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libwebsockets/lib/event-libs/glib/glib.c
Andy Green c6c7ab2b44 event libs: default to building as dynamically loaded plugins
Event lib support as it has been isn't scaling well, at the low level
libevent and libev headers have a namespace conflict so they can't
both be built into the same image, and at the distro level, binding
all the event libs to libwebsockets.so makes a bloaty situation for
packaging, lws will drag in all the event libs every time.

This patch implements the plan discussed here

https://github.com/warmcat/libwebsockets/issues/1980

and refactors the event lib support so they are built into isolated
plugins and bound at runtime according to what the application says
it wants to use.  The event lib plugins can be packaged individually
so that only the needed sets of support are installed (perhaps none
of them if the user code is OK with the default poll() loop).  And
dependent user code can mark the specific event loop plugin package
as required so pieces are added as needed.

The eventlib-foreign example is also refactored to build the selected
lib support isolated.

A readme is added detailing the changes and how to use them.

https://libwebsockets.org/git/libwebsockets/tree/READMEs/README.event-libs.md
2020-08-31 16:51:37 +01:00

513 lines
12 KiB
C

/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2010 - 2020 Andy Green <andy@warmcat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "private-lib-core.h"
#include <glib-unix.h>
#include "private-lib-event-libs-glib.h"
#if !defined(G_SOURCE_FUNC)
#define G_SOURCE_FUNC(f) ((GSourceFunc) (void (*)(void)) (f))
#endif
#define pt_to_priv_glib(_pt) ((struct lws_pt_eventlibs_glib *)(_pt)->evlib_pt)
#define wsi_to_priv_glib(_w) ((struct lws_wsi_eventlibs_glib *)(_w)->evlib_wsi)
#define wsi_to_subclass(_w) (wsi_to_priv_glib(_w)->w_read.source)
#define wsi_to_gsource(_w) ((GSource *)wsi_to_subclass(_w))
#define pt_to_loop(_pt) (pt_to_priv_glib(_pt)->loop)
#define pt_to_g_main_context(_pt) g_main_loop_get_context(pt_to_loop(_pt))
#define lws_gs_valid(t) (t.gs)
#define lws_gs_destroy(t) if (lws_gs_valid(t)) { \
g_source_destroy(t.gs); \
g_source_unref(t.gs); \
t.gs = NULL; t.tag = 0; }
static gboolean
lws_glib_idle_timer_cb(void *p);
static gboolean
lws_glib_hrtimer_cb(void *p);
static gboolean
lws_glib_check(GSource *src)
{
struct lws_io_watcher_glib_subclass *sub =
(struct lws_io_watcher_glib_subclass *)src;
return !!g_source_query_unix_fd(src, sub->tag);
}
/*
* These helpers attach only to the main_context that belongs to the pt's glib
* mainloop. The simpler g_timeout_add() and g_idle_add() are forbidden
* because they implicitly choose the default main context to attach to
* instead of specifically the loop bound to the pt.
*
* https://developer.gnome.org/programming-guidelines/unstable/main-contexts.html.en#what-is-gmaincontext
*/
static int
lws_glib_set_idle(struct lws_context_per_thread *pt)
{
if (lws_gs_valid(pt_to_priv_glib(pt)->idle))
return 0;
pt_to_priv_glib(pt)->idle.gs = g_idle_source_new();
if (!pt_to_priv_glib(pt)->idle.gs)
