCS) $(LIBSRCS)
 	@mkdir -p bin
 	$(CC) $(CPPFLAGS) $(CFLAGS) $^ -o $@ $(LDFLAGS)
 	
 debug: CFLAGS += -g -Wextra -pedantic
 debug: bin/$(PROGN)
 
+lib/lib$(PROGN).so: $(LIBSRCS)
+	@mkdir -p lib
+	$(CC) $(CPPFLAGS) $(CFLAGS) -fPIC -shared -Wl,-soname,lib$(PROGN).so -o lib/lib$(PROGN).so.$(MAJOR).$(MINOR).$(MICRO) $^ $(LDFLAGS)
+	@ln -sf lib$(PROGN).so.$(MAJOR).$(MINOR).$(MICRO) lib/lib$(PROGN).so
+
+bin-linked: lib/lib$(PROGN).so
+	@mkdir -p bin
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(APPSRCS) -o bin/$(PROGN) $(LDFLAGS) -L./lib -l$(PROGN)
+
+lib: lib/lib$(PROGN).so
+
 clean:
 	@rm -rf bin
+	@rm -rf lib
 
 setup:
 	@install -m 755 -d \
@@ -41,6 +65,15 @@ setup:
 		cp systemd/$(PROGN).service $(DESTDIR)$(SYSTEMDDIR)/system && \
 		cp systemd/$(PROGN)-reboot.service $(DESTDIR)$(SYSTEMDDIR)/system
 
+install-lib: lib
+	@install -m 755 -d $(libdir)
+	@install -m 644 lib/lib$(PROGN).so.$(MAJOR).$(MINOR).$(MICRO) $(libdir)/
+	@ln -sf lib$(PROGN).so.$(MAJOR).$(MINOR).$(MICRO) $(libdir)/lib$(PROGN).so
+
+install-dev: install-lib
+	@mkdir -p $(includedir)/$(PROGN)/
+	@install -m 644 src/classes/*.h $(includedir)/$(PROGN)
+
 install: setup
 	@test -s /etc/$(PROGN)/profile || \
 		cp /etc/$(PROGN)/samples/group_keys /etc/$(PROGN)/profile
@@ -53,6 +86,12 @@ install: setup
 		systemctl enable $(PROGN) && \
 		systemctl enable $(PROGN)-reboot
 
+uninstall-lib:
+	@rm -f $(libdir)/lib$(PROGN).so*
+
+uninstall-dev:
+	@rm -rf $(includedir)/$(PROGN)
+
 uninstall:
 	@test -s /usr/bin/systemd-run && \
 		systemctl disable $(PROGN) && \