rust/hg-core/src/revlog/index.rs

50976:9929c8a73488

use std::ops::Deref;

use byteorder::{BigEndian, ByteOrder};

use crate::errors::HgError;
use crate::revlog::node::Node;
use crate::revlog::{Revision, NULL_REVISION};

pub const INDEX_ENTRY_SIZE: usize = 64;

pub struct IndexHeader {
    header_bytes: [u8; 4],

    bytes: Box<dyn Deref<Target = [u8]> + Send>,
    /// Offsets of starts of index blocks.
    /// Only needed when the index is interleaved with data.
    offsets: Option<Vec<usize>>,
    uses_generaldelta: bool,
}

impl Index {
    /// Create an index from bytes.
    /// Calculate the start of each entry when is_inline is true.

    /// exists.
    pub fn get_entry(&self, rev: Revision) -> Option<IndexEntry> {
        if rev == NULL_REVISION {
            return None;
        }
        if let Some(offsets) = &self.offsets {
            self.get_entry_inline(rev, offsets)
        } else {
            self.get_entry_separated(rev)
        }
    }

    fn get_entry_inline(
        &self,
        rev: Revision,
        offsets: &[usize],
    ) -> Option<IndexEntry> {
        let start = *offsets.get(rev as usize)?;
        let end = start.checked_add(INDEX_ENTRY_SIZE)?;
        let bytes = &self.bytes[start..end];

        // See IndexEntry for an explanation of this override.
        let offset_override = Some(end);

        Some(IndexEntry {
            bytes,
            offset_override,
        })
    }

    fn get_entry_separated(&self, rev: Revision) -> Option<IndexEntry> {
        let max_rev = self.bytes.len() / INDEX_ENTRY_SIZE;
        if rev as usize >= max_rev {
            return None;
        }
        let start = rev as usize * INDEX_ENTRY_SIZE;
        let end = start + INDEX_ENTRY_SIZE;
        let bytes = &self.bytes[start..end];

        // Override the offset of the first revision as its bytes are used
        // for the index's metadata (saving space because it is always 0)
        let offset_override = if rev == 0 { Some(0) } else { None };

        Some(IndexEntry {
            bytes,
            offset_override,
        })
    }
}

impl super::RevlogIndex for Index {
    fn len(&self) -> usize {

    pub fn uncompressed_len(&self) -> i32 {
        BigEndian::read_i32(&self.bytes[12..=15])
    }

    /// Return the revision upon which the data has been derived.
    pub fn base_revision_or_base_of_delta_chain(&self) -> Revision {
        // TODO Maybe return an Option when base_revision == rev?
        //      Requires to add rev to IndexEntry

        BigEndian::read_i32(&self.bytes[16..])
    }

    pub fn link_revision(&self) -> Revision {
        BigEndian::read_i32(&self.bytes[20..])
    }

    pub fn p1(&self) -> Revision {
        BigEndian::read_i32(&self.bytes[24..])
    }

    pub fn p2(&self) -> Revision {
        BigEndian::read_i32(&self.bytes[28..])
    }

    /// Return the hash of revision's full text.
    ///
    /// Currently, SHA-1 is used and only the first 20 bytes of this field

        let entry = IndexEntry {
            bytes: &bytes,
            offset_override: None,
        };

        assert_eq!(entry.base_revision_or_base_of_delta_chain(), 1)
    }

    #[test]
    fn link_revision_test() {
        let bytes = IndexEntryBuilder::new().with_link_revision(123).build();

        let entry = IndexEntry {
            bytes: &bytes,
            offset_override: None,
        };

        assert_eq!(entry.link_revision(), 123);
    }

    #[test]
    fn p1_test() {
        let bytes = IndexEntryBuilder::new().with_p1(123).build();

        let entry = IndexEntry {
            bytes: &bytes,
            offset_override: None,
        };

        assert_eq!(entry.p1(), 123);
    }

    #[test]
    fn p2_test() {
        let bytes = IndexEntryBuilder::new().with_p2(123).build();

        let entry = IndexEntry {
            bytes: &bytes,
            offset_override: None,
        };

        assert_eq!(entry.p2(), 123);
    }

    #[test]
    fn node_test() {
        let node = Node::from_hex("0123456789012345678901234567890123456789")

