Split document permissions code from PDFiumEngine.

Move the code that handles PDF document permissions to
pdfium_permissions.cc.

Change-Id: I01704423d089d24f6bdbfbee3b8c981977f19a38
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1726904
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683345}

pdf/BUILD.gn

@@ -107,6 +107,8 @@ if (enable_pdf) {
         "pdfium/pdfium_mem_buffer_file_write.h",
         "pdfium/pdfium_page.cc",
         "pdfium/pdfium_page.h",
+        "pdfium/pdfium_permissions.cc",
+        "pdfium/pdfium_permissions.h",
         "pdfium/pdfium_print.cc",
         "pdfium/pdfium_print.h",
         "pdfium/pdfium_range.cc",

pdf/pdfium/pdfium_engine.cc

@@ -34,6 +34,7 @@
 #include "pdf/pdfium/pdfium_document.h"
 #include "pdf/pdfium/pdfium_mem_buffer_file_read.h"
 #include "pdf/pdfium/pdfium_mem_buffer_file_write.h"
+#include "pdf/pdfium/pdfium_permissions.h"
 #include "pdf/pdfium/pdfium_unsupported_features.h"
 #include "pdf/url_loader_wrapper_impl.h"
 #include "ppapi/cpp/instance.h"
@@ -110,13 +111,6 @@ constexpr bool kViewerImplementedPanning = false;
 constexpr bool kViewerImplementedPanning = true;
 #endif
 
-// See Table 3.20 in
-// http://www.adobe.com/devnet/acrobat/pdfs/pdf_reference_1-7.pdf
-constexpr uint32_t kPDFPermissionPrintLowQualityMask = 1 << 2;
-constexpr uint32_t kPDFPermissionPrintHighQualityMask = 1 << 11;
-constexpr uint32_t kPDFPermissionCopyMask = 1 << 4;
-constexpr uint32_t kPDFPermissionCopyAccessibleMask = 1 << 9;
-
 constexpr int32_t kLoadingTextVerticalOffset = 50;
 
 // The maximum amount of time we'll spend doing a paint before we give back
@@ -1998,35 +1992,10 @@ std::string PDFiumEngine::GetLinkAtPosition(const pp::Point& point) {
 }
 
 bool PDFiumEngine::HasPermission(DocumentPermission permission) const {
-  // PDF 1.7 spec, section 3.5.2 says: "If the revision number is 2 or greater,
-  // the operations to which user access can be controlled are as follows: ..."
-  //
-  // Thus for revision numbers less than 2, permissions are ignored and this
-  // always returns true.
-  if (permissions_handler_revision_ < 2)
+  // No |permissions_| means no restrictions.
+  if (!permissions_)
     return true;
-
-  // Handle high quality printing permission separately for security handler
-  // revision 3+. See table 3.20 in the PDF 1.7 spec.
-  if (permission == PERMISSION_PRINT_HIGH_QUALITY &&
-      permissions_handler_revision_ >= 3) {
-    return (permissions_ & kPDFPermissionPrintLowQualityMask) != 0 &&
-           (permissions_ & kPDFPermissionPrintHighQualityMask) != 0;
-  }
-
-  switch (permission) {
-    case PERMISSION_COPY:
-      return (permissions_ & kPDFPermissionCopyMask) != 0;
-    case PERMISSION_COPY_ACCESSIBLE:
-      return (permissions_ & kPDFPermissionCopyAccessibleMask) != 0;
-    case PERMISSION_PRINT_LOW_QUALITY:
-    case PERMISSION_PRINT_HIGH_QUALITY:
-      // With security handler revision 2 rules, check the same bit for high
-      // and low quality. See table 3.20 in the PDF 1.7 spec.
-      return (permissions_ & kPDFPermissionPrintLowQualityMask) != 0;
-    default:
-      return true;
-  }
+  return permissions_->HasPermission(permission);
 }
 
 void PDFiumEngine::SelectAll() {
@@ -2396,8 +2365,7 @@ void PDFiumEngine::ContinueLoadingDocument(const std::string& password) {
   if (FPDFDoc_GetPageMode(doc()) == PAGEMODE_USEOUTLINES)
     client_->DocumentHasUnsupportedFeature("Bookmarks");
 
-  permissions_ = FPDF_GetDocPermissions(doc());
-  permissions_handler_revision_ = FPDF_GetSecurityHandlerRevision(doc());
+  permissions_ = std::make_unique<PDFiumPermissions>(doc());
 
