global: snapshot

crates/brk_vec/src/structs/version.rs

@@ -1,12 +1,13 @@
 use std::{
     fs,
     io::{self, Read},
+    ops::Add,
     path::Path,
 };
 
 use zerocopy::{FromBytes, Immutable, IntoBytes, KnownLayout};
 
-use crate::Error;
+use crate::{Error, Result};
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, FromBytes, IntoBytes, Immutable, KnownLayout)]
 pub struct Version(u32);
@@ -19,6 +20,22 @@ impl Version {
     pub fn swap_bytes(self) -> Self {
         Self(self.0.swap_bytes())
     }
+
+    pub fn validate(&self, path: &Path) -> Result<()> {
+        if let Ok(prev_version) = Version::try_from(path) {
+            if prev_version != *self {
+                if prev_version.swap_bytes() == *self {
+                    return Err(Error::WrongEndian);
+                }
+                return Err(Error::DifferentVersion {
+                    found: prev_version,
+                    expected: *self,
+                });
+            }
+        }
+
+        Ok(())
+    }
 }
 
 impl From<u32> for Version {
@@ -35,3 +52,10 @@ impl TryFrom<&Path> for Version {
         Ok(*(Self::ref_from_bytes(&buf)?))
     }
 }
+
+impl Add<Version> for Version {
+    type Output = Version;
+    fn add(self, rhs: Version) -> Self::Output {
+        Self(self.0 + rhs.0)
+    }
+}