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/backtrace/src/symbolize/gimli/stash.rs | 50 +++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 vendor/backtrace/src/symbolize/gimli/stash.rs (limited to 'vendor/backtrace/src/symbolize/gimli/stash.rs') diff --git a/vendor/backtrace/src/symbolize/gimli/stash.rs b/vendor/backtrace/src/symbolize/gimli/stash.rs new file mode 100644 index 0000000..792f9a6 --- /dev/null +++ b/vendor/backtrace/src/symbolize/gimli/stash.rs @@ -0,0 +1,50 @@ +// only used on Linux right now, so allow dead code elsewhere +#![cfg_attr(not(target_os = "linux"), allow(dead_code))] + +use super::Mmap; +use alloc::vec; +use alloc::vec::Vec; +use core::cell::UnsafeCell; + +/// A simple arena allocator for byte buffers. +pub struct Stash { + buffers: UnsafeCell>>, + mmaps: UnsafeCell>, +} + +impl Stash { + pub fn new() -> Stash { + Stash { + buffers: UnsafeCell::new(Vec::new()), + mmaps: UnsafeCell::new(Vec::new()), + } + } + + /// Allocates a buffer of the specified size and returns a mutable reference + /// to it. + pub fn allocate(&self, size: usize) -> &mut [u8] { + // SAFETY: this is the only function that ever constructs a mutable + // reference to `self.buffers`. + let buffers = unsafe { &mut *self.buffers.get() }; + let i = buffers.len(); + buffers.push(vec![0; size]); + // SAFETY: we never remove elements from `self.buffers`, so a reference + // to the data inside any buffer will live as long as `self` does. + &mut buffers[i] + } + + /// Stores a `Mmap` for the lifetime of this `Stash`, returning a pointer + /// which is scoped to just this lifetime. + pub fn cache_mmap(&self, map: Mmap) -> &[u8] { + // SAFETY: this is the only location for a mutable pointer to + // `mmaps`, and this structure isn't threadsafe to shared across + // threads either. We also never remove elements from `self.mmaps`, + // so a reference to the data inside the map will live as long as + // `self` does. + unsafe { + let mmaps = &mut *self.mmaps.get(); + mmaps.push(map); + mmaps.last().unwrap() + } + } +} -- cgit v1.2.3