From 4ba9e8fe256f6c28c816da0fa4d183760751b44d Mon Sep 17 00:00:00 2001
From: "James R. Barlow" <jim@purplerock.ca>
Date: Tue, 30 Oct 2018 22:28:34 -0700
Subject: [PATCH] Add AcroForm detection

---
 src/ocrmypdf/_pipeline.py        | 19 +++++++++++++++++++
 src/ocrmypdf/pdfinfo/__init__.py |  5 +++++
 2 files changed, 24 insertions(+)

diff --git a/src/ocrmypdf/_pipeline.py b/src/ocrmypdf/_pipeline.py
index 0d4dc87c..1e494b39 100644
--- a/src/ocrmypdf/_pipeline.py
+++ b/src/ocrmypdf/_pipeline.py
@@ -193,6 +193,25 @@ def repair_and_parse_pdf(
             "high page count files.  Python 3.6 or newer is recommended."
         )
 
+    if pdfinfo.has_acroform:
+        if options.redo_ocr:
+            log.error(
+                "This PDF has a user fillable form. --redo-ocr is not "
+                "currently possible on such files."
+            )
+            raise PriorOcrFoundError()
+        else:
+            log.warning(
+                "This PDF has a fillable form. Chances are it is a pure digital "
+                "document that does not need OCR."
+            )
+            if not options.force_ocr:
+                log.info(
+                    "Use the option --force-ocr to produce an image of the "
+                    "form and all filled form fields. The output PDF will be "
+                    "'flattened' and will no longer be fillable."
+                )
+
     context.set_pdfinfo(pdfinfo)
     log.debug(pdfinfo)
 
diff --git a/src/ocrmypdf/pdfinfo/__init__.py b/src/ocrmypdf/pdfinfo/__init__.py
index 842340bd..b2f23879 100644
--- a/src/ocrmypdf/pdfinfo/__init__.py
+++ b/src/ocrmypdf/pdfinfo/__init__.py
@@ -803,6 +803,7 @@ class PdfInfo:
         self._infile = infile
         self._pages, pdf = _pdf_get_all_pageinfo(infile, log=log)
         self._needs_rendering = pdf.root.get('/NeedsRendering', False)
+        self._has_acroform = pdf.root.get('/AcroForm', False)
 
     @property
     def pages(self):
@@ -817,6 +818,10 @@ class PdfInfo:
     def has_userunit(self):
         return any(page.userunit != 1.0 for page in self.pages)
 
+    @property
+    def has_acroform(self):
+        return self._has_acroform
+
     @property
     def filename(self):
         if not isinstance(self._infile, (str, Path)):