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feat: works

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This commit is contained in:
Hatter Jiang
2023-01-22 00:41:15 +08:00
parent 2de77003fb
commit 49b6d71886
3 changed files with 55 additions and 20 deletions
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6
javascript-engine/src/lib.rs
View File

@@ -2,10 +2,10 @@ mod mem;
mod engine;
#[no_mangle]
pub unsafe fn eval(ptr: *mut u8, len: usize) -> (*mut u8, usize) {
let js = mem::read_string(ptr, len);
pub unsafe fn eval(ptr: *mut u8) -> *mut u8 {
let js = mem::read_string(ptr);
let eval_result = engine::inner_eval(&js);
let eval_result_json_string = serde_json::to_string(&eval_result).expect("SHOULD NOT HAPPEN");
mem::malloc_and_write_string(&eval_result_json_string)
mem::malloc_and_write_string(&eval_result_json_string).0
}

45
javascript-engine/src/mem.rs
View File

@@ -3,23 +3,24 @@ use std::ptr;
#[no_mangle]
pub unsafe fn malloc(len: usize) -> *mut u8 {
let align = std::mem::align_of::<usize>();
let layout = std::alloc::Layout::from_size_align_unchecked(len, align);
std::alloc::alloc(layout)
let layout = std::alloc::Layout::from_size_align_unchecked(len + 4, align);
let addr = std::alloc::alloc(layout);
let len_in_bytes = (len as u32).to_be_bytes();
write_bytes(addr, 0, 4, &len_in_bytes);
addr
}
#[no_mangle]
pub unsafe fn free(ptr: *mut u8, len: usize) {
pub unsafe fn free(ptr: *mut u8) {
let len = read_u32(ptr);
let align = std::mem::align_of::<usize>();
let layout = std::alloc::Layout::from_size_align_unchecked(len, align);
let layout = std::alloc::Layout::from_size_align_unchecked(4 + len as usize, align);
std::alloc::dealloc(ptr, layout)
}
pub(crate) fn read_string(ptr: *const u8, len: usize) -> String {
let mut buffer = Vec::with_capacity(len);
let len = len as isize;
for i in 0..len {
buffer.push(unsafe { ptr::read(ptr.offset(i)) });
}
pub(crate) fn read_string(ptr: *const u8) -> String {
let len = read_u32(ptr);
let buffer = read_bytes(ptr, 4, len as usize);
unsafe { String::from_utf8_unchecked(buffer) }
}
@@ -27,14 +28,32 @@ pub(crate) unsafe fn malloc_and_write_string(str: &str) -> (*mut u8, usize) {
let bytes = str.as_bytes();
let bytes_len = bytes.len();
let ptr = malloc(bytes_len);
write_bytes(ptr, bytes_len, bytes);
write_bytes(ptr, 4, bytes_len, bytes);
(ptr, bytes_len)
}
pub(crate) fn write_bytes(ptr: *mut u8, len: usize, bytes: &[u8]) {
pub(crate) fn read_u32(ptr: *const u8) -> u32 {
let vec_u32 = read_bytes(ptr, 0, 4);
let mut bytes_u32 = [0_u8; 4];
bytes_u32[0] = vec_u32[0];
bytes_u32[1] = vec_u32[1];
bytes_u32[2] = vec_u32[2];
bytes_u32[3] = vec_u32[3];
u32::from_be_bytes(bytes_u32)
}
pub(crate) fn read_bytes(ptr: *const u8, offset: isize, len: usize) -> Vec<u8> {
let mut buffer = Vec::with_capacity(len);
for i in 0..len {
buffer.push(unsafe { ptr::read(ptr.offset(offset + i as isize)) });
}
buffer
}
pub(crate) fn write_bytes(ptr: *mut u8, offset: isize, len: usize, bytes: &[u8]) {
let bytes_len = bytes.len();
assert!(bytes_len <= len);
for i in 0..bytes_len {
unsafe { ptr::write(ptr.offset(i as isize), bytes[i]) };
unsafe { ptr::write(ptr.offset(offset + i as isize), bytes[i]) };
}
}