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Add ability to nicely handle NSError** parameters
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@madsmtm
madsmtm committed Oct 27, 2022
1 parent 3bddf4d commit 9c8e9f7
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Showing 24 changed files with 1,151 additions and 174 deletions.
8 changes: 7 additions & 1 deletion objc2/CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
msg_send_id![NSObject::alloc(), init]
};
```
* Add `Class::class_method`.
* Added `Class::class_method`.
* Added the ability to specify `error: _`, `somethingReturningError: _` and
so on at the end of `msg_send!`/`msg_send_id!`, and have it automatically
return a `Result<..., Id<NSError, Shared>>`.
* Added the ability to specify an extra parameter at the end of the selector
in methods declared with `extern_methods!`, and let that be the `NSError**`
parameter.

### Changed
* Allow other types than `&Class` as the receiver in `msg_send_id!` methods
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194 changes: 126 additions & 68 deletions objc2/src/__macro_helpers.rs
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Original file line number Diff line number Diff line change
@@ -1,12 +1,15 @@
#[cfg(feature = "verify_message")]
use alloc::vec::Vec;
use core::ptr;
#[cfg(feature = "verify_message")]
use std::collections::HashSet;

use crate::declare::ClassBuilder;
#[cfg(feature = "verify_message")]
use crate::declare::MethodImplementation;
use crate::rc::{Allocated, Id, Ownership};
use crate::encode::Encode;
use crate::message::__TupleExtender;
use crate::rc::{Allocated, Id, Ownership, Shared};
#[cfg(feature = "verify_message")]
use crate::runtime::MethodDescription;
use crate::runtime::{Class, Object, Protocol, Sel};
Expand Down Expand Up @@ -103,6 +106,48 @@ pub trait MsgSendId<T, U> {
sel: Sel,
args: A,
) -> R;

/// Add an extra error argument to the argument list, call
/// `send_message_id` with that, and return an error if one occurred.
#[inline]
#[track_caller]
unsafe fn send_message_id_error<A, E>(obj: T, sel: Sel, args: A) -> Result<U, Id<E, Shared>>
where
*mut *mut E: Encode,
A: __TupleExtender<*mut *mut E>,
<A as __TupleExtender<*mut *mut E>>::PlusOneArgument: MessageArguments,
E: Message,
Option<U>: MaybeUnwrap<Input = U>,
{
let mut err: *mut E = ptr::null_mut();
let args = args.add_argument(&mut err);
let res: Option<U> = unsafe { Self::send_message_id(obj, sel, args) };
if let Some(res) = res {
// In this case, the error is likely not created. If it is, it is
// autoreleased anyhow, so it would be a waste to retain and
// release it.
Ok(res)
} else {
// In this case, the error has very likely been created, but has
// been autoreleased (as is common for "out parameters"). Hence we
// need to retain it if we want it to live across autorelease
// pools.
//
// SAFETY: The closure `f` is guaranteed to populate the error
// object, or leave it as NULL. The error is shared, and all
// holders of the error know this, so is safe to retain.
Err(unsafe { encountered_error(err) })
}
}
}

// Marked `cold` to tell the optimizer that errors are comparatively rare.
// And intentionally not inlined, for much the same reason.
#[cold]
#[track_caller]
unsafe fn encountered_error<E: Message>(err: *mut E) -> Id<E, Shared> {
// SAFETY: Ensured by caller
unsafe { Id::retain(err) }.expect("error parameter should be set if the method returns NULL")
}

impl<T: MessageReceiver, U: ?Sized + Message, O: Ownership> MsgSendId<T, Id<U, O>> for New {
Expand Down Expand Up @@ -555,6 +600,7 @@ impl Drop for ClassProtocolMethodsBuilder<'_, '_> {
mod tests {
use super::*;

use alloc::string::ToString;
use alloc::vec;
use core::ptr;

Expand Down Expand Up @@ -777,80 +823,92 @@ mod tests {

#[test]
fn test_in_selector_family() {
fn assert_in_family(selector: &str, family: &str) {
assert!(in_selector_family(selector.as_bytes(), family.as_bytes()));
let selector = selector.to_string() + "\0";
assert!(in_selector_family(selector.as_bytes(), family.as_bytes()));
}

fn assert_not_in_family(selector: &str, family: &str) {
assert!(!in_selector_family(selector.as_bytes(), family.as_bytes()));
let selector = selector.to_string() + "\0";
assert!(!in_selector_family(selector.as_bytes(), family.as_bytes()));
}

// Common cases

assert!(in_selector_family(b"alloc", b"alloc"));
assert!(in_selector_family(b"allocWithZone:", b"alloc"));
assert!(!in_selector_family(b"dealloc", b"alloc"));
assert!(!in_selector_family(b"initialize", b"init"));
assert!(!in_selector_family(b"decimalNumberWithDecimal:", b"init"));
assert!(in_selector_family(b"initWithCapacity:", b"init"));
assert!(in_selector_family(b"_initButPrivate:withParam:", b"init"));
assert!(!in_selector_family(b"description", b"init"));
assert!(!in_selector_family(b"inIT", b"init"));

assert!(!in_selector_family(b"init", b"copy"));
