Improve CasADi Function interface

Author: tttapa

src/interop/casadi/include/alpaqa/casadi/casadi-external-function.hpp

@@ -24,7 +24,26 @@ namespace casadi {
 /// Designed to match (part of) the `casadi::Function` API.
 class CASADI_LOADER_EXPORT Function {
   public:
+    struct Functions {
+        fname_incref::signature_t *incref             = nullptr;
+        fname_decref::signature_t *decref             = nullptr;
+        fname_n_in::signature_t *n_in                 = nullptr;
+        fname_n_out::signature_t *n_out               = nullptr;
+        fname_name_in::signature_t *name_in           = nullptr;
+        fname_name_out::signature_t *name_out         = nullptr;
+        fname_sparsity_in::signature_t *sparsity_in   = nullptr;
+        fname_sparsity_out::signature_t *sparsity_out = nullptr;
+        fname_alloc_mem::signature_t *alloc_mem       = nullptr;
+        fname_init_mem::signature_t *init_mem         = nullptr;
+        fname_free_mem::signature_t *free_mem         = nullptr;
+        fname_work::signature_t *work                 = nullptr;
+        fname::signature_t *call                      = nullptr;
+    };
+
+  public:
+    Function();
     Function(std::shared_ptr<void> so_handle, const std::string &func_name);
+    Function(const Functions &functions);
     Function(const Function &);
     Function(Function &&) noexcept;
     ~Function();
@@ -80,29 +99,15 @@ class CASADI_LOADER_EXPORT Function {
 
   private:
     std::shared_ptr<void> so_handle;
-    struct Functions {
-        fname_incref::signature_t *incref             = nullptr;
-        fname_decref::signature_t *decref             = nullptr;
-        fname_n_in::signature_t *n_in                 = nullptr;
-        fname_n_out::signature_t *n_out               = nullptr;
-        fname_name_in::signature_t *name_in           = nullptr;
-        fname_name_out::signature_t *name_out         = nullptr;
-        fname_sparsity_in::signature_t *sparsity_in   = nullptr;
-        fname_sparsity_out::signature_t *sparsity_out = nullptr;
-        fname_alloc_mem::signature_t *alloc_mem       = nullptr;
-        fname_init_mem::signature_t *init_mem         = nullptr;
-        fname_free_mem::signature_t *free_mem         = nullptr;
-        fname_work::signature_t *work                 = nullptr;
-        fname::signature_t *call                      = nullptr;
-    } functions;
+    Functions functions;
     struct Work {
         std::vector<const casadi_real *> arg;
         std::vector<casadi_real *> res;
         std::vector<casadi_int> iw;
         std::vector<casadi_real> w;
     };
     std::optional<Work> work;
-    void *mem = nullptr;
+    int mem = 0;
 };
 
 inline std::pair<casadi_int, casadi_int> Function::Sparsity::size() const {

src/interop/casadi/include/alpaqa/casadi/casadi-functions.hpp

@@ -19,11 +19,11 @@ using fname_name_in      = ExternalFunction<"_name_in", const char *(casadi_int
 using fname_name_out     = ExternalFunction<"_name_out", const char *(casadi_int ind)>;
 using fname_sparsity_in  = ExternalFunction<"_sparsity_in", const casadi_int *(casadi_int ind)>;
 using fname_sparsity_out = ExternalFunction<"_sparsity_out", const casadi_int *(casadi_int ind)>;
-using fname_alloc_mem    = ExternalFunction<"_alloc_mem", void *(void)>;
-using fname_init_mem     = ExternalFunction<"_init_mem", int(void *mem)>;
-using fname_free_mem     = ExternalFunction<"_free_mem", int(void *mem)>;
+using fname_alloc_mem    = ExternalFunction<"_alloc_mem", int(void)>;
+using fname_init_mem     = ExternalFunction<"_init_mem", int(int mem)>;
+using fname_free_mem     = ExternalFunction<"_free_mem", void(int mem)>;
 using fname_work         = ExternalFunction<"_work", int(casadi_int *sz_arg, casadi_int *sz_res, casadi_int *sz_iw, casadi_int *sz_w)>;
-using fname              = ExternalFunction<"", int(const casadi_real **arg, casadi_real **res, casadi_int *iw, casadi_real *w, void *mem)>;
+using fname              = ExternalFunction<"", int(const casadi_real **arg, casadi_real **res, casadi_int *iw, casadi_real *w, int mem)>;
 // clang-format on
 
 template <Name Nm, class Sgn>

src/interop/casadi/src/casadi-external-function.cpp

@@ -42,21 +42,27 @@ void Function::init_work() {
     w.w.resize(static_cast<size_t>(sz_w));
 }
 
+Function::Function() = default;
 Function::Function(std::shared_ptr<void> so_handle,
                    const std::string &func_name)
     : so_handle{std::move(so_handle)} {
     load(this->so_handle.get(), func_name);
 }
+static char no_handle;
+Function::Function(const Functions &functions)
+    : so_handle{&no_handle, [](void *) {}}, functions{functions} {
+    functions.incref();
+}
 Function::Function(const Function &o)
     : so_handle{o.so_handle}, functions{o.functions} {
     functions.incref();
 }
 Function::Function(Function &&o) noexcept
     : so_handle{std::move(o.so_handle)}, functions{o.functions},
-      work{std::move(o.work)}, mem{std::exchange(o.mem, nullptr)} {}
+      work{std::move(o.work)}, mem{std::exchange(o.mem, 0)} {}
 Function::~Function() {
     if (so_handle) {
-        if (mem)
+        if (work)
             functions.free_mem(mem);
         functions.decref();
     }