crashpad/util/stdlib/strnlen.cc
Mark Mentovai bdf9471324 mac: Switch from <AvailabilityMacros.h> to <Availability.h>
The macOS 11.0 SDK, as of Xcode 12b6 12A8189n, has not updated
<AvailabilityMacros.h> with a MAC_OS_X_VERSION_11_0 or
MAC_OS_X_VERSION_10_16 constant. However, the <Availability.h> interface
has been updated to provide both __MAC_11_0 and __MAC_10_16.
<AvailabilityMacros.h>’s MAC_OS_X_VERSION_MAX_ALLOWED, which is supposed
to identify the SDK version, is broken in the 11.0 SDK in that whenever
the deployment target is set to 10.15 or earlier, the SDK will be
mis-identified through this interface as 10.15. When using the
<Availability.h> equivalent, __MAC_OS_X_VERSION_MAX_ALLOWED, the 11.0
SDK is identified as 10.16 (arguably it should be internally versioned
as 11.0, but at least this interface allows it to be detected
unambiguously.) It’s clear that the <AvailabilityMacros.h> interface
provides no meaningful support for the macOS 11.0 SDK at all, but
<Availability.h> does.

<Availability.h> was introduced in the Mac OS X 10.5 SDK, so there is no
relevant SDK version compatibility problem with this interface.

Key differences between these interfaces for the purposes used by
Crashpad:
 - <AvailabilityMacros.h> → <Availability.h>
 - MAC_OS_X_VERSION_MIN_REQUIRED (DT) → __MAC_OS_X_VERSION_MIN_REQUIRED
 - MAC_OS_X_VERSION_MAX_ALLOWED (SDK) → __MAC_OS_X_VERSION_MAX_ALLOWED
 - MAC_OS_X_VERSION_x_y → __MAC_x_y
 - <Availability.h> __MAC_OS_X_VERSION_* SDK/DT macros are only
   available when targeting macOS, while <AvailabilityMacros.h>
   MAC_OS_X_VERSION_* SDK/DT macros are available on all Apple platforms,
   which may be a source of confusion. (<Availability.h> __MAC_* macros
   do remain available on all Apple platforms.)

This change was made mostly mechanically by:

sed -i '' -Ee 's/<AvailabilityMacros.h>/<Availability.h>/g' \
    $(git grep -E -l '<AvailabilityMacros.h>' |
          grep -v AvailabilityMacros.h)

sed -i '' -Ee 's/(MAC_OS_X_VERSION_(MIN_REQUIRED|MAX_ALLOWED))/__\1/g' \
    $(git grep -E -l 'MAC_OS_X_VERSION_(MIN_REQUIRED|MAX_ALLOWED)' |
          grep -v AvailabilityMacros.h)

sed -i '' -Ee 's/(MAC_OS_X_VERSION_(10_[0-9]+))/__MAC_\2/g' \
    $(git grep -E -l 'MAC_OS_X_VERSION_(10_[0-9]+)' |
          grep -v AvailabilityMacros.h)

Bug: crashpad:347
Change-Id: Ibdcd7a6215a82f7060b7b67d98691f88454085fc
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/2382421
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Mark Mentovai <mark@chromium.org>
2020-08-31 21:11:29 +00:00

48 lines
1.3 KiB
C++

// Copyright 2014 The Crashpad Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "util/stdlib/strnlen.h"
#if defined(OS_MAC) && __MAC_OS_X_VERSION_MIN_REQUIRED < __MAC_10_7
#if __MAC_OS_X_VERSION_MAX_ALLOWED >= __MAC_10_7
// Redeclare a method only available on Mac OS X 10.7 and later to suppress a
// -Wpartial-availability warning.
extern "C" {
size_t strnlen(const char* string, size_t max_length);
} // extern "C"
#endif
namespace crashpad {
size_t strnlen(const char* string, size_t max_length) {
#if __MAC_OS_X_VERSION_MAX_ALLOWED >= __MAC_10_7
if (::strnlen) {
return ::strnlen(string, max_length);
}
#endif
for (size_t index = 0; index < max_length; ++index) {
if (string[index] == '\0') {
return index;
}
}
return max_length;
}
} // namespace crashpad
#endif