Commit 67ba114c authored by Kunshan Wang's avatar Kunshan Wang

API-GEN: Testing the API...

Test whether the generated stubs are reasonable.
parent 913aed14
......@@ -2,6 +2,10 @@ RUSTC=rustc
.PHONY: all
all: cclient
rustpart.a: *.rs
$(RUSTC) --crate-type=staticlib -o rustpart.a
#![allow(unused_variables)] // stubs
#![allow(dead_code)] // stubs
* This is a mock micro VM implementation. The purpose is to check whether the `` structs,
* the `` forwarder and the filler codes are correctly implemented (specifically,
* whether the parameters and the return values are correctly passed), and whether the
* auto-generated stubs are reasonable.
* This file can be used as a guideline for implementing the API. Some concerns are highlighted in
* the docstrings.
use std::os::raw::*;
use std::ffi::CStr;
use std::ffi::CString;
use std::collections::HashMap;
use api_c::*;
use api_bridge::*;
use deps::*;
* NOTE: This could be one of the two top-level functions that are exposed to the client.
* Unlike the MuVM, MuCtx and MuIRBuilder structs, this function is not standardised. The reason is
* that in a production setting, the micro VM may not even be created by the client. For example,
* if we use boot-images, the micro VM exists since the beginning of the execution. The pointer to
* the MuVM struct may be held by a global (static) variable and can never be freed.
* If the micro VM implementation allows the client to create new micro VM instances as requested,
* it can provide functions that return the C-level `struct MuVM*` pointers, such as this one, and
* the `mu_refimpl2_new` and `mu_refimpl2_new_ex` functions found in the reference implementation.
* In this example, the micro VM instance is created on the heap, using Box. The C-visible struct
* is created by the `make_new_MuVM` function generated in `api_bridge`, which populates the
* method table and sets the "real" MuVM pointer as its header.
pub extern fn new_mock_micro_vm(name: CMuCString) -> *mut CMuVM {
println!("name: {:?}", name);
......@@ -17,9 +46,12 @@ pub extern fn new_mock_micro_vm(name: CMuCString) -> *mut CMuVM {
println!("The client asked to create a micro VM: {}", rust_name);
// let mut muvm: Box<MuVM> = Default::default();
// muvm.my_name = rust_name;
let muvm = Box::new(MuVM {
my_name: rust_name,
contexts: Vec::new(),
let muvm_ptr = Box::into_raw(muvm);
......@@ -46,11 +78,32 @@ pub extern fn free_mock_micro_vm(cmvm: *mut CMuVM) {
println!("All structures re-boxed and ready for deallocation. By the way, is it really possible to destroy a micro VM in a productional setting?");
* The micro VM itself.
* NOTE: If the "real" micro VM is implemented in a different place (such as `../`), it could
* be defined as:
* ```rust
* pub type MuVM = vm.VM;
* // in
* impl VM {
* // copy the stubs here.
* }
* ```
* Neither the client nor the `` can tell which is the actual MuVM struct, because it
* is not exposed to C, and the `` forwarders never access any field in the high-level
* MuVM struct.
pub struct MuVM {
my_name: String,
contexts: Vec<MuCtx>,
cname_dict: HashMap<MuID, CString>,
trap_handler: Option<CMuTrapHandler>,
trap_handler_user_data: Option<CMuCPtr>,
pub struct MuCtx {
......@@ -67,19 +120,40 @@ impl MuVM {
pub fn id_of(&mut self, name: MuName) -> MuID {
if name == "@truth" {
if name == "@forty_two" {
} else {
panic!("I don't know the id of it")
panic!("I don't know the id of {}", name)
* The client expects a "const char*" (expressed in the muapi.h as "char*", but "const char*"
* should be more appropriate). The client does not know when it should free that string, so
* the micro VM has to immortalise a CString object. In this example, the Rust-level MuVM
* struct holds a `cname_dict` hashmap which owns all CString instances.
pub fn name_of(&mut self, id: MuID) -> CMuCString {
panic!("Not implemented")
let c_string = self.cname_dict.entry(id).or_insert_with(|| {
println!("Creating name for ID {}...", id);
let rust_string = format!("{}", id);
// Indeed the returned string is const, but the C API does not properly express the
// constness. Perhaps the C API can be improved without adding too much complexity.
c_string.as_ptr() as CMuCString
pub fn set_trap_handler(&mut self, trap_handler: CMuTrapHandler, userdata: CMuCPtr) {
panic!("Not implemented")
self.trap_handler = Some(trap_handler);
self.trap_handler_user_data = Some(userdata);
println!("Set the trap handler to {:?} and the userdata to {:?}", trap_handler, userdata);
println!("Let's call the trap handler now.");
// TODO: Call the trap handler to test it.
......@@ -9,6 +9,18 @@ int main() {
MuVM *mvm = new_mock_micro_vm("cclientt");
MuID forty_two = mvm->id_of(mvm, "@forty_two");
printf("forty_two = %d\n", forty_two);
MuName name_43 = mvm->name_of(mvm, 43);
printf("name_43 = '%s'\n", name_43);
MuName name_43_2 = mvm->name_of(mvm, 43);
printf("name_43_2 = '%s'\n", name_43_2);
// TODO: Register a trap handler to see if Rust can really call back.
return 0;
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