// 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. use std::slice;use std::time::Duration;use std::time::SystemTime; use jj_lib::repo::Repo as _; use crate::cli_util::CommandHelper;use crate::command_error::CommandError;use crate::command_error::user_error;use crate::ui::Ui; /// Run backend-dependent garbage collection.////// To garbage-collect old operations and the commits/objects referenced by/// them, run `jj op abandon ..<some old operation>` before `jj util gc`.#[derive(clap::Args, Clone, Debug)]pub struct UtilGcArgs {    /// Time threshold    ///    /// By default, only obsolete objects and operations older than 2 weeks are    /// pruned.    ///    /// Only the string "now" can be passed to this parameter. Support for    /// arbitrary absolute and relative timestamps will come in a subsequent    /// release.    #[arg(long)]    expire: Option<String>,} pub fn cmd_util_gc(    ui: &mut Ui,    command: &CommandHelper,    args: &UtilGcArgs,) -> Result<(), CommandError> {    if !command.is_at_head_operation() {        return Err(user_error(            "Cannot garbage collect from a non-head operation",        ));    }    let keep_newer = match args.expire.as_deref() {        None => SystemTime::now() - Duration::from_secs(14 * 86400),        Some("now") => SystemTime::now() - Duration::ZERO,        _ => return Err(user_error("--expire only accepts 'now'")),    };    let workspace_command = command.workspace_helper(ui)?;     let repo = workspace_command.repo();    repo.op_store()        .gc(slice::from_ref(repo.op_id()), keep_newer)?;    repo.store().gc(repo.index(), keep_newer)?;    Ok(())}