op_store: move logic out of OperationMetadata

`OperationMetadata` is a data type used in the interface. It seems
wrong for it to know where to get data from.

lib/src/op_store.rs

@@ -244,22 +244,6 @@ content_hash! {
     }
 }
 
-impl OperationMetadata {
-    pub fn new(description: String, start_time: Timestamp) -> Self {
-        let end_time = Timestamp::now();
-        let hostname = whoami::hostname();
-        let username = whoami::username();
-        OperationMetadata {
-            start_time,
-            end_time,
-            description,
-            hostname,
-            username,
-            tags: Default::default(),
-        }
-    }
-}
-
 #[derive(Debug, Error)]
 pub enum OpStoreError {
     #[error("Operation not found")]

lib/src/repo.rs

@@ -33,9 +33,7 @@ use crate::index::{IndexRef, MutableIndex, ReadonlyIndex};
 use crate::index_store::IndexStore;
 use crate::local_backend::LocalBackend;
 use crate::op_heads_store::{LockedOpHeads, OpHeads, OpHeadsStore};
-use crate::op_store::{
-    BranchTarget, OpStore, OperationId, OperationMetadata, RefTarget, WorkspaceId,
-};
+use crate::op_store::{BranchTarget, OpStore, OperationId, RefTarget, WorkspaceId};
 use crate::operation::Operation;
 use crate::rewrite::DescendantRebaser;
 use crate::settings::{RepoSettings, UserSettings};
@@ -139,7 +137,7 @@ impl ReadonlyRepo {
         let op_heads_path = repo_path.join("op_heads");
         fs::create_dir(&op_heads_path).context(&op_heads_path)?;
         let operation_metadata =
-            OperationMetadata::new("initialize repo".to_string(), Timestamp::now());
+            crate::transaction::create_op_metadata(Timestamp::now(), "initialize repo".to_string());
         let (op_heads_store, init_op) =
             OpHeadsStore::init(op_heads_path, &op_store, &root_view, operation_metadata);
         let op_heads_store = Arc::new(op_heads_store);

lib/src/transaction.rs

@@ -97,7 +97,7 @@ impl Transaction {
 
         let view_id = base_repo.op_store().write_view(view.store_view()).unwrap();
         let mut operation_metadata =
-            OperationMetadata::new(self.description.clone(), self.start_time.clone());
+            create_op_metadata(self.start_time.clone(), self.description.clone());
         operation_metadata.tags = self.tags.clone();
         let parents = self.parent_ops.iter().map(|op| op.id().clone()).collect();
         let store_operation = op_store::Operation {
@@ -119,6 +119,20 @@ impl Transaction {
     }
 }
 
+pub fn create_op_metadata(start_time: Timestamp, description: String) -> OperationMetadata {
+    let end_time = Timestamp::now();
+    let hostname = whoami::hostname();
+    let username = whoami::username();
+    OperationMetadata {
+        start_time,
+        end_time,
+        description,
+        hostname,
+        username,
+        tags: Default::default(),
+    }
+}
+
 struct NewRepoData {
     operation: Operation,
     view: View,