chore(nim-bindings): replace dynlib dlopen with plain importc

.cargo/config.toml

@@ -0,0 +1,7 @@
+[env]
+# Pin the macOS deployment target so vendored C/C++ builds (SQLCipher, OpenSSL)
+# compile with the same minimum version as the Nim linker expects.
+# Without this, the host SDK version is used (currently 15.5), causing
+# "was built for newer macOS version" linker warnings.
+# This is caused by nimble and cargo defaulting to different targets.
+MACOSX_DEPLOYMENT_TARGET = { value = "15.0", force = false }

.github/workflows/ci.yml

@@ -2,11 +2,11 @@ name: CI
 
 on:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
-    branches: [ main ]
+    branches: [main]
 
-env: 
+env:
   CARGO_TERM_COLOR: always
 
 jobs:
@@ -36,3 +36,21 @@ jobs:
       - run: rustup update stable && rustup default stable
       - run: rustup component add rustfmt
       - run: cargo fmt --all -- --check
+
+  nim-bindings-test:
+    name: Nim Bindings Test
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+    steps:
+      - uses: actions/checkout@v4
+      - run: rustup update stable && rustup default stable
+      - name: Install Nim via choosenim
+        run: |
+          curl https://nim-lang.org/choosenim/init.sh -sSf | sh -s -- -y
+          echo "$HOME/.nimble/bin" >> $GITHUB_PATH
+      - run: nimble install -dy
+        working-directory: nim-bindings
+      - run: nimble pingpong
+        working-directory: nim-bindings

conversations/src/api.rs

@@ -55,9 +55,12 @@ pub fn create_context(name: repr_c::String) -> repr_c::Box<ContextHandle> {
 }
 
 /// Returns the friendly name of the contexts installation.
+///
+/// # ABI note
+/// The result is written through `out` (Nim's calling convention for large struct returns).
 #[ffi_export]
-pub fn installation_name(ctx: &ContextHandle) -> repr_c::String {
-    ctx.0.installation_name().to_string().into()
+pub fn installation_name(ctx: &ContextHandle, out: &mut repr_c::String) {
+    *out = ctx.0.installation_name().to_string().into();
 }
 
 /// Destroys a conversation store and frees its memory
@@ -74,11 +77,13 @@ pub fn destroy_context(ctx: repr_c::Box<ContextHandle>) {
 /// Creates an intro bundle for sharing with other users
 ///
 /// # Returns
-/// Returns the number of bytes written to bundle_out
 /// Check error_code field: 0 means success, negative values indicate errors (see ErrorCode).
+///
+/// # ABI note
+/// The result is written through `out` (Nim's calling convention for large struct returns).
 #[ffi_export]
-pub fn create_intro_bundle(ctx: &mut ContextHandle) -> CreateIntroResult {
-    match ctx.0.create_intro_bundle() {
+pub fn create_intro_bundle(ctx: &mut ContextHandle, out: &mut CreateIntroResult) {
+    *out = match ctx.0.create_intro_bundle() {
         Ok(v) => CreateIntroResult {
             error_code: ErrorCode::None as i32,
             intro_bytes: v.into(),
@@ -87,27 +92,32 @@ pub fn create_intro_bundle(ctx: &mut ContextHandle) -> CreateIntroResult {
             error_code: ErrorCode::UnknownError as i32,
             intro_bytes: repr_c::Vec::EMPTY,
         },
-    }
+    };
 }
 
 /// Creates a new private conversation
 ///
 /// # Returns
 /// Returns a struct with payloads that must be sent, the conversation_id that was created.
 /// The NewConvoResult must be freed.
+///
+/// # ABI note
+/// The result is written through `out` (Nim's calling convention for large struct returns).
 #[ffi_export]
 pub fn create_new_private_convo(
     ctx: &mut ContextHandle,
     bundle: c_slice::Ref<'_, u8>,
     content: c_slice::Ref<'_, u8>,
-) -> NewConvoResult {
+    out: &mut NewConvoResult,
+) {
     // Convert input bundle to Introduction
     let Ok(intro) = Introduction::try_from(bundle.as_slice()) else {
-        return NewConvoResult {
+        *out = NewConvoResult {
             error_code: ErrorCode::BadIntro as i32,
             convo_id: "".into(),
             payloads: Vec::new().into(),
         };
+        return;
     };
 
     // Create conversation
@@ -122,31 +132,36 @@ pub fn create_new_private_convo(
         })
         .collect();
 
-    NewConvoResult {
+    *out = NewConvoResult {
         error_code: 0,
         convo_id: convo_id.to_string().into(),
         payloads: ffi_payloads.into(),
-    }
+    };
 }
 
 /// Sends content to an existing conversation
 ///
 /// # Returns
 /// Returns a PayloadResult with payloads that must be delivered to participants.
 /// Check error_code field: 0 means success, negative values indicate errors (see ErrorCode).
+///
+/// # ABI note
+/// The result is written through `out` (Nim's calling convention for large struct returns).
 #[ffi_export]
 pub fn send_content(
     ctx: &mut ContextHandle,
     convo_id: repr_c::String,
     content: c_slice::Ref<'_, u8>,
-) -> SendContentResult {
+    out: &mut SendContentResult,
+) {
     let payloads = match ctx.0.send_content(&convo_id, &content) {
         Ok(p) => p,
         Err(_) => {
-            return SendContentResult {
+            *out = SendContentResult {
                 error_code: ErrorCode::UnknownError as i32,
                 payloads: safer_ffi::Vec::EMPTY,
             };
+            return;
         }
     };
 
@@ -158,10 +173,10 @@ pub fn send_content(
         })
         .collect();
 
