repo_description: A Git-compatible VCS that is both simple and powerful
code: // Copyright 2020 The Jujutsu Authors
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  // https://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  #![expect(missing_docs)]
  
  use std::cmp::Ordering;
  use std::fmt::Debug;
  use std::fmt::Error;
  use std::fmt::Formatter;
  use std::hash::Hash;
  use std::hash::Hasher;
  use std::iter;
  use std::sync::Arc;
  
  use futures::future::try_join_all;
  
  use crate::backend::CommitId;
  use crate::op_store;
  use crate::op_store::OpStore;
  use crate::op_store::OpStoreResult;
  use crate::op_store::OperationId;
  use crate::op_store::OperationMetadata;
  use crate::op_store::ViewId;
  use crate::view::View;
  
  /// A wrapper around [`op_store::Operation`] that defines additional methods and
  /// stores a pointer to the `OpStore` the operation belongs to.
  #[derive(Clone, serde::Serialize)]
  pub struct Operation {
      #[serde(skip)]
      op_store: Arc<dyn OpStore>,
      id: OperationId,
      #[serde(flatten)]
      data: Arc<op_store::Operation>, // allow cheap clone
  }
  
  impl Debug for Operation {
      fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
          f.debug_struct("Operation").field("id", &self.id).finish()
      }
  }
  
  impl PartialEq for Operation {
      fn eq(&self, other: &Self) -> bool {
          self.id == other.id
      }
  }
  
  impl Eq for Operation {}
  
  impl Ord for Operation {
      fn cmp(&self, other: &Self) -> Ordering {
          self.id.cmp(&other.id)
      }
  }
  
  impl PartialOrd for Operation {
      fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
          Some(self.cmp(other))
      }
  }
  
  impl Hash for Operation {
      fn hash<H: Hasher>(&self, state: &mut H) {
          self.id.hash(state);
      }
  }
  
  impl Operation {
      pub fn new(
          op_store: Arc<dyn OpStore>,
          id: OperationId,
          data: impl Into<Arc<op_store::Operation>>,
      ) -> Self {
          Self {
              op_store,
              id,
              data: data.into(),
          }
      }
  
      pub fn op_store(&self) -> Arc<dyn OpStore> {
          self.op_store.clone()
      }
  
      pub fn id(&self) -> &OperationId {
          &self.id
      }
  
      pub fn view_id(&self) -> &ViewId {
          &self.data.view_id
      }
  
      pub fn parent_ids(&self) -> &[OperationId] {
          &self.data.parents
      }
  
      pub async fn parents(&self) -> OpStoreResult<Vec<Self>> {
          try_join_all(self.data.parents.iter().map(async |parent_id| {
              let data = self.op_store.read_operation(parent_id).await?;
              Ok(Self::new(self.op_store.clone(), parent_id.clone(), data))
          }))
          .await
      }
  
      pub async fn view(&self) -> OpStoreResult<View> {
          let data = self.op_store.read_view(&self.data.view_id).await?;
          Ok(View::new(data))
      }
  
      pub fn metadata(&self) -> &OperationMetadata {
          &self.data.metadata
      }
  
      /// Returns true if predecessors are recorded in this operation.
      ///
      /// This returns false only if the operation was written by jj < 0.30.
      pub fn stores_commit_predecessors(&self) -> bool {
          self.data.commit_predecessors.is_some()
      }
  
      /// Returns predecessors of the specified commit if recorded.
      pub fn predecessors_for_commit(&self, commit_id: &CommitId) -> Option<&[CommitId]> {
          let map = self.data.commit_predecessors.as_ref()?;
          Some(map.get(commit_id)?)
      }
  
      /// Iterates all commit ids referenced by this operation ignoring the view.
      ///
      /// Use this in addition to [`View::all_referenced_commit_ids()`] to build
      /// commit index from scratch. The predecessor commit ids are also included,
      /// which ensures that the old commits to be returned by
      /// [`Self::predecessors_for_commit()`] are still reachable.
      ///
      /// The iteration order is unspecified.
      pub fn all_referenced_commit_ids(&self) -> impl Iterator<Item = &CommitId> {
          self.data.commit_predecessors.iter().flat_map(|map| {
              map.iter()
                  .flat_map(|(new_id, old_ids)| iter::once(new_id).chain(old_ids))
          })
      }
  
      pub fn store_operation(&self) -> &op_store::Operation {
          &self.data
      }
  }
  