return 1;
g_source_set_callback(pt_to_priv_glib(pt)->idle.gs,
lws_glib_idle_timer_cb, pt, NULL);
pt_to_priv_glib(pt)->idle.tag = g_source_attach(
pt_to_priv_glib(pt)->idle.gs, pt_to_g_main_context(pt));
return 0;
}
static int
lws_glib_set_timeout(struct lws_context_per_thread *pt, unsigned int ms)
{
lws_gs_destroy(pt_to_priv_glib(pt)->hrtimer);
pt_to_priv_glib(pt)->hrtimer.gs = g_timeout_source_new(ms);
if (!pt_to_priv_glib(pt)->hrtimer.gs)
return 1;
g_source_set_callback(pt_to_priv_glib(pt)->hrtimer.gs,
lws_glib_hrtimer_cb, pt, NULL);
pt_to_priv_glib(pt)->hrtimer.tag = g_source_attach(
pt_to_priv_glib(pt)->hrtimer.gs,
pt_to_g_main_context(pt));
return 0;
}
static gboolean
lws_glib_dispatch(GSource *src, GSourceFunc x, gpointer userData)
{
struct lws_io_watcher_glib_subclass *sub =
(struct lws_io_watcher_glib_subclass *)src;
struct lws_context_per_thread *pt;
struct lws_pollfd eventfd;
GIOCondition cond;
cond = g_source_query_unix_fd(src, sub->tag);
eventfd.revents = cond;
/* translate from glib event namespace to platform */
if (cond & G_IO_IN)
eventfd.revents |= LWS_POLLIN;
if (cond & G_IO_OUT)
eventfd.revents |= LWS_POLLOUT;
if (cond & G_IO_ERR)
eventfd.revents |= LWS_POLLHUP;
if (cond & G_IO_HUP)
eventfd.revents |= LWS_POLLHUP;
eventfd.events = eventfd.revents;
eventfd.fd = sub->wsi->desc.sockfd;
lwsl_debug("%s: wsi %p: fd %d, events %d\n", __func__, sub->wsi,
eventfd.fd, eventfd.revents);
pt = &sub->wsi->a.context->pt[(int)sub->wsi->tsi];
if (pt->is_destroyed)
return G_SOURCE_CONTINUE;
lws_service_fd_tsi(sub->wsi->a.context, &eventfd, sub->wsi->tsi);
if (!lws_gs_valid(pt_to_priv_glib(pt)->idle))
lws_glib_set_idle(pt);
if (pt->destroy_self)
lws_context_destroy(pt->context);
return G_SOURCE_CONTINUE;
}
static const GSourceFuncs lws_glib_source_ops = {
.prepare = NULL,
.check = lws_glib_check,
.dispatch = lws_glib_dispatch,
.finalize = NULL,
};
/*
* This is the callback for a timer object that is set to the earliest scheduled
* lws event... it services any lws scheduled events that are ready, and then
* resets the event loop timer to the earliest remaining event, if any.
*/
static gboolean
lws_glib_hrtimer_cb(void *p)
{
struct lws_context_per_thread *pt = (struct lws_context_per_thread *)p;
unsigned int ms;
lws_usec_t us;
lws_pt_lock(pt, __func__);
lws_gs_destroy(pt_to_priv_glib(pt)->hrtimer);
us = __lws_sul_service_ripe(pt->pt_sul_owner, LWS_COUNT_PT_SUL_OWNERS,
lws_now_usecs());
if (us) {
ms = us / LWS_US_PER_MS;
if (!ms)
ms = 1;
lws_glib_set_timeout(pt, ms);
}
lws_pt_unlock(pt);
lws_glib_set_idle(pt);
return FALSE; /* stop it repeating */
}
static gboolean
lws_glib_idle_timer_cb(void *p)
{
struct lws_context_per_thread *pt = (struct lws_context_per_thread *)p;
if (pt->is_destroyed)
return FALSE;
lws_service_do_ripe_rxflow(pt);
lws_glib_hrtimer_cb(pt);
/*
* is there anybody with pending stuff that needs service forcing?
*/
if (!lws_service_adjust_timeout(pt->context, 1, pt->tid)) {
/* -1 timeout means just do forced service */
_lws_plat_service_forced_tsi(pt->context, pt->tid);
/* still somebody left who wants forced service? */
if (!lws_service_adjust_timeout(pt->context, 1, pt->tid))