-    SendContentResult {
+    *out = SendContentResult {
         error_code: 0,
         payloads: ffi_payloads.into(),
-    }
+    };
 }
 
 /// Handles an incoming payload
@@ -170,15 +185,19 @@ pub fn send_content(
 /// Returns HandlePayloadResult
 /// This call does not always generate content. If data is zero bytes long then there
 /// is no data, and the converation_id should be ignored.
+///
+/// # ABI note
+/// The result is written through `out` (Nim's calling convention for large struct returns).
 #[ffi_export]
 pub fn handle_payload(
     ctx: &mut ContextHandle,
     payload: c_slice::Ref<'_, u8>,
-) -> HandlePayloadResult {
-    match ctx.0.handle_payload(&payload) {
+    out: &mut HandlePayloadResult,
+) {
+    *out = match ctx.0.handle_payload(&payload) {
         Ok(o) => o.into(),
         Err(e) => e.into(),
-    }
+    };
 }
 
 // ------------------------------------------
@@ -195,9 +214,13 @@ pub struct CreateIntroResult {
 }
 
 /// Free the result from create_intro_bundle
+///
+/// # ABI note
+/// Takes `&mut` instead of ownership because Nim always passes large structs as a pointer;
+/// accepting the struct by value would be an ABI mismatch on the caller side.
 #[ffi_export]
-pub fn destroy_intro_result(result: CreateIntroResult) {
-    drop(result);
+pub fn destroy_intro_result(result: &mut CreateIntroResult) {
+    unsafe { std::ptr::drop_in_place(result) }
 }
 
 /// Payload structure for FFI
@@ -219,9 +242,13 @@ pub struct SendContentResult {
 }
 
 /// Free the result from send_content
+///
+/// # ABI note
+/// Takes `&mut` instead of ownership because Nim always passes large structs as a pointer;
+/// accepting the struct by value would be an ABI mismatch on the caller side.
 #[ffi_export]
-pub fn destroy_send_content_result(result: SendContentResult) {
-    drop(result);
+pub fn destroy_send_content_result(result: &mut SendContentResult) {
+    unsafe { std::ptr::drop_in_place(result) }
 }
 
 /// Result structure for handle_payload
@@ -237,9 +264,13 @@ pub struct HandlePayloadResult {
 }
 
 /// Free the result from handle_payload
+///
+/// # ABI note
+/// Takes `&mut` instead of ownership because Nim always passes large structs as a pointer;
+/// accepting the struct by value would be an ABI mismatch on the caller side.
 #[ffi_export]
-pub fn destroy_handle_payload_result(result: HandlePayloadResult) {
-    drop(result);
+pub fn destroy_handle_payload_result(result: &mut HandlePayloadResult) {
+    unsafe { std::ptr::drop_in_place(result) }
 }
 
 impl From<ContentData> for HandlePayloadResult {
@@ -291,7 +322,11 @@ pub struct NewConvoResult {
 }
 
 /// Free the result from create_new_private_convo
+///
+/// # ABI note
+/// Takes `&mut` instead of ownership because Nim always passes large structs as a pointer;
+/// accepting the struct by value would be an ABI mismatch on the caller side.
 #[ffi_export]
-pub fn destroy_convo_result(result: NewConvoResult) {
-    drop(result);
+pub fn destroy_convo_result(result: &mut NewConvoResult) {
+    unsafe { std::ptr::drop_in_place(result) }
 }

conversations/src/lib.rs

@@ -25,21 +25,36 @@ mod tests {
         let mut raya = create_context("raya".into());
 
         // Raya Creates Bundle and Sends to Saro
-        let intro_result = create_intro_bundle(&mut raya);
+        let mut intro_result = CreateIntroResult {
+            error_code: -99,
+            intro_bytes: safer_ffi::Vec::EMPTY,
+        };
+        create_intro_bundle(&mut raya, &mut intro_result);
         assert!(is_ok(intro_result.error_code));
 
         let raya_bundle = intro_result.intro_bytes.as_ref();
 
         // Saro creates a new conversation with Raya
         let content: &[u8] = "hello".as_bytes();
 
-        let convo_result = create_new_private_convo(&mut saro, raya_bundle, content.into());
+        let mut convo_result = NewConvoResult {
+            error_code: -99,
+            convo_id: "".into(),
+            payloads: safer_ffi::Vec::EMPTY,
+        };
+        create_new_private_convo(&mut saro, raya_bundle, content.into(), &mut convo_result);
         assert!(is_ok(convo_result.error_code));
 
         // Raya recieves initial message
         let payload = convo_result.payloads.first().unwrap();
 
-        let handle_result = handle_payload(&mut raya, payload.data.as_ref());
+        let mut handle_result: HandlePayloadResult = HandlePayloadResult {
+            error_code: -99,
+            convo_id: "".into(),
+            content: safer_ffi::Vec::EMPTY,
+            is_new_convo: false,
+        };
+        handle_payload(&mut raya, payload.data.as_ref(), &mut handle_result);
         assert!(is_ok(handle_result.error_code));
 
         // Check that the Content sent was the content received

nim-bindings/conversations_example.nimble

@@ -13,9 +13,14 @@ bin           = @["libchat"]
 requires "nim >= 2.2.4"
 requires "results"
 
+proc buildRust() =
+  exec "cargo build --release --manifest-path ../Cargo.toml"
+
+
 # Build Rust library before compiling Nim
 before build:
-  exec "cargo build --release --manifest-path ../Cargo.toml"
+  buildRust()
 
 task pingpong, "Run pingpong example":
-  exec "nim c -r --path:src examples/pingpong.nim"
+  buildRust()
+  exec "nim c -r --path:src --passL:../target/release/liblibchat.a --passL:-lm examples/pingpong.nim"