Work towards removing malloc_buf

.github/workflows/ci.yml

@@ -51,7 +51,7 @@ env:
   #
   # Note: The `exception` feature is not enabled here, since it requires
   # compiling C code, even if just running a `check`/`clippy` build.
-  INTERESTING_FEATURES: malloc,block,verify,unstable-private
+  INTERESTING_FEATURES: malloc,block,unstable-private
   UNSTABLE_FEATURES: unstable-autoreleasesafe,unstable-c-unwind
   LATEST_MACOS_FEATURE: unstable-frameworks-macos-14
   # Required when we want to use a different runtime than the default `apple`

crates/objc-sys/CHANGELOG.md

@@ -6,6 +6,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## Unreleased - YYYY-MM-DD
 
+### Added
+* Added `free` method (same as `libc::free`).
+
 
 ## 0.3.2 - 2023-12-03
 

crates/objc-sys/src/class.rs

@@ -53,6 +53,7 @@ extern_c! {
     pub fn objc_lookUpClass(name: *const c_char) -> *const objc_class;
     #[cfg(any(doc, not(objfw)))]
     pub fn objc_getMetaClass(name: *const c_char) -> *const objc_class;
+    /// The returned array is deallocated with [`free`][crate::free].
     pub fn objc_copyClassList(out_len: *mut c_uint) -> *mut *const objc_class;
     pub fn objc_getClassList(buffer: *mut *const objc_class, buffer_len: c_int) -> c_int;
 
@@ -98,21 +99,25 @@ extern_c! {
         -> BOOL;
 
     #[cfg(any(doc, not(objfw)))] // Available in newer versions
+    /// The return value is deallocated with [`free`][crate::free].
     pub fn class_copyIvarList(
         cls: *const objc_class,
         out_len: *mut c_uint,
     ) -> *mut *const objc_ivar;
     #[cfg(any(doc, not(objfw)))] // Available in newer versions
+    /// The returned array is deallocated with [`free`][crate::free].
     pub fn class_copyMethodList(
         cls: *const objc_class,
         out_len: *mut c_uint,
     ) -> *mut *const objc_method;
     #[cfg(any(doc, not(objfw)))] // Available in newer versions
+    /// The returned array is deallocated with [`free`][crate::free].
     pub fn class_copyPropertyList(
         cls: *const objc_class,
         out_len: *mut c_uint,
     ) -> *mut *const objc_property;
     #[cfg(any(doc, not(objfw)))]
+    /// The returned array is deallocated with [`free`][crate::free].
     pub fn class_copyProtocolList(
         cls: *const objc_class,
         out_len: *mut c_uint,

crates/objc-sys/src/lib.rs

@@ -142,9 +142,9 @@ macro_rules! extern_c_unwind {
 
 mod class;
 mod constants;
-
 mod exception;
 mod image_info;
+mod libc;
 mod message;
 mod method;
 mod object;
@@ -155,19 +155,20 @@ mod selector;
 mod types;
 mod various;
 
-pub use class::*;
-pub use constants::*;
-pub use exception::*;
-pub use image_info::*;
-pub use message::*;
-pub use method::*;
-pub use object::*;
-pub use property::*;
-pub use protocol::*;
-pub use rc::*;
-pub use selector::*;
-pub use types::*;
-pub use various::*;
+pub use self::class::*;
+pub use self::constants::*;
+pub use self::exception::*;
+pub use self::image_info::*;
+pub use self::libc::*;
+pub use self::message::*;
+pub use self::method::*;
+pub use self::object::*;
+pub use self::property::*;
+pub use self::protocol::*;
+pub use self::rc::*;
+pub use self::selector::*;
+pub use self::types::*;
+pub use self::various::*;
 
