From 29ee45de6cf809e1a78250476d914a5e34308163 Mon Sep 17 00:00:00 2001
From: Julien Cretin <cretin@google.com>
Date: Tue, 24 Nov 2020 11:29:14 +0100
Subject: [PATCH] Do not crash in the driver for store errors

We prefer to return those errors to the fuzzer which can then decide whether
they are expected or not (e.g. when starting from a dirty storage, the store is
expected to have errors).
---
 libraries/persistent_store/src/driver.rs | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/libraries/persistent_store/src/driver.rs b/libraries/persistent_store/src/driver.rs
index 15001cb..e529274 100644
--- a/libraries/persistent_store/src/driver.rs
+++ b/libraries/persistent_store/src/driver.rs
@@ -181,6 +181,12 @@ pub enum StoreInvariant {
     },
 }
 
+impl From<StoreError> for StoreInvariant {
+    fn from(error: StoreError) -> StoreInvariant {
+        StoreInvariant::StoreError(error)
+    }
+}
+
 impl StoreDriver {
     /// Provides read-only access to the storage.
     pub fn storage(&self) -> &BufferStorage {
@@ -249,6 +255,10 @@ impl StoreDriverOff {
     }
 
     /// Powers on the store without interruption.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the store cannot be powered on.
     pub fn power_on(self) -> Result<StoreDriverOn, StoreInvariant> {
         Ok(self
             .partial_power_on(StoreInterruption::none())
@@ -506,8 +516,8 @@ impl StoreDriverOn {
     /// Checks that the store and model are in sync.
     fn check_model(&self) -> Result<(), StoreInvariant> {
         let mut model_content = self.model.content().clone();
-        for handle in self.store.iter().unwrap() {
-            let handle = handle.unwrap();
+        for handle in self.store.iter()? {
+            let handle = handle?;
             let model_value = match model_content.remove(&handle.get_key()) {
                 None => {
                     return Err(StoreInvariant::OnlyInStore {
@@ -516,7 +526,7 @@ impl StoreDriverOn {
                 }
                 Some(x) => x,
             };
-            let store_value = handle.get_value(&self.store).unwrap().into_boxed_slice();
+            let store_value = handle.get_value(&self.store)?.into_boxed_slice();
             if store_value != model_value {
                 return Err(StoreInvariant::DifferentValue {
                     key: handle.get_key(),
@@ -528,7 +538,7 @@ impl StoreDriverOn {
         if let Some(&key) = model_content.keys().next() {
             return Err(StoreInvariant::OnlyInModel { key });
         }
-        let store_capacity = self.store.capacity().unwrap().remaining();
+        let store_capacity = self.store.capacity()?.remaining();
         let model_capacity = self.model.capacity().remaining();
         if store_capacity != model_capacity {
             return Err(StoreInvariant::DifferentCapacity {
@@ -544,8 +554,8 @@ impl StoreDriverOn {
         let format = self.model.format();
         let storage = self.store.storage();
         let num_words = format.page_size() / format.word_size();
-        let head = self.store.head().unwrap();
-        let tail = self.store.tail().unwrap();
+        let head = self.store.head()?;
+        let tail = self.store.tail()?;
         for page in 0..format.num_pages() {
             // Check the erase cycle of the page.
             let store_erase = head.cycle(format) + (page < head.page(format)) as Nat;