cadcraft/crates/doc/src/foreign.rs

//! Data from a drawing file that CADCraft does not model, kept so that saving the drawing writes
//! it back: other programs' objects, extension dictionaries, xdata and properties (#528).
//!
//! It is kept as the file's own DXF groups, with the file's handles. The file reader fills it and
//! the writer puts it back, pointing references at whatever now has the referenced role (the
//! named object dictionary, a table record, a block, an entity); references to objects that are
//! gone are dropped. Commands don't edit it.

use std::collections::BTreeMap;

use crate::{Handle, RawTag};

/// What a file handle stood for when the object it named is one CADCraft writes itself (under a
/// new handle on save): a kind and an upper-case name, e.g. `("LAYER", "WALLS")`,
/// `("TABLE", "LAYER")`, `("BLOCK", "DOOR")`, `("NOD", "")` for the named object dictionary and
/// `("NOD", "ACAD_GROUP")` for one of its entries.
pub type ForeignKey = (String, String);

/// A non-graphical object of a type or role CADCraft does not model.
#[derive(Clone, Debug, Default, PartialEq)]
pub struct ForeignObject {
    /// Its handle in the file it came from (kept on save).
    pub handle: Handle,
    /// Its DXF type (group 0), e.g. `XRECORD`.
    pub kind: String,
    /// Its groups after the type, as read.
    pub tags: Vec<RawTag>,
}

/// What an entity, table record or block carries beyond what CADCraft models.
#[derive(Clone, Debug, Default, PartialEq)]
pub struct ForeignExtra {
    /// Its extension dictionary (one of [`Foreign::objects`]).
    pub xdict: Option<Handle>,
    /// Objects of [`Foreign::objects`] that react to it (persistent reactors).
    pub reactors: Vec<Handle>,
    /// Other applications' extended data: groups from `1001` on.
    pub xdata: Vec<RawTag>,
    /// The colour book colour (group 430) and the true colour (group 420) it was read with: it is
    /// written back while the colour is unchanged.
    pub color_book: Option<(String, String)>,
    /// Other unmodelled property groups (material 347, shadow mode 284).
    pub props: Vec<RawTag>,
}

impl ForeignExtra {
    pub fn is_empty(&self) -> bool {
        self.xdict.is_none() && self.reactors.is_empty() && self.xdata.is_empty() && self.color_book.is_none() && self.props.is_empty()
    }
}

/// Everything of a file CADCraft keeps without modelling it.
#[derive(Clone, Debug, Default, PartialEq)]
pub struct Foreign {
    /// CLASS records (groups after `0 CLASS`) of the kept objects' and entities' types.
    pub classes: Vec<Vec<RawTag>>,
    /// Kept objects, in file order.
    pub objects: Vec<ForeignObject>,
    /// Entries of the named object dictionary that CADCraft doesn't write itself: (key, object).
    pub dictionary: Vec<(String, Handle)>,
    /// Extras of entities, by handle.
    pub entities: BTreeMap<Handle, ForeignExtra>,
    /// Extras of table records (`("LAYER", "WALLS")`), tables (`("TABLE", "LAYER")`) and blocks
    /// (`("BLOCK", "DOOR")`), by [`ForeignKey`].
    pub records: BTreeMap<ForeignKey, ForeignExtra>,
    /// The roles of the file handles the kept data refers to, for objects CADCraft rewrites.
    pub targets: BTreeMap<Handle, ForeignKey>,
}

impl Foreign {
    pub fn is_empty(&self) -> bool {
        self.objects.is_empty()
            && self.dictionary.is_empty()
            && self.entities.is_empty()
            && self.records.is_empty()
            && self.classes.is_empty()
            && self.targets.is_empty()
    }
}