sl4f_lib/fidl/sl4f.rs
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// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
use crate::common_utils::common::{read_json_from_vmo, write_json_to_vmo};
use crate::server::constants::CONCURRENT_REQ_LIMIT;
use crate::server::Facade;
use anyhow::Error;
use async_trait::async_trait;
use fidl_fuchsia_testing_sl4f::{
FacadeIteratorRequest, FacadeProviderRequest, FacadeProviderRequestStream,
};
use futures::stream::{StreamExt, TryStreamExt};
use serde_json::Value;
use std::sync::Arc;
use tracing::{error, info, warn};
/// Trait for the implementation of the FacadeProvider protocol.
#[async_trait(?Send)]
pub trait FacadeProvider {
/// Returns the object implementing Facade for the given facade name.
/// # Arguments:
/// * 'name' - A string representing the name of the facade.
fn get_facade(&self, name: &str) -> Option<Arc<dyn Facade>>;
/// Returns an iterator over all of the Facade implementations.
fn get_facades(&self) -> Box<dyn Iterator<Item = &Arc<dyn Facade>> + '_>;
/// Returns an iterator over all of the facade names.
fn get_facade_names(&self) -> Vec<String>;
/// Invoked on FacadeProvider.GetFacades(). Sends the list of hosted facades back to the client on
/// subsequent calls to FacadeIterator.GetNext() over the channel given to GetFacades().
/// # Arguments
/// * 'request' - A request from the FacadeProvider client. Must be a GetFacades() request.
async fn get_facades_impl(&self, request: FacadeProviderRequest) {
let iterator = match request {
FacadeProviderRequest::GetFacades { iterator, control_handle: _ } => iterator,
_ => panic!(
"get_facade_impl() must only be called with a FacadeProviderRequest::GetFacades."
),
};
// Wrap operation in an async block in order to capture any error.
let get_facades_fut = async {
let mut iterator = iterator.into_stream();
if let Some(FacadeIteratorRequest::GetNext { responder }) = iterator.try_next().await? {
// NOTE: if the list of facade names would exceed the channel buffer size,
// they should be split over back-to-back responses to GetNext().
responder.send(&self.get_facade_names())?;
if let Some(FacadeIteratorRequest::GetNext { responder }) =
iterator.try_next().await?
{
responder.send(&[])?; // Indicates completion.
}
}
Ok::<(), Error>(())
};
if let Err(error) = get_facades_fut.await {
error!(%error, "Failed to handle GetFacades()");
}
}
/// Invoked on FacadeProvider.Execute(). Executes the given command on a hosted facade.
/// # Arguments
/// * 'request' - A request from a FacadeProvider client. Must be an Execute() request.
async fn execute_impl(&self, request: FacadeProviderRequest) {
let (facade, command, params_blob, responder) = match request {
FacadeProviderRequest::Execute { facade, command, params_blob, responder } => {
(facade, command, params_blob, responder)
}
_ => {
panic!("execute_impl() must only be called with a FacadeProviderRequest::Execute.")
}
};
// Look-up the facade.
let facade = if let Some(f) = self.get_facade(&facade) {
f
} else {
let err_str = format!("Could not find facade: {}", facade);
error!("{}", err_str);
if let Err(send_error) = responder.send(None, Some(&err_str)) {
error!("Failed to send response with: {}", send_error);
}
return;
};
// Construct a JSON Value out of the params_blob.
let params = match read_json_from_vmo(¶ms_blob) {
Ok(value) => value,
Err(error) => {
if let Err(send_error) =
responder.send(None, Some(&format!("Failed to extract params: {}", error)))
{
error!(error = %send_error, "Failed to send response");
}
return;
}
};
// Execute the command on the facade. On error or empty result, send the response.
let result = match facade.handle_request(command, params).await {
Ok(Value::Null) => {
if let Err(error) = responder.send(None, None) {
error!(%error, "Failed to send response");
}
return;
}
Ok(result) => result,
Err(error) => {
if let Err(error) = responder.send(None, Some(&error.to_string())) {
error!(%error, "Failed to send response");
}
return;
}
};
// Write the result blob into a VMO and send the response.
