layout-types.rs

struct LayoutObjectRef<T>(Arc<RwLock<LayoutObject<T>>>);

struct LayoutObject<T> {
    style: Arc<ComputedValues>,
    // position? borders? padding? margins?
    contents: T,
}

struct BlockFormattingContext(BlockOrInline);

enum BlockOrInline {
    Block(List<BlockLevel>),
    Inline(List<InlineLevel>),
}

enum BlockLevel {
    Normal(LayoutObjectRef<BlockOrInline>),
    NewContext(LayoutObjectRef<FormattingContext>),
}

enum InlineLevel {
    Text(LayoutObjectRef<Text>),
    Inline(LayoutObjectRef<Inline>),
    Replaced(LayoutObjectRef<FormattingContext>),
}

struct Text {
    content: DOMString,
}

struct Inline {
    flags: InlineFlags,
}

bitflags! {
    flags InlineFlags: u8 {
        const FIRST_FRAGMENT = 0x01;
        const LAST_FRAGMENT  = 0x02;
    }
}

enum FormattingContext {
    Flow(BlockFormattingContext),
    Replaced,
    ...
}