From 41d8f9b4a7891873f3f2d882664e49a8842802c9 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Mon, 5 Aug 2019 12:11:48 +0530
Subject: [PATCH 34/71] Utility function to detect if a PDF is encrypted

---
 src/calibre/ebooks/metadata/pdf.py | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/calibre/ebooks/metadata/pdf.py b/src/calibre/ebooks/metadata/pdf.py
index fd0604d204..bf29d62e1f 100644
--- a/src/calibre/ebooks/metadata/pdf.py
+++ b/src/calibre/ebooks/metadata/pdf.py
@@ -8,7 +8,7 @@ import os, subprocess, shutil, re
 from functools import partial
 
 from calibre import prints
-from calibre.constants import iswindows
+from calibre.constants import iswindows, ispy3
 from calibre.ptempfile import TemporaryDirectory
 from calibre.ebooks.metadata import (
     MetaInformation, string_to_authors, check_isbn, check_doi)
@@ -97,6 +97,17 @@ def page_images(pdfpath, outputdir, first=1, last=1):
         raise ValueError('Failed to render PDF, pdftoppm errorcode: %s'%e.returncode)
 
 
+def is_pdf_encrypted(path_to_pdf):
+    if not ispy3 and not isinstance(path_to_pdf, bytes):
+        path_to_pdf = path_to_pdf.encode('mbcs' if iswindows else 'utf-8')
+    pdfinfo = get_tools()[0]
+    raw = subprocess.check_output([pdfinfo, path_to_pdf])
+    q = re.search(br'^Encrypted:\s*(\S+)', raw, flags=re.MULTILINE)
+    if q is not None:
+        return q.group(1) == b'yes'
+    return False
+
+
 def get_metadata(stream, cover=True):
     with TemporaryDirectory('_pdf_metadata_read') as pdfpath:
         stream.seek(0)