Use Mutex, simplify everything

Cargo.lock

@@ -46,6 +46,7 @@ dependencies = [
  "fluence-faas",
  "log",
  "maplit",
+ "parking_lot 0.11.1",
  "serde",
  "serde_json",
  "stepper-interface",
@@ -1203,6 +1204,15 @@ dependencies = [
  "safe-transmute",
 ]
 
+[[package]]
+name = "instant"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "61124eeebbd69b8190558df225adf7e4caafce0d743919e5d6b19652314ec5ec"
+dependencies = [
+ "cfg-if 1.0.0",
+]
+
 [[package]]
 name = "inventory"
 version = "0.1.10"
@@ -1338,6 +1348,15 @@ dependencies = [
  "scopeguard",
 ]
 
+[[package]]
+name = "lock_api"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd96ffd135b2fd7b973ac026d28085defbe8983df057ced3eb4f2130b0831312"
+dependencies = [
+ "scopeguard",
+]
+
 [[package]]
 name = "log"
 version = "0.4.11"
@@ -1639,8 +1658,19 @@ version = "0.10.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d3a704eb390aafdc107b0e392f56a82b668e3a71366993b5340f5833fd62505e"
 dependencies = [
- "lock_api",
+ "lock_api 0.3.4",
- "parking_lot_core",
+ "parking_lot_core 0.7.2",
+]
+
+[[package]]
+name = "parking_lot"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6d7744ac029df22dca6284efe4e898991d28e3085c706c972bcd7da4a27a15eb"
+dependencies = [
+ "instant",
+ "lock_api 0.4.2",
+ "parking_lot_core 0.8.2",
 ]
 
 [[package]]
@@ -1657,6 +1687,20 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "parking_lot_core"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ccb628cad4f84851442432c60ad8e1f607e29752d0bf072cbd0baf28aa34272"
+dependencies = [
+ "cfg-if 1.0.0",
+ "instant",
+ "libc",
+ "redox_syscall",
+ "smallvec",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "percent-encoding"
 version = "2.1.0"
@@ -2848,7 +2892,7 @@ dependencies = [
  "libc",
  "nix 0.15.0",
  "page_size",
- "parking_lot",
+ "parking_lot 0.10.2",
  "rustc_version",
  "serde",
  "serde-bench",
@@ -2877,7 +2921,7 @@ dependencies = [
  "libc",
  "nix 0.15.0",
  "page_size",
- "parking_lot",
+ "parking_lot 0.10.2",
  "rustc_version",
  "serde",
  "serde-bench",

aquamarine-vm/Cargo.toml

@@ -18,6 +18,7 @@ maplit = "1.0.2"
 serde_json = "1.0.60"
 serde = "1.0.118"
 log = "0.4.11"
+parking_lot = "0.11.1"
 
 [features]
 # enable raw AquamarineVM API intended for testing

aquamarine-vm/src/aquamarine_stepper_vm.rs

@@ -25,10 +25,9 @@ use fluence_faas::IValue;
 use stepper_interface::StepperOutcome;
 
 use std::path::PathBuf;
-use std::cell::{RefCell};
-use std::rc::Rc;
 use std::ops::{Deref, DerefMut};
-use std::borrow::Cow;
+use std::sync::Arc;
+use parking_lot::{Mutex};
 
 const CALL_SERVICE_NAME: &str = "call_service";
 const CURRENT_PEER_ID_ENV_NAME: &str = "CURRENT_PEER_ID";
@@ -49,9 +48,9 @@ impl DerefMut for SendSafeFaaS {
     }
 }
 
-#[derive(Debug, Default)]
+#[derive(Debug, Default, Clone)]
 pub struct ParticleParams {
-    pub init_peer_id: String,
+    pub init_user_id: String,
     pub particle_id: String,
 }
 
@@ -60,7 +59,8 @@ pub struct AquamarineVM {
     particle_data_store: PathBuf,
     /// file name of the AIR interpreter .wasm
     wasm_filename: String,
-    current_particle: Rc<RefCell<ParticleParams>>,
+    /// information about the particle that is being executed at the moment
+    current_particle: Arc<Mutex<ParticleParams>>,
 }
 
 impl AquamarineVM {
@@ -68,20 +68,15 @@ impl AquamarineVM {
     pub fn new(config: AquamarineVMConfig) -> Result<Self> {
         use AquamarineVMError::InvalidDataStorePath;
 