   LoadBody();
 

pdf/pdfium/pdfium_engine.h

@@ -39,6 +39,7 @@
 namespace chrome_pdf {
 
 class PDFiumDocument;
+class PDFiumPermissions;
 
 namespace draw_utils {
 class ShadowMatrix;
@@ -612,11 +613,7 @@ class PDFiumEngine : public PDFEngine,
   // Where to resume searching. (0-based)
   base::Optional<size_t> resume_find_index_;
 
-  // Permissions bitfield.
-  unsigned long permissions_ = 0;
-
-  // Permissions security handler revision number. -1 for unknown.
-  int permissions_handler_revision_ = -1;
+  std::unique_ptr<PDFiumPermissions> permissions_;
 
   pp::Size default_page_size_;
 

pdf/pdfium/pdfium_permissions.cc

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "pdf/pdfium/pdfium_permissions.h"
+
+namespace chrome_pdf {
+
+namespace {
+
+// See Table 3.20 in
+// http://www.adobe.com/devnet/acrobat/pdfs/pdf_reference_1-7.pdf
+constexpr uint32_t kPDFPermissionPrintLowQualityMask = 1 << 2;
+constexpr uint32_t kPDFPermissionPrintHighQualityMask = 1 << 11;
+constexpr uint32_t kPDFPermissionCopyMask = 1 << 4;
+constexpr uint32_t kPDFPermissionCopyAccessibleMask = 1 << 9;
+
+}  // namespace
+
+PDFiumPermissions::PDFiumPermissions(FPDF_DOCUMENT doc)
+    : permissions_handler_revision_(FPDF_GetSecurityHandlerRevision(doc)),
+      permission_bits_(FPDF_GetDocPermissions(doc)) {}
+
+bool PDFiumPermissions::HasPermission(
+    PDFEngine::DocumentPermission permission) const {
+  // PDF 1.7 spec, section 3.5.2 says: "If the revision number is 2 or greater,
+  // the operations to which user access can be controlled are as follows: ..."
+  //
+  // Thus for revision numbers less than 2, permissions are ignored and this
+  // always returns true.
+  if (permissions_handler_revision_ < 2)
+    return true;
+
+  // Handle high quality printing permission separately for security handler
+  // revision 3+. See table 3.20 in the PDF 1.7 spec.
+  if (permission == PDFEngine::PERMISSION_PRINT_HIGH_QUALITY &&
+      permissions_handler_revision_ >= 3) {
+    return (permission_bits_ & kPDFPermissionPrintLowQualityMask) != 0 &&
+           (permission_bits_ & kPDFPermissionPrintHighQualityMask) != 0;
+  }
+
+  switch (permission) {
+    case PDFEngine::PERMISSION_COPY:
+      return (permission_bits_ & kPDFPermissionCopyMask) != 0;
+    case PDFEngine::PERMISSION_COPY_ACCESSIBLE:
+      return (permission_bits_ & kPDFPermissionCopyAccessibleMask) != 0;
+    case PDFEngine::PERMISSION_PRINT_LOW_QUALITY:
+    case PDFEngine::PERMISSION_PRINT_HIGH_QUALITY:
+      // With security handler revision 2 rules, check the same bit for high
+      // and low quality. See table 3.20 in the PDF 1.7 spec.
+      return (permission_bits_ & kPDFPermissionPrintLowQualityMask) != 0;
+    default:
+      return true;
+  }
+}
+
+}  // namespace chrome_pdf

pdf/pdfium/pdfium_permissions.h

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef PDF_PDFIUM_PDFIUM_PERMISSIONS_H_
+#define PDF_PDFIUM_PDFIUM_PERMISSIONS_H_
+
+#include "pdf/pdf_engine.h"
+#include "third_party/pdfium/public/fpdfview.h"
+
+namespace chrome_pdf {
+
+// The permissions for a given FPDF_DOCUMENT.
+class PDFiumPermissions final {
+ public:
+  explicit PDFiumPermissions(FPDF_DOCUMENT doc);
+
+  bool HasPermission(PDFEngine::DocumentPermission permission) const;
+
+ private:
+  // Permissions security handler revision number. -1 for unknown.
+  const int permissions_handler_revision_;
+
+  // Permissions bitfield.
+  const unsigned long permission_bits_;
+};
+
+}  // namespace chrome_pdf
+
+#endif  // PDF_PDFIUM_PDFIUM_PERMISSIONS_H_