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// Copyright (C) 2011-2015 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef UTIL_UNITTESTS_NEWHOOK_H
#define UTIL_UNITTESTS_NEWHOOK_H 1
/**
* \file newhook.h
* \brief Enable the use of special operator new that throws for testing.
*
* This small utility allows a test case to force the global operator new
* to throw for a given size to test a case where memory allocation fails
* (which normally doesn't happen). To enable the feature, everything must
* be built with defining ENABLE_CUSTOM_OPERATOR_NEW beforehand, and set
* \c force_throw_on_new to \c true and \c throw_size_on_new to the size
* of data that should trigger the exception, immediately before starting
* the specific test that needs the exception.
*
* Example:
* \code #include <util/unittests/newhook.h>
* ...
* TEST(SomeTest, newException) {
* isc::util::unittests::force_throw_on_new = true;
* isc::util::unittests::throw_size_on_new = sizeof(Foo);
* try {
* // this will do 'new Foo()' internally and should throw
* createFoo();
* isc::util::unittests::force_throw_on_new = false;
* ASSERT_FALSE(true) << "Expected throw on new";
* } catch (const std::bad_alloc&) {
* isc::util::unittests::force_throw_on_new = false;
* // do some integrity check, etc, if necessary
* }
* } \endcode
*
* Replacing the global operator new (and delete) is a dangerous technique,
* and triggering an exception solely based on the allocation size is not
* reliable, so this feature is disabled by default two-fold: The
* ENABLE_CUSTOM_OPERATOR_NEW build time variable, and run-time
* \c force_throw_on_new.
*/
namespace isc {
namespace util {
namespace unittests {
/// Switch to enable the use of special operator new
///
/// This is set to \c false by default.
extern bool force_throw_on_new;
/// The allocation size that triggers an exception in the special operator new
///
/// This is the exact size that causes an exception to be thrown;
/// for example, if it is set to 100, an attempt of allocating 100 bytes
/// will result in an exception, but allocation attempt for 101 bytes won't
/// (unless, of course, memory is really exhausted and allocation really
/// fails).
///
/// The default value is 0. The value of this variable has no meaning
/// unless the use of the special operator is enabled at build time and
/// via \c force_throw_on_new.
extern size_t throw_size_on_new;
}
}
}
#endif // UTIL_UNITTESTS_NEWHOOK_H
// Local Variables:
// mode: c++
// End:
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