Move some code

src/libutil/rust-ffi.cc

@@ -19,4 +19,15 @@ std::ostream & operator << (std::ostream & str, const String & s)
     return str;
 }
 
+size_t Source::sourceWrapper(void * _this, rust::Slice<uint8_t> data)
+{
+    try {
+        // FIXME: how to propagate exceptions?
+        auto n = ((nix::Source *) _this)->read((unsigned char *) data.ptr, data.size);
+        return n;
+    } catch (...) {
+        abort();
+    }
+}
+
 }

src/libutil/rust-ffi.hh

@@ -140,12 +140,7 @@ struct Source
         : fun(sourceWrapper), _this(&_this)
     {}
 
-    // FIXME: how to propagate exceptions?
+    static size_t sourceWrapper(void * _this, rust::Slice<uint8_t> data);
-    static size_t sourceWrapper(void * _this, rust::Slice<uint8_t> data)
-    {
-        auto n = ((nix::Source *) _this)->read((unsigned char *) data.ptr, data.size);
-        return n;
-    }
 };
 
 /* C++ representation of Rust's Result<T, CppException>. */