205 lines
6.6 KiB
C++
205 lines
6.6 KiB
C++
/*
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Copyright (C) 2012 Paul Davis
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <cstring>
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#include <pthread.h>
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#include "pbd/compose.h"
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#include "pbd/debug.h"
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#include "pbd/event_loop.h"
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#include "pbd/error.h"
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#include "pbd/stacktrace.h"
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#include "i18n.h"
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using namespace PBD;
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using namespace std;
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static void do_not_delete_the_loop_pointer (void*) { }
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Glib::Threads::Private<EventLoop> EventLoop::thread_event_loop (do_not_delete_the_loop_pointer);
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Glib::Threads::RWLock EventLoop::thread_buffer_requests_lock;
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EventLoop::ThreadRequestBufferList EventLoop::thread_buffer_requests;
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EventLoop::RequestBufferSuppliers EventLoop::request_buffer_suppliers;
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EventLoop::EventLoop (string const& name)
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: _name (name)
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{
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}
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EventLoop*
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EventLoop::get_event_loop_for_thread()
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{
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return thread_event_loop.get ();
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}
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void
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EventLoop::set_event_loop_for_thread (EventLoop* loop)
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{
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thread_event_loop.set (loop);
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}
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void*
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EventLoop::invalidate_request (void* data)
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{
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InvalidationRecord* ir = (InvalidationRecord*) data;
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/* Some of the requests queued with an EventLoop may involve functors
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* that make method calls to objects whose lifetime is shorter
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* than the EventLoop's. We do not want to make those calls if the
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* object involve has been destroyed. To prevent this, we
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* provide a way to invalidate those requests when the object is
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* destroyed.
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*
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* An object was passed to __invalidator() which added a callback to
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* EventLoop::invalidate_request() to its "notify when destroyed"
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* list. __invalidator() returned an InvalidationRecord that has been
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* to passed to this function as data.
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*
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* The object is currently being destroyed and so we want to
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* mark all requests involving this object that are queued with
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* any EventLoop as invalid.
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*
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* As of April 2012, we are usign sigc::trackable as the base object
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* used to queue calls to ::invalidate_request() to be made upon
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* destruction, via its ::add_destroy_notify_callback() API. This is
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* not necessarily ideal, but it is very close to precisely what we
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* want, and many of the objects we want to do this with already
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* inherit (indirectly) from sigc::trackable.
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*/
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if (ir->event_loop) {
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Glib::Threads::Mutex::Lock lm (ir->event_loop->slot_invalidation_mutex());
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for (list<BaseRequestObject*>::iterator i = ir->requests.begin(); i != ir->requests.end(); ++i) {
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(*i)->valid = false;
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(*i)->invalidation = 0;
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}
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delete ir;
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}
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return 0;
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}
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vector<EventLoop::ThreadBufferMapping>
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EventLoop::get_request_buffers_for_target_thread (const std::string& target_thread)
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{
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vector<ThreadBufferMapping> ret;
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Glib::Threads::RWLock::WriterLock lm (thread_buffer_requests_lock);
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for (ThreadRequestBufferList::const_iterator x = thread_buffer_requests.begin();
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x != thread_buffer_requests.end(); ++x) {
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if (x->second.target_thread_name == target_thread) {
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ret.push_back (x->second);
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}
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}
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DEBUG_TRACE (PBD::DEBUG::EventLoop, string_compose ("for thread \"%1\", found %2 request buffers\n", target_thread, ret.size()));
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return ret;
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}
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void
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EventLoop::register_request_buffer_factory (const string& target_thread_name,
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void* (*factory)(uint32_t))
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{
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RequestBufferSupplier trs;
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trs.name = target_thread_name;
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trs.factory = factory;
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{
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Glib::Threads::RWLock::WriterLock lm (thread_buffer_requests_lock);
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request_buffer_suppliers.push_back (trs);
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}
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}
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void
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EventLoop::pre_register (const string& emitting_thread_name, uint32_t num_requests)
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{
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/* Threads that need to emit signals "towards" other threads, but with
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RT safe behavior may be created before the receiving threads
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exist. This makes it impossible for them to use the
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ThreadCreatedWithRequestSize signal to notify receiving threads of
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their existence.
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This function creates a request buffer for them to use with
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the (not yet) created threads, and stores it where the receiving
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thread can find it later.
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*/
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ThreadBufferMapping mapping;
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Glib::Threads::RWLock::ReaderLock lm (thread_buffer_requests_lock);
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for (RequestBufferSuppliers::iterator trs = request_buffer_suppliers.begin(); trs != request_buffer_suppliers.end(); ++trs) {
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if (!trs->factory) {
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/* no factory - no request buffer required or expected */
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continue;
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}
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if (emitting_thread_name == trs->name) {
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/* no need to register an emitter with itself */
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continue;
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}
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mapping.emitting_thread = pthread_self();
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mapping.target_thread_name = trs->name;
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/* Allocate a suitably sized request buffer. This will set the
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* thread-local variable that holds a pointer to this request
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* buffer.
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*/
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mapping.request_buffer = trs->factory (num_requests);
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/* now store it where the receiving thread (trs->name) can find
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it if and when it is created. (Discovery happens in the
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AbstractUI constructor. Note that if
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*/
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const string key = string_compose ("%1/%2", mapping.emitting_thread, mapping.target_thread_name);
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/* note that there is no cleanup mechanism to remove
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* dead/out-of-date entries from this map.
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*
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* the request buffers themselves will be cleaned up
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* when the requesting thread exits (by the
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* thread-local-storage (TLS) cleanup mechanism).
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*
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* but an entry will remain in the map.
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*
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* really need a way to register some end-of-thread callback
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* that will remove the entry from the thread_buffer_requests
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* container. but there is no such thing in the pthreads API
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*
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* the target thread only searches the map once, when the event
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* loop object is constructed. if it finds invalid buffers
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* it will (a) never get any requests for them anyway (b) will
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* find them marked "dead" and delete them.
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*/
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thread_buffer_requests[key] = mapping;
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DEBUG_TRACE (PBD::DEBUG::EventLoop, string_compose ("pre-registered request buffer for \"%1\" to send to \"%2\", buffer @ %3 (key was %4)\n",
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emitting_thread_name, trs->name, mapping.request_buffer, key));
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}
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}
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