Improved Module api along with Exports

lib/api/src/module.rs

@@ -7,7 +7,7 @@ use std::sync::Arc;
 use thiserror::Error;
 use wasmer_compiler::{CompileError, WasmError};
 use wasmer_jit::{CompiledModule, DeserializeError, Resolver, SerializeError};
-use wasmer_runtime::InstanceHandle;
+use wasmer_runtime::{ExportsIterator, InstanceHandle, Module as ModuleInfo};
 
 #[derive(Error, Debug)]
 pub enum IoCompileError {
@@ -274,11 +274,21 @@ impl Module {
     ///     export.ty();
     /// }
     /// ```
-    pub fn exports<'a>(&'a self) -> impl Iterator<Item = ExportType> + 'a {
+    pub fn exports<'a>(&'a self) -> ExportsIterator<impl Iterator<Item = ExportType> + 'a> {
         self.compiled.module().exports()
     }
 
     pub fn store(&self) -> &Store {
         &self.store
     }
+
+    // The ABI of the ModuleInfo is very unstable, we refactor it very often.
+    // This funciton is public because in some cases it can be useful to get some
+    // extra information from the module.
+    //
+    // However, the usage is highly discouraged.
+    #[doc(hidden)]
+    pub fn info(&self) -> &ModuleInfo {
+        &self.compiled.module()
+    }
 }

lib/runtime/src/instance.rs

@@ -339,7 +339,7 @@ impl Instance {
 
     /// Return an iterator over the exports of this instance.
     ///
-    /// Specifically, it provides access to the key-value pairs, where they keys
+    /// Specifically, it provides access to the key-value pairs, where the keys
     /// are export names, and the values are export declarations which can be
     /// resolved `lookup_by_declaration`.
     pub fn exports(&self) -> indexmap::map::Iter<String, ExportIndex> {

lib/runtime/src/lib.rs

@@ -41,7 +41,9 @@ pub use crate::imports::Imports;
 pub use crate::instance::InstanceHandle;
 pub use crate::memory::LinearMemory;
 pub use crate::mmap::Mmap;
-pub use crate::module::{MemoryPlan, MemoryStyle, Module, TableElements, TablePlan, TableStyle};
+pub use crate::module::{
+    ExportsIterator, MemoryPlan, MemoryStyle, Module, TableElements, TablePlan, TableStyle,
+};
 pub use crate::probestack::PROBESTACK;
 pub use crate::sig_registry::SignatureRegistry;
 pub use crate::table::Table;

lib/runtime/src/module.rs

@@ -5,6 +5,7 @@ use indexmap::IndexMap;
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 use std::fmt;
+use std::iter::ExactSizeIterator;
 use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
 use std::sync::Arc;
 use wasm_common::entity::{EntityRef, PrimaryMap};
@@ -134,7 +135,7 @@ pub struct Module {
     /// WebAssembly function signatures.
     pub signatures: PrimaryMap<SignatureIndex, FunctionType>,
 
-    /// Types of functions (imported and local).
+    /// WebAssembly functions (imported and local).
     pub functions: PrimaryMap<FunctionIndex, SignatureIndex>,
 
     /// WebAssembly tables (imported and local).
@@ -206,8 +207,8 @@ impl Module {
     }
 
     /// Get the export types of the module
-    pub fn exports<'a>(&'a self) -> impl Iterator<Item = ExportType> + 'a {
+    pub fn exports<'a>(&'a self) -> ExportsIterator<impl Iterator<Item = ExportType> + 'a> {
-        self.exports.iter().map(move |(name, export_index)| {
+        let iter = self.exports.iter().map(move |(name, export_index)| {
             let extern_type = match export_index {
                 ExportIndex::Function(i) => {
                     let signature = self.functions.get(i.clone()).unwrap();
@@ -228,7 +229,11 @@ impl Module {
                 }
             };
             ExportType::new(name, extern_type)
-        })
+        });
+        ExportsIterator {
+            iter,
+            size: self.exports.len(),
+        }
     }
 
     /// Get the export types of the module
@@ -348,3 +353,56 @@ impl fmt::Display for Module {
         write!(f, "{}", self.name())
     }
 }
+
+// Code inspired from
+// https://www.reddit.com/r/rust/comments/9vspv4/extending_iterators_ergonomically/
+/// This iterator allows us to iterate
+pub struct ExportsIterator<I: Iterator<Item = ExportType> + Sized> {
+    iter: I,
+    size: usize,
+}
+
+impl<I: Iterator<Item = ExportType> + Sized> ExactSizeIterator for ExportsIterator<I> {
+    // We can easily calculate the remaining number of iterations.
+    fn len(&self) -> usize {
+        self.size
+    }
+}
+
+impl<I: Iterator<Item = ExportType> + Sized> ExportsIterator<I> {
+    /// Get only the functions
+    pub fn functions(self) -> impl Iterator<Item = ExportType<FunctionType>> + Sized {
+        self.iter.filter_map(|extern_| match extern_.ty() {
+            ExternType::Function(ty) => Some(ExportType::new(extern_.name(), ty.clone())),
+            _ => None,
+        })
+    }
+    /// Get only the memories
+    pub fn memories(self) -> impl Iterator<Item = ExportType<MemoryType>> + Sized {
+        self.iter.filter_map(|extern_| match extern_.ty() {
+            ExternType::Memory(ty) => Some(ExportType::new(extern_.name(), ty.clone())),
+            _ => None,
+        })
+    }
+    /// Get only the tables
+    pub fn tables(self) -> impl Iterator<Item = ExportType<TableType>> + Sized {
+        self.iter.filter_map(|extern_| match extern_.ty() {
+            ExternType::Table(ty) => Some(ExportType::new(extern_.name(), ty.clone())),
+            _ => None,
+        })
+    }
+    /// Get only the globals
+    pub fn globals(self) -> impl Iterator<Item = ExportType<GlobalType>> + Sized {
+        self.iter.filter_map(|extern_| match extern_.ty() {
+            ExternType::Global(ty) => Some(ExportType::new(extern_.name(), ty.clone())),
+            _ => None,
+        })
+    }
+}
+
+impl<I: Iterator<Item = ExportType> + Sized> Iterator for ExportsIterator<I> {
+    type Item = ExportType;
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next()
+    }
+}

lib/wasm-common/src/types.rs

@@ -502,17 +502,21 @@ impl ImportType {
 /// [`Module::exports`](crate::Module::exports) accessor and describes what
 /// names are exported from a wasm module and the type of the item that is
 /// exported.
+///
+/// The `<T>` refefers to `ExternType`, however it can also refer to use
+/// `MemoryType`, `TableType`, `FunctionType` and `GlobalType` for ease of
+/// use.
 #[derive(Debug, Clone)]
 #[cfg_attr(feature = "enable-serde", derive(Serialize, Deserialize))]
-pub struct ExportType {
+pub struct ExportType<T = ExternType> {
     name: String,
-    ty: ExternType,
+    ty: T,
 }
 
-impl ExportType {
+impl<T> ExportType<T> {
     /// Creates a new export which is exported with the given `name` and has the
     /// given `ty`.
-    pub fn new(name: &str, ty: ExternType) -> ExportType {
+    pub fn new(name: &str, ty: T) -> Self {
         ExportType {
             name: name.to_string(),
             ty,
@@ -525,7 +529,7 @@ impl ExportType {
     }
 
     /// Returns the type of this export.
-    pub fn ty(&self) -> &ExternType {
+    pub fn ty(&self) -> &T {
         &self.ty
     }
 }