// dirstate module

//

// Copyright 2019 Raphaël Gomès <rgomes@octobus.net>

//

// 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::dirstate_tree::on_disk::DirstateV2ParseError;

use crate::errors::HgError;

use crate::revlog::Node;

use crate::utils::hg_path::{HgPath, HgPathBuf};

use crate::FastHashMap;

use bytes_cast::{unaligned, BytesCast};

use std::convert::TryFrom;

pub mod dirs_multiset;

pub mod dirstate_map;

pub mod parsers;

pub mod status;

#[derive(Debug, PartialEq, Clone, BytesCast)]

#[repr(C)]

pub struct DirstateParents {

    pub p1: Node,

    pub p2: Node,

}

/// The C implementation uses all signed types. This will be an issue

/// either when 4GB+ source files are commonplace or in 2038, whichever

/// comes first.

#[derive(Debug, PartialEq, Copy, Clone)]

pub struct DirstateEntry {

    pub state: EntryState,

    pub mode: i32,

    pub mtime: i32,

    pub size: i32,

}

impl DirstateEntry {

    pub fn is_non_normal(&self) -> bool {

        self.state != EntryState::Normal || self.mtime == MTIME_UNSET

    }

    pub fn is_from_other_parent(&self) -> bool {

        self.state == EntryState::Normal && self.size == SIZE_FROM_OTHER_PARENT

    }

    // TODO: other platforms

    #[cfg(unix)]

    pub fn mode_changed(

        &self,

        filesystem_metadata: &std::fs::Metadata,

    ) -> bool {

        use std::os::unix::fs::MetadataExt;

        const EXEC_BIT_MASK: u32 = 0o100;

        let dirstate_exec_bit = (self.mode as u32) & EXEC_BIT_MASK;

        let fs_exec_bit = filesystem_metadata.mode() & EXEC_BIT_MASK;

        dirstate_exec_bit != fs_exec_bit

    }

}

#[derive(BytesCast)]

#[repr(C)]

struct RawEntry {

    state: u8,

    mode: unaligned::I32Be,

    size: unaligned::I32Be,

    mtime: unaligned::I32Be,

    length: unaligned::I32Be,

}

const MTIME_UNSET: i32 = -1;

/// A `DirstateEntry` with a size of `-2` means that it was merged from the

/// other parent. This allows revert to pick the right status back during a

/// merge.

pub const SIZE_FROM_OTHER_PARENT: i32 = -2;

pub type StateMap = FastHashMap<HgPathBuf, DirstateEntry>;

pub type StateMapIter<'a> = Box<

    dyn Iterator<

            Item = Result<(&'a HgPath, DirstateEntry), DirstateV2ParseError>,

        > + Send

        + 'a,

>;

pub type CopyMap = FastHashMap<HgPathBuf, HgPathBuf>;

pub type CopyMapIter<'a> = Box<

    dyn Iterator<Item = Result<(&'a HgPath, &'a HgPath), DirstateV2ParseError>>

        + Send

        + 'a,

>;

#[derive(Copy, Clone, Debug, Eq, PartialEq)]

pub enum EntryState {

    Normal,

    Added,

    Removed,

    Merged,

    Unknown,

}

impl EntryState {

    pub fn is_tracked(self) -> bool {

        use EntryState::*;

        match self {

            Normal | Added | Merged => true,

            Removed | Unknown => false,

        }

    }

}

impl TryFrom<u8> for EntryState {

    type Error = HgError;

    fn try_from(value: u8) -> Result<Self, Self::Error> {

        match value {

            b'n' => Ok(EntryState::Normal),

            b'a' => Ok(EntryState::Added),

            b'r' => Ok(EntryState::Removed),

            b'm' => Ok(EntryState::Merged),

            b'?' => Ok(EntryState::Unknown),

            _ => Err(HgError::CorruptedRepository(format!(

                "Incorrect dirstate entry state {}",

                value

            ))),

        }

    }

}

impl Into<u8> for EntryState {

    fn into(self) -> u8 {

        match self {

            EntryState::Normal => b'n',

            EntryState::Added => b'a',

            EntryState::Removed => b'r',

            EntryState::Merged => b'm',

            EntryState::Unknown => b'?',

        }

    }

}