Break up Database impl into multiple files, organized by topic

crates/collab/src/db/queries/projects.rs

@@ -0,0 +1,926 @@
+use super::*;
+
+impl Database {
+    pub async fn project_count_excluding_admins(&self) -> Result<usize> {
+        #[derive(Copy, Clone, Debug, EnumIter, DeriveColumn)]
+        enum QueryAs {
+            Count,
+        }
+
+        self.transaction(|tx| async move {
+            Ok(project::Entity::find()
+                .select_only()
+                .column_as(project::Column::Id.count(), QueryAs::Count)
+                .inner_join(user::Entity)
+                .filter(user::Column::Admin.eq(false))
+                .into_values::<_, QueryAs>()
+                .one(&*tx)
+                .await?
+                .unwrap_or(0i64) as usize)
+        })
+        .await
+    }
+
+    pub async fn share_project(
+        &self,
+        room_id: RoomId,
+        connection: ConnectionId,
+        worktrees: &[proto::WorktreeMetadata],
+    ) -> Result<RoomGuard<(ProjectId, proto::Room)>> {
+        self.room_transaction(room_id, |tx| async move {
+            let participant = room_participant::Entity::find()
+                .filter(
+                    Condition::all()
+                        .add(
+                            room_participant::Column::AnsweringConnectionId
+                                .eq(connection.id as i32),
+                        )
+                        .add(
+                            room_participant::Column::AnsweringConnectionServerId
+                                .eq(connection.owner_id as i32),
+                        ),
+                )
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("could not find participant"))?;
+            if participant.room_id != room_id {
+                return Err(anyhow!("shared project on unexpected room"))?;
+            }
+
+            let project = project::ActiveModel {
+                room_id: ActiveValue::set(participant.room_id),
+                host_user_id: ActiveValue::set(participant.user_id),
+                host_connection_id: ActiveValue::set(Some(connection.id as i32)),
+                host_connection_server_id: ActiveValue::set(Some(ServerId(
+                    connection.owner_id as i32,
+                ))),
+                ..Default::default()
+            }
+            .insert(&*tx)
+            .await?;
+
+            if !worktrees.is_empty() {
+                worktree::Entity::insert_many(worktrees.iter().map(|worktree| {
+                    worktree::ActiveModel {
+                        id: ActiveValue::set(worktree.id as i64),
+                        project_id: ActiveValue::set(project.id),
+                        abs_path: ActiveValue::set(worktree.abs_path.clone()),
+                        root_name: ActiveValue::set(worktree.root_name.clone()),
+                        visible: ActiveValue::set(worktree.visible),
+                        scan_id: ActiveValue::set(0),
+                        completed_scan_id: ActiveValue::set(0),
+                    }
+                }))
+                .exec(&*tx)
+                .await?;
+            }
+
+            project_collaborator::ActiveModel {
+                project_id: ActiveValue::set(project.id),
+                connection_id: ActiveValue::set(connection.id as i32),
+                connection_server_id: ActiveValue::set(ServerId(connection.owner_id as i32)),
+                user_id: ActiveValue::set(participant.user_id),
+                replica_id: ActiveValue::set(ReplicaId(0)),
+                is_host: ActiveValue::set(true),
+                ..Default::default()
+            }
+            .insert(&*tx)
+            .await?;
+
+            let room = self.get_room(room_id, &tx).await?;
+            Ok((project.id, room))
+        })
+        .await
+    }
+
+    pub async fn unshare_project(
+        &self,
+        project_id: ProjectId,
+        connection: ConnectionId,
+    ) -> Result<RoomGuard<(proto::Room, Vec<ConnectionId>)>> {
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            let guest_connection_ids = self.project_guest_connection_ids(project_id, &tx).await?;
+
+            let project = project::Entity::find_by_id(project_id)
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("project not found"))?;
+            if project.host_connection()? == connection {
+                project::Entity::delete(project.into_active_model())
+                    .exec(&*tx)
+                    .await?;
+                let room = self.get_room(room_id, &tx).await?;
+                Ok((room, guest_connection_ids))
+            } else {
+                Err(anyhow!("cannot unshare a project hosted by another user"))?
