view rust/hg-core/src/logging.rs @ 49779:7d6c8943353a stable

hg: show the correct message when cloning an LFS repo with extension disabled

The `extensions._disabledpaths()` doesn't handle fetching help from `__index__`,
so it returns an empty dictionary of paths.  That means None is always returned
from `extensions.disabled_help()` when embedding resources inside the pyoxidizer
or py2exe binary, regardless of the arg or if is an external extension stored in
the filesystem.  And that means wrongly telling the user with an explicitly
disabled LFS extension that it will be enabled locally upon cloning from an LFS
remote.  That causes test-lfs-serve.t:295 to fail.

This effectively reverts most of the rest of 843418dc0b1b, while keeping the
help text change in place (which was specifically identified as a problem).

use crate::errors::{HgError, HgResultExt, IoErrorContext, IoResultExt};
use crate::vfs::Vfs;
use std::io::Write;

/// An utility to append to a log file with the given name, and optionally
/// rotate it after it reaches a certain maximum size.
///
/// Rotation works by renaming "example.log" to "example.log.1", after renaming
/// "example.log.1" to "example.log.2" etc up to the given maximum number of
/// files.
pub struct LogFile<'a> {
    vfs: Vfs<'a>,
    name: &'a str,
    max_size: Option<u64>,
    max_files: u32,
}

impl<'a> LogFile<'a> {
    pub fn new(vfs: Vfs<'a>, name: &'a str) -> Self {
        Self {
            vfs,
            name,
            max_size: None,
            max_files: 0,
        }
    }

    /// Rotate before writing to a log file that was already larger than the
    /// given size, in bytes. `None` disables rotation.
    pub fn max_size(mut self, value: Option<u64>) -> Self {
        self.max_size = value;
        self
    }

    /// Keep this many rotated files `{name}.1` up to `{name}.{max}`, in
    /// addition to the original `{name}` file.
    pub fn max_files(mut self, value: u32) -> Self {
        self.max_files = value;
        self
    }

    /// Append the given `bytes` as-is to the log file, after rotating if
    /// needed.
    ///
    /// No trailing newline is added. Make sure to include one in `bytes` if
    /// desired.
    pub fn write(&self, bytes: &[u8]) -> Result<(), HgError> {
        let path = self.vfs.join(self.name);
        let context = || IoErrorContext::WritingFile(path.clone());
        let open = || {
            std::fs::OpenOptions::new()
                .create(true)
                .append(true)
                .open(&path)
                .with_context(context)
        };
        let mut file = open()?;
        if let Some(max_size) = self.max_size {
            if file.metadata().with_context(context)?.len() >= max_size {
                // For example with `max_files == 5`, the first iteration of
                // this loop has `i == 4` and renames `{name}.4` to `{name}.5`.
                // The last iteration renames `{name}.1` to
                // `{name}.2`
                for i in (1..self.max_files).rev() {
                    self.vfs
                        .rename(
                            format!("{}.{}", self.name, i),
                            format!("{}.{}", self.name, i + 1),
                        )
                        .io_not_found_as_none()?;
                }
                // Then rename `{name}` to `{name}.1`. This is the
                // previously-opened `file`.
                self.vfs
                    .rename(self.name, format!("{}.1", self.name))
                    .io_not_found_as_none()?;
                // Finally, create a new `{name}` file and replace our `file`
                // handle.
                file = open()?;
            }
        }
        file.write_all(bytes).with_context(context)?;
        file.sync_all().with_context(context)
    }
}

#[test]
fn test_rotation() {
    let temp = tempfile::tempdir().unwrap();
    let vfs = Vfs { base: temp.path() };
    let logger = LogFile::new(vfs, "log").max_size(Some(3)).max_files(2);
    logger.write(b"one\n").unwrap();
    logger.write(b"two\n").unwrap();
    logger.write(b"3\n").unwrap();
    logger.write(b"four\n").unwrap();
    logger.write(b"five\n").unwrap();
    assert_eq!(vfs.read("log").unwrap(), b"five\n");
    assert_eq!(vfs.read("log.1").unwrap(), b"3\nfour\n");
    assert_eq!(vfs.read("log.2").unwrap(), b"two\n");
    assert!(vfs.read("log.3").io_not_found_as_none().unwrap().is_none());
}