merge dasher which has been introduced in BRANCH first (wtf?) into HEAD

1 files changed, 39 insertions, 0 deletions

diff --git a/inputmethods/dasher/NoClones.h b/inputmethods/dasher/NoClones.h
new file mode 100644
index 0000000..11cdabb
--- a/dev/null
+++ b/inputmethods/dasher/NoClones.h
@@ -0,0 +1,39 @@
+#ifndef __NoClones_h__
+#define __NoClones_h__
+
+/* Explanation of NoClones {{{
+
+C++ defines default copy constructors and assignment operators, which clone
+every member of a class. Stroustrup describes this behaviour as the result of
+"historical accident". For many non-trivial classes, especially those
+containing pointers, this default behaviour is too naive. In fact it often leads
+to heap corruption.
+
+Sometimes it does not make any sense to copy an instance of a class. For
+example if it contains a unique file handle, or other lock on a system resource.
+Sometimes it is too much effort to write reliable replacement copy operations[1].
+In either case a private copy constructor and a private assignment operator
+prevent accidental copying. [2]
+
+Deriving a class from this class has the same preventative effect. It is also a
+bit neater and means that all the above explanation is centralised here.
+
+IAM 09/2002
+
+[1] An example of how it is very easy to make mistakes:
+http://www.mistybeach.com/articles/WhyIDontLikeCPlusPlusForLargeProjects.html
+If we don't need a copy feature it really isn't worth the hassle.
+[2] The C++ Programming Language. Stroustrup. 3rd edition. Section 10.4.6.3
+
+}}} */
+
+class NoClones
+{
+protected: // Default constructor doesn't need to be public, but can't be private.
+	NoClones() {}; // Lots of compiler complaints without default constructor.
+private:
+	NoClones(const NoClones&);
+	NoClones& operator=(const NoClones&);
+};
+
+#endif /* #ifndef __NoClones_h__ */