1 #![cfg(feature = "alloc")] 2 #![allow(missing_docs)] 3 4 use crate::rust_string::RustString; 5 use alloc::string::String; 6 use alloc::vec::Vec; 7 use core::ffi::c_void; 8 use core::marker::PhantomData; 9 use core::mem::{self, ManuallyDrop, MaybeUninit}; 10 use core::ptr; 11 12 // ABI compatible with C++ rust::Vec<T> (not necessarily alloc::vec::Vec<T>). 13 #[repr(C)] 14 pub struct RustVec<T> { 15 repr: [MaybeUninit<usize>; mem::size_of::<Vec<c_void>>() / mem::size_of::<usize>()], 16 marker: PhantomData<Vec<T>>, 17 } 18 19 impl<T> RustVec<T> { new() -> Self20 pub fn new() -> Self { 21 Self::from(Vec::new()) 22 } 23 from(v: Vec<T>) -> Self24 pub fn from(v: Vec<T>) -> Self { 25 unsafe { mem::transmute::<Vec<T>, RustVec<T>>(v) } 26 } 27 from_ref(v: &Vec<T>) -> &Self28 pub fn from_ref(v: &Vec<T>) -> &Self { 29 unsafe { &*(v as *const Vec<T> as *const RustVec<T>) } 30 } 31 from_mut(v: &mut Vec<T>) -> &mut Self32 pub fn from_mut(v: &mut Vec<T>) -> &mut Self { 33 unsafe { &mut *(v as *mut Vec<T> as *mut RustVec<T>) } 34 } 35 into_vec(self) -> Vec<T>36 pub fn into_vec(self) -> Vec<T> { 37 unsafe { mem::transmute::<RustVec<T>, Vec<T>>(self) } 38 } 39 as_vec(&self) -> &Vec<T>40 pub fn as_vec(&self) -> &Vec<T> { 41 unsafe { &*(self as *const RustVec<T> as *const Vec<T>) } 42 } 43 as_mut_vec(&mut self) -> &mut Vec<T>44 pub fn as_mut_vec(&mut self) -> &mut Vec<T> { 45 unsafe { &mut *(self as *mut RustVec<T> as *mut Vec<T>) } 46 } 47 len(&self) -> usize48 pub fn len(&self) -> usize { 49 self.as_vec().len() 50 } 51 capacity(&self) -> usize52 pub fn capacity(&self) -> usize { 53 self.as_vec().capacity() 54 } 55 as_ptr(&self) -> *const T56 pub fn as_ptr(&self) -> *const T { 57 self.as_vec().as_ptr() 58 } 59 reserve_total(&mut self, new_cap: usize)60 pub fn reserve_total(&mut self, new_cap: usize) { 61 let vec = self.as_mut_vec(); 62 if new_cap > vec.capacity() { 63 let additional = new_cap - vec.len(); 64 vec.reserve(additional); 65 } 66 } 67 set_len(&mut self, len: usize)68 pub unsafe fn set_len(&mut self, len: usize) { 69 unsafe { self.as_mut_vec().set_len(len) } 70 } 71 truncate(&mut self, len: usize)72 pub fn truncate(&mut self, len: usize) { 73 self.as_mut_vec().truncate(len); 74 } 75 } 76 77 impl RustVec<RustString> { from_vec_string(v: Vec<String>) -> Self78 pub fn from_vec_string(v: Vec<String>) -> Self { 79 let mut v = ManuallyDrop::new(v); 80 let ptr = v.as_mut_ptr().cast::<RustString>(); 81 let len = v.len(); 82 let cap = v.capacity(); 83 Self::from(unsafe { Vec::from_raw_parts(ptr, len, cap) }) 84 } 85 from_ref_vec_string(v: &Vec<String>) -> &Self86 pub fn from_ref_vec_string(v: &Vec<String>) -> &Self { 87 Self::from_ref(unsafe { &*(v as *const Vec<String> as *const Vec<RustString>) }) 88 } 89 from_mut_vec_string(v: &mut Vec<String>) -> &mut Self90 pub fn from_mut_vec_string(v: &mut Vec<String>) -> &mut Self { 91 Self::from_mut(unsafe { &mut *(v as *mut Vec<String> as *mut Vec<RustString>) }) 92 } 93 into_vec_string(self) -> Vec<String>94 pub fn into_vec_string(self) -> Vec<String> { 95 let mut v = ManuallyDrop::new(self.into_vec()); 96 let ptr = v.as_mut_ptr().cast::<String>(); 97 let len = v.len(); 98 let cap = v.capacity(); 99 unsafe { Vec::from_raw_parts(ptr, len, cap) } 100 } 101 as_vec_string(&self) -> &Vec<String>102 pub fn as_vec_string(&self) -> &Vec<String> { 103 unsafe { &*(self as *const RustVec<RustString> as *const Vec<String>) } 104 } 105 as_mut_vec_string(&mut self) -> &mut Vec<String>106 pub fn as_mut_vec_string(&mut self) -> &mut Vec<String> { 107 unsafe { &mut *(self as *mut RustVec<RustString> as *mut Vec<String>) } 108 } 109 } 110 111 impl<T> Drop for RustVec<T> { drop(&mut self)112 fn drop(&mut self) { 113 unsafe { ptr::drop_in_place(self.as_mut_vec()) } 114 } 115 } 116