Reordering FFI libs

utils/utils.rkt

@@ -1,8 +1,15 @@
 (module utils racket/base
 
+  (require racket/path
+           racket/runtime-path
+           ffi/unsafe
+           setup/dirs
+           )
+  
   (provide while
            until
-           get-lib-path
+           build-lib-path
+           get-lib
            do-for
            )
 
@@ -47,23 +54,27 @@
                                          (do-for-f))))))
            (do-for-f))))))
 
-  (define (get-lib-path lib)
-    (let ((platform (system-type)))
-      (cond
-        [(eq? platform 'windows) 
-         (let ((try1 (build-path (current-directory) ".." "lib" "dll" lib))
-               (try2 (build-path (current-directory) "lib" "dll" lib)))
-           (if (file-exists? try1)
-               try1
-               try2)
-           )]
-        [(eq? platform 'unix)
-         (let ((try1 (build-path (current-directory) "lib" lib)))
-           (when (file-exists? try1)
-             try1))]
-        [else
-         (error (format "Install the shared library: ~a" lib))]
-        )))
-                              
 
+  (define-runtime-path lib-path "..")
+
+  (define (build-lib-path)
+    (let ((os-type (system-type 'os*)))
+      (if (eq? os-type 'windows)
+          (build-path lib-path "lib" "dll")
+          (let* ((arch (symbol->string (system-type 'arch)))
+                 (subdir (string-append (symbol->string os-type) "-" arch)))
+            (let ((path (build-path lib-path "lib" subdir)))
+              path)))))
+
+  (define (get-lib* libs-to-try orig-libs versions)
+    (if (null? libs-to-try)
+        (error (format "Cannot find library, tried ~a" orig-libs)) 
+        (ffi-lib (car libs-to-try) versions
+                 #:get-lib-dirs (λ () (cons (build-lib-path) (get-lib-search-dirs)))
+                 #:fail (λ () (get-lib* (cdr libs-to-try) orig-libs versions))
+                 )))
+
+  (define (get-lib libs-to-try versions)
+    (get-lib* libs-to-try libs-to-try versions))
+  
   ) ; end of module