50977:1928b770e3e7

use std::fmt::Debug;
use std::ops::Deref;

use byteorder::{BigEndian, ByteOrder};

use crate::errors::HgError;
use crate::revlog::node::Node;
use crate::revlog::{Revision, NULL_REVISION};
use crate::UncheckedRevision;

pub const INDEX_ENTRY_SIZE: usize = 64;

pub struct IndexHeader {
    header_bytes: [u8; 4],

    bytes: Box<dyn Deref<Target = [u8]> + Send>,
    /// Offsets of starts of index blocks.
    /// Only needed when the index is interleaved with data.
    offsets: Option<Vec<usize>>,
    uses_generaldelta: bool,
}

impl Debug for Index {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("Index")
            .field("offsets", &self.offsets)
            .field("uses_generaldelta", &self.uses_generaldelta)
            .finish()
    }
}

impl Index {
    /// Create an index from bytes.
    /// Calculate the start of each entry when is_inline is true.

    /// exists.
    pub fn get_entry(&self, rev: Revision) -> Option<IndexEntry> {
        if rev == NULL_REVISION {
            return None;
        }
        Some(if let Some(offsets) = &self.offsets {
            self.get_entry_inline(rev, offsets)
        } else {
            self.get_entry_separated(rev)
        })
    }

    fn get_entry_inline(
        &self,
        rev: Revision,
        offsets: &[usize],
    ) -> IndexEntry {
        let start = offsets[rev as usize];
        let end = start + INDEX_ENTRY_SIZE;
        let bytes = &self.bytes[start..end];

        // See IndexEntry for an explanation of this override.
        let offset_override = Some(end);

        IndexEntry {
            bytes,
            offset_override,
        }
    }

    fn get_entry_separated(&self, rev: Revision) -> IndexEntry {
        let start = rev as usize * INDEX_ENTRY_SIZE;
        let end = start + INDEX_ENTRY_SIZE;
        let bytes = &self.bytes[start..end];

        // Override the offset of the first revision as its bytes are used
        // for the index's metadata (saving space because it is always 0)
        let offset_override = if rev == 0 { Some(0) } else { None };

        IndexEntry {
            bytes,
            offset_override,
        }
    }
}

impl super::RevlogIndex for Index {
    fn len(&self) -> usize {

    pub fn uncompressed_len(&self) -> i32 {
        BigEndian::read_i32(&self.bytes[12..=15])
    }

    /// Return the revision upon which the data has been derived.
    pub fn base_revision_or_base_of_delta_chain(&self) -> UncheckedRevision {
        // TODO Maybe return an Option when base_revision == rev?
        //      Requires to add rev to IndexEntry

        BigEndian::read_i32(&self.bytes[16..]).into()
    }

    pub fn link_revision(&self) -> UncheckedRevision {
        BigEndian::read_i32(&self.bytes[20..]).into()
    }

    pub fn p1(&self) -> UncheckedRevision {
        BigEndian::read_i32(&self.bytes[24..]).into()
    }

    pub fn p2(&self) -> UncheckedRevision {
        BigEndian::read_i32(&self.bytes[28..]).into()
    }

    /// Return the hash of revision's full text.
    ///
    /// Currently, SHA-1 is used and only the first 20 bytes of this field

        let entry = IndexEntry {
            bytes: &bytes,
            offset_override: None,
        };

        assert_eq!(entry.base_revision_or_base_of_delta_chain(), 1.into())
    }

    #[test]
    fn link_revision_test() {
        let bytes = IndexEntryBuilder::new().with_link_revision(123).build();

        let entry = IndexEntry {
            bytes: &bytes,
            offset_override: None,
        };

        assert_eq!(entry.link_revision(), 123.into());
    }

    #[test]
    fn p1_test() {
        let bytes = IndexEntryBuilder::new().with_p1(123).build();

        let entry = IndexEntry {
            bytes: &bytes,
            offset_override: None,
        };

        assert_eq!(entry.p1(), 123.into());
    }

    #[test]
    fn p2_test() {
        let bytes = IndexEntryBuilder::new().with_p2(123).build();

        let entry = IndexEntry {
            bytes: &bytes,
            offset_override: None,
        };

        assert_eq!(entry.p2(), 123.into());
    }

    #[test]
    fn node_test() {
        let node = Node::from_hex("0123456789012345678901234567890123456789")