 /// We don't know much about the actual structs, so better mark them `!Send`,
 /// `!Sync`, `!UnwindSafe`, `!RefUnwindSafe`, `!Unpin` and as mutable behind

crates/objc-sys/src/libc.rs

@@ -0,0 +1,19 @@
+use core::ffi::c_void;
+
+// SAFETY: The signatures in here are the exact same as in `libc`.
+extern_c! {
+    /// The Objective-C runtime has several methods, usually with "`copy`" in
+    /// their name, whose return value is allocated with C's `malloc` and
+    /// deallocated with C's `free` method.
+    ///
+    /// As such, `free` is actually also part of the Objective-C runtime.
+    ///
+    /// We expose this instead of using [`libc::free`], to avoid having `libc`
+    /// as a dependency.
+    ///
+    /// [`libc::free`]: https://docs.rs/libc/latest/libc/fn.free.html
+    //
+    // Note: This is linked automatically by either `std` or transitively by
+    // `libobjc`.
+    pub fn free(p: *mut c_void);
+}

crates/objc-sys/src/method.rs

@@ -25,8 +25,10 @@ pub struct objc_method_description {
 
 extern_c! {
     #[cfg(any(doc, not(objfw)))]
+    /// The return value is deallocated with [`free`][crate::free].
     pub fn method_copyArgumentType(method: *const objc_method, index: c_uint) -> *mut c_char;
     #[cfg(any(doc, not(objfw)))]
+    /// The return value is deallocated with [`free`][crate::free].
     pub fn method_copyReturnType(method: *const objc_method) -> *mut c_char;
     #[cfg(any(doc, not(objfw)))]
     pub fn method_exchangeImplementations(method1: *mut objc_method, method2: *mut objc_method);

crates/objc-sys/src/property.rs

@@ -25,6 +25,7 @@ pub struct objc_property_attribute_t {
 
 extern_c! {
     #[cfg(any(doc, not(objfw)))]
+    /// The returned array is deallocated with [`free`][crate::free].
     pub fn property_copyAttributeList(
         property: *const objc_property,
         out_len: *mut c_uint,

crates/objc-sys/src/protocol.rs

@@ -23,6 +23,7 @@ extern_c! {
     #[cfg(any(doc, not(objfw)))]
     pub fn objc_getProtocol(name: *const c_char) -> *const objc_protocol;
     #[cfg(any(doc, not(objfw)))]
+    /// The returned array is deallocated with [`free`][crate::free].
     pub fn objc_copyProtocolList(out_len: *mut c_uint) -> *mut *const objc_protocol;
 
     #[cfg(any(doc, not(objfw)))]
@@ -57,18 +58,21 @@ extern_c! {
     #[cfg(any(doc, not(objfw)))]
     pub fn protocol_addProtocol(proto: *mut objc_protocol, addition: *const objc_protocol);
     #[cfg(any(doc, not(objfw)))]
+    /// The returned array is deallocated with [`free`][crate::free].
     pub fn protocol_copyMethodDescriptionList(
         proto: *const objc_protocol,
         is_required_method: BOOL,
         is_instance_method: BOOL,
         out_len: *mut c_uint,
     ) -> *mut objc_method_description;
     #[cfg(any(doc, not(objfw)))]
+    /// The returned array is deallocated with [`free`][crate::free].
     pub fn protocol_copyPropertyList(
         proto: *const objc_protocol,
         out_len: *mut c_uint,
     ) -> *mut *const objc_property;
     #[cfg(any(doc, not(objfw)))]
+    /// The returned array is deallocated with [`free`][crate::free].
     pub fn protocol_copyProtocolList(
         proto: *const objc_protocol,
         out_len: *mut c_uint,

crates/objc-sys/src/various.rs

@@ -64,6 +64,7 @@ extern_c! {
         out_len: *mut c_uint,
     ) -> *mut *const c_char;
     #[cfg(any(doc, apple))]
+    /// The returned array is deallocated with [`free`][crate::free].
     pub fn objc_copyImageNames(out_len: *mut c_uint) -> *mut *const c_char;
 
     #[cfg(any(doc, apple, objfw))]

crates/objc2/CHANGELOG.md

@@ -6,9 +6,23 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## Unreleased - YYYY-MM-DD
 
+### Added
+* Made the following runtime methods available without the `"malloc"` feature
+  flag:
+  - `Method::return_type`.
+  - `Method::argument_type`.
+  - `AnyClass::classes`.
+  - `AnyClass::instance_methods`.
+  - `AnyClass::adopted_protocols`.
+  - `AnyClass::instance_variables`.
+  - `AnyProtocol::protocols`.
+  - `AnyProtocol::adopted_protocols`.
+
 ### Changed
 * Moved `ClassBuilder` and `ProtocolBuilder` from the `declare` module to the
   `runtime` module. The old locations are deprecated.
+* Enabled the `"verify"` feature flag's functionality when debug assertions are
+  enabled.
 
