COMMON: Add DisposablePtr and DisposableArray templates

Similar to ScopedPtr, but with a flag that drives whether the pointer
will be deallocated.

src/common/disposableptr.h

@@ -0,0 +1,147 @@
+/* xoreos - A reimplementation of BioWare's Aurora engine
+ *
+ * xoreos is the legal property of its developers, whose names
+ * can be found in the AUTHORS file distributed with this source
+ * distribution.
+ *
+ * xoreos is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 3
+ * of the License, or (at your option) any later version.
+ *
+ * xoreos is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with xoreos. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file
+ *  A smart pointer with a deletion flag.
+ */
+
+/* Based on Cabal (<https://github.com/project-cabal/cabal/>) code,
+ * which in turn is based on ScummVM (<http://scummvm.org>) code,
+ * which is released under the terms of version 2 or later of the
+ * GNU General Public License.
+ *
+ * The original copyright note in ScummVM reads as follows:
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef COMMON_DISPOSABLEPTR_H
+#define COMMON_DISPOSABLEPTR_H
+
+#include <boost/noncopyable.hpp>
+
+#include "src/common/system.h"
+#include "src/common/types.h"
+#include "src/common/deallocator.h"
+
+namespace Common {
+
+/** Base template class for a disposable pointer.
+ *
+ *  Manages the pointer and allows for optional, automatic deletion
+ *  through a deallocator template parameter.
+ */
+template<typename T, class Deallocator>
+class DisposablePtrBase : boost::noncopyable {
+public:
+	typedef T ValueType;
+	typedef T *PointerType;
+	typedef T &ReferenceType;
+
+	explicit DisposablePtrBase(PointerType o, bool d) : _pointer(o), _dispose(d) {}
+
+	/** Implicit conversion operator to bool for convenience, to make
+	 *  checks like "if (disposablePtr) ..." possible.
+	 */
+	XOREOS_EXPLICIT_OPERATOR_CONV operator bool() const { return _pointer != 0; }
+
+	~DisposablePtrBase() {
+		if (_dispose)
+			Deallocator::destroy(_pointer);
+	}
+
+	/** Resets the pointer with the new value. The old object will be destroyed. */
+	void reset(PointerType o = 0) {
+		if (_dispose)
+			Deallocator::destroy(_pointer);
+
+		_pointer = o;
+	}
+
+	/** Returns the plain pointer value.
+	 *
+	 *  @return the pointer the DisposablePtr manages.
+	 */
+	PointerType get() const { return _pointer; }
+
+	/** Change the disposable flag. */
+	void setDisposable(bool d) { _dispose = d; }
+
+	/** Unconditionally dispose of the pointer, destroying the old object. */
+	void dispose() {
+		Deallocator::destroy(_pointer);
+		_pointer = 0;
+	}
+
+private:
+	PointerType _pointer;
+
+	bool _dispose;
+};
+
+/** A disposable plain pointer, allowing pointer-y access and normal deletion. */
+template<typename T, class Deallocator = DeallocatorDefault>
+class DisposablePtr : public DisposablePtrBase<T, Deallocator> {
+public:
+	explicit DisposablePtr(typename DisposablePtrBase<T, Deallocator>::PointerType o, bool d) :
+		DisposablePtrBase<T, Deallocator>(o, d) {
+	}
+
+	typename DisposablePtrBase<T, Deallocator>::ReferenceType operator*() const {
+		return *DisposablePtrBase<T, Deallocator>::get();
+	}
+
+	typename DisposablePtrBase<T, Deallocator>::PointerType operator->() const {
+		return DisposablePtrBase<T, Deallocator>::get();
+	}
+};
+
+/** A disposable array pointer, allowing array-y access and array deletion. */
+template<typename T, class Deallocator = DeallocatorArray>
+class DisposableArray : public DisposablePtrBase<T, Deallocator> {
+public:
+	explicit DisposableArray(typename DisposablePtrBase<T, Deallocator>::PointerType o, bool d) :
+		DisposablePtrBase<T, Deallocator>(o, d) {
+	}
+
+	typename DisposablePtrBase<T, Deallocator>::ReferenceType operator[](size_t i) const {
+		return DisposablePtrBase<T, Deallocator>::get()[i];
+	}
+};
+
+} // End of namespace Common
+
+#endif // COMMON_DISPOSABLEPTR_H

src/common/rules.mk

@@ -29,6 +29,7 @@ src_common_libcommon_la_SOURCES += \
     src/common/endianness.h \
     src/common/deallocator.h \
     src/common/scopedptr.h \
+    src/common/disposableptr.h \
     src/common/singleton.h \
     src/common/maths.h \
     src/common/sinetables.h \