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LibCore: Make CObject reference-counted

Okay, I've spent a whole day on this now, and it finally kinda works!
With this patch, CObject and all of its derived classes are reference
counted instead of tree-owned.

The previous, Qt-like model was nice and familiar, but ultimately also
outdated and difficult to reason about.

CObject-derived types should now be stored in RefPtr/NonnullRefPtr and
each class can be constructed using the forwarding construct() helper:

    auto widget = GWidget::construct(parent_widget);

Note that construct() simply forwards all arguments to an existing
constructor. It is inserted into each class by the C_OBJECT macro,
see CObject.h to understand how that works.

CObject::delete_later() disappears in this patch, as there is no longer
a single logical owner of a CObject.
This commit is contained in:
Andreas Kling 2019-09-22 00:17:53 +02:00
parent 0c72e0c09f
commit bc319d9e88
45 changed files with 174 additions and 233 deletions

View file

@ -49,22 +49,22 @@ namespace Server {
};
template<typename T, class... Args>
T* new_connection_for_client(Args&&... args)
NonnullRefPtr<T> new_connection_for_client(Args&&... args)
{
auto conn = new T(AK::forward<Args>(args)...) /* arghs */;
auto conn = T::construct(forward<Args>(args)...);
conn->send_greeting();
return conn;
}
template<typename T, class... Args>
T* new_connection_ng_for_client(Args&&... args)
NonnullRefPtr<T> new_connection_ng_for_client(Args&&... args)
{
return new T(AK::forward<Args>(args)...) /* arghs */;
return T::construct(forward<Args>(args)...) /* arghs */;
}
template<typename ServerMessage, typename ClientMessage>
class Connection : public CObject {
public:
protected:
Connection(CLocalSocket& socket, int client_id)
: m_socket(socket)
, m_client_id(client_id)
@ -76,6 +76,7 @@ namespace Server {
#endif
}
public:
~Connection()
{
#if defined(CIPC_DEBUG)
@ -108,14 +109,12 @@ namespace Server {
switch (errno) {
case EPIPE:
dbgprintf("Connection::post_message: Disconnected from peer.\n");
delete_later();
shutdown();
return;
break;
case EAGAIN:
dbgprintf("Connection::post_message: Client buffer overflowed.\n");
did_misbehave();
return;
break;
default:
perror("Connection::post_message writev");
ASSERT_NOT_REACHED();
@ -134,7 +133,6 @@ namespace Server {
ssize_t nread = recv(m_socket->fd(), &message, sizeof(ClientMessage), MSG_DONTWAIT);
if (nread == 0 || (nread == -1 && errno == EAGAIN)) {
if (!messages_received) {
// TODO: is delete_later() sufficient?
CEventLoop::current().post_event(*this, make<DisconnectedEvent>(client_id()));
}
break;
@ -171,8 +169,13 @@ namespace Server {
void did_misbehave()
{
dbgprintf("Connection{%p} (id=%d, pid=%d) misbehaved, disconnecting.\n", this, client_id(), m_client_pid);
shutdown();
}
void shutdown()
{
m_socket->close();
delete_later();
die();
}
int client_id() const { return m_client_id; }
@ -182,13 +185,15 @@ namespace Server {
// ### having this public is sad
virtual void send_greeting() = 0;
virtual void die() = 0;
protected:
void event(CEvent& event)
{
if (event.type() == Event::Disconnected) {
int client_id = static_cast<const DisconnectedEvent&>(event).client_id();
dbgprintf("Connection: Client disconnected: %d\n", client_id);
delete this;
die();
return;
}
@ -228,13 +233,12 @@ namespace Server {
switch (errno) {
case EPIPE:
dbg() << "Connection::post_message: Disconnected from peer";
delete_later();
shutdown();
return;
case EAGAIN:
dbg() << "Connection::post_message: Client buffer overflowed.";
did_misbehave();
return;
break;
default:
perror("Connection::post_message write");
ASSERT_NOT_REACHED();
@ -252,7 +256,6 @@ namespace Server {
ssize_t nread = recv(m_socket->fd(), buffer, sizeof(buffer), MSG_DONTWAIT);
if (nread == 0 || (nread == -1 && errno == EAGAIN)) {
if (!messages_received) {
// TODO: is delete_later() sufficient?
CEventLoop::current().post_event(*this, make<DisconnectedEvent>(client_id()));
}
break;
@ -278,21 +281,28 @@ namespace Server {
void did_misbehave()
{
dbg() << "Connection{" << this << "} (id=" << m_client_id << ", pid=" << m_client_pid << ") misbehaved, disconnecting.";
shutdown();
}
void shutdown()
{
m_socket->close();
delete_later();
die();
}
int client_id() const { return m_client_id; }
pid_t client_pid() const { return m_client_pid; }
void set_client_pid(pid_t pid) { m_client_pid = pid; }
virtual void die() = 0;
protected:
void event(CEvent& event) override
{
if (event.type() == Event::Disconnected) {
int client_id = static_cast<const DisconnectedEvent&>(event).client_id();
dbgprintf("Connection: Client disconnected: %d\n", client_id);
delete this;
die();
return;
}