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use crate::Module;
use memmap::Mmap;
use std::{
fmt,
fs::{create_dir_all, File},
io::{self, Write},
path::PathBuf,
};
pub use super::Backend;
use wasmer_runtime_core::cache::Error as CacheError;
pub use wasmer_runtime_core::cache::{Artifact, WasmHash};
pub trait Cache {
type LoadError: fmt::Debug;
type StoreError: fmt::Debug;
fn load(&self, key: WasmHash) -> Result<Module, Self::LoadError>;
fn load_with_backend(&self, key: WasmHash, backend: Backend)
-> Result<Module, Self::LoadError>;
fn store(&mut self, key: WasmHash, module: Module) -> Result<(), Self::StoreError>;
}
pub struct FileSystemCache {
path: PathBuf,
}
impl FileSystemCache {
pub unsafe fn new<P: Into<PathBuf>>(path: P) -> io::Result<Self> {
let path: PathBuf = path.into();
if path.exists() {
let metadata = path.metadata()?;
if metadata.is_dir() {
if !metadata.permissions().readonly() {
Ok(Self { path })
} else {
Err(io::Error::new(
io::ErrorKind::PermissionDenied,
format!("the supplied path is readonly: {}", path.display()),
))
}
} else {
Err(io::Error::new(
io::ErrorKind::PermissionDenied,
format!(
"the supplied path already points to a file: {}",
path.display()
),
))
}
} else {
create_dir_all(&path)?;
Ok(Self { path })
}
}
}
impl Cache for FileSystemCache {
type LoadError = CacheError;
type StoreError = CacheError;
fn load(&self, key: WasmHash) -> Result<Module, CacheError> {
self.load_with_backend(key, Backend::default())
}
fn load_with_backend(&self, key: WasmHash, backend: Backend) -> Result<Module, CacheError> {
let filename = key.encode();
let mut new_path_buf = self.path.clone();
new_path_buf.push(backend.to_string());
new_path_buf.push(filename);
let file = File::open(new_path_buf)?;
let mmap = unsafe { Mmap::map(&file)? };
let serialized_cache = Artifact::deserialize(&mmap[..])?;
unsafe {
wasmer_runtime_core::load_cache_with(
serialized_cache,
crate::compiler_for_backend(backend)
.ok_or_else(|| CacheError::UnsupportedBackend(backend.to_string().to_owned()))?
.as_ref(),
)
}
}
fn store(&mut self, key: WasmHash, module: Module) -> Result<(), CacheError> {
let filename = key.encode();
let backend_str = module.info().backend.to_string();
let mut new_path_buf = self.path.clone();
new_path_buf.push(backend_str);
let serialized_cache = module.cache()?;
let buffer = serialized_cache.serialize()?;
std::fs::create_dir_all(&new_path_buf)?;
new_path_buf.push(filename);
let mut file = File::create(new_path_buf)?;
file.write_all(&buffer)?;
Ok(())
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::env;
#[test]
fn test_file_system_cache_run() {
use crate::{compile, imports, Func};
use wabt::wat2wasm;
static WAT: &'static str = r#"
(module
(type $t0 (func (param i32) (result i32)))
(func $add_one (export "add_one") (type $t0) (param $p0 i32) (result i32)
get_local $p0
i32.const 1
i32.add))
"#;
let wasm = wat2wasm(WAT).unwrap();
let module = compile(&wasm).unwrap();
let cache_dir = env::temp_dir();
println!("test temp_dir {:?}", cache_dir);
let mut fs_cache = unsafe {
FileSystemCache::new(cache_dir)
.map_err(|e| format!("Cache error: {:?}", e))
.unwrap()
};
let key = WasmHash::generate(&wasm);
fs_cache.store(key, module.clone()).unwrap();
let cached_module = fs_cache.load(key).unwrap();
let import_object = imports! {};
let instance = cached_module.instantiate(&import_object).unwrap();
let add_one: Func<i32, i32> = instance.func("add_one").unwrap();
let value = add_one.call(42).unwrap();
assert_eq!(value, 43);
}
}