Call CGGetActiveDisplayList once to avoid panic (#4069)

This contains two changes in order to hopefully avoid the panic we saw
in #panics:

```
thread 'main' panicked at 'called `Option::unwrap()` on a `None` value'
crates/gpui/src/platform/mac/display.rs:30
<backtrace::capture::Backtrace as core::fmt::Debug>::fmt
<backtrace::capture::Backtrace as core::fmt::Debug>::fmt
Zed::init_panic_hook::{closure#0}
std::panicking::rust_panic_with_hook
std::panicking::rust_panic_with_hook
std::sys_common::backtrace::output_filename
<std::panicking::begin_panic_handler::FormatStringPayload as core::panic::PanicPayload>::take_box
core::panicking::panic_fmt
core::panicking::panic
gpui::platform::mac::display::display_bounds_to_native
<gpui::platform::mac:🪟:MacWindow as gpui::platform::PlatformWindow>::bounds
<gpui:🪟:WindowContext>::window_bounds_changed
<gpui:🪟:Window>:🆕:{closure#1}
gpui::platform::mac:🪟:view_did_change_backing_properties
<gpui::platform::mac::platform::MacPlatform as gpui::platform::Platform>::run
Zed::main
<core::marker::PhantomData<core::option::Option<Zed::LocationData>> as serde:🇩🇪:DeserializeSeed>::deserialize::<&mut serde_json:🇩🇪:Deserializer<serde_json::read::StrRead>>
workspace::open_new::<Zed::restore_or_create_workspace::{closure#0}::{closure#0}::{closure#0}::{closure#2}::{closure#0}>::{closure#0}::{closure#0}
std::rt::lang_start_internal
serde_json:🇩🇪:from_trait::<serde_json::read::StrRead, core::option::Option<Zed::Panic>>
```

Two changes:
* Reduce the number of calls to `CGGetActiveDisplayList` in the hopes
that this will also reduce chances of it returning an empty list.
Previously, in the worst case, we called it 6 times. Now the worst case
is that we call it 3 times.
* Instead of calling `CGGetActiveDisplayList` to get the primary display
we do what Chromium does and construct the primary display from
NSScreen.

Release Notes:

- Fixed a bug that caused a panic that could happen when Zed attempted
to render on a sleeping display.
This commit is contained in:
Thorsten Ball 2024-01-16 14:40:46 +01:00 committed by GitHub
commit 0bf66e486a
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2 changed files with 32 additions and 8 deletions

View File

@ -1,10 +1,16 @@
use crate::{point, size, Bounds, DisplayId, GlobalPixels, PlatformDisplay};
use anyhow::Result;
use cocoa::{
appkit::NSScreen,
base::{id, nil},
foundation::{NSDictionary, NSString},
};
use core_foundation::uuid::{CFUUIDGetUUIDBytes, CFUUIDRef};
use core_graphics::{
display::{CGDirectDisplayID, CGDisplayBounds, CGGetActiveDisplayList},
geometry::{CGPoint, CGRect, CGSize},
};
use objc::{msg_send, sel, sel_impl};
use std::any::Any;
use uuid::Uuid;
@ -27,23 +33,41 @@ impl MacDisplay {
/// Get the primary screen - the one with the menu bar, and whose bottom left
/// corner is at the origin of the AppKit coordinate system.
pub fn primary() -> Self {
Self::all().next().unwrap()
// Instead of iterating through all active systems displays via `all()` we use the first
// NSScreen and gets its CGDirectDisplayID, because we can't be sure that `CGGetActiveDisplayList`
// will always return a list of active displays (machine might be sleeping).
//
// The following is what Chromium does too:
//
// https://chromium.googlesource.com/chromium/src/+/66.0.3359.158/ui/display/mac/screen_mac.mm#56
unsafe {
let screens = NSScreen::screens(nil);
let screen = cocoa::foundation::NSArray::objectAtIndex(screens, 0);
let device_description = NSScreen::deviceDescription(screen);
let screen_number_key: id = NSString::alloc(nil).init_str("NSScreenNumber");
let screen_number = device_description.objectForKey_(screen_number_key);
let screen_number: CGDirectDisplayID = msg_send![screen_number, unsignedIntegerValue];
Self(screen_number)
}
}
/// Obtains an iterator over all currently active system displays.
pub fn all() -> impl Iterator<Item = Self> {
unsafe {
let mut display_count: u32 = 0;
let result = CGGetActiveDisplayList(0, std::ptr::null_mut(), &mut display_count);
// We're assuming there aren't more than 32 displays connected to the system.
let mut displays = Vec::with_capacity(32);
let mut display_count = 0;
let result = CGGetActiveDisplayList(
displays.capacity() as u32,
displays.as_mut_ptr(),
&mut display_count,
);
if result == 0 {
let mut displays = Vec::with_capacity(display_count as usize);
CGGetActiveDisplayList(display_count, displays.as_mut_ptr(), &mut display_count);
displays.set_len(display_count as usize);
displays.into_iter().map(MacDisplay)
} else {
panic!("Failed to get active display list");
panic!("Failed to get active display list. Result: {result}");
}
}
}

View File

@ -484,7 +484,7 @@ impl MacWindow {
let display = options
.display_id
.and_then(|display_id| MacDisplay::all().find(|display| display.id() == display_id))
.and_then(MacDisplay::find_by_id)
.unwrap_or_else(MacDisplay::primary);
let mut target_screen = nil;