view rust/rhg/src/blackbox.rs @ 48409:005ae1a343f8

rhg: add support for narrow clones and sparse checkouts

This adds a minimal support that can be implemented without parsing the narrowspec.
We can parse the narrowspec and add support for more operations later.

The reason we need so few code changes is as follows:

Most operations need no special treatment of sparse because
some of them only read dirstate (`rhg files` without `-r`),
which bakes in the filtering,
some of them only read store (`rhg files -r`, `rhg cat`),
and some of them read no data at all (`rhg root`, `rhg debugrequirements`).

`status` is the command that might care about sparse, so we just disable
rhg on it.

For narrow clones, `rhg files` clearly needs the narrowspec to work
correctly, so we fall back.
`rhg cat` seems to work consistently with `hg cat` if the file exists.
If the file is hidden by narrow spec, the error message is different and confusing, so
that's something that we should improve in follow-up patches.

Differential Revision: https://phab.mercurial-scm.org/D11764

//! Logging for repository events, including commands run in the repository.

use crate::CliInvocation;
use format_bytes::format_bytes;
use hg::errors::HgError;
use hg::repo::Repo;
use hg::utils::{files::get_bytes_from_os_str, shell_quote};

const ONE_MEBIBYTE: u64 = 1 << 20;

// TODO: somehow keep defaults in sync with `configitem` in `hgext/blackbox.py`
const DEFAULT_MAX_SIZE: u64 = ONE_MEBIBYTE;
const DEFAULT_MAX_FILES: u32 = 7;

// Python does not support %.3f, only %f
const DEFAULT_DATE_FORMAT: &str = "%Y/%m/%d %H:%M:%S%.3f";

type DateTime = chrono::DateTime<chrono::Local>;

pub struct ProcessStartTime {
    /// For measuring duration
    monotonic_clock: std::time::Instant,
    /// For formatting with year, month, day, etc.
    calendar_based: DateTime,
}

impl ProcessStartTime {
    pub fn now() -> Self {
        Self {
            monotonic_clock: std::time::Instant::now(),
            calendar_based: chrono::Local::now(),
        }
    }
}

pub struct Blackbox<'a> {
    process_start_time: &'a ProcessStartTime,
    /// Do nothing if this is `None`
    configured: Option<ConfiguredBlackbox<'a>>,
}

struct ConfiguredBlackbox<'a> {
    repo: &'a Repo,
    max_size: u64,
    max_files: u32,
    date_format: &'a str,
}

impl<'a> Blackbox<'a> {
    pub fn new(
        invocation: &'a CliInvocation<'a>,
        process_start_time: &'a ProcessStartTime,
    ) -> Result<Self, HgError> {
        let configured = if let Ok(repo) = invocation.repo {
            if invocation.config.get(b"extensions", b"blackbox").is_none() {
                // The extension is not enabled
                None
            } else {
                Some(ConfiguredBlackbox {
                    repo,
                    max_size: invocation
                        .config
                        .get_byte_size(b"blackbox", b"maxsize")?
                        .unwrap_or(DEFAULT_MAX_SIZE),
                    max_files: invocation
                        .config
                        .get_u32(b"blackbox", b"maxfiles")?
                        .unwrap_or(DEFAULT_MAX_FILES),
                    date_format: invocation
                        .config
                        .get_str(b"blackbox", b"date-format")?
                        .unwrap_or(DEFAULT_DATE_FORMAT),
                })
            }
        } else {
            // Without a local repository there’s no `.hg/blackbox.log` to
            // write to.
            None
        };
        Ok(Self {
            process_start_time,
            configured,
        })
    }

    pub fn log_command_start(&self) {
        if let Some(configured) = &self.configured {
            let message = format_bytes!(b"(rust) {}", format_cli_args());
            configured.log(&self.process_start_time.calendar_based, &message);
        }
    }

    pub fn log_command_end(&self, exit_code: i32) {
        if let Some(configured) = &self.configured {
            let now = chrono::Local::now();
            let duration = self
                .process_start_time
                .monotonic_clock
                .elapsed()
                .as_secs_f64();
            let message = format_bytes!(
                b"(rust) {} exited {} after {} seconds",
                format_cli_args(),
                exit_code,
                format_bytes::Utf8(format_args!("{:.03}", duration))
            );
            configured.log(&now, &message);
        }
    }
}

impl ConfiguredBlackbox<'_> {
    fn log(&self, date_time: &DateTime, message: &[u8]) {
        let date = format_bytes::Utf8(date_time.format(self.date_format));
        let user = users::get_current_username().map(get_bytes_from_os_str);
        let user = user.as_deref().unwrap_or(b"???");
        let rev = format_bytes::Utf8(match self.repo.dirstate_parents() {
            Ok(parents) if parents.p2 == hg::revlog::node::NULL_NODE => {
                format!("{:x}", parents.p1)
            }
            Ok(parents) => format!("{:x}+{:x}", parents.p1, parents.p2),
            Err(_dirstate_corruption_error) => {
                // TODO: log a non-fatal warning to stderr
                "???".to_owned()
            }
        });
        let pid = std::process::id();
        let line = format_bytes!(
            b"{} {} @{} ({})> {}\n",
            date,
            user,
            rev,
            pid,
            message
        );
        let result =
            hg::logging::LogFile::new(self.repo.hg_vfs(), "blackbox.log")
                .max_size(Some(self.max_size))
                .max_files(self.max_files)
                .write(&line);
        match result {
            Ok(()) => {}
            Err(_io_error) => {
                // TODO: log a non-fatal warning to stderr
            }
        }
    }
}

fn format_cli_args() -> Vec<u8> {
    let mut args = std::env::args_os();
    let _ = args.next(); // Skip the first (or zeroth) arg, the name of the `rhg` executable
    let mut args = args.map(|arg| shell_quote(&get_bytes_from_os_str(arg)));
    let mut formatted = Vec::new();
    if let Some(arg) = args.next() {
        formatted.extend(arg)
    }
    for arg in args {
        formatted.push(b' ');
        formatted.extend(arg)
    }
    formatted
}