From 1b6a04ca5504955c571d1c97504fb45ea0befee4 Mon Sep 17 00:00:00 2001 From: Valentin Popov Date: Mon, 8 Jan 2024 01:21:28 +0400 Subject: Initial vendor packages Signed-off-by: Valentin Popov --- vendor/addr2line/src/lazy.rs | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 vendor/addr2line/src/lazy.rs (limited to 'vendor/addr2line/src/lazy.rs') diff --git a/vendor/addr2line/src/lazy.rs b/vendor/addr2line/src/lazy.rs new file mode 100644 index 0000000..2df2ed6 --- /dev/null +++ b/vendor/addr2line/src/lazy.rs @@ -0,0 +1,31 @@ +use core::cell::UnsafeCell; + +pub struct LazyCell { + contents: UnsafeCell>, +} +impl LazyCell { + pub fn new() -> LazyCell { + LazyCell { + contents: UnsafeCell::new(None), + } + } + + pub fn borrow(&self) -> Option<&T> { + unsafe { &*self.contents.get() }.as_ref() + } + + pub fn borrow_with(&self, closure: impl FnOnce() -> T) -> &T { + // First check if we're already initialized... + let ptr = self.contents.get(); + if let Some(val) = unsafe { &*ptr } { + return val; + } + // Note that while we're executing `closure` our `borrow_with` may + // be called recursively. This means we need to check again after + // the closure has executed. For that we use the `get_or_insert` + // method which will only perform mutation if we aren't already + // `Some`. + let val = closure(); + unsafe { (*ptr).get_or_insert(val) } + } +} -- cgit v1.2.3