COMMON: Add DisposablePtr<T>, which replaces many repeated implementations of a dispose flag.

3 files changed, 42 insertions, 14 deletions

diff --git a/common/ptr.h b/common/ptr.h
index d06a25edb8..2b0670caae 100644
--- a/common/ptr.h
+++ b/common/ptr.h
@@ -24,6 +24,7 @@
 
 #include "common/scummsys.h"
 #include "common/noncopyable.h"
+#include "common/types.h"
 
 namespace Common {
 
@@ -273,6 +274,41 @@ private:
 	PointerType _pointer;
 };
 
+
+template<typename T>
+class DisposablePtr : NonCopyable {
+public:
+	typedef T  ValueType;
+	typedef T *PointerType;
+	typedef T &ReferenceType;
+
+	explicit DisposablePtr(PointerType o, DisposeAfterUse::Flag dispose) : _pointer(o), _dispose(dispose) {}
+
+	~DisposablePtr() {
+		if (_dispose) delete _pointer;
+	}
+
+	ReferenceType operator*() const { return *_pointer; }
+	PointerType operator->() const { return _pointer; }
+
+	/**
+	 * Implicit conversion operator to bool for convenience, to make
+	 * checks like "if (scopedPtr) ..." possible.
+	 */
+	operator bool() const { return _pointer; }
+
+	/**
+	 * Returns the plain pointer value.
+	 *
+	 * @return the pointer the DisposablePtr manages
+	 */
+	PointerType get() const { return _pointer; }
+
+private:
+	PointerType           _pointer;
+	DisposeAfterUse::Flag _dispose;
+};
+
 } // End of namespace Common
 
 #endif
diff --git a/common/stream.cpp b/common/stream.cpp
index 60b40d0df2..30b3bca497 100644
--- a/common/stream.cpp
+++ b/common/stream.cpp
@@ -20,6 +20,7 @@
  *
  */
 
+#include "common/ptr.h"
 #include "common/stream.h"
 #include "common/memstream.h"
 #include "common/substream.h"
@@ -258,8 +259,7 @@ namespace {
  */
 class BufferedReadStream : virtual public ReadStream {
 protected:
-	ReadStream *_parentStream;
-	DisposeAfterUse::Flag _disposeParentStream;
+	DisposablePtr<ReadStream> _parentStream;
 	byte *_buf;
 	uint32 _pos;
 	bool _eos; // end of stream
@@ -278,8 +278,7 @@ public:
 };
 
 BufferedReadStream::BufferedReadStream(ReadStream *parentStream, uint32 bufSize, DisposeAfterUse::Flag disposeParentStream)
-	: _parentStream(parentStream),
-	_disposeParentStream(disposeParentStream),
+	: _parentStream(parentStream, disposeParentStream),
 	_pos(0),
 	_eos(false),
 	_bufSize(0),
@@ -291,8 +290,6 @@ BufferedReadStream::BufferedReadStream(ReadStream *parentStream, uint32 bufSize,
 }
 
 BufferedReadStream::~BufferedReadStream() {
-	if (_disposeParentStream)
-		delete _parentStream;
 	delete[] _buf;
 }
 
diff --git a/common/substream.h b/common/substream.h
index f4f79ff02f..7e67389da1 100644
--- a/common/substream.h
+++ b/common/substream.h
@@ -23,6 +23,7 @@
 #ifndef COMMON_SUBSTREAM_H
 #define COMMON_SUBSTREAM_H
 
+#include "common/ptr.h"
 #include "common/stream.h"
 #include "common/types.h"
 
@@ -38,24 +39,18 @@ namespace Common {
  */
 class SubReadStream : virtual public ReadStream {
 protected:
-	ReadStream *_parentStream;
-	DisposeAfterUse::Flag _disposeParentStream;
+	DisposablePtr<ReadStream> _parentStream;
 	uint32 _pos;
 	uint32 _end;
 	bool _eos;
 public:
 	SubReadStream(ReadStream *parentStream, uint32 end, DisposeAfterUse::Flag disposeParentStream = DisposeAfterUse::NO)
-		: _parentStream(parentStream),
-		  _disposeParentStream(disposeParentStream),
+		: _parentStream(parentStream, disposeParentStream),
 		  _pos(0),
 		  _end(end),
 		  _eos(false) {
 		assert(parentStream);
 	}
-	~SubReadStream() {
-		if (_disposeParentStream)
-			delete _parentStream;
-	}
 
 	virtual bool eos() const { return _eos | _parentStream->eos(); }
 	virtual bool err() const { return _parentStream->err(); }