if let Err(send_error) = match write_json_to_vmo(¶ms_blob, &result) {
Ok(()) => responder.send(Some(params_blob), None),
Err(error) => responder.send(None, Some(&format!("Failed to write result: {}", error))),
} {
error!(error = %send_error, "Failed to send response");
}
}
/// Cleans up transient state on all hosted facades. Invoked on FacadeProvider.Cleanup().
fn cleanup_impl(&self) {
for facade in self.get_facades() {
facade.cleanup();
}
}
/// Prints state for all hosted facades. Invoked on FacadeProvider.Print().
fn print_impl(&self) {
for facade in self.get_facades() {
facade.print();
}
}
/// Invoked on each incoming request. Invokes the appropriate handler code.
/// # Arguments
/// * 'request' - Incoming request on the FacadeProvider connection.
async fn handle_request(&self, request: FacadeProviderRequest) {
match request {
FacadeProviderRequest::GetFacades { iterator, control_handle } => {
self.get_facades_impl(FacadeProviderRequest::GetFacades {
iterator,
control_handle,
})
.await;
}
FacadeProviderRequest::Execute { facade, command, params_blob, responder } => {
info!("Received command {}.{}", facade, command);
self.execute_impl(FacadeProviderRequest::Execute {
facade,
command,
params_blob,
responder,
})
.await;
}
FacadeProviderRequest::Cleanup { responder } => {
self.cleanup_impl();
if let Err(error) = responder.send() {
warn!(%error, "Failed to notify completion of Cleanup()");
}
}
FacadeProviderRequest::Print { responder } => {
self.print_impl();
if let Err(error) = responder.send() {
error!(%error, "Failed to notify completion of Print()");
}
}
}
}
/// Invoked on an incoming FacadeProvider connection request. Requests arriving on the stream
/// will be handled concurrently.
/// NOTE: The main SL4F server doesn't appear to wait before any outstanding requests are
/// completed before allowing a cleanup operation to move forward, and this code similarly
/// makes no such effort. As such, it is up to the test harness to ensure that cleanup and
/// command requests do not interleave in order to ensure that the facades and device remain in
/// a consistent state.
/// # Arguments
/// * 'stream' - Incoming FacadeProvider request stream.
async fn run_facade_provider(&self, stream: FacadeProviderRequestStream) {
stream
.for_each_concurrent(CONCURRENT_REQ_LIMIT, |request| {
self.handle_request(request.unwrap())
})
.await;
}
}
#[cfg(test)]
mod tests {
use super::*;
use anyhow::format_err;
use fidl_fuchsia_testing_sl4f::FacadeProviderMarker;
use fuchsia_async as fasync;
use serde_json::json;
use std::cell::RefCell;
use std::collections::HashMap;
use std::pin::pin;
use std::task::Poll;
/// TestFacade provides a trivial Facade implementation which supports commands to interact
/// with the state.
#[derive(Debug)]
struct TestFacade {
// Trivial state accessed through TestFacade's implementation of Facade.
state: RefCell<bool>,
}
impl TestFacade {
pub fn new() -> TestFacade {
TestFacade { state: RefCell::new(false) }
}
}
#[async_trait(?Send)]
impl Facade for TestFacade {
async fn handle_request(&self, method: String, args: Value) -> Result<Value, Error> {
match method.as_str() {
"set" => {
if let Value::Bool(new_state) = args {
*self.state.borrow_mut() = new_state;
return Ok(json!(null));
}
panic!("Received invalid args");
}
"get" => {
if let Value::Null = args {
return Ok(json!(*self.state.borrow()));
}
panic!("Received invalid args");
}
_ => return Err(format_err!("Invalid TestFacade method {}", method)),
}
}
fn cleanup(&self) {
*self.state.borrow_mut() = false;
}
fn print(&self) {}
}
/// TestFacadeProvider provides a simple implementation of the FacadeProvider trait and hosts
/// the TestFacade.