return TRUE;
}
if (pt->destroy_self)
lws_context_destroy(pt->context);
/*
* For glib, this disables the idle callback. Otherwise we keep
* coming back here immediately endlessly.
*
* We reenable the idle callback on the next network or scheduled event
*/
lws_gs_destroy(pt_to_priv_glib(pt)->idle);
return FALSE;
}
void
lws_glib_sigint_cb(void *ctx)
{
struct lws_context_per_thread *pt = ctx;
pt->inside_service = 1;
if (pt->context->eventlib_signal_cb) {
pt->context->eventlib_signal_cb(NULL, 0);
return;
}
if (!pt->event_loop_foreign)
g_main_loop_quit(pt_to_loop(pt));
}
static int
elops_init_context_glib(struct lws_context *context,
const struct lws_context_creation_info *info)
{
// int n;
context->eventlib_signal_cb = info->signal_cb;
// for (n = 0; n < context->count_threads; n++)
// pt_to_priv_glib(&context->pt[n])->w_sigint.context = context;
return 0;
}
static int
elops_accept_glib(struct lws *wsi)
{
struct lws_context_per_thread *pt = &wsi->a.context->pt[(int)wsi->tsi];
struct lws_wsi_eventlibs_glib *wsipr = wsi_to_priv_glib(wsi);
int fd;
assert(!wsi_to_subclass(wsi));
wsi_to_subclass(wsi) = (struct lws_io_watcher_glib_subclass *)
g_source_new((GSourceFuncs *)&lws_glib_source_ops,
sizeof(*wsi_to_subclass(wsi)));
if (!wsi_to_subclass(wsi))
return 1;
wsipr->w_read.context = wsi->a.context;
wsi_to_subclass(wsi)->wsi = wsi;
if (wsi->role_ops->file_handle)
fd = wsi->desc.filefd;
else
fd = wsi->desc.sockfd;
wsi_to_subclass(wsi)->tag = g_source_add_unix_fd(wsi_to_gsource(wsi),
fd, (GIOCondition)LWS_POLLIN);
wsipr->w_read.actual_events = LWS_POLLIN;
g_source_set_callback(wsi_to_gsource(wsi),
G_SOURCE_FUNC(lws_service_fd), wsi->a.context, NULL);
g_source_attach(wsi_to_gsource(wsi), pt_to_g_main_context(pt));
return 0;
}
static int
elops_init_pt_glib(struct lws_context *context, void *_loop, int tsi)
{
struct lws_context_per_thread *pt = &context->pt[tsi];
struct lws_pt_eventlibs_glib *ptpr = pt_to_priv_glib(pt);
struct lws_vhost *vh = context->vhost_list;
GMainLoop *loop = (GMainLoop *)_loop;
if (!loop)
loop = g_main_loop_new(NULL, 0);
else
context->pt[tsi].event_loop_foreign = 1;
if (!loop) {
lwsl_err("%s: creating glib loop failed\n", __func__);
return -1;
}
ptpr->loop = loop;
/*
* Initialize all events with the listening sockets
* and register a callback for read operations
*/
while (vh) {
if (vh->lserv_wsi)
elops_accept_glib(vh->lserv_wsi);
vh = vh->vhost_next;
}
lws_glib_set_idle(pt);
/* Register the signal watcher unless it's a foreign loop */
if (pt->event_loop_foreign)
return 0;
ptpr->sigint.tag = g_unix_signal_add(SIGINT,
G_SOURCE_FUNC(lws_glib_sigint_cb), pt);
return 0;
}
/*
* We are changing the event wait for this guy
*/
static void
elops_io_glib(struct lws *wsi, int flags)
{
struct lws_context_per_thread *pt = &wsi->a.context->pt[(int)wsi->tsi];
struct lws_wsi_eventlibs_glib *wsipr = wsi_to_priv_glib(wsi);
GIOCondition cond = wsipr->w_read.actual_events | G_IO_ERR;
if (!pt_to_loop(pt) || wsi->a.context->being_destroyed ||
pt->is_destroyed)
return;
if (!wsi_to_subclass(wsi))
return;
/*
* We are being given individual set / clear operations using
