Add start of buffer abstraction code

Signed-off-by: Chris Michael <cp.michael@samsung.com>

src/modules/evas/engines/drm/evas_buffer_manager.c

@@ -0,0 +1,88 @@
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include "evas_engine.h"
+#include <dlfcn.h>
+
+static int _init_count = 0;
+
+/* the actual Manager device returned from init of the library */
+static void *bufmgr;
+
+/* the actual library we successfully dlopen'd */
+static void *libbufmgr;
+
+/* pointers to library functions that we need */
+void *(*libbufmgr_init)(int fd);
+void (*libbufmgr_shutdown)(void *mgr);
+
+//void *(*libbufmgr_buffer_create)(void *mgr);
+
+int 
+evas_buffer_manager_init(void)
+{
+   LOGFN(__FILE__, __LINE__, __FUNCTION__);
+
+   if (++_init_count != 1) return _init_count;
+
+   /* try to dlopen various buffer managers until we find one that works
+    * (libgbm, libtbm, etc)
+    * 
+    * NB: as I am testing this on desktop and do not have libtbm, I am 
+    * just going to code for that. Feel free to hack in libtbm support */
+   libbufmgr = dlopen("libgbm.so", (RTLD_LAZY | RTLD_GLOBAL));
+   if (!libbufmgr) 
+     libbufmgr = dlopen("libgbm.so.1", (RTLD_LAZY | RTLD_GLOBAL));
+   if (!libbufmgr) 
+     libbufmgr = dlopen("libgbm.so.1.0.0", (RTLD_LAZY | RTLD_GLOBAL));
+   if (!libbufmgr) return --_init_count;
+
+   /* with the library found, symlink the functions we need */
+   libbufmgr_init = dlsym(libbufmgr, "gbm_create_device");
+   libbufmgr_shutdown = dlsym(libbufmgr, "gbm_device_destroy");
+
+   return _init_count;
+}
+
+int 
+evas_buffer_manager_shutdown(void)
+{
+   LOGFN(__FILE__, __LINE__, __FUNCTION__);
+
+   if (--_init_count != 0) return _init_count;
+
+   /* call function to shutdown the manager */
+   evas_buffer_manager_close();
+}
+
+Eina_Bool 
+evas_buffer_manager_open(int fd)
+{
+   Eina_Bool ret = EINA_FALSE;
+
+   LOGFN(__FILE__, __LINE__, __FUNCTION__);
+
+   if (bufmgr) return EINA_TRUE;
+
+   /* call any init functions required by the dlsym'd buffer manager */
+   if (libbufmgr_init)
+     {
+        if ((bufmgr = libbufmgr_init(fd)))
+          ret = EINA_TRUE;
+     }
+
+   return ret;
+}
+
+void 
+evas_buffer_manager_close(void)
+{
+   LOGFN(__FILE__, __LINE__, __FUNCTION__);
+
+   /* call any shutdown functions required by the dlsym'd buffer manager */
+   if (libbufmgr_shutdown)
+     libbufmgr_shutdown(bufmgr);
+
+   bufmgr = NULL;
+}