Merge #2821

2821: build(wasmer/cache): opt 'sys' into default feature r=syrusakbary a=kwonoj

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# Description
Context: this is originated from #2817 (comment) , where SWC (https://github.com/swc-project/swc) trying to setup its package dependencies orthogonally requires two distinct features of wasmer (js / sys), encounters feature selection getting merged by cargo. We have workaround it by manual opt in into each features, but the common dependency we have imports wasmer-cache, which ends up to enabling `sys` mandatory. It is also possible to do some workaround by having a feature with make dep as optional, but I feel it'd be better if `cache` allows to opt out from feature.

I am honestly not sure if this is acceptable or recommended approach to resolve issue. Please feel free to close if that's the case. 

# Review

- [ ] Add a short description of the change to the CHANGELOG.md file


Co-authored-by: OJ Kwon <[email protected]>
Co-authored-by: Syrus Akbary <[email protected]>

lib/api/Cargo.toml

@@ -154,5 +154,7 @@ js-default = ["js", "std", "wasm-types-polyfill"]
 
 wasm-types-polyfill = ["js", "wasmparser"]
 
+js-serializable-module = []
+
 [package.metadata.docs.rs]
 features = ["compiler", "core", "cranelift", "default-compiler", "default-dylib", "default-engine", "dylib", "engine", "jit", "native", "singlepass", "sys", "sys-default", "universal"]

lib/api/src/js/error.rs

@@ -87,3 +87,40 @@ pub enum WasmError {
     #[cfg_attr(feature = "std", error("{0}"))]
     Generic(String),
 }
+
+/// The Serialize error can occur when serializing a
+/// compiled Module into a binary.
+/// Copied from wasmer_engine::SerializeError
+#[derive(Debug)]
+#[cfg_attr(feature = "std", derive(Error))]
+pub enum SerializeError {
+    /// An IO error
+    #[cfg_attr(feature = "std", error(transparent))]
+    Io(#[from] std::io::Error),
+    /// A generic serialization error
+    #[cfg_attr(feature = "std", error("{0}"))]
+    Generic(String),
+}
+
+/// The Deserialize error can occur when loading a
+/// compiled Module from a binary.
+/// Copied from wasmer_engine::DeSerializeError
+#[derive(Error, Debug)]
+pub enum DeserializeError {
+    /// An IO error
+    #[cfg_attr(feature = "std", error(transparent))]
+    Io(#[from] std::io::Error),
+    /// A generic deserialization error
+    #[cfg_attr(feature = "std", error("{0}"))]
+    Generic(String),
+    /// Incompatible serialized binary
+    #[cfg_attr(feature = "std", error("incompatible binary: {0}"))]
+    Incompatible(String),
+    /// The provided binary is corrupted
+    #[cfg_attr(feature = "std", error("corrupted binary: {0}"))]
+    CorruptedBinary(String),
+    /// The binary was valid, but we got an error when
+    /// trying to allocate the required resources.
+    #[cfg_attr(feature = "std", error(transparent))]
+    Compiler(CompileError),
+}

lib/api/src/js/mod.rs

@@ -51,6 +51,7 @@ pub use wasmer_derive::WasmerEnv;
 
 pub use crate::js::cell::WasmCell;
 pub use crate::js::env::{HostEnvInitError, LazyInit, WasmerEnv};
+pub use crate::js::error::{DeserializeError, SerializeError};
 pub use crate::js::export::Export;
 pub use crate::js::exports::{ExportError, Exportable, Exports, ExportsIterator};
 pub use crate::js::externals::{

lib/api/src/js/module.rs

@@ -3,9 +3,9 @@ use crate::js::resolver::Resolver;
 use crate::js::store::Store;
 use crate::js::types::{ExportType, ImportType};
 // use crate::js::InstantiationError;
-use crate::js::error::CompileError;
 #[cfg(feature = "wat")]
 use crate::js::error::WasmError;
+use crate::js::error::{CompileError, DeserializeError, SerializeError};
 use crate::js::RuntimeError;
 use js_sys::{Reflect, Uint8Array, WebAssembly};
 use std::fmt;
@@ -62,6 +62,8 @@ pub struct Module {
     name: Option<String>,
     // WebAssembly type hints
     type_hints: Option<ModuleTypeHints>,
+    #[cfg(feature = "js-serializable-module")]
+    raw_bytes: Option<Vec<u8>>,
 }
 
