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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/malloc_buf | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/malloc_buf')
-rw-r--r-- | third_party/rust/malloc_buf/.cargo-checksum.json | 1 | ||||
-rw-r--r-- | third_party/rust/malloc_buf/Cargo.toml | 14 | ||||
-rw-r--r-- | third_party/rust/malloc_buf/src/lib.rs | 95 |
3 files changed, 110 insertions, 0 deletions
diff --git a/third_party/rust/malloc_buf/.cargo-checksum.json b/third_party/rust/malloc_buf/.cargo-checksum.json new file mode 100644 index 0000000000..70cd125dfe --- /dev/null +++ b/third_party/rust/malloc_buf/.cargo-checksum.json @@ -0,0 +1 @@ +{"files":{"Cargo.toml":"d87624d9d117489bd49dbaeb70077a0721e00ac2a76eb371faec818a92da5661","src/lib.rs":"1130dacbe045a20c1ea1e65e00976f18eb7513da492b07d538e7b1b5c64b8842"},"package":"62bb907fe88d54d8d9ce32a3cceab4218ed2f6b7d35617cafe9adf84e43919cb"}
\ No newline at end of file diff --git a/third_party/rust/malloc_buf/Cargo.toml b/third_party/rust/malloc_buf/Cargo.toml new file mode 100644 index 0000000000..cfb0c082d8 --- /dev/null +++ b/third_party/rust/malloc_buf/Cargo.toml @@ -0,0 +1,14 @@ +[package] +name = "malloc_buf" +version = "0.0.6" +authors = ["Steven Sheldon"] + +description = "Structs for handling malloc'd memory passed to Rust." +repository = "https://github.com/SSheldon/malloc_buf" +documentation = "http://ssheldon.github.io/malloc_buf/malloc_buf/" +license = "MIT" + +exclude = [".gitignore"] + +[dependencies] +libc = ">= 0.1, < 0.3" diff --git a/third_party/rust/malloc_buf/src/lib.rs b/third_party/rust/malloc_buf/src/lib.rs new file mode 100644 index 0000000000..24066b69d4 --- /dev/null +++ b/third_party/rust/malloc_buf/src/lib.rs @@ -0,0 +1,95 @@ +extern crate libc; + +use std::marker::PhantomData; +use std::ops::Deref; +use std::slice; +use libc::c_void; + +struct MallocPtr(*mut c_void); + +impl Drop for MallocPtr { + fn drop(&mut self) { + unsafe { + libc::free(self.0); + } + } +} + +/// A type that represents a `malloc`'d chunk of memory. +pub struct MallocBuffer<T> { + ptr: MallocPtr, + len: usize, + items: PhantomData<[T]>, +} + +impl<T: Copy> MallocBuffer<T> { + /// Constructs a new `MallocBuffer` for a `malloc`'d buffer + /// with the given length at the given pointer. + /// Returns `None` if the given pointer is null and the length is not 0. + /// + /// When this `MallocBuffer` drops, the buffer will be `free`'d. + /// + /// Unsafe because there must be `len` contiguous, valid instances of `T` + /// at `ptr`. + pub unsafe fn new(ptr: *mut T, len: usize) -> Option<MallocBuffer<T>> { + if len > 0 && ptr.is_null() { + None + } else { + Some(MallocBuffer { + ptr: MallocPtr(ptr as *mut c_void), + len: len, + items: PhantomData, + }) + } + } +} + +impl<T> Deref for MallocBuffer<T> { + type Target = [T]; + + fn deref(&self) -> &[T] { + let ptr = if self.len == 0 && self.ptr.0.is_null() { + // Even a 0-size slice cannot be null, so just use another pointer + 0x1 as *const T + } else { + self.ptr.0 as *const T + }; + unsafe { + slice::from_raw_parts(ptr, self.len) + } + } +} + +#[cfg(test)] +mod tests { + use std::ptr; + use libc; + + use super::MallocBuffer; + + #[test] + fn test_null_buf() { + let buf = unsafe { + MallocBuffer::<u32>::new(ptr::null_mut(), 0).unwrap() + }; + assert!(&*buf == []); + assert!(Some(&*buf) == Some(&[])); + + let buf = unsafe { + MallocBuffer::<u32>::new(ptr::null_mut(), 7) + }; + assert!(buf.is_none()); + } + + #[test] + fn test_buf() { + let buf = unsafe { + let ptr = libc::malloc(12) as *mut u32; + *ptr = 1; + *ptr.offset(1) = 2; + *ptr.offset(2) = 3; + MallocBuffer::new(ptr, 3).unwrap() + }; + assert!(&*buf == [1, 2, 3]); + } +} |