targets/egl-static: allow st/mesa to be dynamically loaded

When shared glapi is not enabled, there are two glapi providers and we
cannot decide which one to link to at build time.  It results in
unresolved symbols in st/mesa.  This commit makes st/mesa a loadable
module when shared glapi is not enabled, and hopes that the apps will
link to one of the glapi providers (GL or GLES).

1 files changed, 109 insertions, 18 deletions

diff --git a/src/gallium/targets/egl-static/egl_st.c b/src/gallium/targets/egl-static/egl_st.c
index 3db5262..81d7bb4 100644
--- a/src/gallium/targets/egl-static/egl_st.c
+++ b/src/gallium/targets/egl-static/egl_st.c
@@ -29,52 +29,143 @@
 #include "state_tracker/st_api.h"
 #include "egl_st.h"
 
-/* for st/mesa */
+#if FEATURE_GL || FEATURE_ES1 || FEATURE_ES2
 #include "state_tracker/st_gl_api.h"
-/* for st/vega */
+#endif
+
+#if FEATURE_VG
 #include "vg_api.h"
+#endif
+
+#if _EGL_EXTERNAL_GL
+
+#include "util/u_string.h"
+#include "util/u_dl.h"
+#include "egldriver.h"
+#include "egllog.h"
+
+static struct util_dl_library *egl_st_gl_lib;
+
+static EGLBoolean
+dlopen_gl_lib_cb(const char *dir, size_t len, void *callback_data)
+{
+   const char *name = (const char *) callback_data;
+   char path[1024];
+   int ret;
+
+   if (len) {
+      ret = util_snprintf(path, sizeof(path), "%.*s/%s" UTIL_DL_EXT,
+            len, dir, name);
+   }
+   else {
+      ret = util_snprintf(path, sizeof(path), "%s" UTIL_DL_EXT, name);
+   }
+
+   if (ret > 0 && ret < sizeof(path)) {
+      egl_st_gl_lib = util_dl_open(path);
+      if (egl_st_gl_lib)
+         _eglLog(_EGL_DEBUG, "loaded %s", path);
+   }
+
+   return !egl_st_gl_lib;
+}
 
 static struct st_api *
-st_GL_create_api(void)
+load_gl(const char *name, const char *procname)
 {
-#if FEATURE_GL || FEATURE_ES1 || FEATURE_ES2
-   return st_gl_api_create();
-#else
-   return NULL;
-#endif
+   struct st_api *(*create_api)(void);
+   struct st_api *stapi = NULL;
+
+   _eglSearchPathForEach(dlopen_gl_lib_cb, (void *) name);
+   if (!egl_st_gl_lib)
+      return NULL;
+
+   create_api = (struct st_api *(*)(void))
+      util_dl_get_proc_address(egl_st_gl_lib, procname);
+   if (create_api)
+      stapi = create_api();
+
+   if (!stapi) {
+      util_dl_close(egl_st_gl_lib);
+      egl_st_gl_lib = NULL;
+   }
+
+   return stapi;
 }
 
 static struct st_api *
-st_OpenVG_create_api(void)
+egl_st_load_gl(void)
 {
-#if FEATURE_VG
-   return (struct st_api *) vg_api_get();
-#else
-   return NULL;
-#endif
+   const char module[] = "st_GL";
+   const char symbol[] = "st_api_create_OpenGL";
+   struct st_api *stapi;
+
+   stapi = load_gl(module, symbol);
+
+   /* try again with libglapi.so loaded */
+   if (!stapi) {
+      struct util_dl_library *glapi = util_dl_open("libglapi" UTIL_DL_EXT);
+
+      if (glapi) {
+         _eglLog(_EGL_DEBUG, "retry with libglapi" UTIL_DL_EXT " loaded");
+
+         stapi = load_gl(module, symbol);
+         util_dl_close(glapi);
+      }
+   }
+   if (!stapi)
+      _eglLog(_EGL_WARNING, "unable to load %s" UTIL_DL_EXT, module);
+
+   return stapi;
 }
 
+#endif /* _EGL_EXTERNAL_GL */
+
 struct st_api *
 egl_st_create_api(enum st_api_type api)
 {
-   struct st_api *stapi;
+   struct st_api *stapi = NULL;
 
    switch (api) {
    case ST_API_OPENGL:
-      stapi = st_GL_create_api();
+#if FEATURE_GL || FEATURE_ES1 || FEATURE_ES2
+#if _EGL_EXTERNAL_GL
+      stapi = egl_st_load_gl();
+#else
+      stapi = st_gl_api_create();
+#endif
+#endif
       break;
    case ST_API_OPENVG:
-      stapi = st_OpenVG_create_api();
+#if FEATURE_VG
+      stapi = (struct st_api *) vg_api_get();
+#endif
       break;
    default:
       assert(!"Unknown API Type\n");
-      stapi = NULL;
       break;
    }
 
    return stapi;
 }
 
+void
+egl_st_destroy_api(struct st_api *stapi)
+{
+#if _EGL_EXTERNAL_GL
+   boolean is_gl = (stapi->api == ST_API_OPENGL);
+
+   stapi->destroy(stapi);
+
+   if (is_gl) {
+      util_dl_close(egl_st_gl_lib);
+      egl_st_gl_lib = NULL;
+   }
+#else
+   stapi->destroy(stapi);
+#endif
+}
+
 uint
 egl_st_get_profile_mask(enum st_api_type api)
 {