+            }
+        })
+        .await
+    }
+
+    pub async fn update_project(
+        &self,
+        project_id: ProjectId,
+        connection: ConnectionId,
+        worktrees: &[proto::WorktreeMetadata],
+    ) -> Result<RoomGuard<(proto::Room, Vec<ConnectionId>)>> {
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            let project = project::Entity::find_by_id(project_id)
+                .filter(
+                    Condition::all()
+                        .add(project::Column::HostConnectionId.eq(connection.id as i32))
+                        .add(
+                            project::Column::HostConnectionServerId.eq(connection.owner_id as i32),
+                        ),
+                )
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("no such project"))?;
+
+            self.update_project_worktrees(project.id, worktrees, &tx)
+                .await?;
+
+            let guest_connection_ids = self.project_guest_connection_ids(project.id, &tx).await?;
+            let room = self.get_room(project.room_id, &tx).await?;
+            Ok((room, guest_connection_ids))
+        })
+        .await
+    }
+
+    pub(in crate::db) async fn update_project_worktrees(
+        &self,
+        project_id: ProjectId,
+        worktrees: &[proto::WorktreeMetadata],
+        tx: &DatabaseTransaction,
+    ) -> Result<()> {
+        if !worktrees.is_empty() {
+            worktree::Entity::insert_many(worktrees.iter().map(|worktree| worktree::ActiveModel {
+                id: ActiveValue::set(worktree.id as i64),
+                project_id: ActiveValue::set(project_id),
+                abs_path: ActiveValue::set(worktree.abs_path.clone()),
+                root_name: ActiveValue::set(worktree.root_name.clone()),
+                visible: ActiveValue::set(worktree.visible),
+                scan_id: ActiveValue::set(0),
+                completed_scan_id: ActiveValue::set(0),
+            }))
+            .on_conflict(
+                OnConflict::columns([worktree::Column::ProjectId, worktree::Column::Id])
+                    .update_column(worktree::Column::RootName)
+                    .to_owned(),
+            )
+            .exec(&*tx)
+            .await?;
+        }
+
+        worktree::Entity::delete_many()
+            .filter(worktree::Column::ProjectId.eq(project_id).and(
+                worktree::Column::Id.is_not_in(worktrees.iter().map(|worktree| worktree.id as i64)),
+            ))
+            .exec(&*tx)
+            .await?;
+
+        Ok(())
+    }
+
+    pub async fn update_worktree(
+        &self,
+        update: &proto::UpdateWorktree,
+        connection: ConnectionId,
+    ) -> Result<RoomGuard<Vec<ConnectionId>>> {
+        let project_id = ProjectId::from_proto(update.project_id);
+        let worktree_id = update.worktree_id as i64;
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            // Ensure the update comes from the host.
+            let _project = project::Entity::find_by_id(project_id)
+                .filter(
+                    Condition::all()
+                        .add(project::Column::HostConnectionId.eq(connection.id as i32))
+                        .add(
+                            project::Column::HostConnectionServerId.eq(connection.owner_id as i32),
+                        ),
+                )
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("no such project"))?;
+
+            // Update metadata.
