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>

1 files changed, 18 insertions, 16 deletions

diff --git a/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp b/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
index c12314f88d..c0c28db192 100644
--- a/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
+++ b/fpdfsdk/fpdfxfa/cpdfxfa_docenvironment.cpp
@@ -809,19 +809,19 @@ bool CPDFXFA_DocEnvironment::ExportSubmitFile(FPDF_FILEHANDLER* pFileHandler,
 
 void CPDFXFA_DocEnvironment::ToXFAContentFlags(CFX_WideString csSrcContent,
                                                FPDF_DWORD& flag) {
-  if (csSrcContent.Find(L" config ", 0) != FX_STRNPOS)
+  if (csSrcContent.Contains(L" config "))
     flag |= FXFA_CONFIG;
-  if (csSrcContent.Find(L" template ", 0) != FX_STRNPOS)
+  if (csSrcContent.Contains(L" template "))
     flag |= FXFA_TEMPLATE;
-  if (csSrcContent.Find(L" localeSet ", 0) != FX_STRNPOS)
+  if (csSrcContent.Contains(L" localeSet "))
     flag |= FXFA_LOCALESET;
-  if (csSrcContent.Find(L" datasets ", 0) != FX_STRNPOS)
+  if (csSrcContent.Contains(L" datasets "))
     flag |= FXFA_DATASETS;
-  if (csSrcContent.Find(L" xmpmeta ", 0) != FX_STRNPOS)
+  if (csSrcContent.Contains(L" xmpmeta "))
     flag |= FXFA_XMPMETA;
-  if (csSrcContent.Find(L" xfdf ", 0) != FX_STRNPOS)
+  if (csSrcContent.Contains(L" xfdf "))
     flag |= FXFA_XFDF;
-  if (csSrcContent.Find(L" form ", 0) != FX_STRNPOS)
+  if (csSrcContent.Contains(L" form "))
     flag |= FXFA_FORM;
   if (flag == 0) {
     flag = FXFA_CONFIG | FXFA_TEMPLATE | FXFA_LOCALESET | FXFA_DATASETS |
@@ -840,16 +840,16 @@ bool CPDFXFA_DocEnvironment::MailToInfo(CFX_WideString& csURL,
   if (srcURL.Left(7).CompareNoCase(L"mailto:") != 0)
     return false;
 
-  FX_STRSIZE pos = srcURL.Find(L'?', 0);
+  auto pos = srcURL.Find(L'?');
   CFX_WideString tmp;
-  if (pos == FX_STRNPOS) {
-    pos = srcURL.Find(L'@', 0);
-    if (pos == FX_STRNPOS)
+  if (!pos.has_value()) {
+    pos = srcURL.Find(L'@');
+    if (!pos.has_value())
       return false;
 
     tmp = srcURL.Right(csURL.GetLength() - 7);
   } else {
-    tmp = srcURL.Left(pos);
+    tmp = srcURL.Left(pos.value());
     tmp = tmp.Right(tmp.GetLength() - 7);
   }
   tmp.TrimLeft();
@@ -857,13 +857,13 @@ bool CPDFXFA_DocEnvironment::MailToInfo(CFX_WideString& csURL,
 
   csToAddress = tmp;
 
-  srcURL = srcURL.Right(srcURL.GetLength() - (pos + 1));
+  srcURL = srcURL.Right(srcURL.GetLength() - (pos.value() + 1));
   while (!srcURL.IsEmpty()) {
     srcURL.TrimLeft();
     srcURL.TrimRight();
-    pos = srcURL.Find(L'&', 0);
+    pos = srcURL.Find(L'&');
 
-    tmp = (pos == FX_STRNPOS) ? srcURL : srcURL.Left(pos);
+    tmp = (!pos.has_value()) ? srcURL : srcURL.Left(pos.value());
     tmp.TrimLeft();
     tmp.TrimRight();
     if (tmp.GetLength() >= 3 && tmp.Left(3).CompareNoCase(L"cc=") == 0) {
@@ -886,7 +886,9 @@ bool CPDFXFA_DocEnvironment::MailToInfo(CFX_WideString& csURL,
       tmp = tmp.Right(tmp.GetLength() - 5);
       csMsg += tmp;
     }
-    srcURL = (pos == -1) ? L"" : srcURL.Right(csURL.GetLength() - (pos + 1));
+    srcURL = !pos.has_value()
+                 ? L""
+                 : srcURL.Right(csURL.GetLength() - (pos.value() + 1));
   }
   csToAddress.Replace(L",", L";");
   csCCAddress.Replace(L",", L";");