wasmer/lib/runtime/src/cache.rs

use crate::Module;
use std::path::Path;
use wasmer_runtime_core::cache::{hash_data, Cache as CoreCache};
use wasmer_runtime_core::module::WasmHash;

pub use wasmer_runtime_core::cache::Error;

// /// On-disk storage of compiled WebAssembly.
// ///
// /// A `Cache` can be used to quickly reload already
// /// compiled WebAssembly from a previous execution
// /// during which the wasm was explicitly compiled
// /// as a `Cache`.
// ///
// /// # Usage:
// ///
// /// ```
// /// use wasmer_runtime::{compile_cache, Cache};
// ///
// /// # use wasmer_runtime::error::{CompileResult, CacheError};
// /// # fn make_cache(wasm: &[u8]) -> CompileResult<()> {
// /// // Make a cache.
// /// let cache = compile_cache(wasm)?;
// ///
// /// # Ok(())
// /// # }
// /// # fn usage_cache(cache: Cache) -> Result<(), CacheError> {
// /// // Store the cache in a file.
// /// cache.store("some_cache_file")?;
// ///
// /// // Load the cache.
// /// let cache = Cache::load("some_cache_file")?;
// /// let module = unsafe { cache.into_module()? };
// /// # Ok(())
// /// # }
// /// ```
// ///
// /// # Performance Characteristics:
// ///
// /// Loading caches from files has been optimized for latency.
// /// There is still more work to do that will reduce
// /// loading time, especially for very large modules,
// /// but it will require signifigant internal work.
// ///
// /// # Drawbacks:
// ///
// /// Due to internal shortcomings, you cannot convert
// /// a module into a `Cache`. This means that compiling
// /// into a `Cache` and then converting into a module
// /// has more overhead than directly compiling
// /// into a [`Module`].
// ///
// /// [`Module`]: struct.Module.html
// pub struct Cache(pub(crate) CoreCache);

// impl Cache {
//     /// Load a `Cache` from the file specified by `path`.
//     ///
//     /// # Usage:
//     ///
//     /// ```
//     /// use wasmer_runtime::Cache;
//     /// # use wasmer_runtime::error::CacheError;
//     ///
//     /// # fn load_cache() -> Result<(), CacheError> {
//     /// let cache = Cache::load("some_file.cache")?;
//     /// # Ok(())
//     /// # }
//     /// ```
//     pub fn load<P: AsRef<Path>>(path: P) -> Result<Self, Error> {
//         CoreCache::open(path).map(|core_cache| Cache(core_cache))
//     }

//     /// Convert a `Cache` into a [`Module`].
//     ///
//     /// [`Module`]: struct.Module.html
//     ///
//     /// # Usage:
//     ///
//     /// ```
//     /// use wasmer_runtime::Cache;
//     ///
//     /// # use wasmer_runtime::error::CacheError;
//     /// # fn cache2module(cache: Cache) -> Result<(), CacheError> {
//     /// let module = unsafe { cache.into_module()? };
//     /// # Ok(())
//     /// # }
//     /// ```
//     ///
//     /// # Notes:
//     ///
//     /// This method is unsafe because the runtime cannot confirm
//     /// that this cache was not tampered with or corrupted.
//     pub unsafe fn into_module(self) -> Result<Module, Error> {
//         let default_compiler = super::default_compiler();

//         wasmer_runtime_core::load_cache_with(self.0, default_compiler)
//     }

//     /// Compare the Sha256 hash of the wasm this cache was build
//     /// from with some other WebAssembly.
//     ///
//     /// The main use-case for this is invalidating old caches.
//     pub fn compare_wasm(&self, wasm: &[u8]) -> bool {
//         let param_wasm_hash = hash_data(wasm);
//         self.0.wasm_hash() as &[u8] == &param_wasm_hash as &[u8]
//     }

//     /// Store this cache in a file.
//     ///
//     /// # Notes:
//     ///
//     /// If a file exists at the specified path, it will be overwritten.
//     ///
//     /// # Usage:
//     ///
//     /// ```
//     /// use wasmer_runtime::Cache;
//     ///
//     /// # use wasmer_runtime::error::CacheError;
//     /// # fn store_cache(cache: Cache) -> Result<(), CacheError> {
//     /// cache.store("some_file.cache")?;
//     /// # Ok(())
//     /// # }
//     /// ```
//     pub fn store<P: AsRef<Path>>(&self, path: P) -> Result<(), Error> {
//         self.0.store(path)
//     }
// }

pub trait Cache {
    type Key;
    type LoadError;
    type StoreError;

    unsafe fn load(&self, key: Self::Key) -> Result<Module, Self::LoadError>;
    fn store(&mut self, module: Module) -> Result<Self::Key, Self::StoreError>;
}