index: move ReadonlyFile::associate_with_operation() to IndexStore

After this patch, the `index` module no longer knows about the
".jj/index/operations/" directory; that knowledge is now only in
`IndexStore`.

lib/src/index.rs

@@ -28,8 +28,6 @@ use tempfile::NamedTempFile;
 
 use crate::commit::Commit;
 
-use crate::op_store::OperationId;
-
 use crate::store::{ChangeId, CommitId};
 
 use std::fmt::{Debug, Formatter};
@@ -1344,19 +1342,14 @@ impl ReadonlyIndex {
         }))
     }
 
-    /// Records a link from the given operation to the this index version.
-    pub fn associate_with_operation(&self, op_id: &OperationId) -> io::Result<()> {
-        let mut temp_file = NamedTempFile::new_in(&self.dir)?;
-        let file = temp_file.as_file_mut();
-        file.write_all(&self.name.as_bytes()).unwrap();
-        temp_file.persist(&self.dir.join("operations").join(op_id.hex()))?;
-        Ok(())
-    }
-
     pub fn num_commits(&self) -> u32 {
         CompositeIndex(self).num_commits()
     }
 
+    pub fn name(&self) -> &str {
+        &self.name
+    }
+
     pub fn stats(&self) -> IndexStats {
         CompositeIndex(self).stats()
     }

lib/src/index_store.rs

@@ -23,9 +23,10 @@ use crate::store_wrapper::StoreWrapper;
 use std::collections::{HashMap, HashSet};
 use std::fs::File;
 use std::io;
-use std::io::Read;
+use std::io::{Read, Write};
 use std::path::PathBuf;
 use std::sync::Arc;
+use tempfile::NamedTempFile;
 
 pub struct IndexStore {
     dir: PathBuf,
@@ -132,10 +133,23 @@ impl IndexStore {
 
         let index_file = data.save()?;
 
-        index_file.associate_with_operation(operation.id())?;
+        self.associate_file_with_operation(&index_file, operation.id())?;
 
         Ok(index_file)
     }
+
+    /// Records a link from the given operation to the this index version.
+    pub fn associate_file_with_operation(
+        &self,
+        index: &ReadonlyIndex,
+        op_id: &OperationId,
+    ) -> io::Result<()> {
+        let mut temp_file = NamedTempFile::new_in(&self.dir)?;
+        let file = temp_file.as_file_mut();
+        file.write_all(&index.name().as_bytes()).unwrap();
+        temp_file.persist(&self.dir.join("operations").join(op_id.hex()))?;
+        Ok(())
+    }
 }
 
 // Returns the ancestors of heads with parents and predecessors come before the

lib/src/repo.rs

@@ -298,6 +298,10 @@ impl ReadonlyRepo {
         &self.store
     }
 
+    pub fn index_store(&self) -> &IndexStore {
+        &self.index_store
+    }
+
     pub fn settings(&self) -> &RepoSettings {
         &self.settings
     }

lib/src/transaction.rs

@@ -202,10 +202,13 @@ impl<'r> Transaction<'r> {
 
     pub fn commit(mut self) -> Operation {
         let mut_repo = Arc::try_unwrap(self.repo.take().unwrap()).ok().unwrap();
+        let index_store = mut_repo.base_repo().index_store();
         let (mut_index, mut_view) = mut_repo.consume();
         let index = mut_index.save().unwrap();
         let operation = mut_view.save(self.description.clone(), self.start_time.clone());
-        index.associate_with_operation(operation.id()).unwrap();
+        index_store
+            .associate_file_with_operation(&index, operation.id())
+            .unwrap();
         self.closed = true;
         operation
     }