Split the modules and include files between weston and libweston

The backends are now installed in lib/libweston-0, and the include
files that will be used by libweston in include/libweston-0. The other
modules and weston-specific include files are kept in the old paths.
A new wet_load_module() is added to load plugins in the old path,
which is not part of libweston, but weston only and defined in main.c.
To allow that to be used by out of tree weston plugins, the function
is declared in a new weston.h, installed in include/weston.

The -0 in the paths is the abi version of libweston, and it will also
be used by the libweston .so. If the abi changes the number will need
to be increased.

Signed-off-by: Giulio Camuffo <giuliocamuffo@gmail.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

src/compositor.c

@@ -4791,7 +4791,7 @@ weston_load_module(const char *name, const char *entrypoint)
 		if (builddir)
 			snprintf(path, sizeof path, "%s/.libs/%s", builddir, name);
 		else
-			snprintf(path, sizeof path, "%s/%s", MODULEDIR, name);
+			snprintf(path, sizeof path, "%s/%s", LIBWESTON_MODULEDIR, name);
 	} else {
 		snprintf(path, sizeof path, "%s", name);
 	}

src/main.c

@@ -40,12 +40,14 @@
 #include <sys/socket.h>
 #include <libinput.h>
 #include <sys/time.h>
+#include <linux/limits.h>
 
 #ifdef HAVE_LIBUNWIND
 #define UNW_LOCAL_ONLY
 #include <libunwind.h>
 #endif
 
+#include "weston.h"
 #include "compositor.h"
 #include "../shared/os-compatibility.h"
 #include "../shared/helpers.h"
@@ -690,6 +692,49 @@ weston_create_listening_socket(struct wl_display *display, const char *socket_na
 	return 0;
 }
 
+WL_EXPORT void *
+wet_load_module(const char *name, const char *entrypoint)
+{
+	const char *builddir = getenv("WESTON_BUILD_DIR");
+	char path[PATH_MAX];
+	void *module, *init;
+
+	if (name == NULL)
+		return NULL;
+
+	if (name[0] != '/') {
+		if (builddir)
+			snprintf(path, sizeof path, "%s/.libs/%s", builddir, name);
+		else
+			snprintf(path, sizeof path, "%s/%s", MODULEDIR, name);
+	} else {
+		snprintf(path, sizeof path, "%s", name);
+	}
+
+	module = dlopen(path, RTLD_NOW | RTLD_NOLOAD);
+	if (module) {
+		weston_log("Module '%s' already loaded\n", path);
+		dlclose(module);
+		return NULL;
+	}
+
+	weston_log("Loading module '%s'\n", path);
+	module = dlopen(path, RTLD_NOW);
+	if (!module) {
+		weston_log("Failed to load module: %s\n", dlerror());
+		return NULL;
+	}
+
+	init = dlsym(module, entrypoint);
+	if (!init) {
+		weston_log("Failed to lookup init function: %s\n", dlerror());
+		dlclose(module);
+		return NULL;
+	}
+
+	return init;
+}
+
 static int
 load_modules(struct weston_compositor *ec, const char *modules,
 	     int *argc, char *argv[])
@@ -706,7 +751,7 @@ load_modules(struct weston_compositor *ec, const char *modules,
 	while (*p) {
 		end = strchrnul(p, ',');
 		snprintf(buffer, sizeof buffer, "%.*s", (int) (end - p), p);
-		module_init = weston_load_module(buffer, "module_init");
+		module_init = wet_load_module(buffer, "module_init");
 		if (!module_init)
 			return -1;
 		if (module_init(ec, argc, argv) < 0)

src/weston.h

@@ -30,7 +30,7 @@
 extern "C" {
 #endif
 
-#include "compositor.h"
+#include <compositor.h>
 
 void
 screenshooter_create(struct weston_compositor *ec);
@@ -60,6 +60,9 @@ weston_watch_process(struct weston_process *process);
 struct weston_config *
 wet_get_config(struct weston_compositor *compositor);
 
+void *
+wet_load_module(const char *name, const char *entrypoint);
+
 #ifdef  __cplusplus
 }
 #endif

src/weston.pc.in

@@ -9,4 +9,4 @@ Name: Weston Plugin API
 Description: Header files for Weston plugin development
 Version: @WESTON_VERSION@
 Requires.private: wayland-server pixman-1 xkbcommon
-Cflags: -I${includedir}
+Cflags: -I${includedir}/weston -I{includedir}/libweston-@LIBWESTON_ABI_VERSION@