+            worktree::Entity::update(worktree::ActiveModel {
+                id: ActiveValue::set(worktree_id),
+                project_id: ActiveValue::set(project_id),
+                root_name: ActiveValue::set(update.root_name.clone()),
+                scan_id: ActiveValue::set(update.scan_id as i64),
+                completed_scan_id: if update.is_last_update {
+                    ActiveValue::set(update.scan_id as i64)
+                } else {
+                    ActiveValue::default()
+                },
+                abs_path: ActiveValue::set(update.abs_path.clone()),
+                ..Default::default()
+            })
+            .exec(&*tx)
+            .await?;
+
+            if !update.updated_entries.is_empty() {
+                worktree_entry::Entity::insert_many(update.updated_entries.iter().map(|entry| {
+                    let mtime = entry.mtime.clone().unwrap_or_default();
+                    worktree_entry::ActiveModel {
+                        project_id: ActiveValue::set(project_id),
+                        worktree_id: ActiveValue::set(worktree_id),
+                        id: ActiveValue::set(entry.id as i64),
+                        is_dir: ActiveValue::set(entry.is_dir),
+                        path: ActiveValue::set(entry.path.clone()),
+                        inode: ActiveValue::set(entry.inode as i64),
+                        mtime_seconds: ActiveValue::set(mtime.seconds as i64),
+                        mtime_nanos: ActiveValue::set(mtime.nanos as i32),
+                        is_symlink: ActiveValue::set(entry.is_symlink),
+                        is_ignored: ActiveValue::set(entry.is_ignored),
+                        is_external: ActiveValue::set(entry.is_external),
+                        git_status: ActiveValue::set(entry.git_status.map(|status| status as i64)),
+                        is_deleted: ActiveValue::set(false),
+                        scan_id: ActiveValue::set(update.scan_id as i64),
+                    }
+                }))
+                .on_conflict(
+                    OnConflict::columns([
+                        worktree_entry::Column::ProjectId,
+                        worktree_entry::Column::WorktreeId,
+                        worktree_entry::Column::Id,
+                    ])
+                    .update_columns([
+                        worktree_entry::Column::IsDir,
+                        worktree_entry::Column::Path,
+                        worktree_entry::Column::Inode,
+                        worktree_entry::Column::MtimeSeconds,
+                        worktree_entry::Column::MtimeNanos,
+                        worktree_entry::Column::IsSymlink,
+                        worktree_entry::Column::IsIgnored,
+                        worktree_entry::Column::GitStatus,
+                        worktree_entry::Column::ScanId,
+                    ])
+                    .to_owned(),
+                )
+                .exec(&*tx)
+                .await?;
+            }
+
+            if !update.removed_entries.is_empty() {
+                worktree_entry::Entity::update_many()
+                    .filter(
+                        worktree_entry::Column::ProjectId
+                            .eq(project_id)
+                            .and(worktree_entry::Column::WorktreeId.eq(worktree_id))
+                            .and(
+                                worktree_entry::Column::Id
+                                    .is_in(update.removed_entries.iter().map(|id| *id as i64)),
+                            ),
+                    )
+                    .set(worktree_entry::ActiveModel {
+                        is_deleted: ActiveValue::Set(true),
+                        scan_id: ActiveValue::Set(update.scan_id as i64),
+                        ..Default::default()
+                    })
+                    .exec(&*tx)
+                    .await?;
+            }
+
+            if !update.updated_repositories.is_empty() {
+                worktree_repository::Entity::insert_many(update.updated_repositories.iter().map(
+                    |repository| worktree_repository::ActiveModel {
+                        project_id: ActiveValue::set(project_id),
+                        worktree_id: ActiveValue::set(worktree_id),
+                        work_directory_id: ActiveValue::set(repository.work_directory_id as i64),
+                        scan_id: ActiveValue::set(update.scan_id as i64),
+                        branch: ActiveValue::set(repository.branch.clone()),
+                        is_deleted: ActiveValue::set(false),
+                    },
+                ))
+                .on_conflict(
+                    OnConflict::columns([
+                        worktree_repository::Column::ProjectId,
+                        worktree_repository::Column::WorktreeId,
+                        worktree_repository::Column::WorkDirectoryId,
+                    ])
+                    .update_columns([
+                        worktree_repository::Column::ScanId,
+                        worktree_repository::Column::Branch,
+                    ])
+                    .to_owned(),
+                )
+                .exec(&*tx)
+                .await?;
+            }
+
+            if !update.removed_repositories.is_empty() {
+                worktree_repository::Entity::update_many()
+                    .filter(
+                        worktree_repository::Column::ProjectId
+                            .eq(project_id)
+                            .and(worktree_repository::Column::WorktreeId.eq(worktree_id))
+                            .and(
+                                worktree_repository::Column::WorkDirectoryId
+                                    .is_in(update.removed_repositories.iter().map(|id| *id as i64)),
+                            ),
+                    )
+                    .set(worktree_repository::ActiveModel {
+                        is_deleted: ActiveValue::Set(true),
+                        scan_id: ActiveValue::Set(update.scan_id as i64),
+                        ..Default::default()
+                    })
+                    .exec(&*tx)
+                    .await?;
+            }
+
+            let connection_ids = self.project_guest_connection_ids(project_id, &tx).await?;
+            Ok(connection_ids)
+        })
+        .await
+    }
+
+    pub async fn update_diagnostic_summary(
+        &self,
+        update: &proto::UpdateDiagnosticSummary,
+        connection: ConnectionId,
+    ) -> Result<RoomGuard<Vec<ConnectionId>>> {
+        let project_id = ProjectId::from_proto(update.project_id);
+        let worktree_id = update.worktree_id as i64;
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            let summary = update
+                .summary
+                .as_ref()
+                .ok_or_else(|| anyhow!("invalid summary"))?;
+
+            // Ensure the update comes from the host.
