Use the Wayland embedded linked list implementation instead of BSD's

This removes cogl-queue.h and adds a copy of Wayland's embedded list
implementation. The advantage of the Wayland model is that it is much
simpler and so it is easier to follow. It also doesn't require
defining a typedef for every list type.

The downside is that there is only one list type which is a
doubly-linked list where the head has a pointer to both the beginning
and the end. The BSD implementation has many more combinations some of
which we were taking advantage of to reduce the size of critical
structs where we didn't need a pointer to the end of the list.

The corresponding changes to uses of cogl-queue.h are:

• COGL_STAILQ_* was used for onscreen the list of events and dirty
  notifications. This makes the size of the CoglContext grow by one
  pointer.

• COGL_TAILQ_* was used for fences.

• COGL_LIST_* for CoglClosures. In this case the list head now has an
  extra pointer which means CoglOnscreen will grow by the size of
  three pointers, but this doesn't seem like a particularly important
  struct to optimise for size anyway.

• COGL_LIST_* was used for the list of foreign GLES2 offscreens.

• COGL_TAILQ_* was used for the list of sub stacks in a
  CoglMemoryStack.

• COGL_LIST_* was used to track the list of layers that haven't had
  code generated yet while generating a fragment shader for a
  pipeline.

• COGL_LIST_* was used to track the pipeline hierarchy in CoglNode.

The last part is a bit more controversial because it increases the
size of CoglPipeline and CoglPipelineLayer by one pointer in order to
have the redundant tail pointer for the list head. Normally we try to
be very careful about the size of the CoglPipeline struct. Because
CoglPipeline is slice-allocated, this effectively ends up adding two
pointers to the size because GSlice rounds up to the size of two
pointers.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

1 files changed, 123 insertions, 0 deletions

diff --git a/cogl/cogl-list.h b/cogl/cogl-list.h
new file mode 100644
index 00000000..7d716a89
--- /dev/null
+++ b/cogl/cogl-list.h
@@ -0,0 +1,123 @@
+/*
+ * Copyright © 2008 Kristian Høgsberg
+ * Copyright © 2012, 2013 Intel Corporation
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+/* This list implementation is based on the Wayland source code */
+
+#ifndef COGL_LIST_H
+#define COGL_LIST_H
+
+/**
+ * CoglList - linked list
+ *
+ * The list head is of "CoglList" type, and must be initialized
+ * using cogl_list_init().  All entries in the list must be of the same
+ * type.  The item type must have a "CoglList" member. This
+ * member will be initialized by cogl_list_insert(). There is no need to
+ * call cogl_list_init() on the individual item. To query if the list is
+ * empty in O(1), use cogl_list_empty().
+ *
+ * Let's call the list reference "CoglList foo_list", the item type as
+ * "item_t", and the item member as "CoglList link". The following code
+ *
+ * The following code will initialize a list:
+ *
+ *      cogl_list_init (foo_list);
+ *      cogl_list_insert (foo_list, item1);      Pushes item1 at the head
+ *      cogl_list_insert (foo_list, item2);      Pushes item2 at the head
+ *      cogl_list_insert (item2, item3);         Pushes item3 after item2
+ *
+ * The list now looks like [item2, item3, item1]
+ *
+ * Will iterate the list in ascending order:
+ *
+ *      item_t *item;
+ *      cogl_list_for_each(item, foo_list, link) {
+ *              Do_something_with_item(item);
+ *      }
+ */
+
+typedef struct _CoglList CoglList;
+
+struct _CoglList
+{
+  CoglList *prev;
+  CoglList *next;
+};
+
+void
+_cogl_list_init (CoglList *list);
+
+void
+_cogl_list_insert (CoglList *list,
+                   CoglList *elm);
+
+void
+_cogl_list_remove (CoglList *elm);
+
+int
+_cogl_list_length (CoglList *list);
+
+int
+_cogl_list_empty (CoglList *list);
+
+void
+_cogl_list_insert_list (CoglList *list,
+                        CoglList *other);
+
+#ifdef __GNUC__
+#define _cogl_container_of(ptr, sample, member)                         \
+  (__typeof__(sample))((char *)(ptr)    -                               \
+                       ((char *)&(sample)->member - (char *)(sample)))
+#else
+#define _cogl_container_of(ptr, sample, member)                 \
+  (void *)((char *)(ptr)        -                               \
+           ((char *)&(sample)->member - (char *)(sample)))
+#endif
+
+#define _cogl_list_for_each(pos, head, member)                          \
+  for (pos = 0, pos = _cogl_container_of((head)->next, pos, member);    \
+       &pos->member != (head);                                          \
+       pos = _cogl_container_of(pos->member.next, pos, member))
+
+#define _cogl_list_for_each_safe(pos, tmp, head, member)                \
+  for (pos = 0, tmp = 0,                                                \
+         pos = _cogl_container_of((head)->next, pos, member),           \
+         tmp = _cogl_container_of((pos)->member.next, tmp, member);     \
+       &pos->member != (head);                                          \
+       pos = tmp,                                                       \
+         tmp = _cogl_container_of(pos->member.next, tmp, member))
+
+#define _cogl_list_for_each_reverse(pos, head, member)                  \
+  for (pos = 0, pos = _cogl_container_of((head)->prev, pos, member);    \
+       &pos->member != (head);                                          \
+       pos = _cogl_container_of(pos->member.prev, pos, member))
+
+#define _cogl_list_for_each_reverse_safe(pos, tmp, head, member)        \
+  for (pos = 0, tmp = 0,                                                \
+         pos = _cogl_container_of((head)->prev, pos, member),           \
+         tmp = _cogl_container_of((pos)->member.prev, tmp, member);     \
+       &pos->member != (head);                                          \
+       pos = tmp,                                                       \
+         tmp = _cogl_container_of(pos->member.prev, tmp, member))
+
+#endif /* COGL_LIST_H */