/usr/include/pqxx/notification.hxx is in libpqxx-dev 4.0.1+dfsg3-8.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 | /*-------------------------------------------------------------------------
*
* FILE
* pqxx/notification.hxx
*
* DESCRIPTION
* definition of the pqxx::notification_receiver functor interface.
* pqxx::notification_receiver handles incoming notifications.
* DO NOT INCLUDE THIS FILE DIRECTLY; include pqxx/notification instead.
*
* Copyright (c) 2011, Jeroen T. Vermeulen <jtv@xs4all.nl>
*
* See COPYING for copyright license. If you did not receive a file called
* COPYING with this source code, please notify the distributor of this mistake,
* or contact the author.
*
*-------------------------------------------------------------------------
*/
#ifndef PQXX_H_NOTIFICATION
#define PQXX_H_NOTIFICATION
#include "pqxx/compiler-public.hxx"
#include "pqxx/compiler-internal-pre.hxx"
namespace pqxx
{
class connection_base;
/// "Observer" base class for notifications.
/** @addtogroup notification Notifications and Receivers
*
* To listen on a notification issued using the NOTIFY command, derive your own
* class from notification_receiver and define its function-call operator to
* perform whatever action you wish to take when the given notification arrives.
* Then create an object of that class and pass it to your connection. DO NOT
* use raw SQL to listen for notifications, or your attempts to listen won't be
* resumed when a connection fails--and you'll have no way to notice.
*
* Notifications never arrive inside a transaction, not even in a
* nontransaction. Therefore, you are free to open a transaction of your own
* inside your receiver's function invocation operator.
*
* Notifications you are listening for may arrive anywhere within libpqxx code,
* but be aware that @b PostgreSQL @b defers @b notifications @b occurring
* @b inside @b transactions. (This was done for excellent reasons; just think
* about what happens if the transaction where you happen to handle an incoming
* notification is later rolled back for other reasons). So if you're keeping a
* transaction open, don't expect any of your receivers on the same connection
* to be notified.
*
* (For very similar reasons, outgoing notifications are also not sent until the
* transaction that sends them commits.)
*
* Multiple receivers on the same connection may listen on a notification of the
* same name. An incoming notification is processed by invoking all receivers
* (zero or more) of the same name.
*/
class PQXX_LIBEXPORT PQXX_NOVTABLE notification_receiver :
public PGSTD::binary_function<const PGSTD::string &, int, void>
{
public:
/// Register the receiver with a connection.
/**
* @param c Connnection to operate on.
* @param channel Name of the notification to listen for.
*/
notification_receiver(connection_base &c, const PGSTD::string &channel);
virtual ~notification_receiver();
/// The channel that this receiver listens on.
const PGSTD::string &channel() const { return m_channel; }
/// Overridable: action to invoke when notification arrives.
/**
* @param payload On PostgreSQL 9.0 or later, an optional string that may have
* been passed to the NOTIFY command.
* @param backend_pid Process ID of the database backend process that served
* our connection when the notification arrived. The actual process ID behind
* the connection may have changed by the time this method is called.
*/
virtual void operator()(const PGSTD::string &payload, int backend_pid) =0;
protected:
connection_base &conn() const throw () { return m_conn; }
private:
// Not allowed.
notification_receiver(const notification_receiver &);
// Not allowed.
notification_receiver &operator=(const notification_receiver &);
connection_base &m_conn;
PGSTD::string m_channel;
};
}
#include "pqxx/compiler-internal-pre.hxx"
#include "pqxx/compiler-internal-post.hxx"
#endif
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