+            let project = project::Entity::find_by_id(project_id)
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("no such project"))?;
+            if project.host_connection()? != connection {
+                return Err(anyhow!("can't update a project hosted by someone else"))?;
+            }
+
+            // Update summary.
+            worktree_diagnostic_summary::Entity::insert(worktree_diagnostic_summary::ActiveModel {
+                project_id: ActiveValue::set(project_id),
+                worktree_id: ActiveValue::set(worktree_id),
+                path: ActiveValue::set(summary.path.clone()),
+                language_server_id: ActiveValue::set(summary.language_server_id as i64),
+                error_count: ActiveValue::set(summary.error_count as i32),
+                warning_count: ActiveValue::set(summary.warning_count as i32),
+                ..Default::default()
+            })
+            .on_conflict(
+                OnConflict::columns([
+                    worktree_diagnostic_summary::Column::ProjectId,
+                    worktree_diagnostic_summary::Column::WorktreeId,
+                    worktree_diagnostic_summary::Column::Path,
+                ])
+                .update_columns([
+                    worktree_diagnostic_summary::Column::LanguageServerId,
+                    worktree_diagnostic_summary::Column::ErrorCount,
+                    worktree_diagnostic_summary::Column::WarningCount,
+                ])
+                .to_owned(),
+            )
+            .exec(&*tx)
+            .await?;
+
+            let connection_ids = self.project_guest_connection_ids(project_id, &tx).await?;
+            Ok(connection_ids)
+        })
+        .await
+    }
+
+    pub async fn start_language_server(
+        &self,
+        update: &proto::StartLanguageServer,
+        connection: ConnectionId,
+    ) -> Result<RoomGuard<Vec<ConnectionId>>> {
+        let project_id = ProjectId::from_proto(update.project_id);
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            let server = update
+                .server
+                .as_ref()
+                .ok_or_else(|| anyhow!("invalid language server"))?;
+
+            // Ensure the update comes from the host.
+            let project = project::Entity::find_by_id(project_id)
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("no such project"))?;
+            if project.host_connection()? != connection {
+                return Err(anyhow!("can't update a project hosted by someone else"))?;
+            }
+
+            // Add the newly-started language server.
+            language_server::Entity::insert(language_server::ActiveModel {
+                project_id: ActiveValue::set(project_id),
+                id: ActiveValue::set(server.id as i64),
+                name: ActiveValue::set(server.name.clone()),
+                ..Default::default()
+            })
+            .on_conflict(
+                OnConflict::columns([
+                    language_server::Column::ProjectId,
+                    language_server::Column::Id,
+                ])
+                .update_column(language_server::Column::Name)
+                .to_owned(),
+            )
+            .exec(&*tx)
+            .await?;
+
+            let connection_ids = self.project_guest_connection_ids(project_id, &tx).await?;
+            Ok(connection_ids)
+        })
+        .await
+    }
+
+    pub async fn update_worktree_settings(
+        &self,
+        update: &proto::UpdateWorktreeSettings,
+        connection: ConnectionId,
+    ) -> Result<RoomGuard<Vec<ConnectionId>>> {
+        let project_id = ProjectId::from_proto(update.project_id);
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            // Ensure the update comes from the host.
