From ab6f23fdf2700b879b3c204e7792e9faf81d1d59 Mon Sep 17 00:00:00 2001
From: Dan Pashin <danypashin@yandex.ru>
Date: Fri, 14 Jun 2024 11:14:16 +0300
Subject: [PATCH] Fix possible bug when allocator in FFI is not malloc when
 requesting packages

---
 .../Twackup/Sources/FFI Models/Dpkg.swift     |  2 +-
 twackup/src/ffi/c_dpkg.rs                     |  4 ++--
 twackup/src/ffi/mod.rs                        | 19 ++++++++++++++++++-
 3 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/twackup-gui/Twackup/Sources/FFI Models/Dpkg.swift b/twackup-gui/Twackup/Sources/FFI Models/Dpkg.swift
index 4d253f3..afcd42d 100644
--- a/twackup-gui/Twackup/Sources/FFI Models/Dpkg.swift	
+++ b/twackup-gui/Twackup/Sources/FFI Models/Dpkg.swift	
@@ -56,7 +56,7 @@ actor Dpkg {
         let count = tw_get_packages(innerDpkg, onlyLeaves, TW_PACKAGES_SORT_NAME.clampedToU8, &packagesPtr)
 
         let buffer = UnsafeBufferPointer(start: packagesPtr, count: Int(count))
-        defer { buffer.deallocate() }
+        defer { tw_free_packages(packagesPtr, count) }
 
         return buffer.compactMap { package in
             let model = FFIPackage(package)
diff --git a/twackup/src/ffi/c_dpkg.rs b/twackup/src/ffi/c_dpkg.rs
index a54c36b..6180370 100644
--- a/twackup/src/ffi/c_dpkg.rs
+++ b/twackup/src/ffi/c_dpkg.rs
@@ -91,10 +91,10 @@ impl TwDpkg {
         let packages: Option<Vec<_>> = tokio_rt.block_on(async {
             if sort == TwPackagesSort::Unsorted {
                 let packages = dpkg.unsorted_packages(leaves_only).await.ok()?;
-                Some(packages.into_iter().map(TwPackage::from).collect())
+                Some(packages.into_iter().map(Into::into).collect())
             } else {
                 let packages = dpkg.packages(leaves_only, sort.into()).await.ok()?;
-                Some(packages.into_values().map(TwPackage::from).collect())
+                Some(packages.into_values().map(Into::into).collect())
             }
         });
 
diff --git a/twackup/src/ffi/mod.rs b/twackup/src/ffi/mod.rs
index 8f9b8a9..9d9193a 100644
--- a/twackup/src/ffi/mod.rs
+++ b/twackup/src/ffi/mod.rs
@@ -37,7 +37,7 @@ use crate::{
     Dpkg,
 };
 use safer_ffi::{boxed, derive_ReprC, ffi_export, prelude::c_slice, prelude::char_p};
-use std::{mem, mem::ManuallyDrop, ptr::NonNull};
+use std::{mem, mem::ManuallyDrop, ptr::NonNull, slice};
 
 #[derive_ReprC]
 #[repr(i8)]
@@ -82,6 +82,15 @@ fn tw_get_packages(
     if let Some(packages) = dpkg.get_packages(leaves_only, sort) {
         let packages = ManuallyDrop::new(packages);
 
+        // Since memory allocators for Rust and outer FFI callee can be different
+        // we must release slice by ourselves
+        //
+        // To do that, slice must have valid length and layout
+        // Releasing func will decrement counter on ARC, so we need to increase it here
+        for package in packages.as_slice() {
+            package.inner.retain();
+        }
+
         let packages_ptr = packages.as_ptr().cast_mut();
         unsafe { output.write(NonNull::new_unchecked(packages_ptr)) };
 
@@ -91,6 +100,14 @@ fn tw_get_packages(
     }
 }
 
+#[ffi_export]
+fn tw_free_packages(mut start: NonNull<TwPackage>, length: i64) {
+    unsafe {
+        let packages = slice::from_raw_parts_mut(start.as_mut(), length as usize);
+        drop(Box::from_raw(packages))
+    }
+}
+
 /// Returns package section description
 ///
 /// \param[in] package package instance