virtualization: properly restore cold/warm states, cache, and scry st…

…ack when catching an error
zorp-corp · Dec 4, 2023 · 7beca7e · 7beca7e
1 parent 9774da7
commit 7beca7e
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Showing 4 changed files with 47 additions and 3 deletions.
diff --git a/rust/ares/src/interpreter.rs b/rust/ares/src/interpreter.rs
@@ -254,6 +254,12 @@ enum NockWork {
     Work12(Nock12),
 }
 
+pub struct SavedContext {
+    cold: Cold,
+    warm: Warm,
+    cache: Hamt<Noun>,
+}
+
 pub struct Context {
     pub stack: NockStack,
     // For printing slogs; if None, print to stdout; Option slated to be removed
@@ -268,6 +274,23 @@ pub struct Context {
     pub trace_info: Option<TraceInfo>,
 }
 
+impl Context {
+    pub fn save(&self) -> SavedContext {
+        SavedContext {
+            cold: self.cold,
+            warm: self.warm,
+            cache: self.cache,
+        }
+    }
+
+    pub fn restore(&mut self, saved: SavedContext) {
+        self.cold = saved.cold;
+        self.warm = saved.warm;
+        self.cache = saved.cache;
+    }
+}
+
+
 #[derive(Clone, Copy, Debug)]
 pub enum Error {
     ScryBlocked(Noun),      // path

diff --git a/rust/ares/src/jets/cold.rs b/rust/ares/src/jets/cold.rs
@@ -267,6 +267,7 @@ impl Iterator for NounList {
     }
 }
 
+#[derive(Copy, Clone)]
 pub struct Cold(*mut ColdMem);
 
 struct ColdMem {

diff --git a/rust/ares/src/jets/nock.rs b/rust/ares/src/jets/nock.rs
@@ -91,6 +91,8 @@ pub fn jet_mure(context: &mut Context, subject: Noun) -> Result {
     let scry = util::pass_thru_scry(&mut context.stack);
 
     context.scry_stack = T(&mut context.stack, &[scry, context.scry_stack]);
+
+    let saved = context.save();
     match interpret(context, tap, fol) {
         Ok(res) => {
             context.scry_stack = context.scry_stack.as_cell()?.tail();
@@ -100,7 +102,11 @@ pub fn jet_mure(context: &mut Context, subject: Noun) -> Result {
             // Since we are using the pass-through scry handler, we know for a fact that a scry
             // crash must have come from a senior virtualization context.
             Error::NonDeterministic(_) | Error::ScryCrashed(_) => Err(JetErr::Fail(error)),
-            Error::Deterministic(_) | Error::ScryBlocked(_) => Ok(D(0)),
+            Error::Deterministic(_) | Error::ScryBlocked(_) => { 
+                context.restore(saved);
+                context.scry_stack = context.scry_stack.as_cell()?.tail();
+                Ok(D(0))
+            },
         },
     }
 }
@@ -111,6 +117,8 @@ pub fn jet_mute(context: &mut Context, subject: Noun) -> Result {
     let scry = util::pass_thru_scry(&mut context.stack);
 
     context.scry_stack = T(&mut context.stack, &[scry, context.scry_stack]);
+
+    let saved = context.save();
     match interpret(context, tap, fol) {
         Ok(res) => {
             context.scry_stack = context.scry_stack.as_cell()?.tail();
@@ -121,12 +129,16 @@ pub fn jet_mute(context: &mut Context, subject: Noun) -> Result {
             // crash must have come from a senior virtualization context.
             Error::NonDeterministic(_) | Error::ScryCrashed(_) => Err(JetErr::Fail(error)),
             Error::ScryBlocked(path) => {
+                context.scry_stack = context.scry_stack.as_cell()?.tail();
+                context.restore(saved);
                 //  XX: Need to check that result is actually of type path
                 //      return [[%leaf "mute.hunk"] ~] if not
                 let bon = util::smyt(&mut context.stack, path)?;
                 Ok(T(&mut context.stack, &[NO, bon, D(0)]))
             }
             Error::Deterministic(trace) => {
+                context.scry_stack = context.scry_stack.as_cell()?.tail();
+                context.restore(saved);
                 let ton = Cell::new(&mut context.stack, D(2), trace);
                 let tun = util::mook(context, ton, false)?;
                 Ok(T(&mut context.stack, &[NO, tun.tail()]))
@@ -177,11 +189,18 @@ pub mod util {
     }
 
     pub fn mink(context: &mut Context, subject: Noun, formula: Noun) -> Result<Noun, Error> {
+        let saved = context.save();
         match interpret(context, subject, formula) {
             Ok(res) => Ok(T(&mut context.stack, &[D(0), res])),
             Err(err) => match err {
-                Error::ScryBlocked(path) => Ok(T(&mut context.stack, &[D(1), path])),
-                Error::Deterministic(trace) => Ok(T(&mut context.stack, &[D(2), trace])),
+                Error::ScryBlocked(path) => {
+                    context.restore(saved);
+                    Ok(T(&mut context.stack, &[D(1), path]))
+                },
+                Error::Deterministic(trace) => {
+                    context.restore(saved);
+                    Ok(T(&mut context.stack, &[D(2), trace]))
+                },
                 Error::NonDeterministic(_) | Error::ScryCrashed(_) => Err(err),
             },
         }

diff --git a/rust/ares/src/jets/warm.rs b/rust/ares/src/jets/warm.rs
@@ -7,6 +7,7 @@ use crate::noun::{Noun, Slots};
 use std::ptr::{copy_nonoverlapping, null_mut};
 
 /// key = formula
+#[derive(Copy, Clone)]
 pub struct Warm(Hamt<WarmEntry>);
 
 impl Preserve for Warm {