* LWS_EV_ common namespace, convert them to glib namespace bitfield
*/
if (flags & LWS_EV_READ) {
if (flags & LWS_EV_STOP)
cond &= ~(G_IO_IN | G_IO_HUP);
else
cond |= G_IO_IN | G_IO_HUP;
}
if (flags & LWS_EV_WRITE) {
if (flags & LWS_EV_STOP)
cond &= ~G_IO_OUT;
else
cond |= G_IO_OUT;
}
wsipr->w_read.actual_events = cond;
lwsl_debug("%s: wsi %p, fd %d, 0x%x/0x%x\n", __func__, wsi,
wsi->desc.sockfd, flags, (int)cond);
g_source_modify_unix_fd(wsi_to_gsource(wsi), wsi_to_subclass(wsi)->tag,
cond);
}
static void
elops_run_pt_glib(struct lws_context *context, int tsi)
{
struct lws_context_per_thread *pt = &context->pt[tsi];
if (pt_to_loop(pt))
g_main_loop_run(pt_to_loop(pt));
}
static void
elops_destroy_wsi_glib(struct lws *wsi)
{
struct lws_context_per_thread *pt;
if (!wsi)
return;
pt = &wsi->a.context->pt[(int)wsi->tsi];
if (pt->is_destroyed)
return;
if (!wsi_to_gsource(wsi))
return;
if (wsi_to_subclass(wsi)->tag) {
g_source_remove_unix_fd(wsi_to_gsource(wsi),
wsi_to_subclass(wsi)->tag);
wsi_to_subclass(wsi)->tag = NULL;
}
g_source_destroy(wsi_to_gsource(wsi));
g_source_unref(wsi_to_gsource(wsi));
wsi_to_subclass(wsi) = NULL;
}
static void
elops_destroy_pt_glib(struct lws_context *context, int tsi)
{
struct lws_context_per_thread *pt = &context->pt[tsi];
struct lws_pt_eventlibs_glib *ptpr = pt_to_priv_glib(pt);
struct lws_vhost *vh = context->vhost_list;
if (!pt_to_loop(pt))
return;
/*
* Free all events with the listening sockets
*/
while (vh) {
if (vh->lserv_wsi)
elops_destroy_wsi_glib(vh->lserv_wsi);
vh = vh->vhost_next;
}
lws_gs_destroy(ptpr->idle);
lws_gs_destroy(ptpr->hrtimer);
if (!pt->event_loop_foreign) {
g_main_loop_quit(pt_to_loop(pt));
lws_gs_destroy(ptpr->sigint);
g_main_loop_unref(pt_to_loop(pt));
}
pt_to_loop(pt) = NULL;
}
static int
elops_destroy_context2_glib(struct lws_context *context)
{
struct lws_context_per_thread *pt = &context->pt[0];
int n;
for (n = 0; n < (int)context->count_threads; n++) {
if (!pt->event_loop_foreign)
g_main_loop_quit(pt_to_loop(pt));
pt++;
}
return 0;
}
static int
elops_wsi_logical_close_glib(struct lws *wsi)
{
elops_destroy_wsi_glib(wsi);
return 0;
}
static const struct lws_event_loop_ops event_loop_ops_glib = {
/* name */ "glib",
/* init_context */ elops_init_context_glib,
/* destroy_context1 */ NULL,
/* destroy_context2 */ elops_destroy_context2_glib,
/* init_vhost_listen_wsi */ elops_accept_glib,
/* init_pt */ elops_init_pt_glib,
/* wsi_logical_close */ elops_wsi_logical_close_glib,
/* check_client_connect_ok */ NULL,
/* close_handle_manually */ NULL,
/* accept */ elops_accept_glib,
/* io */ elops_io_glib,
/* run_pt */ elops_run_pt_glib,
/* destroy_pt */ elops_destroy_pt_glib,
/* destroy wsi */ elops_destroy_wsi_glib,
/* flags */ LELOF_DESTROY_FINAL,
/* evlib_size_ctx */ 0,
/* evlib_size_pt */ sizeof(struct lws_pt_eventlibs_glib),
/* evlib_size_vh */ 0,
/* evlib_size_wsi */ sizeof(struct lws_io_watcher_glib),
};
#if defined(LWS_WITH_EVLIB_PLUGINS)
LWS_VISIBLE
#endif
const lws_plugin_evlib_t evlib_glib = {
.hdr = {
"glib event loop",
"lws_evlib_plugin",
LWS_PLUGIN_API_MAGIC
},
.ops = &event_loop_ops_glib
};