Integrate Ivan's arg parsing code into --invoke

Co-authored-by: Ivan Enderlin <ivan.enderlin@hoa-project.net>

src/bin/wasmer.rs

@@ -38,6 +38,7 @@ use wasmer_runtime_core::{
     backend::{Backend, Compiler, CompilerConfig, Features, MemoryBoundCheckMode},
     debug,
     loader::{Instance as LoadedInstance, LocalLoader},
+    Module,
 };
 #[cfg(feature = "wasi")]
 use wasmer_wasi;
@@ -246,18 +247,9 @@ struct Run {
 
 impl Run {
     /// Used with the `invoke` argument
-    fn parse_args(&self) -> Result<Vec<Value>, String> {
-        let mut args: Vec<Value> = Vec::new();
-        for arg in self.args.iter() {
-            let x = arg.as_str().parse().map_err(|_| {
-                format!(
-                    "Can't parse the provided argument {:?} as a integer",
-                    arg.as_str()
-                )
-            })?;
-            args.push(Value::I32(x));
-        }
-        Ok(args)
+    fn parse_args(&self, module: &Module, fn_name: &str) -> Result<Vec<Value>, String> {
+        utils::parse_args(module, fn_name, &self.args)
+            .map_err(|e| format!("Invoke failed: {:?}", e))
     }
 }
 
@@ -493,7 +485,7 @@ fn execute_wasi(
 
         if let Some(invoke_fn) = options.invoke.as_ref() {
             eprintln!("WARNING: Invoking aribtrary functions with WASI is not officially supported in the WASI standard yet.  Use this feature at your own risk!");
-            let args = options.parse_args()?;
+            let args = options.parse_args(&module, invoke_fn)?;
             let invoke_result = instance
                 .dyn_func(invoke_fn)
                 .map_err(|e| format!("Invoke failed: {:?}", e))?
@@ -825,12 +817,12 @@ fn execute_wasm(options: &Run) -> Result<(), String> {
                 .instantiate(&import_object)
                 .map_err(|e| format!("Can't instantiate module: {:?}", e))?;
 
-            let args = options.parse_args()?;
-
             let invoke_fn = match options.invoke.as_ref() {
                 Some(fun) => fun,
                 _ => "main",
             };
+            let args = options.parse_args(&module, invoke_fn)?;
+
             let result = instance
                 .dyn_func(&invoke_fn)
                 .map_err(|e| format!("{:?}", e))?

src/utils.rs

@@ -1,6 +1,105 @@
 //! Utility functions for the WebAssembly module
 
+use wasmer_runtime::{types::Type, Module, Value};
+use wasmer_runtime_core::{backend::SigRegistry, module::ExportIndex};
+
 /// Detect if a provided binary is a Wasm file
 pub fn is_wasm_binary(binary: &[u8]) -> bool {
     binary.starts_with(&[b'\0', b'a', b's', b'm'])
 }
+
+#[derive(Debug, Clone, Copy)]
+pub enum InvokeError {
+    CouldNotFindFunction,
+    ExportNotFunction,
+    WrongNumArgs { expected: u16, found: u16 },
+    CouldNotParseArgs,
+}
+
+/// Parses arguments for the `--invoke` flag on the run command
+pub fn parse_args(
+    module: &Module,
+    fn_name: &str,
+    args: &[String],
+) -> Result<Vec<Value>, InvokeError> {
+    let export_index = module
+        .info()
+        .exports
+        .get(fn_name)
+        .ok_or(InvokeError::CouldNotFindFunction)?;
+
+    let signature = if let ExportIndex::Func(func_index) = export_index {
+        let sig_index = module
+            .info()
+            .func_assoc
+            .get(*func_index)
+            .expect("broken invariant, incorrect func index");
+        SigRegistry.lookup_signature_ref(&module.info().signatures[*sig_index])
+    } else {
+        return Err(InvokeError::ExportNotFunction);
+    };
+
+    let parameter_types = signature.params();
+
+    if args.len() != parameter_types.len() {
+        return Err(InvokeError::WrongNumArgs {
+            expected: parameter_types.len() as _,
+            found: args.len() as _,
+        });
+    } else {
+        args.iter()
+            .enumerate()
+            .try_fold(
+                Vec::with_capacity(args.len()),
+                |mut accumulator, (nth, argument)| {
+                    if let Some(value) = match parameter_types[nth] {
+                        Type::I32 => argument
+                            .parse::<i32>()
+                            .map(|v| Some(Value::I32(v)))
+                            .unwrap_or_else(|_| {
+                                eprintln!("Failed to parse `{:?}` as an `i32`", argument);
+                                None
+                            }),
+                        Type::I64 => argument
+                            .parse::<i64>()
+                            .map(|v| Some(Value::I64(v)))
+                            .unwrap_or_else(|_| {
+                                eprintln!("Failed to parse `{:?}` as an `i64`", argument);
+                                None
+                            }),
+                        Type::V128 => argument
+                            .parse::<u128>()
+                            .map(|v| Some(Value::V128(v)))
+                            .unwrap_or_else(|_| {
+                                eprintln!("Failed to parse `{:?}` as an `i64`", argument);
+                                None
+                            }),
+                        Type::F32 => argument
+                            .parse::<f32>()
+                            .map(|v| Some(Value::F32(v)))
+                            .unwrap_or_else(|_| {
+                                eprintln!("Failed to parse `{:?}` as an `f32`", argument);
+                                None
+                            }),
+                        Type::F64 => argument
+                            .parse::<f64>()
+                            .map(|v| Some(Value::F64(v)))
+                            .unwrap_or_else(|_| {
+                                eprintln!("Failed to parse `{:?}` as an `f64`", argument);
+                                None
+                            }),
+                    } {
+                        accumulator.push(value);
+
+                        Some(accumulator)
+                    } else {
+                        None
+                    }
+                },
+            )
+            .map_or_else(
+                || Err(InvokeError::CouldNotParseArgs),
+                |arguments: Vec<Value>| Ok(arguments),
+            )
+    }
+}