Allow propogation of OOM errors to apps

This allows apps to catch out-of-memory errors when allocating textures.

Textures can be pretty huge at times and so it's quite possible for an
application to try and allocate more memory than is available. It's also
very possible that the application can take some action in response to
reduce memory pressure (such as freeing up texture caches perhaps) so
we shouldn't just automatically abort like we do for trivial heap
allocations.

These public functions now take a CoglError argument so applications can
catch out of memory errors:

cogl_buffer_map
cogl_buffer_map_range
cogl_buffer_set_data
cogl_framebuffer_read_pixels_into_bitmap
cogl_pixel_buffer_new
cogl_texture_new_from_data
cogl_texture_new_from_bitmap

Note: we've been quite conservative with how many apis we let throw OOM
CoglErrors since we don't really want to put a burdon on developers to
be checking for errors with every cogl api call. So long as there is
some lower level api for apps to use that let them catch OOM errors
for everything necessary that's enough and we don't have to make more
convenient apis more awkward to use.

The main focus is on bitmaps and texture allocations since they
can be particularly large and prone to failing.

A new cogl_attribute_buffer_new_with_size() function has been added in
case developers need to catch OOM errors when allocating attribute buffers
whereby they can first use _buffer_new_with_size() (which doesn't take a
CoglError) followed by cogl_buffer_set_data() which will lazily allocate
the buffer storage and report OOM errors.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit f7735e141ad537a253b02afa2a8238f96340b978)

Note: since we can't break the API for Cogl 1.x then actually the main
purpose of cherry picking this patch is to keep in-line with changes
on the master branch so that we can easily cherry-pick patches.

All the api changes relating stable apis released on the 1.12 branch
have been reverted as part of cherry-picking this patch so this most
just applies all the internal plumbing changes that enable us to
correctly propagate OOM errors.

cogl/cogl-attribute-buffer.h

@@ -50,18 +50,57 @@ COGL_BEGIN_DECLS
 
 #define COGL_ATTRIBUTE_BUFFER(buffer) ((CoglAttributeBuffer *)(buffer))
 
+/**
+ * cogl_attribute_buffer_new_with_size:
+ * @context: A #CoglContext
+ * @bytes: The number of bytes to allocate for vertex attribute data.
+ *
+ * Describes a new #CoglAttributeBuffer of @size bytes to contain
+ * arrays of vertex attribute data. Afterwards data can be set using
+ * cogl_buffer_set_data() or by mapping it into the application's
+ * address space using cogl_buffer_map().
+ *
+ * The underlying storage of this buffer isn't allocated by this
+ * function so that you have an opportunity to use the
+ * cogl_buffer_set_update_hint() and cogl_buffer_set_usage_hint()
+ * functions which may influence how the storage is allocated. The
+ * storage will be allocated once you upload data to the buffer.
+ *
+ * Note: You can assume this function always succeeds and won't return
+ * %NULL
+ *
+ * Return value: A newly allocated #CoglAttributeBuffer. Never %NULL.
+ *
+ * Stability: Unstable
+ */
+CoglAttributeBuffer *
+cogl_attribute_buffer_new_with_size (CoglContext *context,
+                                     size_t bytes);
+
 /**
  * cogl_attribute_buffer_new:
  * @context: A #CoglContext
  * @bytes: The number of bytes to allocate for vertex attribute data.
  * @data: An optional pointer to vertex data to upload immediately.
  *
- * Declares a new #CoglAttributeBuffer of @size bytes to contain arrays of vertex
- * attribute data. Once declared, data can be set using cogl_buffer_set_data()
- * or by mapping it into the application's address space using cogl_buffer_map().
+ * Describes a new #CoglAttributeBuffer of @size bytes to contain
+ * arrays of vertex attribute data and also uploads @size bytes read
+ * from @data to the new buffer.
  *
- * If @data isn't %NULL then @size bytes will be read from @data and
- * immediately copied into the new buffer.
+ * You should never pass a %NULL data pointer.
+ *
+ * <note>This function does not report out-of-memory errors back to
+ * the caller by returning %NULL and so you can assume this function
+ * always succeeds.</note>
+ *
+ * <note>In the unlikely case that there is an out of memory problem
+ * then Cogl will abort the application with a message. If your
+ * application needs to gracefully handle out-of-memory errors then
+ * you can use cogl_attribute_buffer_new_with_size() and then
+ * explicitly catch errors with cogl_buffer_set_data() or
+ * cogl_buffer_map().</note>
+ *
+ * Return value: A newly allocated #CoglAttributeBuffer (never %NULL)
  *
  * Since: 1.4
  * Stability: Unstable