mirror of https://gitee.com/openkylin/qemu.git
f545504420
qapi-code-gen.txt already claims that types, commands, and events share a common namespace; set this in stone by further documenting that our introspection output will never have collisions with the same name tied to more than one meta-type. Our largest QMP enum currently has 125 values, our largest object type has 27 members, and the mean for each is less than 10. These sizes are small enough that the per-element overhead of O(log n) binary searching probably outweighs the speed possible with direct O(n) linear searching (a better algorithm with more overhead will only beat a leaner naive algorithm only as you scale to larger input sizes). Arguably, the overall SchemaInfo array could be sorted by name; there, we currently have 531 entities, large enough for a binary search to be faster than linear. However, remember that we have mutually-recursive types, which means there is no topological ordering that will allow clients to learn all information about that type in a single linear pass; thus clients will want to do random access over the data, and they will probably read the introspection output into a hashtable for O(1) lookup rather than O(log n) binary searching, at which point, pre-sorting our introspection output doesn't help the client. It doesn't help that sorting can be subjective if you introduce locales into the mix (I'm not experienced enough with Python to know for sure, but at least it looks like it defaults to sorting in the C locale even when run under a different locale). And while our current introspection output is deterministic (because we visit entities in a sorted order), we may want to change that order in the future (such as using OrderedDict to stick to .json declaration order). For these reasons, we simply document that clients should not rely on any particular order of items in introspection output. And since it is now a documented part of the contract, we have the freedom to later rearrange output if needed, without worrying about breaking well-written clients. Signed-off-by: Eric Blake <eblake@redhat.com> Message-Id: <1446791754-23823-13-git-send-email-eblake@redhat.com> [Commit message tweaked] Signed-off-by: Markus Armbruster <armbru@redhat.com> |
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| .. | ||
| Makefile.objs | ||
| block-core.json | ||
| block.json | ||
| common.json | ||
| crypto.json | ||
| event.json | ||
| introspect.json | ||
| opts-visitor.c | ||
| qapi-dealloc-visitor.c | ||
| qapi-util.c | ||
| qapi-visit-core.c | ||
| qmp-dispatch.c | ||
| qmp-event.c | ||
| qmp-input-visitor.c | ||
| qmp-output-visitor.c | ||
| qmp-registry.c | ||
| rocker.json | ||
| string-input-visitor.c | ||
| string-output-visitor.c | ||
| trace.json | ||