+            let project = project::Entity::find_by_id(project_id)
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("no such project"))?;
+            if project.host_connection()? != connection {
+                return Err(anyhow!("can't update a project hosted by someone else"))?;
+            }
+
+            if let Some(content) = &update.content {
+                worktree_settings_file::Entity::insert(worktree_settings_file::ActiveModel {
+                    project_id: ActiveValue::Set(project_id),
+                    worktree_id: ActiveValue::Set(update.worktree_id as i64),
+                    path: ActiveValue::Set(update.path.clone()),
+                    content: ActiveValue::Set(content.clone()),
+                })
+                .on_conflict(
+                    OnConflict::columns([
+                        worktree_settings_file::Column::ProjectId,
+                        worktree_settings_file::Column::WorktreeId,
+                        worktree_settings_file::Column::Path,
+                    ])
+                    .update_column(worktree_settings_file::Column::Content)
+                    .to_owned(),
+                )
+                .exec(&*tx)
+                .await?;
+            } else {
+                worktree_settings_file::Entity::delete(worktree_settings_file::ActiveModel {
+                    project_id: ActiveValue::Set(project_id),
+                    worktree_id: ActiveValue::Set(update.worktree_id as i64),
+                    path: ActiveValue::Set(update.path.clone()),
+                    ..Default::default()
+                })
+                .exec(&*tx)
+                .await?;
+            }
+
+            let connection_ids = self.project_guest_connection_ids(project_id, &tx).await?;
+            Ok(connection_ids)
+        })
+        .await
+    }
+
+    pub async fn join_project(
+        &self,
+        project_id: ProjectId,
+        connection: ConnectionId,
+    ) -> Result<RoomGuard<(Project, ReplicaId)>> {
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            let participant = room_participant::Entity::find()
+                .filter(
+                    Condition::all()
+                        .add(
+                            room_participant::Column::AnsweringConnectionId
+                                .eq(connection.id as i32),
+                        )
+                        .add(
+                            room_participant::Column::AnsweringConnectionServerId
+                                .eq(connection.owner_id as i32),
+                        ),
+                )
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("must join a room first"))?;
+
+            let project = project::Entity::find_by_id(project_id)
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("no such project"))?;
+            if project.room_id != participant.room_id {
+                return Err(anyhow!("no such project"))?;
+            }
+
+            let mut collaborators = project
+                .find_related(project_collaborator::Entity)
+                .all(&*tx)
+                .await?;
+            let replica_ids = collaborators
+                .iter()
+                .map(|c| c.replica_id)
+                .collect::<HashSet<_>>();
+            let mut replica_id = ReplicaId(1);
+            while replica_ids.contains(&replica_id) {
+                replica_id.0 += 1;
+            }
+            let new_collaborator = project_collaborator::ActiveModel {
+                project_id: ActiveValue::set(project_id),
+                connection_id: ActiveValue::set(connection.id as i32),
+                connection_server_id: ActiveValue::set(ServerId(connection.owner_id as i32)),
+                user_id: ActiveValue::set(participant.user_id),
+                replica_id: ActiveValue::set(replica_id),
+                is_host: ActiveValue::set(false),
+                ..Default::default()
+            }
+            .insert(&*tx)
+            .await?;
+            collaborators.push(new_collaborator);
+
+            let db_worktrees = project.find_related(worktree::Entity).all(&*tx).await?;
+            let mut worktrees = db_worktrees
+                .into_iter()
+                .map(|db_worktree| {
+                    (
+                        db_worktree.id as u64,
+                        Worktree {
+                            id: db_worktree.id as u64,
+                            abs_path: db_worktree.abs_path,
+                            root_name: db_worktree.root_name,
+                            visible: db_worktree.visible,
+                            entries: Default::default(),
+                            repository_entries: Default::default(),
+                            diagnostic_summaries: Default::default(),
+                            settings_files: Default::default(),
+                            scan_id: db_worktree.scan_id as u64,
+                            completed_scan_id: db_worktree.completed_scan_id as u64,
+                        },
+                    )
+                })
+                .collect::<BTreeMap<_, _>>();
+
+            // Populate worktree entries.