 impl Module {
@@ -194,6 +196,8 @@ impl Module {
             module,
             type_hints,
             name,
+            #[cfg(feature = "js-serializable-module")]
+            raw_bytes: Some(binary.to_vec()),
         })
     }
 
@@ -273,6 +277,25 @@ impl Module {
         // self.artifact.module_ref().name.as_deref()
     }
 
+    /// Serializes a module into a binary representation that the `Engine`
+    /// can later process via [`Module::deserialize`].
+    ///
+    #[cfg(feature = "js-serializable-module")]
+    pub fn serialize(&self) -> Result<Vec<u8>, SerializeError> {
+        self.raw_bytes.clone().ok_or(SerializeError::Generic(
+            "Not able to serialize module".to_string(),
+        ))
+    }
+
+    /// Deserializes a serialized Module binary into a `Module`.
+    ///
+    /// This is safe since deserialization under `js` is essentially same as reconstructing `Module`.
+    /// We maintain the `unsafe` to preserve the same API as Wasmer
+    #[cfg(feature = "js-serializable-module")]
+    pub unsafe fn deserialize(store: &Store, bytes: &[u8]) -> Result<Self, DeserializeError> {
+        Self::new(store, bytes).map_err(|e| DeserializeError::Compiler(e))
+    }
+
     /// Sets the name of the current module.
     /// This is normally useful for stacktraces and debugging.
     ///
@@ -512,6 +535,8 @@ impl From<WebAssembly::Module> for Module {
             module,
             name: None,
             type_hints: None,
+            #[cfg(feature = "js-serializable-module")]
+            raw_bytes: None,
         }
     }
 }

lib/cache/Cargo.toml

@@ -11,7 +11,7 @@ readme = "README.md"
 edition = "2018"
 
 [dependencies]
-wasmer = { path = "../api", version = "=2.2.1", default-features = false, features = ["sys"] }
+wasmer = { path = "../api", version = "=2.2.1", default-features = false}
 hex = "0.4"
 thiserror = "1"
 blake3 = "1.0"
@@ -25,6 +25,8 @@ wasmer-engine-universal = { path = "../engine-universal", version = "=2.2.1" }
 wasmer-engine-dylib = { path = "../engine-dylib", version = "=2.2.1" }
 
 [features]
+default = ["wasmer/js-serializable-module", "filesystem"]
+filesystem = []
 blake3-pure = ["blake3/pure"]
 
 [[bench]]

lib/cache/src/filesystem.rs

@@ -1,3 +1,4 @@
+#![cfg_attr(not(feature = "filesystem"), allow(unused))]
 use crate::cache::Cache;
 use crate::hash::Hash;
 use std::fs::{create_dir_all, File};
@@ -35,6 +36,7 @@ pub struct FileSystemCache {
     ext: Option<String>,
 }
 
+#[cfg(feature = "filesystem")]
 impl FileSystemCache {
     /// Construct a new `FileSystemCache` around the specified directory.
     pub fn new<P: Into<PathBuf>>(path: P) -> io::Result<Self> {
@@ -84,6 +86,7 @@ impl FileSystemCache {
     }
 }
 
+#[cfg(feature = "filesystem")]
 impl Cache for FileSystemCache {
     type DeserializeError = DeserializeError;
     type SerializeError = SerializeError;

lib/cache/src/lib.rs

@@ -24,6 +24,7 @@ mod filesystem;
 mod hash;
 
 pub use crate::cache::Cache;
+#[cfg(feature = "filesystem")]
 pub use crate::filesystem::FileSystemCache;
 pub use crate::hash::Hash;