 
 ## 0.5.0 - 2023-12-03

crates/objc2/Cargo.toml

@@ -32,9 +32,6 @@ exception = ["objc-sys/unstable-exception"]
 # Wrap every `objc2::msg_send` call in a `@try/@catch` block
 catch-all = ["exception"]
 
-# Enable all verification steps when debug assertions are enabled.
-verify = ["malloc"]
-
 # Allow `*const c_void` and `*mut c_void` to be used as arguments and return
 # types where other pointers were expected.
 #
@@ -45,12 +42,14 @@ relax-void-encoding = []
 # Enable deprecation of using `msg_send!` without a comma between arguments.
 unstable-msg-send-always-comma = []
 
-# Expose features that require linking to `libc::free`.
-#
-# This is not enabled by default because most users won't need it, and it
-# increases compilation time.
+# This was necessary to access certain functionality in the past, but it is no
+# longer required.
 malloc = ["malloc_buf"]
 
+# This was necessary to enable certain debug assertions in the past, but it is
+# no longer required.
+verify = []
+
 # Make the `sel!` macro look up the selector statically.
 #
 # The plan is to enable this by default, but right now we are uncertain of
@@ -116,7 +115,7 @@ harness = false
 
 [package.metadata.docs.rs]
 default-target = "x86_64-apple-darwin"
-features = ["exception", "malloc", "unstable-docsrs"]
+features = ["exception", "unstable-docsrs"]
 
 targets = [
     # MacOS

crates/objc2/examples/introspection.rs

@@ -37,12 +37,9 @@ fn main() {
         "-[NSObject hash] takes {} parameters",
         method.arguments_count()
     );
-    #[cfg(feature = "malloc")]
-    {
-        let hash_return = method.return_type();
-        println!("-[NSObject hash] return type: {hash_return:?}");
-        assert!(usize::ENCODING.equivalent_to_str(&hash_return));
-    }
+    let hash_return = method.return_type();
+    println!("-[NSObject hash] return type: {hash_return:?}");
+    assert!(usize::ENCODING.equivalent_to_str(&hash_return));
 
     // Create an instance
     let obj = NSObject::new();

crates/objc2/src/__macro_helpers/declare_class.rs

@@ -1,15 +1,15 @@
-#[cfg(all(debug_assertions, feature = "verify"))]
+#[cfg(debug_assertions)]
 use alloc::vec::Vec;
 use core::marker::PhantomData;
-#[cfg(all(debug_assertions, feature = "verify"))]
+#[cfg(debug_assertions)]
 use std::collections::HashSet;
 
 use crate::encode::{Encode, Encoding};
 use crate::rc::{Allocated, Id};
 use crate::runtime::{
     AnyClass, AnyObject, ClassBuilder, MessageReceiver, MethodImplementation, Sel,
 };
-#[cfg(all(debug_assertions, feature = "verify"))]
+#[cfg(debug_assertions)]
 use crate::runtime::{AnyProtocol, MethodDescription};
 use crate::{ClassType, DeclaredClass, Message, ProtocolType};
 
@@ -243,7 +243,7 @@ impl<T: DeclaredClass> ClassBuilderHelper<T> {
             self.builder.add_protocol(protocol);
         }
 
-        #[cfg(all(debug_assertions, feature = "verify"))]
+        #[cfg(debug_assertions)]
         {
             ClassProtocolMethodsBuilder {
                 builder: self,
@@ -265,7 +265,7 @@ impl<T: DeclaredClass> ClassBuilderHelper<T> {
             }
         }
 
