From 648348bd380170c36b0204bb4b1f4c16992e8710 Mon Sep 17 00:00:00 2001
From: Soispha <soispha@vhack.eu>
Date: Sun, 24 Mar 2024 21:11:58 +0100
Subject: [PATCH] fix(types): Improve support for generic rust types

The support might be improved, but I still sort of want to remove
generic types, as the current implementation is just _bad_.
---
 trixy-types/src/traits/convert_trait.rs | 70 ++++++++++++++++++-------
 trixy-types/src/types_list.rs           |  2 +
 2 files changed, 52 insertions(+), 20 deletions(-)

diff --git a/trixy-types/src/traits/convert_trait.rs b/trixy-types/src/traits/convert_trait.rs
index 8971e18..1521911 100644
--- a/trixy-types/src/traits/convert_trait.rs
+++ b/trixy-types/src/traits/convert_trait.rs
@@ -129,12 +129,11 @@ pub extern "C" fn string_free(ptr: *const c_char) {
 }
 
 impl<T: Convertible> Convertible for Option<T> {
-    type Ptr = *const T;
+    type Ptr = *const <T as Convertible>::Ptr;
 
     fn into_ptr(self) -> Self::Ptr {
         if let Some(inner) = self {
-            let mut_ref = &mut inner.into_ptr();
-            mut_ref as *mut _ as *const T
+            &inner.into_ptr()
         } else {
             ptr::null()
         }
@@ -153,14 +152,11 @@ impl<T: Convertible> Convertible for Option<T> {
 }
 
 impl<T: Convertible, E: Error> Convertible for Result<T, E> {
-    type Ptr = *const T;
+    type Ptr = *const <T as Convertible>::Ptr;
 
     fn into_ptr(self) -> Self::Ptr {
         match self {
-            Ok(ok) => {
-                let mut_ref = &mut ok.into_ptr();
-                mut_ref as *mut _ as *const T
-            }
+            Ok(ok) => &ok.into_ptr(),
             Err(err) => {
                 errno::set(TypeConversionError::ResultWasErr {
                     original_message: err.to_string(),
@@ -183,15 +179,16 @@ impl<T: Convertible, E: Error> Convertible for Result<T, E> {
     }
 }
 
-impl<T> Convertible for Vec<T> {
-    type Ptr = crate::Vec<T>;
+impl<T: Convertible> Convertible for Vec<T> {
+    type Ptr = crate::Vec<<T as Convertible>::Ptr>;
 
     fn into_ptr(self) -> Self::Ptr {
-        let mut me = ManuallyDrop::new(self);
+        let data_vec: Vec<_> = self.into_iter().map(|val| val.into_ptr()).collect();
+        let data_vec = ManuallyDrop::new(data_vec);
         Self::Ptr {
-            data: me.as_mut_ptr() as *const T,
-            length: me.len(),
-            capacity: me.capacity(),
+            data: data_vec.as_ptr(),
+            length: data_vec.len(),
+            capacity: data_vec.capacity(),
         }
     }
 
@@ -203,18 +200,51 @@ impl<T> Convertible for Vec<T> {
         // if !ptr.data.is_aligned() {
         //     return Err(TypeConversionError::NotAligned);
         // }
-        let vec = unsafe {
+        let base_vec = unsafe {
             // SAFETY:
             // We simply hope that c treated our vector as read-only and didn't modify it.
             // See the SAFETY section of the String implementation for more detail.
-            Vec::from_raw_parts(ptr.data as *mut T, ptr.length, ptr.capacity)
+            Vec::from_raw_parts(
+                ptr.data as *mut <T as Convertible>::Ptr,
+                ptr.length,
+                ptr.capacity,
+            )
         };
+
+        let vec: Vec<_> = base_vec
+            .into_iter()
+            .map(|val| <T as Convertible>::from_ptr(val))
+            .collect::<Result<Vec<_>, _>>()?;
         Ok(vec)
     }
 }
 
-// FIXME(@soispha): Add the required generic support here <2024-02-18>
-#[no_mangle]
-pub extern "C" fn vec_free(ptr: crate::Vec<u8>) {
-    Vec::drop_ptr(ptr);
+macro_rules! make_vec_free {
+    ($value:ident, $name:ident) => {
+        #[no_mangle]
+        pub extern "C" fn $name(ptr: crate::Vec<<$value as Convertible>::Ptr>) {
+            Vec::<$value>::drop_ptr(ptr);
+        }
+    };
 }
+
+// Unsigned
+make_vec_free!(u8, vec_free_u8);
+make_vec_free!(u16, vec_free_u16);
+make_vec_free!(u32, vec_free_u32);
+make_vec_free!(u64, vec_free_u64);
+// Signed
+make_vec_free!(i8, vec_free_i8);
+make_vec_free!(i16, vec_free_i16);
+make_vec_free!(i32, vec_free_i32);
+make_vec_free!(i64, vec_free_i64);
+// Float
+make_vec_free!(f32, vec_free_f32);
+make_vec_free!(f64, vec_free_f64);
+// Other
+make_vec_free!(String, vec_free_String);
+
+// FIXME(@soispha): Find a way to support these <2024-02-27>
+// make_vec_free!(Option<?>, vec_free_Option);
+// make_vec_free!(Vec<?>, vec_free_Vec);
+// make_vec_free!(Result<?, ?>, vec_free_Result);
diff --git a/trixy-types/src/types_list.rs b/trixy-types/src/types_list.rs
index e4695d2..bdbd680 100644
--- a/trixy-types/src/types_list.rs
+++ b/trixy-types/src/types_list.rs
@@ -22,6 +22,8 @@
 // NOTE(@soispha): All types specified here *MUST* be include in the BASE_TYPES constant, otherwise
 // they are not usable from Trixy code <2023-12-25>
 
+// NOTE(@soispha): All types added here must also have an added free impl for the vector type (./traits/convert_trait.rs) <2024-02-27>
+
 use std::ffi::c_char;
 
 #[derive(Debug, Clone)]