+            {
+                let mut db_entries = worktree_entry::Entity::find()
+                    .filter(
+                        Condition::all()
+                            .add(worktree_entry::Column::ProjectId.eq(project_id))
+                            .add(worktree_entry::Column::IsDeleted.eq(false)),
+                    )
+                    .stream(&*tx)
+                    .await?;
+                while let Some(db_entry) = db_entries.next().await {
+                    let db_entry = db_entry?;
+                    if let Some(worktree) = worktrees.get_mut(&(db_entry.worktree_id as u64)) {
+                        worktree.entries.push(proto::Entry {
+                            id: db_entry.id as u64,
+                            is_dir: db_entry.is_dir,
+                            path: db_entry.path,
+                            inode: db_entry.inode as u64,
+                            mtime: Some(proto::Timestamp {
+                                seconds: db_entry.mtime_seconds as u64,
+                                nanos: db_entry.mtime_nanos as u32,
+                            }),
+                            is_symlink: db_entry.is_symlink,
+                            is_ignored: db_entry.is_ignored,
+                            is_external: db_entry.is_external,
+                            git_status: db_entry.git_status.map(|status| status as i32),
+                        });
+                    }
+                }
+            }
+
+            // Populate repository entries.
+            {
+                let mut db_repository_entries = worktree_repository::Entity::find()
+                    .filter(
+                        Condition::all()
+                            .add(worktree_repository::Column::ProjectId.eq(project_id))
+                            .add(worktree_repository::Column::IsDeleted.eq(false)),
+                    )
+                    .stream(&*tx)
+                    .await?;
+                while let Some(db_repository_entry) = db_repository_entries.next().await {
+                    let db_repository_entry = db_repository_entry?;
+                    if let Some(worktree) =
+                        worktrees.get_mut(&(db_repository_entry.worktree_id as u64))
+                    {
+                        worktree.repository_entries.insert(
+                            db_repository_entry.work_directory_id as u64,
+                            proto::RepositoryEntry {
+                                work_directory_id: db_repository_entry.work_directory_id as u64,
+                                branch: db_repository_entry.branch,
+                            },
+                        );
+                    }
+                }
+            }
+
+            // Populate worktree diagnostic summaries.
+            {
+                let mut db_summaries = worktree_diagnostic_summary::Entity::find()
+                    .filter(worktree_diagnostic_summary::Column::ProjectId.eq(project_id))
+                    .stream(&*tx)
+                    .await?;
+                while let Some(db_summary) = db_summaries.next().await {
+                    let db_summary = db_summary?;
+                    if let Some(worktree) = worktrees.get_mut(&(db_summary.worktree_id as u64)) {
+                        worktree
+                            .diagnostic_summaries
+                            .push(proto::DiagnosticSummary {
+                                path: db_summary.path,
+                                language_server_id: db_summary.language_server_id as u64,
+                                error_count: db_summary.error_count as u32,
+                                warning_count: db_summary.warning_count as u32,
+                            });
+                    }
+                }
+            }
+
+            // Populate worktree settings files
+            {
+                let mut db_settings_files = worktree_settings_file::Entity::find()
+                    .filter(worktree_settings_file::Column::ProjectId.eq(project_id))
+                    .stream(&*tx)
+                    .await?;
+                while let Some(db_settings_file) = db_settings_files.next().await {
+                    let db_settings_file = db_settings_file?;
+                    if let Some(worktree) =
+                        worktrees.get_mut(&(db_settings_file.worktree_id as u64))
+                    {
+                        worktree.settings_files.push(WorktreeSettingsFile {
+                            path: db_settings_file.path,
+                            content: db_settings_file.content,
+                        });
+                    }
+                }
+            }
+
+            // Populate language servers.
