feat: add embedder api for accessing imports/exports of a module

Signed-off-by: Florian Hartung <florian.hartung@dlr.de>

Author: florianhartung

src/execution/linker.rs

@@ -1,4 +1,5 @@
 use alloc::{
+    borrow::ToOwned,
     collections::btree_map::{BTreeMap, Entry},
     string::String,
     vec::Vec,
@@ -138,10 +139,9 @@ impl Linker {
         validation_info: &ValidationInfo,
     ) -> Result<Vec<ExternVal>, RuntimeError> {
         validation_info
-            .imports
-            .iter()
-            .map(|import| {
-                self.get_unchecked(import.module_name.clone(), import.name.clone())
+            .imports()
+            .map(|(module_name, name, _desc)| {
+                self.get_unchecked(module_name.to_owned(), name.to_owned())
                     .ok_or(RuntimeError::UnableToResolveExternLookup)
             })
             .collect()

src/lib.rs

@@ -11,7 +11,8 @@ extern crate log_wrapper;
 
 pub use core::error::ValidationError;
 pub use core::reader::types::{
-    export::ExportDesc, global::GlobalType, Limits, MemType, NumType, RefType, TableType, ValType,
+    export::ExportDesc, global::GlobalType, ExternType, Limits, MemType, NumType, RefType, FuncType, ResultType,
+    TableType, ValType,
 };
 pub use core::rw_spinlock;
 pub use execution::error::{RuntimeError, TrapError};

src/validation/mod.rs

@@ -1,3 +1,5 @@
+use core::iter::Map;
+
 use alloc::collections::btree_set::{self, BTreeSet};
 use alloc::vec::Vec;
 
@@ -9,7 +11,7 @@ use crate::core::reader::types::element::ElemType;
 use crate::core::reader::types::export::Export;
 use crate::core::reader::types::global::{Global, GlobalType};
 use crate::core::reader::types::import::{Import, ImportDesc};
-use crate::core::reader::types::{FuncType, MemType, ResultType, TableType};
+use crate::core::reader::types::{ExternType, FuncType, MemType, ResultType, TableType};
 use crate::core::reader::WasmReader;
 use crate::core::sidetable::Sidetable;
 use crate::{ExportDesc, ValidationError};
@@ -480,3 +482,34 @@ fn handle_section<T, F: FnOnce(&mut WasmReader, SectionHeader) -> Result<T, Vali
         _ => Ok(None),
     }
 }
+
+impl ValidationInfo<'_> {
+    /// Returns the imports of this module as an iterator. Each import consist
+    /// of a module name, a name and an extern type.
+    ///
+    /// See: WebAssembly Specification 2.0 - 7.1.5 - module_imports
+    pub fn imports<'a>(
+        &'a self,
+    ) -> Map<core::slice::Iter<'a, Import>, impl FnMut(&'a Import) -> (&'a str, &'a str, ExternType)>
+    {
+        self.imports.iter().map(|import| {
+            (
+                &*import.module_name,
+                &*import.name,
+                import.desc.extern_type(self),
+            )
+        })
+    }
+
+    /// Returns the exports of this module as an iterator. Each export consist
+    /// of a name, and an extern type.
+    ///
+    /// See: WebAssembly Specification 2.0 - 7.1.5 - module_exports
+    pub fn exports<'a>(
+        &'a self,
+    ) -> Map<core::slice::Iter<'a, Export>, impl FnMut(&'a Export) -> (&'a str, ExternType)> {
+        self.exports
+            .iter()
+            .map(|export| (&*export.name, export.desc.extern_type(self)))
+    }
+}

tests/module_imports_exports.rs

@@ -0,0 +1,103 @@
+use wasm::{validate, ExternType, FuncType, GlobalType, NumType, ResultType, ValType};
+
+#[test_log::test]
+fn empty_module() {
+    const EMPTY_MODULE: &str = r#"
+        (module)
+    "#;
+    let wasm_bytes = wat::parse_str(EMPTY_MODULE).unwrap();
+
+    let validation_info = validate(&wasm_bytes).unwrap();
+
+    assert_eq!(validation_info.imports().len(), 0);
+    assert_eq!(validation_info.exports().len(), 0);
+}
+
+#[test_log::test]
+fn imports() {
+    const MODULE_WITH_IMPORTS: &str = r#"
+        (module
+            (import "foo" "baz" (func))
+            (import "bar" "bat" (global (mut i64)))
+        )
+    "#;
+
+    let wasm_bytes = wat::parse_str(MODULE_WITH_IMPORTS).unwrap();
+
+    let validation_info = validate(&wasm_bytes).unwrap();
+
+    let imports: Vec<(&str, &str, ExternType)> = validation_info.imports().collect();
+
+    assert_eq!(
+        &imports,
+        &[
+            (
+                "foo",
+                "baz",
+                ExternType::Func(FuncType {
+                    params: ResultType {
+                        valtypes: Vec::new()
+                    },
+                    returns: ResultType {
+                        valtypes: Vec::new()
+                    },
+                })
+            ),
+            (
+                "bar",
+                "bat",
+                ExternType::Global(GlobalType {
+                    ty: ValType::NumType(NumType::I64),
+                    is_mut: true,
+                }),
+            )
+        ]
+    );
+
+    assert_eq!(validation_info.exports().len(), 0);
+}
+
+#[test_log::test]
+fn exports() {
+    const MODULE_WITH_EXPORTED_DEFINITIONS: &str = r#"
+        (module
+            (func $my_func (export "foo") (param i32) (result i64)
+                local.get 0
+                i64.extend_i32_u
+            )
+            (global $my_global (export "bar") (mut i32)
+                i32.const 123
+            )
+        )
+    "#;
+
+    let wasm_bytes = wat::parse_str(MODULE_WITH_EXPORTED_DEFINITIONS).unwrap();
+
+    let validation_info = validate(&wasm_bytes).unwrap();
+
+    let exports: Vec<(&str, ExternType)> = validation_info.exports().collect();
+
+    assert_eq!(
+        &exports,
+        &[
+            (
+                "foo",
+                ExternType::Func(FuncType {
+                    params: ResultType {
+                        valtypes: vec![ValType::NumType(NumType::I32)]
+                    },
+                    returns: ResultType {
+                        valtypes: vec![ValType::NumType(NumType::I64)],
+                    }
+                }),
+            ),
+            (
+                "bar",
+                ExternType::Global(GlobalType {
+                    ty: ValType::NumType(NumType::I32),
+                    is_mut: true
+                })
+            )
+        ]
+    )
+}