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app/.venv/Lib/site-packages/weasyprint/pdf/pdfa.py

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+"""PDF/A generation."""
+
+try:
+    # Available in Python 3.9+
+    from importlib.resources import files
+except ImportError:
+    # Deprecated in Python 3.11+
+    from importlib.resources import read_binary
+else:
+    def read_binary(package, resource):
+        return (files(package) / resource).read_bytes()
+
+from functools import partial
+
+import pydyf
+
+from .metadata import add_metadata
+
+
+def pdfa(pdf, metadata, document, page_streams, attachments, compress,
+         version, variant):
+    """Set metadata for PDF/A documents."""
+    # Add ICC profile.
+    profile = pydyf.Stream(
+        [read_binary(__package__, 'sRGB2014.icc')],
+        pydyf.Dictionary({'N': 3, 'Alternate': '/DeviceRGB'}),
+        compress=compress)
+    pdf.add_object(profile)
+    pdf.catalog['OutputIntents'] = pydyf.Array([
+        pydyf.Dictionary({
+            'Type': '/OutputIntent',
+            'S': '/GTS_PDFA1',
+            'OutputConditionIdentifier': pydyf.String('sRGB IEC61966-2.1'),
+            'DestOutputProfile': profile.reference,
+        }),
+    ])
+
+    # Handle attachments.
+    if version == 1:
+        # Remove embedded files dictionary.
+        if 'Names' in pdf.catalog and 'EmbeddedFiles' in pdf.catalog['Names']:
+            del pdf.catalog['Names']['EmbeddedFiles']
+    if version <= 2:
+        # Remove attachments.
+        for pdf_object in pdf.objects:
+            if not isinstance(pdf_object, dict):
+                continue
+            if pdf_object.get('Type') != '/Filespec':
+                continue
+            reference = int(pdf_object['EF']['F'].split()[0])
+            stream = pdf.objects[reference]
+            # Remove all attachments for version 1.
+            # Remove non-PDF attachments for version 2.
+            # TODO: check that PDFs are actually PDF/A-2+ files.
+            if version == 1 or stream.extra['Subtype'] != '/application#2fpdf':
+                del pdf_object['EF']
+    if version >= 3:
+        # Add AF for attachments.
+        relationships = {
+            f'<{attachment.md5}>': attachment.relationship
+            for attachment in attachments if attachment.md5}
+        pdf_attachments = []
+        if 'Names' in pdf.catalog and 'EmbeddedFiles' in pdf.catalog['Names']:
+            reference = int(pdf.catalog['Names']['EmbeddedFiles'].split()[0])
+            names = pdf.objects[reference]
+            for name in names['Names'][1::2]:
+                pdf_attachments.append(name)
+        for pdf_object in pdf.objects:
+            if not isinstance(pdf_object, dict):
+                continue
+            if pdf_object.get('Type') != '/Filespec':
+                continue
+            reference = int(pdf_object['EF']['F'].split()[0])
+            checksum = pdf.objects[reference].extra['Params']['CheckSum']
+            relationship = relationships.get(checksum, 'Unspecified')
+            pdf_object['AFRelationship'] = f'/{relationship}'
+            pdf_attachments.append(pdf_object.reference)
+        if pdf_attachments:
+            if 'AF' not in pdf.catalog:
+                pdf.catalog['AF'] = pydyf.Array()
+            pdf.catalog['AF'].extend(pdf_attachments)
+
+    # Print annotations.
+    for pdf_object in pdf.objects:
+        if isinstance(pdf_object, dict) and pdf_object.get('Type') == '/Annot':
+            pdf_object['F'] = 2 ** (3 - 1)
+
+    # Common PDF metadata stream.
+    if version == 1:
+        # Metadata compression is forbidden for version 1.
+        compress = False
+    add_metadata(pdf, metadata, 'a', version, variant, compress)
+
+
+VARIANTS = {
+    'pdf/a-1b': (
+        partial(pdfa, version=1, variant='B'),
+        {'version': '1.4', 'identifier': True}),
+    'pdf/a-2b': (
+        partial(pdfa, version=2, variant='B'),
+        {'version': '1.7', 'identifier': True}),
+    'pdf/a-3b': (
+        partial(pdfa, version=3, variant='B'),
+        {'version': '1.7', 'identifier': True}),
+    'pdf/a-4b': (
+        partial(pdfa, version=4, variant='B'),
+        {'version': '2.0', 'identifier': True}),
+    'pdf/a-2u': (
+        partial(pdfa, version=2, variant='U'),
+        {'version': '1.7', 'identifier': True}),
+    'pdf/a-3u': (
+        partial(pdfa, version=3, variant='U'),
+        {'version': '1.7', 'identifier': True}),
+    'pdf/a-4u': (
+        partial(pdfa, version=4, variant='U'),
+        {'version': '2.0', 'identifier': True}),
+}