feat: add store ids

Signed-off-by: Henry Gressmann <mail@henrygressmann.de>

5 files changed, 60 insertions, 7 deletions

diff --git a/crates/cli/Cargo.toml b/crates/cli/Cargo.toml
index 60c3ad8..d34aeff 100644
--- a/crates/cli/Cargo.toml
+++ b/crates/cli/Cargo.toml
@@ -12,7 +12,7 @@ path="src/bin.rs"
 [dependencies]
 tinywasm={path="../tinywasm"}
 argh="0.1"
-color-eyre={default-features=false}
+color-eyre={version="0.6", default-features=false}
 log="0.4"
 pretty_env_logger="0.5"
 wast={version="69.0", optional=true}
diff --git a/crates/tinywasm/src/error.rs b/crates/tinywasm/src/error.rs
index 084a49c..82f00b9 100644
--- a/crates/tinywasm/src/error.rs
+++ b/crates/tinywasm/src/error.rs
@@ -11,6 +11,8 @@ pub enum Error {
     FuncDidNotReturn,
     StackUnderflow,
 
+    InvalidStore,
+
     #[cfg(feature = "std")]
     Io(crate::std::io::Error),
 }
@@ -23,6 +25,7 @@ impl Display for Error {
             Self::ParseError(err) => write!(f, "error parsing module: {:?}", err),
             Self::UnsupportedFeature(feature) => write!(f, "unsupported feature: {}", feature),
             Self::Other(message) => write!(f, "unknown error: {}", message),
+            Self::InvalidStore => write!(f, "invalid store"),
             #[cfg(feature = "std")]
             Self::Io(err) => write!(f, "I/O error: {}", err),
         }
diff --git a/crates/tinywasm/src/instance.rs b/crates/tinywasm/src/instance.rs
index c90cec6..598dba1 100644
--- a/crates/tinywasm/src/instance.rs
+++ b/crates/tinywasm/src/instance.rs
@@ -3,17 +3,20 @@ use tinywasm_types::{Export, FuncAddr, FuncType, ModuleInstanceAddr};
 
 use crate::{
     func::{FromWasmValueTuple, IntoWasmValueTuple},
-    ExportInstance, FuncHandle, Result, Store, TypedFuncHandle,
+    Error, ExportInstance, FuncHandle, Result, Store, TypedFuncHandle,
 };
 
-/// A WebAssembly Module Instance.
+/// A WebAssembly Module Instance
+///
 /// Addrs are indices into the store's data structures.
+///
 /// See https://webassembly.github.io/spec/core/exec/runtime.html#module-instances
 #[derive(Debug, Clone)]
 pub struct ModuleInstance(Arc<ModuleInstanceInner>);
 
 #[derive(Debug)]
 struct ModuleInstanceInner {
+    pub(crate) store_id: usize,
     pub(crate) _idx: ModuleInstanceAddr,
     pub(crate) func_start: Option<FuncAddr>,
     pub(crate) types: Box<[FuncType]>,
@@ -34,8 +37,10 @@ impl ModuleInstance {
         exports: Box<[Export]>,
         func_addrs: Vec<FuncAddr>,
         idx: ModuleInstanceAddr,
+        store_id: usize,
     ) -> Self {
         Self(Arc::new(ModuleInstanceInner {
+            store_id,
             _idx: idx,
             types,
             func_start,
@@ -46,6 +51,10 @@ impl ModuleInstance {
 
     /// Get an exported function by name
     pub fn get_func(&self, store: &Store, name: &str) -> Result<FuncHandle> {
+        if self.0.store_id != store.id() {
+            return Err(Error::InvalidStore);
+        }
+
         let export = self.0.exports.func(name)?;
         let func_addr = self.0.func_addrs[export.index as usize];
         let func = store.get_func(func_addr as usize)?;
@@ -78,6 +87,10 @@ impl ModuleInstance {
     /// (which is not part of the spec, but used by llvm)
     /// https://webassembly.github.io/spec/core/syntax/modules.html#start-function
     pub fn get_start_func(&mut self, store: &Store) -> Result<Option<FuncHandle>> {
+        if self.0.store_id != store.id() {
+            return Err(Error::InvalidStore);
+        }
+
         let func_index = match self.0.func_start {
             Some(func_index) => func_index,
             None => {
diff --git a/crates/tinywasm/src/module.rs b/crates/tinywasm/src/module.rs
index 8e258fd..04320a2 100644
--- a/crates/tinywasm/src/module.rs
+++ b/crates/tinywasm/src/module.rs
@@ -52,6 +52,7 @@ impl Module {
             self.data.exports,
             func_addrs,
             idx,
+            store.id(),
         );
 
         store.add_instance(instance.clone())?;
diff --git a/crates/tinywasm/src/store.rs b/crates/tinywasm/src/store.rs
index a74163e..0e73ece 100644
--- a/crates/tinywasm/src/store.rs
+++ b/crates/tinywasm/src/store.rs
@@ -1,13 +1,25 @@
+use core::sync::atomic::{AtomicUsize, Ordering};
+
 use alloc::{format, vec::Vec};
 use tinywasm_types::{FuncAddr, Function, Instruction, ModuleInstanceAddr, TypeAddr, ValType};
 
 use crate::{runtime::Runtime, Error, ModuleInstance, Result};
 
-/// global state that can be manipulated by WebAssembly programs
-/// data should only be addressable by the module that owns it
-/// https://webassembly.github.io/spec/core/exec/runtime.html#store
-#[derive(Debug, Default)]
+// global store id counter
+static STORE_ID: AtomicUsize = AtomicUsize::new(0);
+
+/// Global state that can be manipulated by WebAssembly programs
+///
+/// Data should only be addressable by the module that owns it
+///
+/// Note that the state doesn't do any garbage collection - so it will grow
+/// indefinitely if you keep adding modules to it. When calling temporary
+/// functions, you should create a new store and then drop it when you're done (e.g. in a request handler)
+///
+///  See also: https://webassembly.github.io/spec/core/exec/runtime.html#store
+#[derive(Debug)]
 pub struct Store {
+    id: usize,
     module_instances: Vec<ModuleInstance>,
     module_instance_count: usize,
 
@@ -15,6 +27,26 @@ pub struct Store {
     pub(crate) runtime: Runtime,
 }
 
+impl PartialEq for Store {
+    fn eq(&self, other: &Self) -> bool {
+        self.id == other.id
+    }
+}
+
+impl Default for Store {
+    fn default() -> Self {
+        let id = STORE_ID.fetch_add(1, Ordering::Relaxed);
+
+        Self {
+            id,
+            module_instances: Vec::new(),
+            module_instance_count: 0,
+            data: StoreData::default(),
+            runtime: Runtime::default(),
+        }
+    }
+}
+
 #[derive(Debug)]
 pub struct FunctionInstance {
     pub(crate) func: Function,
@@ -50,6 +82,10 @@ pub struct StoreData {
 }
 
 impl Store {
+    pub fn id(&self) -> usize {
+        self.id
+    }
+
     pub(crate) fn next_module_instance_idx(&self) -> ModuleInstanceAddr {
         self.module_instance_count as ModuleInstanceAddr
     }