+            let language_servers = project
+                .find_related(language_server::Entity)
+                .all(&*tx)
+                .await?;
+
+            let project = Project {
+                collaborators: collaborators
+                    .into_iter()
+                    .map(|collaborator| ProjectCollaborator {
+                        connection_id: collaborator.connection(),
+                        user_id: collaborator.user_id,
+                        replica_id: collaborator.replica_id,
+                        is_host: collaborator.is_host,
+                    })
+                    .collect(),
+                worktrees,
+                language_servers: language_servers
+                    .into_iter()
+                    .map(|language_server| proto::LanguageServer {
+                        id: language_server.id as u64,
+                        name: language_server.name,
+                    })
+                    .collect(),
+            };
+            Ok((project, replica_id as ReplicaId))
+        })
+        .await
+    }
+
+    pub async fn leave_project(
+        &self,
+        project_id: ProjectId,
+        connection: ConnectionId,
+    ) -> Result<RoomGuard<(proto::Room, LeftProject)>> {
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            let result = project_collaborator::Entity::delete_many()
+                .filter(
+                    Condition::all()
+                        .add(project_collaborator::Column::ProjectId.eq(project_id))
+                        .add(project_collaborator::Column::ConnectionId.eq(connection.id as i32))
+                        .add(
+                            project_collaborator::Column::ConnectionServerId
+                                .eq(connection.owner_id as i32),
+                        ),
+                )
+                .exec(&*tx)
+                .await?;
+            if result.rows_affected == 0 {
+                Err(anyhow!("not a collaborator on this project"))?;
+            }
+
+            let project = project::Entity::find_by_id(project_id)
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("no such project"))?;
+            let collaborators = project
+                .find_related(project_collaborator::Entity)
+                .all(&*tx)
+                .await?;
+            let connection_ids = collaborators
+                .into_iter()
+                .map(|collaborator| collaborator.connection())
+                .collect();
+
+            follower::Entity::delete_many()
+                .filter(
+                    Condition::any()
+                        .add(
+                            Condition::all()
+                                .add(follower::Column::ProjectId.eq(project_id))
+                                .add(
+                                    follower::Column::LeaderConnectionServerId
+                                        .eq(connection.owner_id),
+                                )
+                                .add(follower::Column::LeaderConnectionId.eq(connection.id)),
+                        )
+                        .add(
+                            Condition::all()
+                                .add(follower::Column::ProjectId.eq(project_id))
+                                .add(
+                                    follower::Column::FollowerConnectionServerId
+                                        .eq(connection.owner_id),
+                                )
+                                .add(follower::Column::FollowerConnectionId.eq(connection.id)),
+                        ),
+                )
+                .exec(&*tx)
+                .await?;
+
+            let room = self.get_room(project.room_id, &tx).await?;
+            let left_project = LeftProject {
+                id: project_id,
+                host_user_id: project.host_user_id,
+                host_connection_id: project.host_connection()?,
+                connection_ids,
+            };
+            Ok((room, left_project))
+        })
+        .await
+    }
+
+    pub async fn project_collaborators(
+        &self,
+        project_id: ProjectId,
+        connection_id: ConnectionId,
+    ) -> Result<RoomGuard<Vec<ProjectCollaborator>>> {
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            let collaborators = project_collaborator::Entity::find()
+                .filter(project_collaborator::Column::ProjectId.eq(project_id))
+                .all(&*tx)
+                .await?
+                .into_iter()
+                .map(|collaborator| ProjectCollaborator {
+                    connection_id: collaborator.connection(),
+                    user_id: collaborator.user_id,
+                    replica_id: collaborator.replica_id,
+                    is_host: collaborator.is_host,
+                })
+                .collect::<Vec<_>>();
+
+            if collaborators
+                .iter()
+                .any(|collaborator| collaborator.connection_id == connection_id)
+            {
+                Ok(collaborators)
+            } else {
+                Err(anyhow!("no such project"))?
