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[ios] introduce weak_nsobject #47947

Merged
merged 8 commits into from
Nov 15, 2023
Merged

[ios] introduce weak_nsobject #47947

merged 8 commits into from
Nov 15, 2023

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cyanglaz
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Introduce weak_nsobject from chromium.

There are some usages of weak_ptr wrapping Objective-C ids, weak_ptr is not really designed for ids and such usages are blocking the arc migration.

This PR mostly copies the weak_nsobject from chromium, at the same hash that we copied the ARC/MRC compatible scoped_nsobject: https://chromium.googlesource.com/chromium/src/+/fd625125b8a6a3aceaf09993a5f74cfe5368b17f

To match how we used weak_ptr for those ids, I made some changes to the weak_nsobject:

  • WeakNSObjects needs to be generated by a WeakNSObjectFactory. The WeakNSObjectFactory is owned by the objc class and acts as the generator of the WeakNSObjects. All the WeakNSObjects' derefing thread should be the same of the WeakNSObjectFactory's creation thread.
  • chromuim's WeakNSObjects can be detached from the thread and re-attached to a new thread. To match our weak_ptr behavior, I changed WeakNSObjects to be only accessed from a single thread, the same as weak_ptr

This PR also moves the FlutterEngine to use WeakNSObject and updated related classes.

part of flutter/flutter#137801

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@cyanglaz cyanglaz marked this pull request as ready for review November 11, 2023 04:27
@cyanglaz cyanglaz marked this pull request as draft November 13, 2023 18:26
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I'm going to migrate all the weakPtr to weakNSObject in this PR, convert to draft until that;s done

stuartmorgan
stuartmorgan requested changes Nov 13, 2023
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fml/platform/darwin/weak_nsobject.h Outdated
~WeakContainer() {}

std::shared_ptr<debug::DebugThreadChecker> checker_;
id object_;
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This doesn't look ARC-safe to me; this is a strong reference under ARC unless I'm misremembering the semantics of id in ARC. I was confused by this so I looked at the history, and although:

This PR mostly copies the weak_nsobject from chromium, at the same hash that we copied the ARC/MRC compatible scoped_nsobject: https://chromium.googlesource.com/chromium/src/+/fd625125b8a6a3aceaf09993a5f74cfe5368b17f

that doesn't appear to have been an ARC-safe version. See https://codereview.chromium.org/2943263003 which landed much later.

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Thanks for catching this. I have adopted the change and updated the NSWeakObjectFactory accordingly.
I have also added a new unittests to test the NSWeakObject under ARC.
Also migrated a XCTest file that contains NSWeakObject to ARC.

@cyanglaz cyanglaz marked this pull request as ready for review November 14, 2023 20:57
@cyanglaz cyanglaz force-pushed the weak_nsobject branch 3 times, most recently from d5a4eae to f738bfd Compare November 15, 2023 14:44
stuartmorgan
stuartmorgan approved these changes Nov 15, 2023
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LGTM

fml/platform/darwin/weak_nsobject.mm Outdated
}

- (void)dealloc {
self.container->nullify();
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Nit: container_; dealloc shouldn't use self.

@cyanglaz cyanglaz added the autosubmit Merge PR when tree becomes green via auto submit App label Nov 15, 2023
@auto-submit auto-submit bot removed the autosubmit Merge PR when tree becomes green via auto submit App label Nov 15, 2023
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auto-submit bot commented Nov 15, 2023

auto label is removed for flutter/engine/47947, due to - The status or check suite Linux Framework Smoke Tests has failed. Please fix the issues identified (or deflake) before re-applying this label.

@cyanglaz cyanglaz added the autosubmit Merge PR when tree becomes green via auto submit App label Nov 15, 2023
@auto-submit auto-submit bot merged commit b29c564 into flutter:main Nov 15, 2023
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b29c56499 [ios] introduce weak_nsobject (flutter/engine#47947)
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Roll Flutter Engine from 3cfcdebe8623 to 8aff9c134b8f (18 revisions) (#…
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flutter/engine@3cfcdeb...8aff9c1

2023-11-16 [email protected] Roll Dart SDK from cc6acfd7d57c to 5cccc24d127f (1 revision) (flutter/engine#48109)
2023-11-16 [email protected] Roll Skia from 5d6bdbf69dea to add865f891c8 (1 revision) (flutter/engine#48108)
2023-11-16 [email protected] Roll Dart SDK from 65819963fb17 to cc6acfd7d57c (5 revisions) (flutter/engine#48100)
2023-11-16 [email protected] Make `fml/status_or.h` compatible with `.clang_tidy`. (flutter/engine#48002)
2023-11-16 [email protected] [Impeller] Gate Vulkan selection on API 29 (flutter/engine#48089)
2023-11-16 [email protected] [macOS] Clean up allocations in menu plugin test (flutter/engine#48093)
2023-11-16 [email protected] Re-land "Make `fml/...` compatible with `.clang_tidy` (flutter/engine#48030)
2023-11-15 [email protected] [ios] introduce weak_nsobject (flutter/engine#47947)
2023-11-15 [email protected] Roll Skia from e954d1a1972c to 5d6bdbf69dea (2 revisions) (flutter/engine#48094)
2023-11-15 [email protected] [Impeller] add async command submission for blit pass. (flutter/engine#48040)
2023-11-15 [email protected] Make `lib/ui/compositing/...` compatible with `.clang_tidy`. (flutter/engine#48001)
2023-11-15 [email protected] Remove the linux fuchsia v1 build. (flutter/engine#48085)
2023-11-15 [email protected] [web] Apply global styles before inserting the DOM element (flutter/engine#48027)
2023-11-15 [email protected] Roll Skia from b23074a79bda to e954d1a1972c (7 revisions) (flutter/engine#48092)
2023-11-15 98614782+auto-submit[bot]@users.noreply.github.com Reverts "Make `lib/ui/{text|window}/...` compatible with `.clang_tidy`." (flutter/engine#48083)
2023-11-15 [email protected] [ios]fix ios 16 auto correction highlight showing on top left corner (flutter/engine#47279)
2023-11-15 [email protected] Roll Skia from c42226314a4f to b23074a79bda (3 revisions) (flutter/engine#48081)
2023-11-15 [email protected] Make `lib/ui/{text|window}/...` compatible with `.clang_tidy`. (flutter/engine#48000)

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@cyanglaz cyanglaz deleted the weak_nsobject branch November 16, 2023 18:00
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