assert!(!in_selector_family(b"copyingStuff:", b"copy"));
assert!(in_selector_family(b"copyWithZone:", b"copy"));
assert!(!in_selector_family(b"initWithArray:copyItems:", b"copy"));
assert!(in_selector_family(b"copyItemAtURL:toURL:error:", b"copy"));

assert!(!in_selector_family(b"mutableCopying", b"mutableCopy"));
assert!(in_selector_family(b"mutableCopyWithZone:", b"mutableCopy"));
assert!(in_selector_family(b"mutableCopyWithZone:", b"mutableCopy"));

assert!(in_selector_family(
b"newScriptingObjectOfClass:forValueForKey:withContentsValue:properties:",
b"new"
));
assert!(in_selector_family(
b"newScriptingObjectOfClass:forValueForKey:withContentsValue:properties:",
b"new"
));
assert!(!in_selector_family(b"newsstandAssetDownload", b"new"));
assert_in_family("alloc", "alloc");
assert_in_family("allocWithZone:", "alloc");
assert_not_in_family("dealloc", "alloc");
assert_not_in_family("initialize", "init");
assert_not_in_family("decimalNumberWithDecimal:", "init");
assert_in_family("initWithCapacity:", "init");
assert_in_family("_initButPrivate:withParam:", "init");
assert_not_in_family("description", "init");
assert_not_in_family("inIT", "init");

assert_not_in_family("init", "copy");
assert_not_in_family("copyingStuff:", "copy");
assert_in_family("copyWithZone:", "copy");
assert_not_in_family("initWithArray:copyItems:", "copy");
assert_in_family("copyItemAtURL:toURL:error:", "copy");

assert_not_in_family("mutableCopying", "mutableCopy");
assert_in_family("mutableCopyWithZone:", "mutableCopy");
assert_in_family("mutableCopyWithZone:", "mutableCopy");

assert_in_family(
"newScriptingObjectOfClass:forValueForKey:withContentsValue:properties:",
"new",
);
assert_in_family(
"newScriptingObjectOfClass:forValueForKey:withContentsValue:properties:",
"new",
);
assert_not_in_family("newsstandAssetDownload", "new");

// Trying to weed out edge-cases:

assert!(in_selector_family(b"__abcDef", b"abc"));
assert!(in_selector_family(b"_abcDef", b"abc"));
assert!(in_selector_family(b"abcDef", b"abc"));
assert!(in_selector_family(b"___a", b"a"));
assert!(in_selector_family(b"__a", b"a"));
assert!(in_selector_family(b"_a", b"a"));
assert!(in_selector_family(b"a", b"a"));

assert!(!in_selector_family(b"_abcdef", b"abc"));
assert!(!in_selector_family(b"_abcdef", b"def"));
assert!(!in_selector_family(b"_bcdef", b"abc"));
assert!(!in_selector_family(b"a_bc", b"abc"));
assert!(!in_selector_family(b"abcdef", b"abc"));
assert!(!in_selector_family(b"abcdef", b"def"));
assert!(!in_selector_family(b"abcdef", b"abb"));
assert!(!in_selector_family(b"___", b"a"));
assert!(!in_selector_family(b"_", b"a"));
assert!(!in_selector_family(b"", b"a"));

assert!(in_selector_family(b"copy", b"copy"));
assert!(in_selector_family(b"copy:", b"copy"));
assert!(in_selector_family(b"copyMe", b"copy"));
assert!(in_selector_family(b"_copy", b"copy"));
assert!(in_selector_family(b"_copy:", b"copy"));
assert!(in_selector_family(b"_copyMe", b"copy"));
assert!(!in_selector_family(b"copying", b"copy"));
assert!(!in_selector_family(b"copying:", b"copy"));
assert!(!in_selector_family(b"_copying", b"copy"));
assert!(!in_selector_family(b"Copy", b"copy"));
assert!(!in_selector_family(b"COPY", b"copy"));
assert_in_family("__abcDef", "abc");
assert_in_family("_abcDef", "abc");
assert_in_family("abcDef", "abc");
assert_in_family("___a", "a");
assert_in_family("__a", "a");
assert_in_family("_a", "a");
assert_in_family("a", "a");

assert_not_in_family("_abcdef", "abc");
assert_not_in_family("_abcdef", "def");
assert_not_in_family("_bcdef", "abc");
assert_not_in_family("a_bc", "abc");
assert_not_in_family("abcdef", "abc");
assert_not_in_family("abcdef", "def");
assert_not_in_family("abcdef", "abb");
assert_not_in_family("___", "a");
assert_not_in_family("_", "a");
assert_not_in_family("", "a");

assert_in_family("copy", "copy");
assert_in_family("copy:", "copy");
assert_in_family("copyMe", "copy");
assert_in_family("_copy", "copy");
assert_in_family("_copy:", "copy");
assert_in_family("_copyMe", "copy");
assert_not_in_family("copying", "copy");
assert_not_in_family("copying:", "copy");
assert_not_in_family("_copying", "copy");
assert_not_in_family("Copy", "copy");
assert_not_in_family("COPY", "copy");

// Empty family (not supported)
assert!(in_selector_family(b"___", b""));
assert!(in_selector_family(b"__", b""));
assert!(in_selector_family(b"_", b""));
assert!(in_selector_family(b"", b""));
assert!(!in_selector_family(b"_a", b""));
assert!(!in_selector_family(b"a", b""));
assert!(in_selector_family(b"_A", b""));
assert!(in_selector_family(b"A", b""));
assert_in_family("___", "");
assert_in_family("__", "");
assert_in_family("_", "");
assert_in_family("", "");
assert_not_in_family("_a", "");
assert_not_in_family("a", "");
assert_in_family("_A", "");
assert_in_family("A", "");
}

mod test_trait_disambugated {
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