gecko-dev/mfbt/tests/gtest
Chris Peterson a48326552c Bug 1405582 - Span: delete implicit constructors for char* and char16_t*. r=froydnj,hsivonen
Delete Span's implicit constructors for char* and char16_t* pointers to avoid accidental construction in cases where a pointer does not point to a zero-terminated string. Use the MakeStringSpan() function instead.

I deleted both the const and non-const char* and char16_t* constructors, in the name of cross-compiler consistency. If we only delete the const char* and char16_t* constructors, for some reason, MSVC complains that `Span<char> s(charArray)` uses a deleted constructor while clang nor gcc permit it. I don't know if this is a compiler bug in MSVC or clang and gcc.

Also, do not permit MakeSpan() for string literals (const char and char16_t arrays) because the Span length would include the zero terminator, which may surprise callers. Use MakeStringSpan() to create a Span whose length that excludes the string literal's zero terminator or use the MakeSpan() overload that accepts a pointer and length and specify the string literal's full length.

The following Span usages are prevented:

  Span<const char> span("literal"); // error
  Span<char> span(charArray); // error

  Span<const char> span;
  span = "literal"; // error
  span = charArray; // error

  MakeSpan("literal"); // error

The following Span usages are still permitted:

  assert(MakeStringSpan("literal") == 8); // OK: span length is calculated with strlen() and excludes the zero terminator
  MakeStringSpan(charArray); // OK: span length is calculated with strlen() and excludes the zero terminator
  MakeSpan(charArray); // OK: span length is the char array size including any zero terminator

MozReview-Commit-ID: Et71CpjsiyI

--HG--
extra : rebase_source : f6f8bdb28726f0f2368fdfdd039fb1d7dcf2914e
extra : source : 0547d8924ffc7713d6cf32cc06eeeaf00e0d69a3
2017-09-20 00:38:07 -07:00
..
TestSpan.cpp Bug 1405582 - Span: delete implicit constructors for char* and char16_t*. r=froydnj,hsivonen 2017-09-20 00:38:07 -07:00
moz.build