-        #[cfg(not(all(debug_assertions, feature = "verify")))]
+        #[cfg(not(debug_assertions))]
         {
             ClassProtocolMethodsBuilder { builder: self }
         }
@@ -303,19 +303,19 @@ impl<T: DeclaredClass> ClassBuilderHelper<T> {
 #[derive(Debug)]
 pub struct ClassProtocolMethodsBuilder<'a, T: ?Sized> {
     builder: &'a mut ClassBuilderHelper<T>,
-    #[cfg(all(debug_assertions, feature = "verify"))]
+    #[cfg(debug_assertions)]
     protocol: Option<&'static AnyProtocol>,
-    #[cfg(all(debug_assertions, feature = "verify"))]
+    #[cfg(debug_assertions)]
     required_instance_methods: Vec<MethodDescription>,
-    #[cfg(all(debug_assertions, feature = "verify"))]
+    #[cfg(debug_assertions)]
     optional_instance_methods: Vec<MethodDescription>,
-    #[cfg(all(debug_assertions, feature = "verify"))]
+    #[cfg(debug_assertions)]
     registered_instance_methods: HashSet<Sel>,
-    #[cfg(all(debug_assertions, feature = "verify"))]
+    #[cfg(debug_assertions)]
     required_class_methods: Vec<MethodDescription>,
-    #[cfg(all(debug_assertions, feature = "verify"))]
+    #[cfg(debug_assertions)]
     optional_class_methods: Vec<MethodDescription>,
-    #[cfg(all(debug_assertions, feature = "verify"))]
+    #[cfg(debug_assertions)]
     registered_class_methods: HashSet<Sel>,
 }
 
@@ -326,7 +326,7 @@ impl<T: DeclaredClass> ClassProtocolMethodsBuilder<'_, T> {
     where
         F: MethodImplementation<Callee = T>,
     {
-        #[cfg(all(debug_assertions, feature = "verify"))]
+        #[cfg(debug_assertions)]
         if let Some(protocol) = self.protocol {
             let _types = self
                 .required_instance_methods
@@ -344,7 +344,7 @@ impl<T: DeclaredClass> ClassProtocolMethodsBuilder<'_, T> {
         // SAFETY: Checked by caller
         unsafe { self.builder.add_method(sel, func) };
 
-        #[cfg(all(debug_assertions, feature = "verify"))]
+        #[cfg(debug_assertions)]
         if !self.registered_instance_methods.insert(sel) {
             unreachable!("already added")
         }
@@ -355,7 +355,7 @@ impl<T: DeclaredClass> ClassProtocolMethodsBuilder<'_, T> {
     where
         F: MethodImplementation<Callee = AnyClass>,
     {
-        #[cfg(all(debug_assertions, feature = "verify"))]
+        #[cfg(debug_assertions)]
         if let Some(protocol) = self.protocol {
             let _types = self
                 .required_class_methods
@@ -373,13 +373,13 @@ impl<T: DeclaredClass> ClassProtocolMethodsBuilder<'_, T> {
         // SAFETY: Checked by caller
         unsafe { self.builder.add_class_method(sel, func) };
 
-        #[cfg(all(debug_assertions, feature = "verify"))]
+        #[cfg(debug_assertions)]
         if !self.registered_class_methods.insert(sel) {
             unreachable!("already added")
         }
     }
 
-    #[cfg(all(debug_assertions, feature = "verify"))]
+    #[cfg(debug_assertions)]
     pub fn finish(self) {
         let superclass = self.builder.builder.superclass();
 
@@ -427,6 +427,6 @@ impl<T: DeclaredClass> ClassProtocolMethodsBuilder<'_, T> {
     }
 
     #[inline]
-    #[cfg(not(all(debug_assertions, feature = "verify")))]
+    #[cfg(not(debug_assertions))]
     pub fn finish(self) {}
 }

crates/objc2/src/lib.rs

@@ -119,8 +119,7 @@
 //! # panic!("does not panic in release mode, so for testing we make it!");
 //! ```
 //!
-//! This library contains further such debug checks, most of which are enabled
-//! by default. To enable all of them, use the `"verify"` cargo feature.
+//! This library contains further such debug checks.
 //!
 //! [`Vec`]: std::vec::Vec
 //!