annotate rust/hg-core/src/operations/cat.rs @ 46243:63c923fd7fa8

setup: when possible, build and bundle man pages

This makes it so the manual pages are built as part of the Python
build, and includes them in any wheel generated. This should make
Python wheels a much more useful and complete way of distributing
Mercurial binaries.

Differential Revision: https://phab.mercurial-scm.org/D9640

// list_tracked_files.rs
//
// Copyright 2020 Antoine Cezar <[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 std::convert::From;
use std::path::PathBuf;

use crate::repo::Repo;
use crate::revlog::changelog::Changelog;
use crate::revlog::manifest::Manifest;
use crate::revlog::path_encode::path_encode;
use crate::revlog::revlog::Revlog;
use crate::revlog::revlog::RevlogError;
use crate::revlog::Node;
use crate::revlog::NodePrefix;
use crate::revlog::Revision;
use crate::utils::files::get_path_from_bytes;
use crate::utils::hg_path::{HgPath, HgPathBuf};

const METADATA_DELIMITER: [u8; 2] = [b'\x01', b'\n'];

/// Kind of error encountered by `CatRev`
#[derive(Debug)]
pub enum CatRevErrorKind {
    /// Error when reading a `revlog` file.
    IoError(std::io::Error),
    /// The revision has not been found.
    InvalidRevision,
    /// Found more than one revision whose ID match the requested prefix
    AmbiguousPrefix,
    /// A `revlog` file is corrupted.
    CorruptedRevlog,
    /// The `revlog` format version is not supported.
    UnsuportedRevlogVersion(u16),
    /// The `revlog` data format is not supported.
    UnknowRevlogDataFormat(u8),
}

/// A `CatRev` error
#[derive(Debug)]
pub struct CatRevError {
    /// Kind of error encountered by `CatRev`
    pub kind: CatRevErrorKind,
}

impl From<CatRevErrorKind> for CatRevError {
    fn from(kind: CatRevErrorKind) -> Self {
        CatRevError { kind }
    }
}

impl From<RevlogError> for CatRevError {
    fn from(err: RevlogError) -> Self {
        match err {
            RevlogError::IoError(err) => CatRevErrorKind::IoError(err),
            RevlogError::UnsuportedVersion(version) => {
                CatRevErrorKind::UnsuportedRevlogVersion(version)
            }
            RevlogError::InvalidRevision => CatRevErrorKind::InvalidRevision,
            RevlogError::AmbiguousPrefix => CatRevErrorKind::AmbiguousPrefix,
            RevlogError::Corrupted => CatRevErrorKind::CorruptedRevlog,
            RevlogError::UnknowDataFormat(format) => {
                CatRevErrorKind::UnknowRevlogDataFormat(format)
            }
        }
        .into()
    }
}

/// List files under Mercurial control at a given revision.
///
/// * `root`: Repository root
/// * `rev`: The revision to cat the files from.
/// * `files`: The files to output.
pub fn cat(
    repo: &Repo,
    rev: &str,
    files: &[HgPathBuf],
) -> Result<Vec<u8>, CatRevError> {
    let changelog = Changelog::open(repo)?;
    let manifest = Manifest::open(repo)?;

    let changelog_entry = match rev.parse::<Revision>() {
        Ok(rev) => changelog.get_rev(rev)?,
        _ => {
            let changelog_node = NodePrefix::from_hex(&rev)
                .map_err(|_| CatRevErrorKind::InvalidRevision)?;
            changelog.get_node(changelog_node.borrow())?
        }
    };
    let manifest_node = Node::from_hex(&changelog_entry.manifest_node()?)
        .map_err(|_| CatRevErrorKind::CorruptedRevlog)?;

    let manifest_entry = manifest.get_node((&manifest_node).into())?;
    let mut bytes = vec![];

    for (manifest_file, node_bytes) in manifest_entry.files_with_nodes() {
        for cat_file in files.iter() {
            if cat_file.as_bytes() == manifest_file.as_bytes() {
                let index_path = store_path(manifest_file, b".i");
                let data_path = store_path(manifest_file, b".d");

                let file_log =
                    Revlog::open(repo, &index_path, Some(&data_path))?;
                let file_node = Node::from_hex(node_bytes)
                    .map_err(|_| CatRevErrorKind::CorruptedRevlog)?;
                let file_rev = file_log.get_node_rev((&file_node).into())?;
                let data = file_log.get_rev_data(file_rev)?;
                if data.starts_with(&METADATA_DELIMITER) {
                    let end_delimiter_position = data
                        [METADATA_DELIMITER.len()..]
                        .windows(METADATA_DELIMITER.len())
                        .position(|bytes| bytes == METADATA_DELIMITER);
                    if let Some(position) = end_delimiter_position {
                        let offset = METADATA_DELIMITER.len() * 2;
                        bytes.extend(data[position + offset..].iter());
                    }
                } else {
                    bytes.extend(data);
                }
            }
        }
    }

    Ok(bytes)
}

fn store_path(hg_path: &HgPath, suffix: &[u8]) -> PathBuf {
    let encoded_bytes =
        path_encode(&[b"data/", hg_path.as_bytes(), suffix].concat());
    get_path_from_bytes(&encoded_bytes).into()
}