commit e4b1341ffff4d0345ce20d676869343a64779b36
author Lei Zhang <thestig@chromium.org> Fri Feb 11 20:12:20 2022 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> Fri Feb 11 20:12:20 2022 +0000
tree af73786fd682bcc39f54d10e56ada1a5f87a6f03
parent 678c730aea099aa99ff1da1b815eddedb9094b41

Add ValidateDictOptionalType() utility function.

This is similar to ValidateDictType(), but considers a dictionary that
omits /Type to be valid.

Change-Id: Ibc17123c26e06db60d90d9071af74d9fd069382a
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/90530
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

core/fpdfapi/parser/fpdf_parser_utility.cpp

diff --git a/core/fpdfapi/parser/fpdf_parser_utility.cpp b/core/fpdfapi/parser/fpdf_parser_utility.cpp
index 143551c..6b01790 100644
--- a/core/fpdfapi/parser/fpdf_parser_utility.cpp
+++ b/core/fpdfapi/parser/fpdf_parser_utility.cpp
@@ -185,6 +185,12 @@
   return ValidateDictAllResourcesOfType(dict, "Font");
 }
 
+bool ValidateDictOptionalType(const CPDF_Dictionary* dict,
+                              ByteStringView type) {
+  DCHECK(!type.IsEmpty());
+  return dict && (!dict->KeyExist("Type") || dict->GetNameFor("Type") == type);
+}
+
 std::ostream& operator<<(std::ostream& buf, const CPDF_Object* pObj) {
   if (!pObj) {
     buf << " null";

core/fpdfapi/parser/fpdf_parser_utility.h

diff --git a/core/fpdfapi/parser/fpdf_parser_utility.h b/core/fpdfapi/parser/fpdf_parser_utility.h
index 7f20a9d..fbe87bd 100644
--- a/core/fpdfapi/parser/fpdf_parser_utility.h
+++ b/core/fpdfapi/parser/fpdf_parser_utility.h
@@ -67,6 +67,9 @@
 // Shorthand for ValidateDictAllResourcesOfType(dict, "Font").
 bool ValidateFontResourceDict(const CPDF_Dictionary* dict);
 
+// Like ValidateDictType(), but /Type can also not exist.
+bool ValidateDictOptionalType(const CPDF_Dictionary* dict, ByteStringView type);
+
 std::ostream& operator<<(std::ostream& buf, const CPDF_Object* pObj);
 
 #endif  // CORE_FPDFAPI_PARSER_FPDF_PARSER_UTILITY_H_

core/fpdfapi/parser/fpdf_parser_utility_unittest.cpp

diff --git a/core/fpdfapi/parser/fpdf_parser_utility_unittest.cpp b/core/fpdfapi/parser/fpdf_parser_utility_unittest.cpp
index 3e4d968..0deb439 100644
--- a/core/fpdfapi/parser/fpdf_parser_utility_unittest.cpp
+++ b/core/fpdfapi/parser/fpdf_parser_utility_unittest.cpp
@@ -108,3 +108,21 @@
 
   CPDF_PageModule::Destroy();
 }
+
+TEST(fpdf_parser_utility, ValidateDictOptionalType) {
+  auto dict = pdfium::MakeRetain<CPDF_Dictionary>();
+
+  // No type is ok.
+  EXPECT_TRUE(ValidateDictOptionalType(dict.Get(), "foo"));
+  EXPECT_TRUE(ValidateDictOptionalType(dict.Get(), "bar"));
+
+  // Add the wrong object type.
+  dict->SetNewFor<CPDF_String>("Type", L"foo");
+  EXPECT_FALSE(ValidateDictOptionalType(dict.Get(), "foo"));
+  EXPECT_FALSE(ValidateDictOptionalType(dict.Get(), "bar"));
+
+  // Add the correct object type.
+  dict->SetNewFor<CPDF_Name>("Type", "foo");
+  EXPECT_TRUE(ValidateDictOptionalType(dict.Get(), "foo"));
+  EXPECT_FALSE(ValidateDictOptionalType(dict.Get(), "bar"));
+}