| // Copyright 2016 The Fuchsia Authors |
| // |
| // Use of this source code is governed by a MIT-style |
| // license that can be found in the LICENSE file or at |
| // https://opensource.org/licenses/MIT |
| |
| #include <object/wait_state_observer.h> |
| |
| #include <assert.h> |
| |
| #include <kernel/event.h> |
| |
| #include <object/handle.h> |
| #include <object/dispatcher.h> |
| |
| #include <fbl/type_support.h> |
| |
| WaitStateObserver::~WaitStateObserver() { |
| DEBUG_ASSERT(!dispatcher_); |
| } |
| |
| zx_status_t WaitStateObserver::Begin(Event* event, |
| Handle* handle, |
| zx_signals_t watched_signals) { |
| canary_.Assert(); |
| DEBUG_ASSERT(!dispatcher_); |
| |
| event_ = event; |
| handle_ = handle; |
| watched_signals_ = watched_signals; |
| dispatcher_ = handle->dispatcher(); |
| wakeup_reasons_ = 0u; |
| |
| auto status = dispatcher_->add_observer(this); |
| if (status != ZX_OK) { |
| dispatcher_.reset(); |
| return status; |
| } |
| return ZX_OK; |
| } |
| |
| zx_signals_t WaitStateObserver::End() { |
| canary_.Assert(); |
| DEBUG_ASSERT(dispatcher_); |
| DEBUG_ASSERT(dispatcher_->has_state_tracker()); |
| |
| dispatcher_->RemoveObserver(this); |
| dispatcher_.reset(); |
| |
| // Return the set of reasons that we may have been woken. Basically, this |
| // is set of satisfied bits which were ever set while we were waiting on the list. |
| return wakeup_reasons_; |
| } |
| |
| StateObserver::Flags WaitStateObserver::OnInitialize(zx_signals_t initial_state, |
| const StateObserver::CountInfo* cinfo) { |
| canary_.Assert(); |
| |
| // Record the initial state of the state tracker as our wakeup reason. If |
| // we are going to become immediately signaled, the reason is contained |
| // somewhere in this initial state. |
| wakeup_reasons_ = initial_state; |
| |
| if (initial_state & watched_signals_) { |
| event_->Signal(); |
| } |
| |
| return 0; |
| } |
| |
| StateObserver::Flags WaitStateObserver::OnStateChange(zx_signals_t new_state) { |
| canary_.Assert(); |
| |
| // If we are still on our StateTracker's list of observers, and the |
| // StateTracker's state has changed, accumulate the reasons that we may have |
| // woken up. In particular any satisfied bits which have become set |
| // while we were on the list may have been reasons to wake up. |
| wakeup_reasons_ |= new_state; |
| |
| if (new_state & watched_signals_) { |
| event_->Signal(); |
| } |
| |
| return 0; |
| } |
| |
| StateObserver::Flags WaitStateObserver::OnCancel(const Handle* handle) { |
| canary_.Assert(); |
| |
| if (handle == handle_) { |
| wakeup_reasons_ |= ZX_SIGNAL_HANDLE_CLOSED; |
| event_->Signal(ZX_ERR_CANCELED); |
| return kHandled; |
| } else { |
| return 0; |
| } |
| } |