... Strong, meaning that the file at the specified path is created or modified
only if all write operations complete without exceptions, barring one very
unlikely possibility that a final file rename fails, but even in that case the
output is successfully written to some path.
This commit does not add throws, but changes the type thrown to a subclass of
AudacityException, so that GuardedCall will cause the user to see an error
dialog in all cases.
Duplicated logic for making temporary files and backups is now all in one
place, the class XMLWriter.
There may be more new GuardedCalls than necessary -- the catch-all for the
event loop, AudacityApp::OnExceptionInMainLoop, might be trusted instead in
some cases -- but they are sufficient.
... whenever they really describe the size of a buffer that fits in memory, or
of a block file (which is never now more than a megabyte and so could be fit in
memory all at once), or a part thereof.
... And in some places where a library uses signed types, assert that
the reported number is not negative.
What led me to this, is that there are many places where a size_t value for
an allocation is the product of a number of channels and some other number.
... This makes much code agnostic about how other things (functions and
arguments) are typed.
Many of these neeed to become size_t instead of sampleCount.
... Busy-waiting will happen on Mac when modal dialogs are open, and a LADSPA,
VST, or AudioUnits effect is also open with "fancy" interface.
Busy-waiting will not happen for modal dialogs at other times.
... Problem was a mismatch between a chunk retrieved for program only, but
then copied to slave effect as for a bank. Plug-in choked on the GIGO.
Fix makes chunk for bank both ways.
... for functions in final classes.
override is like const -- it's not necessary, but it helps the compiler to
catch mistakes.
There may be some overriding functions not explicitly declared virtual and I did
not identify such cases, in which I might also add override.
... Should have no effect on generated code, except perhaps some slight faster
virtual function calls. Mostly useful as documentation of design intent.
Tried to mark every one of our classes that inherits from another, or is a
base for others, or has abstract virtual functions, and a few others besides.
