Replace raw value for constant error value in string operations

Currently Find() and other methods that return a FX_STRSIZE return -1
to indicate error/failure. This means that there is a lot of magic
numbers and magic checks floating around. The standard library for
similar operations uses a npos constant. This CL implements
FX_STRNPOS, and replaces usages of magic number checking. It also does
some type cleanup along the way where it was obvious that FX_STRSIZE
should be being used.

Removing the magic numbers should make eventually changing FX_STRSIZE
to be unsigned easier in the future.

BUG=pdfium:828

Change-Id: I67e481e44cf2f75a1698afa8fbee4f375a74c490
Reviewed-on: https://pdfium-review.googlesource.com/9651
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/xfa/fxfa/parser/cxfa_layoutpagemgr.cpp b/xfa/fxfa/parser/cxfa_layoutpagemgr.cpp
index 4d6886d7e1..55851bb34a 100644
--- a/xfa/fxfa/parser/cxfa_layoutpagemgr.cpp
+++ b/xfa/fxfa/parser/cxfa_layoutpagemgr.cpp
@@ -148,9 +148,10 @@ CXFA_Node* ResolveBreakTarget(CXFA_Node* pPageSetRoot,
   bool bTargetAllFind = true;
   while (iSplitIndex != -1) {
     CFX_WideString wsExpr;
-    int32_t iSplitNextIndex = 0;
+    FX_STRSIZE iSplitNextIndex = 0;
     if (!bTargetAllFind) {
       iSplitNextIndex = wsTargetAll.Find(' ', iSplitIndex);
+      ASSERT(iSplitNextIndex != FX_STRNPOS);
       wsExpr = wsTargetAll.Mid(iSplitIndex, iSplitNextIndex - iSplitIndex);
     } else {
       wsExpr = wsTargetAll;