#102 WIP migrations

lib/src/db.rs

@@ -21,6 +21,7 @@ use self::query_index::{
     update_indexed_member, watch_collection, IndexAtom, QueryFilter, END_CHAR,
 };
 
+mod migrations;
 mod query_index;
 #[cfg(test)]
 pub mod test;
@@ -47,7 +48,7 @@ pub struct Db {
     /// Try not to use this directly, but use the Trees.
     db: sled::Db,
     default_agent: Arc<Mutex<Option<crate::agents::Agent>>>,
-    /// Stores all resources. The Key is the Subject as a string, the value a [PropVals]. Both must be serialized using bincode.
+    /// Stores all resources. The Key is the Subject as a `string.as_bytes()`, the value a [PropVals]. Propvals must be serialized using [bincode].
     resources: sled::Tree,
     /// Index for all AtommicURLs, indexed by their Value. Used to speed up TPF queries. See [key_for_reference_index]
     reference_index: sled::Tree,
@@ -107,20 +108,17 @@ impl Db {
     #[instrument(skip(self))]
     fn set_propvals(&self, subject: &str, propvals: &PropVals) -> AtomicResult<()> {
         let resource_bin = bincode::serialize(propvals)?;
-        let subject_bin = bincode::serialize(subject)?;
-        self.resources.insert(subject_bin, resource_bin)?;
+        self.resources.insert(subject.as_bytes(), resource_bin)?;
         Ok(())
     }
 
     /// Finds resource by Subject, return PropVals HashMap
     /// Deals with the binary API of Sled
     #[instrument(skip(self))]
     fn get_propvals(&self, subject: &str) -> AtomicResult<PropVals> {
-        let subject_binary = bincode::serialize(subject)
-            .map_err(|e| format!("Can't serialize {}: {}", subject, e))?;
         let propval_maybe = self
             .resources
-            .get(subject_binary)
+            .get(subject.as_bytes())
             .map_err(|e| format!("Can't open {} from store: {}", subject, e))?;
         match propval_maybe.as_ref() {
             Some(binpropval) => {
@@ -473,7 +471,7 @@ impl Storelike for Db {
             .expect("No self URL set, is required in DB");
         for item in self.resources.into_iter() {
             let (subject, resource_bin) = item.expect(DB_CORRUPT_MSG);
-            let subject: String = bincode::deserialize(&subject).expect(DB_CORRUPT_MSG);
+            let subject: String = String::from_utf8_lossy(&subject).to_string();
             if !include_external && !subject.starts_with(&self_url) {
                 continue;
             }
@@ -508,8 +506,7 @@ impl Storelike for Db {
                 let remove_atom = crate::Atom::new(subject.into(), prop.clone(), val.clone());
                 self.remove_atom_from_index(&remove_atom, &resource)?;
             }
-            let binary_subject = bincode::serialize(subject)?;
-            let _found = self.resources.remove(&binary_subject)?;
+            let _found = self.resources.remove(&subject.as_bytes())?;
         } else {
             return Err(format!(
                 "Resource {} could not be deleted, because it was not found in the store.",

lib/src/db/migrations.rs

@@ -0,0 +1,20 @@
+/*!
+# Migrations
+
+Whenever the schema of the database changes, a newer version will not be able to read an older database.
+Therefore, we need migrations to convert the old schema to the new one.
+ */
+
+use crate::{errors::AtomicResult, Db};
+
+// Change the subjects from `bincode` to `.as_bytes()`
+fn v0_to_v1(store: &mut Db) -> AtomicResult<()> {
+    let new = store.db.open_tree("resources_new")?;
+    for item in store.resources.into_iter() {
+        let (subject, resource_bin) = item.expect("Unable to perform migration");
+        let subject: String =
+            bincode::deserialize(&subject).expect("Unable to deserialize subject");
+        new.insert(subject.as_bytes(), resource_bin)?;
+    }
+    Ok(())
+}