Add basic c library for testing

build.clj

@@ -21,12 +21,15 @@
 
 (def source-dirs ["src/"])
 
+(def c-test-dirs ["test/c/"])
+
 (def target-dir "target/")
 (def class-dir (str target-dir "classes/"))
 
 (def basis (b/create-basis {:project "deps.edn"}))
 
 (def jar-file (str target-dir "coffi.jar"))
+(def test-c-library (str target-dir "ffi_test.so"))
 
 (defn clean
   "Deletes the `target/` directory."
@@ -76,6 +79,20 @@
             :jar-file jar-file}))
   opts)
 
+(defn compile-test-library
+  "Compiles the C test code for running the tests."
+  [opts]
+  (let [c-files (->> c-test-dirs
+                     (map io/file)
+                     (mapcat file-seq)
+                     (filter #(.isFile %))
+                     (map #(.getAbsolutePath %)))]
+    (.mkdirs (io/file target-dir))
+    (b/process {:command-args (concat ["clang" "-fpic" "-shared"]
+                                      c-files
+                                      ["-o" test-c-library])}))
+  opts)
+
 (defn run-tasks
   "Runs a series of tasks with a set of options.
   The `:tasks` key is a list of symbols of other task names to call. The rest of

test/c/ffi_test.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+
+typedef struct point {
+    float x;
+    float y;
+} Point;
+
+Point add_points(Point a, Point b) {
+    Point res = {};
+
+    res.x = a.x + b.x;
+    res.y = a.y + b.y;
+
+    return res;
+}
+
+typedef char *CString;
+
+typedef CString (*StringFactory)(void);
+
+void upcall_test(StringFactory fun) {
+    return fun();
+}
+
+static int counter = 0;
+
+static char* responses[] = { "Hello, world!", "Goodbye friend.", "co'oi prenu" };
+
+CString get_string1(void) {
+    return responses[counter++ % 3];
+}
+
+CString get_string2(void) {
+    return "Alternate string";
+}
+
+StringFactory get_downcall(int whichString) {
+    switch (whichString % 2) {
+    case 0:
+        return get_string1;
+    case 1:
+        return get_string2;
+    default:
+        return 0;
+    }
+}