struct TestFacadeProvider {
facades: HashMap<String, Arc<dyn Facade>>,
}
impl TestFacadeProvider {
pub fn new() -> TestFacadeProvider {
let mut facades: HashMap<String, Arc<dyn Facade>> = HashMap::new();
facades
.insert("test_facade".to_string(), Arc::new(TestFacade::new()) as Arc<dyn Facade>);
TestFacadeProvider { facades }
}
}
#[async_trait(?Send)]
impl FacadeProvider for TestFacadeProvider {
fn get_facade(&self, name: &str) -> Option<Arc<dyn Facade>> {
self.facades.get(name).map(Arc::clone)
}
fn get_facades(&self) -> Box<dyn Iterator<Item = &Arc<dyn Facade>> + '_> {
Box::new(self.facades.values())
}
fn get_facade_names(&self) -> Vec<String> {
self.facades.keys().cloned().collect()
}
}
/// This test exercises the default FacadeProvider server implementation provided in the
/// FacadeProvider trait using TestFacadeProvider and TestFacade. It creates server and client
/// endpoints to a channel, passing each respectively to async blocks for the server and client
/// functionality. These async blocks are joined and passed to a single-threaded executor. The
/// server simply waits on its endpoint. The client does the following:
/// 1. Gets and verifies initial state.
/// 2. Sets a new state.
/// 3. Gets and verifies a new state.
/// 4. Cleans up state.
/// 5. Gets and verifies the clean state.
/// 6. Releases the client end so that the server end can exit.
#[test]
fn test_facade_provider() -> Result<(), Error> {
let mut executor = fasync::TestExecutor::new();
let (proxy, stream) = fidl::endpoints::create_proxy_and_stream::<FacadeProviderMarker>();
let server_fut = async {
// Run the FacadeProvider server.
let sl4f = TestFacadeProvider::new();
sl4f.run_facade_provider(stream).await;
};
let client_fut = async {
// Get the initial state.
let vmo = zx::Vmo::create_with_opts(zx::VmoOptions::RESIZABLE, 0)?;
write_json_to_vmo(&vmo, &json!(null))?;
if let (Some(vmo), None) = proxy.execute("test_facade", "get", vmo).await? {
assert_eq!(false, read_json_from_vmo(&vmo)?.as_bool().unwrap());
} else {
panic!("Failed to get initial state.");
}
// Set the new state.
let vmo = zx::Vmo::create_with_opts(zx::VmoOptions::RESIZABLE, 0)?;
write_json_to_vmo(&vmo, &json!(true))?;
if let (None, None) = proxy.execute("test_facade", "set", vmo).await? {
} else {
panic!("Failed to set new state.");
}
// Get the new state.
let vmo = zx::Vmo::create_with_opts(zx::VmoOptions::RESIZABLE, 0)?;
write_json_to_vmo(&vmo, &json!(null))?;
if let (Some(vmo), None) = proxy.execute("test_facade", "get", vmo).await? {
assert_eq!(true, read_json_from_vmo(&vmo)?.as_bool().unwrap());
} else {
panic!("Failed to get new state.");
}
// Clean up the state.
proxy.cleanup().await?;
// Get the final state.
let vmo = zx::Vmo::create_with_opts(zx::VmoOptions::RESIZABLE, 0)?;
write_json_to_vmo(&vmo, &json!(null))?;
if let (Some(vmo), None) = proxy.execute("test_facade", "get", vmo).await? {
assert_eq!(false, read_json_from_vmo(&vmo)?.as_bool().unwrap());
} else {
panic!("Failed to get initial state.");
}
// Close the proxy.
drop(proxy);
Ok::<(), Error>(())
};
let mut combined_fut = pin!(async {
let (_, res) = futures::join!(server_fut, client_fut);
res.unwrap();
});
assert_eq!(Poll::Ready(()), executor.run_until_stalled(&mut combined_fut));
Ok(())
}
}