+            }
+        })
+        .await
+    }
+
+    pub async fn project_connection_ids(
+        &self,
+        project_id: ProjectId,
+        connection_id: ConnectionId,
+    ) -> Result<RoomGuard<HashSet<ConnectionId>>> {
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            let mut collaborators = project_collaborator::Entity::find()
+                .filter(project_collaborator::Column::ProjectId.eq(project_id))
+                .stream(&*tx)
+                .await?;
+
+            let mut connection_ids = HashSet::default();
+            while let Some(collaborator) = collaborators.next().await {
+                let collaborator = collaborator?;
+                connection_ids.insert(collaborator.connection());
+            }
+
+            if connection_ids.contains(&connection_id) {
+                Ok(connection_ids)
+            } else {
+                Err(anyhow!("no such project"))?
+            }
+        })
+        .await
+    }
+
+    async fn project_guest_connection_ids(
+        &self,
+        project_id: ProjectId,
+        tx: &DatabaseTransaction,
+    ) -> Result<Vec<ConnectionId>> {
+        let mut collaborators = project_collaborator::Entity::find()
+            .filter(
+                project_collaborator::Column::ProjectId
+                    .eq(project_id)
+                    .and(project_collaborator::Column::IsHost.eq(false)),
+            )
+            .stream(tx)
+            .await?;
+
+        let mut guest_connection_ids = Vec::new();
+        while let Some(collaborator) = collaborators.next().await {
+            let collaborator = collaborator?;
+            guest_connection_ids.push(collaborator.connection());
+        }
+        Ok(guest_connection_ids)
+    }
+
+    pub async fn room_id_for_project(&self, project_id: ProjectId) -> Result<RoomId> {
+        self.transaction(|tx| async move {
+            let project = project::Entity::find_by_id(project_id)
+                .one(&*tx)
+                .await?
+                .ok_or_else(|| anyhow!("project {} not found", project_id))?;
+            Ok(project.room_id)
+        })
+        .await
+    }
+
+    pub async fn follow(
+        &self,
+        project_id: ProjectId,
+        leader_connection: ConnectionId,
+        follower_connection: ConnectionId,
+    ) -> Result<RoomGuard<proto::Room>> {
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            follower::ActiveModel {
+                room_id: ActiveValue::set(room_id),
+                project_id: ActiveValue::set(project_id),
+                leader_connection_server_id: ActiveValue::set(ServerId(
+                    leader_connection.owner_id as i32,
+                )),
+                leader_connection_id: ActiveValue::set(leader_connection.id as i32),
+                follower_connection_server_id: ActiveValue::set(ServerId(
+                    follower_connection.owner_id as i32,
+                )),
+                follower_connection_id: ActiveValue::set(follower_connection.id as i32),
+                ..Default::default()
+            }
+            .insert(&*tx)
+            .await?;
+
+            let room = self.get_room(room_id, &*tx).await?;
+            Ok(room)
+        })
+        .await
+    }
+
+    pub async fn unfollow(
+        &self,
+        project_id: ProjectId,
+        leader_connection: ConnectionId,
+        follower_connection: ConnectionId,
+    ) -> Result<RoomGuard<proto::Room>> {
+        let room_id = self.room_id_for_project(project_id).await?;
+        self.room_transaction(room_id, |tx| async move {
+            follower::Entity::delete_many()
+                .filter(
+                    Condition::all()
+                        .add(follower::Column::ProjectId.eq(project_id))
+                        .add(
+                            follower::Column::LeaderConnectionServerId
+                                .eq(leader_connection.owner_id),
+                        )
+                        .add(follower::Column::LeaderConnectionId.eq(leader_connection.id))
+                        .add(
+                            follower::Column::FollowerConnectionServerId
+                                .eq(follower_connection.owner_id),
+                        )
+                        .add(follower::Column::FollowerConnectionId.eq(follower_connection.id)),
+                )
+                .exec(&*tx)
+                .await?;
+
+            let room = self.get_room(room_id, &*tx).await?;
+            Ok(room)
+        })
+        .await
+    }
+}