[Spice-devel] Added spice allocators

[Alexander Larsson]

I just pushed a set of changes that add custom allocators for spice and
switches all uses of raw malloc() to use these. This is based on current
best practices and has several advantages:

* All out-of-memory allocation failures are handled in a single place,
  and in a consistent way. This lets us delete a lot of open-coded
  checks and aborts.

* It also ensures we always abort on malloc returning NULL. This how
  qemu handles OOM and in general the only sane way. See e.g.
  http://article.gmane.org/gmane.comp.audio.jackit/19998

* There are special allocators for allocating something of the form
  malloc(element_size * num_elements) that abort if the multiplication
  overflows (which could make the result a small number and make the 
  allocation unexpectedly succeed).

* We now have some macros like spice_new() that makes it easier to
  allocate a structure type or array of those, avoiding lots of casts
  and sizeof operators.

* There are also zeroing versions of all allocators, so that you can
  avoid a separate memset call.

Here is a typical change to show how this makes stuff cleaner:

-    if (!(dispatcher = malloc(sizeof(RedDispatcher)))) {
-        red_error("malloc failed");
-    }
-    memset(dispatcher, 0, sizeof(RedDispatcher));
+    dispatcher = spice_new0(RedDispatcher, 1);

-- 
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 Alexander Larsson                                            Red Hat, Inc 
       alexl at redhat.com            alexander.larsson at gmail.com 
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