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// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/gfx/x/event.h"
#include <xcb/xcb.h>
#include <cstring>
#include "base/check_op.h"
#include "base/memory/scoped_refptr.h"
#include "ui/gfx/x/connection.h"
#include "ui/gfx/x/xproto.h"
#include "ui/gfx/x/xproto_internal.h"
#include "ui/gfx/x/xproto_types.h"
namespace x11 {
Event::Event() = default;
Event::Event(scoped_refptr<base::RefCountedMemory> event_bytes,
x11::Connection* connection,
bool sequence_valid) {
auto* xcb_event = reinterpret_cast<xcb_generic_event_t*>(
const_cast<uint8_t*>(event_bytes->data()));
sequence_valid_ = sequence_valid;
sequence_ = xcb_event->full_sequence;
// KeymapNotify events are the only events that don't have a sequence.
if ((xcb_event->response_type & ~kSendEventMask) !=
x11::KeymapNotifyEvent::opcode) {
// On the wire, events are 32 bytes except for generic events which are
// trailed by additional data. XCB inserts an extended 4-byte sequence
// between the 32-byte event and the additional data, so we need to shift
// the additional data over by 4 bytes so the event is back in its wire
// format, which is what Xlib and XProto are expecting.
if ((xcb_event->response_type & ~kSendEventMask) ==
x11::GeGenericEvent::opcode) {
auto* ge = reinterpret_cast<xcb_ge_event_t*>(xcb_event);
constexpr size_t ge_length = sizeof(xcb_raw_generic_event_t);
constexpr size_t offset = sizeof(ge->full_sequence);
size_t extended_length = ge->length * 4;
if (extended_length < ge_length) {
// If the additional data is smaller than the fixed size event, shift
// the additional data to the left.
memmove(&ge->full_sequence, &ge[1], extended_length);
} else {
// Otherwise shift the fixed size event to the right.
char* addr = reinterpret_cast<char*>(xcb_event);
memmove(addr + offset, addr, ge_length);
event_bytes = base::MakeRefCounted<OffsetRefCountedMemory>(
event_bytes, offset, ge_length + extended_length);
xcb_event = reinterpret_cast<xcb_generic_event_t*>(addr + offset);
}
}
}
// Xlib sometimes modifies |xcb_event|, so let it handle the event after
// we parse it with ReadEvent().
ReadBuffer buf(event_bytes);
ReadEvent(this, connection, &buf);
}
Event::Event(Event&& event) {
memcpy(this, &event, sizeof(Event));
memset(&event, 0, sizeof(Event));
}
Event& Event::operator=(Event&& event) {
Dealloc();
memcpy(this, &event, sizeof(Event));
memset(&event, 0, sizeof(Event));
return *this;
}
Event::~Event() {
Dealloc();
}
void Event::Dealloc() {
if (deleter_)
deleter_(event_);
}
} // namespace x11
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