pdfrum-doc 0.1.0

Bookmarks, annotations, AcroForm data model, structure tree
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//! The document's XMP metadata packet, as bytes.
//!
//! There is no XML parsing here and none is planned. Upstream's only use of
//! `/Metadata` is a scan for an Acrobat shared-review workflow marker, whose
//! sole consumer prints an "unsupported feature" line to **stderr** — it
//! reaches no output any consumer diffs. Callers that want the packet's
//! contents parse it themselves.

use pdfrum_common::{Diagnostics, Limits};
use pdfrum_object::{Dict, Resolve};

use crate::names;

/// The catalog's `/Metadata` stream, decoded.
///
/// Returns nothing when the key is absent or does not hold a stream.
///
/// ```
/// use pdfrum_common::{Diagnostics, Limits};
/// use pdfrum_doc::xmp;
/// use pdfrum_object::{Dict, NoResolve};
///
/// let (limits, mut diags) = (Limits::default(), Diagnostics::default());
/// // Absent, or not holding a stream: nothing.
/// assert!(xmp(&Dict::default(), &NoResolve, &limits, &mut diags).is_none());
/// ```
#[must_use]
pub fn xmp<R: Resolve>(
    catalog: &Dict,
    r: &R,
    limits: &Limits,
    diags: &mut Diagnostics,
) -> Option<Vec<u8>> {
    let stream = catalog.stream(names::METADATA, r)?;
    Some(pdfrum_filters::decode_chain(&stream, 0, r, limits, diags).data)
}