From 8465c0d4fe8f690727fe82c8f126cdd9308887fd Mon Sep 17 00:00:00 2001
From: Lars Marius Garshol <larsga@garshol.priv.no>
Date: Thu, 21 Aug 2025 10:18:17 +0200
Subject: [PATCH] ENH: Optimize getting of named destinations in readers

---
 pypdf/_reader.py | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/pypdf/_reader.py b/pypdf/_reader.py
index ef92025ed..9b2ea322e 100644
--- a/pypdf/_reader.py
+++ b/pypdf/_reader.py
@@ -66,6 +66,7 @@
     ArrayObject,
     ContentStream,
     DecodedStreamObject,
+    Destination,
     DictionaryObject,
     EncodedStreamObject,
     IndirectObject,
@@ -75,6 +76,7 @@
     PdfObject,
     StreamObject,
     TextStringObject,
+    TreeObject,
     is_null_or_none,
     read_object,
 )
@@ -138,6 +140,8 @@ def __init__(
         elif password is not None:
             raise PdfReadError("Not an encrypted file")
 
+        self._named_destinations_cache: Optional[dict[str, Destination]] = None
+
     def _initialize_stream(self, stream: Union[StrByteType, Path]) -> None:
         if hasattr(stream, "mode") and "b" not in stream.mode:
             logger_warning(
@@ -1274,3 +1278,18 @@ def _repr_mimebundle_(
             data = {k: v for k, v in data.items() if k not in exclude}
 
         return data
+
+    def _get_named_destinations(
+        self,
+        tree: Union[TreeObject, None] = None,
+        retval: Optional[dict[str, Destination]] = None,
+    ) -> dict[str, Destination]:
+        """Override from PdfDocCommon. In the reader we can assume this is
+        static, but not in the writer.
+        """
+        if tree or retval:
+            return PdfDocCommon._get_named_destinations(self, tree, retval)
+
+        if self._named_destinations_cache is None:
+            self._named_destinations_cache = PdfDocCommon._get_named_destinations(self)
+        return self._named_destinations_cache