1 #![allow(missing_docs)] 2 3 use crate::rust_string::RustString; 4 use alloc::string::String; 5 use alloc::vec::Vec; 6 use core::ffi::c_void; 7 use core::marker::PhantomData; 8 use core::mem::{self, ManuallyDrop, MaybeUninit}; 9 use core::ptr; 10 11 // ABI compatible with C++ rust::Vec<T> (not necessarily alloc::vec::Vec<T>). 12 #[repr(C)] 13 pub struct RustVec<T> { 14 repr: [MaybeUninit<usize>; mem::size_of::<Vec<c_void>>() / mem::size_of::<usize>()], 15 marker: PhantomData<Vec<T>>, 16 } 17 18 impl<T> RustVec<T> { new() -> Self19 pub fn new() -> Self { 20 Self::from(Vec::new()) 21 } 22 from(v: Vec<T>) -> Self23 pub fn from(v: Vec<T>) -> Self { 24 unsafe { mem::transmute::<Vec<T>, RustVec<T>>(v) } 25 } 26 from_ref(v: &Vec<T>) -> &Self27 pub fn from_ref(v: &Vec<T>) -> &Self { 28 unsafe { &*(v as *const Vec<T> as *const RustVec<T>) } 29 } 30 from_mut(v: &mut Vec<T>) -> &mut Self31 pub fn from_mut(v: &mut Vec<T>) -> &mut Self { 32 unsafe { &mut *(v as *mut Vec<T> as *mut RustVec<T>) } 33 } 34 into_vec(self) -> Vec<T>35 pub fn into_vec(self) -> Vec<T> { 36 unsafe { mem::transmute::<RustVec<T>, Vec<T>>(self) } 37 } 38 as_vec(&self) -> &Vec<T>39 pub fn as_vec(&self) -> &Vec<T> { 40 unsafe { &*(self as *const RustVec<T> as *const Vec<T>) } 41 } 42 as_mut_vec(&mut self) -> &mut Vec<T>43 pub fn as_mut_vec(&mut self) -> &mut Vec<T> { 44 unsafe { &mut *(self as *mut RustVec<T> as *mut Vec<T>) } 45 } 46 len(&self) -> usize47 pub fn len(&self) -> usize { 48 self.as_vec().len() 49 } 50 capacity(&self) -> usize51 pub fn capacity(&self) -> usize { 52 self.as_vec().capacity() 53 } 54 as_ptr(&self) -> *const T55 pub fn as_ptr(&self) -> *const T { 56 self.as_vec().as_ptr() 57 } 58 reserve_total(&mut self, new_cap: usize)59 pub fn reserve_total(&mut self, new_cap: usize) { 60 let vec = self.as_mut_vec(); 61 if new_cap > vec.capacity() { 62 let additional = new_cap - vec.len(); 63 vec.reserve(additional); 64 } 65 } 66 set_len(&mut self, len: usize)67 pub unsafe fn set_len(&mut self, len: usize) { 68 unsafe { self.as_mut_vec().set_len(len) } 69 } 70 } 71 72 impl RustVec<RustString> { from_vec_string(v: Vec<String>) -> Self73 pub fn from_vec_string(v: Vec<String>) -> Self { 74 let mut v = ManuallyDrop::new(v); 75 let ptr = v.as_mut_ptr().cast::<RustString>(); 76 let len = v.len(); 77 let cap = v.capacity(); 78 Self::from(unsafe { Vec::from_raw_parts(ptr, len, cap) }) 79 } 80 from_ref_vec_string(v: &Vec<String>) -> &Self81 pub fn from_ref_vec_string(v: &Vec<String>) -> &Self { 82 Self::from_ref(unsafe { &*(v as *const Vec<String> as *const Vec<RustString>) }) 83 } 84 from_mut_vec_string(v: &mut Vec<String>) -> &mut Self85 pub fn from_mut_vec_string(v: &mut Vec<String>) -> &mut Self { 86 Self::from_mut(unsafe { &mut *(v as *mut Vec<String> as *mut Vec<RustString>) }) 87 } 88 into_vec_string(self) -> Vec<String>89 pub fn into_vec_string(self) -> Vec<String> { 90 let mut v = ManuallyDrop::new(self.into_vec()); 91 let ptr = v.as_mut_ptr().cast::<String>(); 92 let len = v.len(); 93 let cap = v.capacity(); 94 unsafe { Vec::from_raw_parts(ptr, len, cap) } 95 } 96 as_vec_string(&self) -> &Vec<String>97 pub fn as_vec_string(&self) -> &Vec<String> { 98 unsafe { &*(self as *const RustVec<RustString> as *const Vec<String>) } 99 } 100 as_mut_vec_string(&mut self) -> &mut Vec<String>101 pub fn as_mut_vec_string(&mut self) -> &mut Vec<String> { 102 unsafe { &mut *(self as *mut RustVec<RustString> as *mut Vec<String>) } 103 } 104 } 105 106 impl<T> Drop for RustVec<T> { drop(&mut self)107 fn drop(&mut self) { 108 unsafe { ptr::drop_in_place(self.as_mut_vec()) } 109 } 110 } 111