rust/rhg/src/commands/status.rs

rhg: Reuse manifest when checking status of multiple ambiguous files

When `rhg status` cannot determine whether a file is clean based on mtime and
size alone, it needs to compare its contents with those found in the parent
commit. Previously, rhg would find the (same) manifest of that commit again
for every such file. This is lifted out of the loop and reused.

Differential Revision: https://phab.mercurial-scm.org/D11411

// status.rs
//
// Copyright 2020, Georges Racinet <[e-mail]>
//
// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.

use crate::error::CommandError;
use crate::ui::Ui;
use clap::{Arg, SubCommand};
use hg;
use hg::dirstate_tree::dispatch::DirstateMapMethods;
use hg::errors::{HgError, IoResultExt};
use hg::manifest::Manifest;
use hg::matchers::AlwaysMatcher;
use hg::repo::Repo;
use hg::utils::hg_path::{hg_path_to_os_string, HgPath};
use hg::{HgPathCow, StatusOptions};
use log::{info, warn};
use std::convert::TryInto;
use std::fs;
use std::io::BufReader;
use std::io::Read;

pub const HELP_TEXT: &str = "
Show changed files in the working directory

This is a pure Rust version of `hg status`.

Some options might be missing, check the list below.
";

pub fn args() -> clap::App<'static, 'static> {
    SubCommand::with_name("status")
        .alias("st")
        .about(HELP_TEXT)
        .arg(
            Arg::with_name("all")
                .help("show status of all files")
                .short("-A")
                .long("--all"),
        )
        .arg(
            Arg::with_name("modified")
                .help("show only modified files")
                .short("-m")
                .long("--modified"),
        )
        .arg(
            Arg::with_name("added")
                .help("show only added files")
                .short("-a")
                .long("--added"),
        )
        .arg(
            Arg::with_name("removed")
                .help("show only removed files")
                .short("-r")
                .long("--removed"),
        )
        .arg(
            Arg::with_name("clean")
                .help("show only clean files")
                .short("-c")
                .long("--clean"),
        )
        .arg(
            Arg::with_name("deleted")
                .help("show only deleted files")
                .short("-d")
                .long("--deleted"),
        )
        .arg(
            Arg::with_name("unknown")
                .help("show only unknown (not tracked) files")
                .short("-u")
                .long("--unknown"),
        )
        .arg(
            Arg::with_name("ignored")
                .help("show only ignored files")
                .short("-i")
                .long("--ignored"),
        )
}

/// Pure data type allowing the caller to specify file states to display
#[derive(Copy, Clone, Debug)]
pub struct DisplayStates {
    pub modified: bool,
    pub added: bool,
    pub removed: bool,
    pub clean: bool,
    pub deleted: bool,
    pub unknown: bool,
    pub ignored: bool,
}

pub const DEFAULT_DISPLAY_STATES: DisplayStates = DisplayStates {
    modified: true,
    added: true,
    removed: true,
    clean: false,
    deleted: true,
    unknown: true,
    ignored: false,
};

pub const ALL_DISPLAY_STATES: DisplayStates = DisplayStates {
    modified: true,
    added: true,
    removed: true,
    clean: true,
    deleted: true,
    unknown: true,
    ignored: true,
};

impl DisplayStates {
    pub fn is_empty(&self) -> bool {
        !(self.modified
            || self.added
            || self.removed
            || self.clean
            || self.deleted
            || self.unknown
            || self.ignored)
    }
}

pub fn run(invocation: &crate::CliInvocation) -> Result<(), CommandError> {
    let status_enabled_default = false;
    let status_enabled = invocation.config.get_option(b"rhg", b"status")?;
    if !status_enabled.unwrap_or(status_enabled_default) {
        return Err(CommandError::unsupported(
            "status is experimental in rhg (enable it with 'rhg.status = true' \
            or enable fallback with 'rhg.on-unsupported = fallback')"
        ));
    }

    let ui = invocation.ui;
    let args = invocation.subcommand_args;
    let display_states = if args.is_present("all") {
        // TODO when implementing `--quiet`: it excludes clean files
        // from `--all`
        ALL_DISPLAY_STATES
    } else {
        let requested = DisplayStates {
            modified: args.is_present("modified"),
            added: args.is_present("added"),
            removed: args.is_present("removed"),
            clean: args.is_present("clean"),
            deleted: args.is_present("deleted"),
            unknown: args.is_present("unknown"),
            ignored: args.is_present("ignored"),
        };
        if requested.is_empty() {
            DEFAULT_DISPLAY_STATES
        } else {
            requested
        }
    };

    let repo = invocation.repo?;
    let mut dmap = repo.dirstate_map_mut()?;

