Fix #389: PDFsharp misreads C2PA manifest stream as external file - #391
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Fix #389: PDFsharp misreads C2PA manifest stream as external file#391wooly905 wants to merge 1 commit into
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Parser.GetStreamLength treated any /F key on a stream dict as an external file stream per PDF 2.0 7.3.8.2, but some producers (e.g. ChatGPT-generated PDFs) misuse /F for embedded-file params instead of /Params. Now only strings or dictionaries that actually look like a file specification (/Type /Filespec, or /FS,/F,/UF,/DOS,/Mac,/Unix) trigger the NotImplementedException; genuine external file streams still throw. Adds PdfSharp.Pdf.C2pa.C2paManager/C2paManifestInfo to read C2PA manifests from a document's /AF array and /EmbeddedFiles name tree, plus a PdfAFRelationship.C2paManifest constant. Wired into PdfDocument and the gdi/wpf mirror csprojs. Adds duck.pdf test asset and 7 xUnit tests covering the fix, manifest reading, and a guard test for real external file streams. Adds a ReadC2paInfo sample app that decodes the manifest's JUMBF/CBOR/COSE structures to verify claim, actions, and signature data end-to-end.
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Parser.GetStreamLength treated any /F key on a stream dictionary as an external file stream per PDF 2.0 section 7.3.8.2, but some producers (e.g. ChatGPT-generated PDFs) misuse /F for embedded-file params instead of /Params. This caused NotImplementedException when opening such PDFs.
Now only strings, or dictionaries that actually look like a file specification (/Type /Filespec, or one of /FS, /F, /UF, /DOS, /Mac, /Unix), trigger the exception. Genuine external file streams still throw as before.
Adds PdfSharp.Pdf.C2pa.C2paManager / C2paManifestInfo to read C2PA manifests from a document's /AF array and /EmbeddedFiles name tree, plus a PdfAFRelationship.C2paManifest constant. Wired into PdfDocument and the gdi/wpf mirror csproj files.
Adds a duck.pdf test asset and 7 xUnit tests covering the fix, manifest reading, and a guard test confirming real external file streams still throw. Adds a ReadC2paInfo sample app that decodes the manifest's JUMBF/CBOR/COSE structures to independently verify claim, actions, and signature data.