Enum Error 

pub enum Error {
    NotFound,
    MultipleManifests,
    MalformedElement(&'static str),
    NoHead,
    MalformedExclusion,
    HashMismatch,
    UnsupportedAlgorithm(String),
}

Errors from locating an HTML-embedded manifest or validating its hard binding.

Multiple manifests is a reportable failure

A document shall carry at most one C2PA Manifest Store association. The specification requires a validator that encounters more than one manifest element to report a manifest.html.multipleManifests failure, so Error::MultipleManifests carries that code and is not a “no manifests located” outcome — the manifests were located, and the document is rejected for carrying too many.

The other two location outcomes carry no status code. Finding nothing is simply an unsigned document, and the specification names no code for an element that matches but yields no Manifest Store. Only Error::code speaks for the specification; Error::is_no_manifest_located draws the line a caller surfacing provenance state to a user actually needs.

Variants

NotFound

The head carries no script with type="application/c2pa" and no link with rel="c2pa-manifest": the document simply carries no manifest.

MultipleManifests

More than one C2PA manifest element was found.

Covers all three prohibited shapes: two script elements, two link elements, and a script alongside a link. Reported as manifest.html.multipleManifests.

MalformedElement(&'static str)

Exactly one manifest element was found but it could not yield a Manifest Store: a script whose content is not valid Base64, or a link with no href.

The specification does not name this case. Treating it as “no manifests located” is the fail-safe reading: nothing was obtained, so there is nothing to validate and nothing to report a failure against.

NoHead

The document has no head to insert into. Embedding needs an explicit </head>; a document relying on HTML’s implied head must be serialized with one first.

MalformedExclusion

The exclusion ranges are malformed: out of order, overlapping, extending past the end of the document, or not matching the located manifest element.

HashMismatch

The recomputed data hash did not match the value in the assertion.

UnsupportedAlgorithm(String)

A hash algorithm identifier outside the C2PA allowed list was requested.

Implementations

impl Error

pub fn code(&self) -> Option<&'static str>

The registered C2PA validation status code for this error, or None when the condition carries no status code.

pub fn is_no_manifest_located(&self) -> bool

Whether this error means the document carries no provenance at all, as opposed to provenance that was found and rejected.

Note that Error::MultipleManifests is not one of these: the manifests were located, and the document is rejected for carrying more than one.

Trait Implementations

impl Clone for Error

fn clone(&self) -> Error

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for Error

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Error

impl Error for Error

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for Error

fn eq(&self, other: &Error) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Error