Convert string Find methods to return an Optional

The Find and ReverseFind methods for WideString, WideStringC,
ByteString, and ByteStringC have been converted from returning a raw
FX_STRSIZE, to returning Optional<FX_STRSIZE>, so that success/failure
can be indicated without using FX_STRNPOS.

This allows for removing FX_STRNPOS and by association makes the
conversion of FX_STRSIZE to size_t easier, since it forces checking
the return value of Find to be explictly done as well as taking the
error value out of the range of FX_STRSIZE.

New Contains methods have been added for cases where the success or
failure is all the call site to Find cared about, and the actual
position was ignored.

BUG=pdfium:828


Change-Id: Id827e508c8660affa68cc08a13d96121369364b7
Reviewed-on: https://pdfium-review.googlesource.com/11350
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

3 files changed, 21 insertions, 19 deletions

diff --git a/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp b/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
index 1f4d821dae..c7a98c9493 100644
--- a/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
+++ b/core/fpdfapi/edit/cpdf_pagecontentgenerator_unittest.cpp
@@ -186,15 +186,18 @@ TEST_F(CPDF_PageContentGeneratorTest, ProcessStandardText) {
   std::ostringstream buf;
   TestProcessText(&generator, &buf, pTextObj.get());
   CFX_ByteString textString(buf);
-  FX_STRSIZE firstResourceAt = textString.Find('/') + 1;
-  FX_STRSIZE secondResourceAt = textString.ReverseFind('/') + 1;
-  EXPECT_NE(FX_STRNPOS, firstResourceAt);
-  EXPECT_NE(FX_STRNPOS, secondResourceAt);
-  CFX_ByteString firstString = textString.Left(firstResourceAt);
+  auto firstResourceAt = textString.Find('/');
+  ASSERT_TRUE(firstResourceAt.has_value());
+  firstResourceAt = firstResourceAt.value() + 1;
+  auto secondResourceAt = textString.ReverseFind('/');
+  ASSERT_TRUE(secondResourceAt.has_value());
+  secondResourceAt = secondResourceAt.value() + 1;
+  CFX_ByteString firstString = textString.Left(firstResourceAt.value());
   CFX_ByteString midString =
-      textString.Mid(firstResourceAt, secondResourceAt - firstResourceAt);
+      textString.Mid(firstResourceAt.value(),
+                     secondResourceAt.value() - firstResourceAt.value());
   CFX_ByteString lastString =
-      textString.Right(textString.GetLength() - secondResourceAt);
+      textString.Right(textString.GetLength() - secondResourceAt.value());
   // q and Q must be outside the BT .. ET operations
   CFX_ByteString compareString1 =
       "q 0.501961 0.701961 0.34902 rg 1 0.901961 0 RG /";
@@ -255,11 +258,12 @@ TEST_F(CPDF_PageContentGeneratorTest, ProcessText) {
   }
 
   CFX_ByteString textString(buf);
-  FX_STRSIZE firstResourceAt = textString.Find('/') + 1;
-  EXPECT_NE(FX_STRNPOS, firstResourceAt);
-  CFX_ByteString firstString = textString.Left(firstResourceAt);
+  auto firstResourceAt = textString.Find('/');
+  ASSERT_TRUE(firstResourceAt.has_value());
+  firstResourceAt = firstResourceAt.value() + 1;
+  CFX_ByteString firstString = textString.Left(firstResourceAt.value());
   CFX_ByteString lastString =
-      textString.Right(textString.GetLength() - firstResourceAt);
+      textString.Right(textString.GetLength() - firstResourceAt.value());
   // q and Q must be outside the BT .. ET operations
   CFX_ByteString compareString1 = "q BT 1 0 0 1 0 0 Tm /";
   CFX_ByteString compareString2 =
diff --git a/core/fpdfapi/page/cpdf_streamcontentparser.cpp b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
index 42ed3fc3b4..6f09f92c60 100644
--- a/core/fpdfapi/page/cpdf_streamcontentparser.cpp
+++ b/core/fpdfapi/page/cpdf_streamcontentparser.cpp
@@ -315,13 +315,13 @@ void CPDF_StreamContentParser::AddNameParam(const CFX_ByteStringC& bsName) {
         m_pDocument->GetByteStringPool(), PDF_NameDecode(bsName));
   } else {
     param.m_Type = ContentParam::NAME;
-    if (bsName.Find('#') == FX_STRNPOS) {
-      memcpy(param.m_Name.m_Buffer, bsName.raw_str(), bsName.GetLength());
-      param.m_Name.m_Len = bsName.GetLength();
-    } else {
+    if (bsName.Contains('#')) {
       CFX_ByteString str = PDF_NameDecode(bsName);
       memcpy(param.m_Name.m_Buffer, str.c_str(), str.GetLength());
       param.m_Name.m_Len = str.GetLength();
+    } else {
+      memcpy(param.m_Name.m_Buffer, bsName.raw_str(), bsName.GetLength());
+      param.m_Name.m_Len = bsName.GetLength();
     }
   }
 }
diff --git a/core/fpdfapi/parser/fpdf_parser_utility.cpp b/core/fpdfapi/parser/fpdf_parser_utility.cpp
index 7cea16569f..a36d640da3 100644
--- a/core/fpdfapi/parser/fpdf_parser_utility.cpp
+++ b/core/fpdfapi/parser/fpdf_parser_utility.cpp
@@ -89,7 +89,7 @@ int32_t GetDirectInteger(CPDF_Dictionary* pDict, const CFX_ByteString& key) {
 }
 
 CFX_ByteString PDF_NameDecode(const CFX_ByteStringC& bstr) {
-  if (bstr.Find('#') == FX_STRNPOS)
+  if (!bstr.Contains('#'))
     return CFX_ByteString(bstr);
 
   int size = bstr.GetLength();
@@ -110,9 +110,7 @@ CFX_ByteString PDF_NameDecode(const CFX_ByteStringC& bstr) {
 }
 
 CFX_ByteString PDF_NameDecode(const CFX_ByteString& orig) {
-  if (orig.Find('#') == FX_STRNPOS)
-    return orig;
-  return PDF_NameDecode(orig.AsStringC());
+  return orig.Contains("#") ? PDF_NameDecode(orig.AsStringC()) : orig;
 }
 
 CFX_ByteString PDF_NameEncode(const CFX_ByteString& orig) {