-        let current_particle: Rc<RefCell<ParticleParams>> = <_>::default();
+        let current_particle: Arc<Mutex<ParticleParams>> = <_>::default();
         let call_service = config.call_service;
         let params = current_particle.clone();
         let call_service_closure: HostExportedFunc = Box::new(move |_, ivalues: Vec<IValue>| {
-            let params = params.deref().try_borrow();
+            let params = {
-            match params {
+                let lock = params.lock();
-                Ok(params) => call_service(params.deref(), ivalues),
+                lock.deref().clone()
-                Err(err) => {
+            };
-                    let err = AquamarineVMError::BorrowParticleParams(err);
+            call_service(params, ivalues)
-                    log::error!("UNEXPECTED: {}", err);
-                    // TODO: return error to the stepper?
-                    None
-                }
-            }
         });
         let import_descriptor = HostImportDescriptor {
             host_exported_func: call_service_closure,
@@ -120,32 +115,28 @@ impl AquamarineVM {
         init_user_id: impl Into<String>,
         aqua: impl Into<String>,
         data: impl Into<Vec<u8>>,
-        particle_id: Cow<'_, str>,
+        particle_id: impl Into<String>,
     ) -> Result<StepperOutcome> {
         use AquamarineVMError::PersistDataError;
 
-        match self.current_particle.try_borrow_mut() {
+        let particle_id = particle_id.into();
-            Ok(mut params) => params.particle_id = particle_id.to_string(),
+        let init_user_id = init_user_id.into();
-            Err(err) => {
-                let err = AquamarineVMError::BorrowMutParticleParams(err);
-                log::error!("UNEXPECTED: {}", err);
-                return Err(err);
-            }
-        }
 
-        let prev_data_path = self.particle_data_store.join(particle_id.deref());
+        let prev_data_path = self.particle_data_store.join(&particle_id);
         // TODO: check for errors related to invalid file content (such as invalid UTF8 string)
         let prev_data = std::fs::read_to_string(&prev_data_path).unwrap_or_default();
 
         let prev_data = into_ibytes_array(prev_data.into_bytes());
         let data = into_ibytes_array(data.into());
         let args = vec![
-            IValue::String(init_user_id.into()),
+            IValue::String(init_user_id.clone()),
             IValue::String(aqua.into()),
             IValue::Array(prev_data),
             IValue::Array(data),
         ];
 
+        self.update_current_particle(particle_id, init_user_id);
+
         let result =
             self.faas
                 .call_with_ivalues(&self.wasm_filename, "invoke", &args, <_>::default())?;
@@ -159,6 +150,12 @@ impl AquamarineVM {
 
         Ok(outcome)
     }
+
+    pub fn update_current_particle(&self, particle_id: String, init_user_id: String) {
+        let mut params = self.current_particle.lock();
+        params.particle_id = particle_id;
+        params.init_user_id = init_user_id;
+    }
 }
 
 /// Splits given path into its directory and file stem

aquamarine-vm/src/config.rs

@@ -19,7 +19,7 @@ use std::path::PathBuf;
 use crate::aquamarine_stepper_vm::ParticleParams;
 use crate::IValue;
 
-type CallServiceClosure = Box<dyn Fn(&ParticleParams, Vec<IValue>) -> Option<IValue> + 'static>;
+type CallServiceClosure = Box<dyn Fn(ParticleParams, Vec<IValue>) -> Option<IValue> + 'static>;
 
 /// Describes behaviour of the Aquamarine VM stepper.
 pub struct AquamarineVMConfig {

aquamarine-vm/src/errors.rs

@@ -19,7 +19,6 @@ use fluence_faas::FaaSError;
 use std::io::Error as IOError;
 use std::error::Error;
 use std::path::PathBuf;
-use std::cell::{BorrowError, BorrowMutError};
 
 #[derive(Debug)]
 pub enum AquamarineVMError {
@@ -41,18 +40,6 @@ pub enum AquamarineVMError {
         io_error: Option<IOError>,
         reason: &'static str,
     },
-
-    /// [[BorrowError]] and [[BorrowMutError] are very serious errors, and shouldn't happen. If happened,
-    /// that means RefCell invariants are broken – we have borrowed [[AquamarineVm::current_particle]] twice.
-    /// Running in several threads? I don't know how else that could be possible.
-    /// But if that happened, chances are that we must avoid using RefCell,
-    /// and switch to [[parking_lot::Mutex]] or [[crossbeam_utils::AtomicCell]]
-
-    /// try_borrow failed on [[AquamarineVm::current_particle]]
-    BorrowParticleParams(BorrowError),
-
-    /// try_borrow_mut failed on [[AquamarineVm::current_particle]]
-    BorrowMutParticleParams(BorrowMutError),
 }
 
 impl Error for AquamarineVMError {}
@@ -82,22 +69,6 @@ impl std::fmt::Display for AquamarineVMError {
                 "path to AIR interpreter .wasm ({:?}) is invalid: {}; IO Error: {:?}",
                 invalid_path, reason, io_error
             ),
-
-            AquamarineVMError::BorrowMutParticleParams(err) => {
-                write!(
-                    f,
-                    "RefCell::try_borrow_mut failed for AquamarineVm::current_particle: {}",
-                    err
-                )
-            }
-
-            AquamarineVMError::BorrowParticleParams(err) => {
-                write!(
-                    f,
-                    "RefCell::try_borrow failed for AquamarineVm::current_particle: {}",
-                    err
-                )
-            }
         }
     }
 }