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libwebsockets/lib
Andy Green 1a93e73402 fakewsi: replace with smaller substructure
Currently we always reserve a fakewsi per pt so events that don't have a related actual
wsi, like vhost-protocol-init or vhost cert init via protocol callback can make callbacks
that look reasonable to user protocol handler code expecting a valid wsi every time.

This patch splits out stuff that user callbacks often unconditionally expect to be in
a wsi, like context pointer, vhost pointer etc into a substructure, which is composed
into struct lws at the top of it.  Internal references (struct lws is opaque, so there
are only internal references) are all updated to go via the substructre, the compiler
should make that a NOP.

Helpers are added when fakewsi is used and referenced.

If not PLAT_FREERTOS, we continue to provide a full fakewsi in the pt as before,
although the helpers improve consistency by zeroing down the substructure.  There is
a huge amount of user code out there over the last 10 years that did not always have
the minimal examples to follow, some of it does some unexpected things.

If it is PLAT_FREERTOS, that is a newer thing in lws and users have the benefit of
being able to follow the minimal examples' approach.  For PLAT_FREERTOS we don't
reserve the fakewsi in the pt any more, saving around 800 bytes.  The helpers then
create a struct lws_a (the substructure) on the stack, zero it down (but it is only
like 4 pointers) and prepare it with whatever we know like the context.

Then we cast it to a struct lws * and use it in the user protocol handler call.
In this case, the remainder of the struct lws is undefined.  However the amount of
old protocol handlers that might touch things outside of the substructure in
PLAT_FREERTOS is very limited compared to legacy lws user code and the saving is
significant on constrained devices.

User handlers should not be touching everything in a wsi every time anyway, there
are several cases where there is no valid wsi to do the call with.  Dereference of
things outside the substructure should only happen when the callback reason shows
there is a valid wsi bound to the activity (as in all the minimal examples).
2020-07-20 06:28:52 +01:00
..
abstract cmakelist: Augean Stables refactor 2020-05-27 08:40:12 +01:00
core fakewsi: replace with smaller substructure 2020-07-20 06:28:52 +01:00
core-net fakewsi: replace with smaller substructure 2020-07-20 06:28:52 +01:00
drivers lws_netdev: use lws_settings 2020-07-07 15:23:19 +01:00
event-libs fakewsi: replace with smaller substructure 2020-07-20 06:28:52 +01:00
jose lws_jwt_token_sanity 2020-07-15 16:18:00 +01:00
misc struct-lejp: handle no path match 2020-07-15 16:18:00 +01:00
plat fakewsi: replace with smaller substructure 2020-07-20 06:28:52 +01:00
roles fakewsi: replace with smaller substructure 2020-07-20 06:28:52 +01:00
secure-streams fakewsi: replace with smaller substructure 2020-07-20 06:28:52 +01:00
system fakewsi: replace with smaller substructure 2020-07-20 06:28:52 +01:00
tls fakewsi: replace with smaller substructure 2020-07-20 06:28:52 +01:00
CMakeLists.txt cmake: pkgconfig: typo fixed 2020-07-20 06:27:16 +01:00
README.md cleaning 2020-01-05 22:17:58 +00:00

Library sources layout

Code that goes in the libwebsockets library itself lives down ./lib

Path Sources
lib/core Core lws code related to generic fd and wsi servicing and management
lib/core-net Core lws code that applies only if networking enabled
lib/event-libs Code containing optional event-lib specific adaptations
lib/jose JOSE / JWS / JWK / JWE implementations
lib/misc Code for various mostly optional miscellaneous features
lib/plat Platform-specific adaptation code
lib/roles Code for specific optional wsi roles, eg, http/1, h2, ws, raw, etc
lib/system Code for system-level features, eg, dhcpclient
lib/tls Code supporting the various TLS libraries