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// Copyright 2021, 2022 Benjamin Barenblat
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#include "src/x/connection.h"
#include <X11/Xlib-xcb.h>
#include <X11/Xlib.h>
#include <stdint.h>
#include <xcb/xcb.h>
#include <array>
#include <stdexcept>
#include <utility>
#include <vector>
#include "src/undo_xlib_dot_h_namespace_pollution.h"
//
#include "src/util.h"
#include "src/x/event.h"
#include "src/x/util.h"
#include "third_party/abseil/absl/cleanup/cleanup.h"
#include "third_party/abseil/absl/container/btree_map.h"
#include "third_party/abseil/absl/strings/string_view.h"
#include "third_party/abseil/absl/synchronization/mutex.h"
#include "third_party/abseil/absl/types/optional.h"
namespace x {
namespace {
std::pair<uint32_t, std::vector<uint32_t>> MarshalValueList(
const absl::btree_map<uint32_t, absl::optional<uint32_t>>&
values) noexcept {
uint32_t value_mask = 0;
std::vector<uint32_t> value_list;
for (auto& [k, v] : values) {
if (v.has_value()) {
value_mask |= k;
value_list.push_back(*v);
}
}
return {value_mask, value_list};
}
} // namespace
Connection::Connection(const char* display_name) {
if (display_name == nullptr) {
throw std::invalid_argument("X: null display name");
}
xlib_ = XOpenDisplay(display_name);
if (xlib_ == nullptr) {
throw std::runtime_error("X: could not connect to X server");
}
XSetEventQueueOwner(xlib_, XCBOwnsEventQueue);
// We make a lot of calls into XCB, so cache the XCB handle.
xcb_ = XGetXCBConnection(xlib_);
}
VoidCompletion Connection::CreateWindow(
const CreateWindowOptions& options) noexcept {
const auto& [value_mask, value_list] =
MarshalValueList({{XCB_CW_BACK_PIXEL, options.background_pixel},
{XCB_CW_EVENT_MASK, options.event_mask}});
return VoidCompletion(
xcb_, xcb_create_window_checked(
xcb_, options.depth, options.window, options.parent, options.x,
options.y, options.width, options.height, options.border_width,
FromEnum(options.window_class), options.visual_id, value_mask,
value_list.data()));
}
VoidCompletion Connection::SendEvent(const Event& event, bool propagate,
Id destination_window,
const std::vector<EventMask>& event_mask) {
uint32_t serialized_event_mask = 0;
for (EventMask m : event_mask) {
serialized_event_mask |= FromEnum(m);
}
std::array<char, 32> serialized_event = SerializeEvent(event);
return VoidCompletion(
xcb_,
xcb_send_event_checked(xcb_, propagate, destination_window,
serialized_event_mask, serialized_event.data()));
}
EventMonitor::EventMonitor(Connection& x)
: x_(x), communication_window_(x_.GenerateId()) {
// Create a window for us to communicate with the watcher thread.
VoidCompletion create_window_completion =
x_.CreateWindow({.depth = 0, // as required for an InputOnly window
.window = communication_window_,
.parent = x_.DefaultScreen().root(),
.x = 0,
.y = 0,
.width = 1,
.height = 1,
.border_width = 0,
.window_class = WindowClass::kInputOnly,
.visual_id = XCB_COPY_FROM_PARENT});
InternAtomCompletion intern_atom_completion =
x_.InternOrGetAtomByName(kDoneAtomName);
std::move(create_window_completion).Check();
close_connection_atom_ = std::move(intern_atom_completion).Get();
watcher_thread_.emplace(&EventMonitor::WatcherThreadMain, this);
}
EventMonitor::~EventMonitor() {
// Send a client message through the connection so the waiter thread knows to
// exit.
xcb_client_message_event_t event = {.response_type = XCB_CLIENT_MESSAGE,
.format = 32,
.sequence = 0,
.window = communication_window_,
.type = close_connection_atom_,
.data = {}};
x_.SendEvent(ClientMessageEvent(event), /*propagate=*/false,
communication_window_, {EventMask::kNoEvent})
.Check();
watcher_thread_->join();
x_.DestroyWindow(communication_window_);
}
absl::optional<Event> EventMonitor::WaitForEventWithTimeout(
absl::Duration timeout) noexcept {
bool events_present = mu_.LockWhenWithTimeout(
absl::Condition(this, &EventMonitor::EventsPresent), timeout);
absl::Cleanup unlock = [&]() noexcept { mu_.Unlock(); };
if (events_present) {
Event event = std::move(pending_events_.front());
pending_events_.pop_front();
return event;
} else {
return absl::nullopt;
}
}
void EventMonitor::WatcherThreadMain() noexcept {
while (true) {
auto generic_event =
std::unique_ptr<xcb_generic_event_t, x_internal::FreeDeleter>(
xcb_wait_for_event(x_.AsXcbConnection()));
if (generic_event == nullptr) {
// The connection dropped or something.
return;
}
Event event = FromXcbGenericEvent(*generic_event);
if (const auto* client_message = absl::get_if<ClientMessageEvent>(&event);
client_message != nullptr &&
client_message->type() == close_connection_atom_) {
// Our destructor is running.
return;
}
absl::MutexLock lock(&mu_);
pending_events_.push_back(event);
}
}
} // namespace x
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