    let options = StatusOptions {
        // TODO should be provided by the dirstate parsing and
        // hence be stored on dmap. Using a value that assumes we aren't
        // below the time resolution granularity of the FS and the
        // dirstate.
        last_normal_time: 0,
        // we're currently supporting file systems with exec flags only
        // anyway
        check_exec: true,
        list_clean: display_states.clean,
        list_unknown: display_states.unknown,
        list_ignored: display_states.ignored,
        collect_traversed_dirs: false,
    };
    let ignore_file = repo.working_directory_vfs().join(".hgignore"); // TODO hardcoded
    let (mut ds_status, pattern_warnings) = dmap.status(
        &AlwaysMatcher,
        repo.working_directory_path().to_owned(),
        vec![ignore_file],
        options,
    )?;
    if !pattern_warnings.is_empty() {
        warn!("Pattern warnings: {:?}", &pattern_warnings);
    }

    if !ds_status.bad.is_empty() {
        warn!("Bad matches {:?}", &(ds_status.bad))
    }
    if !ds_status.unsure.is_empty() {
        info!(
            "Files to be rechecked by retrieval from filelog: {:?}",
            &ds_status.unsure
        );
    }
    if !ds_status.unsure.is_empty()
        && (display_states.modified || display_states.clean)
    {
        let p1 = repo.dirstate_parents()?.p1;
        let manifest = repo.manifest_for_node(p1).map_err(|e| {
            CommandError::from((e, &*format!("{:x}", p1.short())))
        })?;
        for to_check in ds_status.unsure {
            if cat_file_is_modified(repo, &manifest, &to_check)? {
                if display_states.modified {
                    ds_status.modified.push(to_check);
                }
            } else {
                if display_states.clean {
                    ds_status.clean.push(to_check);
                }
            }
        }
    }
    if display_states.modified {
        display_status_paths(ui, &mut ds_status.modified, b"M")?;
    }
    if display_states.added {
        display_status_paths(ui, &mut ds_status.added, b"A")?;
    }
    if display_states.removed {
        display_status_paths(ui, &mut ds_status.removed, b"R")?;
    }
    if display_states.deleted {
        display_status_paths(ui, &mut ds_status.deleted, b"!")?;
    }
    if display_states.unknown {
        display_status_paths(ui, &mut ds_status.unknown, b"?")?;
    }
    if display_states.ignored {
        display_status_paths(ui, &mut ds_status.ignored, b"I")?;
    }
    if display_states.clean {
        display_status_paths(ui, &mut ds_status.clean, b"C")?;
    }
    Ok(())
}

// Probably more elegant to use a Deref or Borrow trait rather than
// harcode HgPathBuf, but probably not really useful at this point
fn display_status_paths(
    ui: &Ui,
    paths: &mut [HgPathCow],
    status_prefix: &[u8],
) -> Result<(), CommandError> {
    paths.sort_unstable();
    for path in paths {
        // Same TODO as in commands::root
        let bytes: &[u8] = path.as_bytes();
        // TODO optim, probably lots of unneeded copies here, especially
        // if out stream is buffered
        ui.write_stdout(&[status_prefix, b" ", bytes, b"\n"].concat())?;
    }
    Ok(())
}

/// Check if a file is modified by comparing actual repo store and file system.
///
/// This meant to be used for those that the dirstate cannot resolve, due
/// to time resolution limits.
///
/// TODO: detect permission bits and similar metadata modifications
fn cat_file_is_modified(
    repo: &Repo,
    manifest: &Manifest,
    hg_path: &HgPath,
) -> Result<bool, HgError> {
    let file_node = manifest
        .find_file(hg_path)?
        .expect("ambgious file not in p1");
    let filelog = repo.filelog(hg_path)?;
    let filelog_entry = filelog.get_node(file_node).map_err(|_| {
        HgError::corrupted("filelog missing node from manifest")
    })?;
    let contents_in_p1 = filelog_entry.data()?;

    let fs_path = repo
        .working_directory_vfs()
        .join(hg_path_to_os_string(hg_path).expect("HgPath conversion"));
    let hg_data_len: u64 = match contents_in_p1.len().try_into() {
        Ok(v) => v,
        Err(_) => {
            // conversion of data length to u64 failed,
            // good luck for any file to have this content
            return Ok(true);
        }
    };
    let fobj = fs::File::open(&fs_path).when_reading_file(&fs_path)?;
    if fobj.metadata().when_reading_file(&fs_path)?.len() != hg_data_len {
        return Ok(true);
    }
    for (fs_byte, &hg_byte) in BufReader::new(fobj).bytes().zip(contents_in_p1)
    {
        if fs_byte.when_reading_file(&fs_path)? != hg_byte {
            return Ok(true);
        }
    }
    Ok(false)
}