Remove GetAt from string classes

This method duplicates the behaviour of the const [] operator and
doesn't offer any additional safety. Folding them into one
implementation.

SetAt is retained, since implementing the non-const [] operator to
replace SetAt has potential performance concerns. Specifically many
non-obvious cases of reading an element using [] will cause a realloc
& copy.

BUG=pdfium:860

Change-Id: I3ef5e5e5a15376f040256b646eb0d90636e24b67
Reviewed-on: https://pdfium-review.googlesource.com/10870
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>

1 files changed, 27 insertions, 50 deletions

diff --git a/core/fxcrt/cfx_widestring_unittest.cpp b/core/fxcrt/cfx_widestring_unittest.cpp
index a23763218d..e7206dde06 100644
--- a/core/fxcrt/cfx_widestring_unittest.cpp
+++ b/core/fxcrt/cfx_widestring_unittest.cpp
@@ -10,26 +10,8 @@
 
 #include "testing/gtest/include/gtest/gtest.h"
 
-TEST(fxcrt, WideStringGetAt) {
-  CFX_WideString short_string(L"a");
-  CFX_WideString longer_string(L"abc");
-  CFX_WideString embedded_nul_string(L"ab\0c", 4);
-
-#ifndef NDEBUG
-  EXPECT_DEATH({ short_string.GetAt(-1); }, ".*");
-#endif
-  EXPECT_EQ(L'a', short_string.GetAt(0));
-#ifndef NDEBUG
-  EXPECT_DEATH({ short_string.GetAt(1); }, ".*");
-#endif
-  EXPECT_EQ(L'c', longer_string.GetAt(2));
-  EXPECT_EQ(L'b', embedded_nul_string.GetAt(1));
-  EXPECT_EQ(L'\0', embedded_nul_string.GetAt(2));
-  EXPECT_EQ(L'c', embedded_nul_string.GetAt(3));
-}
-
-TEST(fxcrt, WideStringOperatorSubscript) {
-  CFX_WideString abc(L"abc");
+TEST(fxcrt, WideStringElementAccess) {
+  const CFX_WideString abc(L"abc");
 #ifndef NDEBUG
   EXPECT_DEATH({ abc[-1]; }, ".*");
 #endif
@@ -39,21 +21,34 @@ TEST(fxcrt, WideStringOperatorSubscript) {
 #ifndef NDEBUG
   EXPECT_DEATH({ abc[4]; }, ".*");
 #endif
-}
 
-TEST(fxcrt, WideStringSetAt) {
-  CFX_WideString abc(L"abc");
+  CFX_WideString mutable_abc = abc;
+  EXPECT_EQ(abc.c_str(), mutable_abc.c_str());
+  EXPECT_EQ(L'a', mutable_abc[0]);
+  EXPECT_EQ(L'b', mutable_abc[1]);
+  EXPECT_EQ(L'c', mutable_abc[2]);
+  EXPECT_EQ(abc.c_str(), mutable_abc.c_str());
 #ifndef NDEBUG
-  EXPECT_DEATH({ abc.SetAt(-1, L'd'); }, ".*");
+  EXPECT_DEATH({ mutable_abc.SetAt(-1, L'd'); }, ".*");
+  EXPECT_EQ(L"abc", abc);
 #endif
-  abc.SetAt(0, L'd');
-  EXPECT_EQ(L"dbc", abc);
-  abc.SetAt(1, L'e');
-  EXPECT_EQ(L"dec", abc);
-  abc.SetAt(2, L'f');
-  EXPECT_EQ(L"def", abc);
+  const wchar_t* c_str = abc.c_str();
+  mutable_abc.SetAt(0, L'd');
+  EXPECT_EQ(c_str, abc.c_str());
+  EXPECT_NE(c_str, mutable_abc.c_str());
+  EXPECT_EQ(L"abc", abc);
+  EXPECT_EQ(L"dbc", mutable_abc);
+
+  mutable_abc.SetAt(1, L'e');
+  EXPECT_EQ(L"abc", abc);
+  EXPECT_EQ(L"dec", mutable_abc);
+
+  mutable_abc.SetAt(2, L'f');
+  EXPECT_EQ(L"abc", abc);
+  EXPECT_EQ(L"def", mutable_abc);
 #ifndef NDEBUG
-  EXPECT_DEATH({ abc.SetAt(3, L'g'); }, ".*");
+  EXPECT_DEATH({ mutable_abc.SetAt(3, L'g'); }, ".*");
+  EXPECT_EQ(L"abc", abc);
 #endif
 }
 
@@ -780,25 +775,7 @@ TEST(fxcrt, WideStringCFromVector) {
   EXPECT_EQ(nullptr, cleared_string.raw_str());
 }
 
-TEST(fxcrt, WideStringCGetAt) {
-  CFX_WideStringC short_string(L"a");
-  CFX_WideStringC longer_string(L"abc");
-  CFX_WideStringC embedded_nul_string(L"ab\0c", 4);
-
-#ifndef NDEBUG
-  EXPECT_DEATH({ short_string.GetAt(-1); }, ".*");
-#endif
-  EXPECT_EQ(L'a', static_cast<wchar_t>(short_string.GetAt(0)));
-#ifndef NDEBUG
-  EXPECT_DEATH({ short_string.GetAt(1); }, ".*");
-#endif
-  EXPECT_EQ(L'c', static_cast<wchar_t>(longer_string.GetAt(2)));
-  EXPECT_EQ(L'b', static_cast<wchar_t>(embedded_nul_string.GetAt(1)));
-  EXPECT_EQ(L'\0', static_cast<wchar_t>(embedded_nul_string.GetAt(2)));
-  EXPECT_EQ(L'c', static_cast<wchar_t>(embedded_nul_string.GetAt(3)));
-}
-
-TEST(fxcrt, WideStringCOperatorSubscript) {
+TEST(fxcrt, WideStringCElementAccess) {
   CFX_WideStringC abc(L"abc");
 #ifndef NDEBUG
   EXPECT_DEATH({ abc[-1]; }, ".*");