Update from feedback, improve docs on new wasi fns

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## **[Unreleased]**
 
+- [#957](https://github.com/wasmerio/wasmer/pull/957) Change the meaning of `wasmer_wasi::is_wasi_module` to detect any type of WASI module, add support for new wasi snapshot_preview1
+
 ## 0.10.0 - 2019-11-11
 
 - [#952](https://github.com/wasmerio/wasmer/pull/952) Use C preprocessor to properly hide trampoline functions on Windows and non-x86_64 targets.

Cargo.lock

@@ -1504,6 +1504,7 @@ dependencies = [
  "tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "wabt 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasmer-clif-backend 0.10.1",
+ "wasmer-llvm-backend 0.10.1",
  "wasmer-runtime-core 0.10.1",
  "wasmer-singlepass-backend 0.10.1",
 ]

lib/wasi/src/lib.rs

@@ -12,7 +12,7 @@
 
 //! Wasmer's WASI implementation
 //!
-//! Use `generate_import_object` to create an `ImportObject`.  This `ImportObject`
+//! Use `generate_import_object` to create an [`ImportObject`].  This [`ImportObject`]
 //! can be combined with a module to create an `Instance` which can execute WASI
 //! Wasm functions.
 //!
@@ -47,7 +47,8 @@ pub struct ExitCode {
     pub code: syscalls::types::__wasi_exitcode_t,
 }
 
-/// Creates a Wasi [`ImportObject`] with [`WasiState`].
+/// Creates a Wasi [`ImportObject`] with [`WasiState`] with the latest snapshot
+/// of WASI.
 pub fn generate_import_object(
     args: Vec<Vec<u8>>,
     envs: Vec<Vec<u8>>,
@@ -130,7 +131,7 @@ pub fn generate_import_object(
 }
 
 #[cfg(feature = "snapshot0")]
-/// Creates a Wasi [`ImportObject`] with [`WasiState`].
+/// Creates a legacy Wasi [`ImportObject`] with [`WasiState`].
 pub fn generate_import_object_snapshot0(
     args: Vec<Vec<u8>>,
     envs: Vec<Vec<u8>>,

lib/wasi/src/utils.rs

@@ -1,9 +1,10 @@
 use wasmer_runtime_core::module::Module;
 
 #[allow(dead_code)]
-/// Check if a provided module is compiled with WASI support
+/// Check if a provided module is compiled for some version of WASI.
+/// Use [`get_wasi_version`] to find out which version of WASI the module is.
 pub fn is_wasi_module(module: &Module) -> bool {
-    get_wasi_version(module) == Some(WasiVersion::Snapshot1)
+    get_wasi_version(module).is_some()
 }
 
 /// The version of WASI.  This is determined by the namespace string
@@ -15,6 +16,7 @@ pub enum WasiVersion {
     Snapshot1,
 }
 
+/// Detect the version of WASI being used from the namespace
 pub fn get_wasi_version(module: &Module) -> Option<WasiVersion> {
     let mut import_iter = module
         .info()
@@ -25,13 +27,15 @@ pub fn get_wasi_version(module: &Module) -> Option<WasiVersion> {
     // returns None if empty
     let first = import_iter.next()?;
     if import_iter.all(|idx| idx == first) {
+        // once we know that all the namespaces are the same, we can use it to
+        // detect which version of WASI this is
         match module.info().namespace_table.get(first) {
             "wasi_unstable" => Some(WasiVersion::Snapshot0),
             "wasi_snapshot_preview1" => Some(WasiVersion::Snapshot1),
             _ => None,
         }
     } else {
-        // not all funcs have the same namespace: therefore it's not WASI
+        // not all funcs have the same namespace, therefore it's not WASI
         None
     }
 }