wasmer/lib/runtime-c-api/src/memory.rs
2019-03-29 16:35:35 +01:00

109 lines
3.3 KiB
Rust

//! Create, read, write, grow, destroy memory of an instance.
use crate::{error::update_last_error, wasmer_limits_t, wasmer_result_t};
use libc::{uint32_t, uint8_t};
use std::cell::Cell;
use wasmer_runtime::Memory;
use wasmer_runtime_core::{
types::MemoryDescriptor,
units::{Bytes, Pages},
};
#[repr(C)]
#[derive(Clone)]
pub struct wasmer_memory_t;
/// Creates a new Memory for the given descriptor and initializes the given
/// pointer to pointer to a pointer to the new memory.
///
/// The caller owns the object and should call `wasmer_memory_destroy` to free it.
///
/// Returns `wasmer_result_t::WASMER_OK` upon success.
///
/// Returns `wasmer_result_t::WASMER_ERROR` upon failure. Use `wasmer_last_error_length`
/// and `wasmer_last_error_message` to get an error message.
#[no_mangle]
pub unsafe extern "C" fn wasmer_memory_new(
memory: *mut *mut wasmer_memory_t,
limits: wasmer_limits_t,
) -> wasmer_result_t {
let max = if limits.max.has_some {
Some(Pages(limits.max.some))
} else {
None
};
let desc = MemoryDescriptor {
minimum: Pages(limits.min),
maximum: max,
shared: false,
};
let result = Memory::new(desc);
let new_memory = match result {
Ok(memory) => memory,
Err(error) => {
update_last_error(error);
return wasmer_result_t::WASMER_ERROR;
}
};
*memory = Box::into_raw(Box::new(new_memory)) as *mut wasmer_memory_t;
wasmer_result_t::WASMER_OK
}
/// Grows a Memory by the given number of pages.
///
/// Returns `wasmer_result_t::WASMER_OK` upon success.
///
/// Returns `wasmer_result_t::WASMER_ERROR` upon failure. Use `wasmer_last_error_length`
/// and `wasmer_last_error_message` to get an error message.
#[allow(clippy::cast_ptr_alignment)]
#[no_mangle]
pub extern "C" fn wasmer_memory_grow(
memory: *mut wasmer_memory_t,
delta: uint32_t,
) -> wasmer_result_t {
let memory = unsafe { &*(memory as *mut Memory) };
let delta_result = memory.grow(Pages(delta));
match delta_result {
Ok(_) => wasmer_result_t::WASMER_OK,
Err(grow_error) => {
update_last_error(grow_error);
wasmer_result_t::WASMER_ERROR
}
}
}
/// Returns the current length in pages of the given memory
#[allow(clippy::cast_ptr_alignment)]
#[no_mangle]
pub extern "C" fn wasmer_memory_length(memory: *const wasmer_memory_t) -> uint32_t {
let memory = unsafe { &*(memory as *const Memory) };
let Pages(len) = memory.size();
len
}
/// Gets the start pointer to the bytes within a Memory
#[allow(clippy::cast_ptr_alignment)]
#[no_mangle]
pub extern "C" fn wasmer_memory_data(mem: *const wasmer_memory_t) -> *mut uint8_t {
let memory = unsafe { &*(mem as *const Memory) };
memory.view::<u8>()[..].as_ptr() as *mut Cell<u8> as *mut u8
}
/// Gets the size in bytes of a Memory
#[allow(clippy::cast_ptr_alignment)]
#[no_mangle]
pub extern "C" fn wasmer_memory_data_length(mem: *mut wasmer_memory_t) -> uint32_t {
let memory = mem as *mut Memory;
let Bytes(len) = unsafe { (*memory).size().bytes() };
len as uint32_t
}
/// Frees memory for the given Memory
#[allow(clippy::cast_ptr_alignment)]
#[no_mangle]
pub extern "C" fn wasmer_memory_destroy(memory: *mut wasmer_memory_t) {
if !memory.is_null() {
unsafe { Box::from_raw(memory as *mut Memory) };
}
}