scope: refuse `&x` where x is a local variable

[nit.git] / lib / socket / socket_c.nit

# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Copyright 2013 Matthieu Lucas <lucasmatthieu@gmail.com>
#
# 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
#
#     http://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.

# Low-level socket functionalities
module socket_c

in "C Header" `{
        #include <stdio.h>
        #include <stdlib.h>
        #include <unistd.h>
        #include <string.h>
        #include <sys/socket.h>
        #include <sys/types.h>
        #include <netinet/in.h>
        #include <arpa/inet.h>
        #include <netdb.h>
        #include <sys/poll.h>
`}

in "C" `{
        #include <fcntl.h>
        #include <netinet/tcp.h>
`}

# Wrapper for the data structure used for polling on a socket
class PollFD
        super FinalizableOnce

        # The PollFD object
        private var poll_struct: NativeSocketPollFD

        # A collection of the events to be watched
        var events: Array[NativeSocketPollValues]

        # Create a PollFD object from NativePollFD informations
        init from_poll_values(pid: Int, events: Array[NativeSocketPollValues])
        do
                assert events.length >= 1

                var events_in_one = events[0]

                for i in [1 .. events.length - 1] do
                        events_in_one += events[i]
                end

                var poll_struct = new NativeSocketPollFD(pid, events_in_one)

                init(poll_struct, events)
        end

        # Reads the response and returns an array with the type of events that have been found
        private fun check_response(response: Int): Array[NativeSocketPollValues]
        do
                var resp_array = new Array[NativeSocketPollValues]
                for i in events do
                        if c_check_resp(response, i) != 0 then
                                resp_array.push(i)
                        end
                end
                return resp_array
        end

        # Checks if the poll call has returned true for a particular type of event
        private fun c_check_resp(response: Int, mask: NativeSocketPollValues): Int
        `{
                return response & mask;
        `}

        redef fun finalize_once
        do
                poll_struct.free
        end
end

# Data structure used by the poll function
private extern class NativeSocketPollFD `{ struct pollfd * `}

        # File descriptor
        fun fd: Int `{ return self->fd; `}

        # List of events to be watched
        fun events: Int `{ return self->events; `}

        # List of events received by the last poll function
        fun revents: Int `{  return self->revents; `}

        new (pid: Int, events: NativeSocketPollValues) `{
                struct pollfd *poll = malloc(sizeof(struct pollfd));
                poll->fd = pid;
                poll->events = events;
                return poll;
        `}
end

# Native C socket
extern class NativeSocket `{ int* `}

        # Create a new C socket
        new socket(domain: NativeSocketAddressFamilies, socketType: NativeSocketTypes, protocol: NativeSocketProtocolFamilies) `{
                int ds = socket(domain, socketType, protocol);
                if(ds == -1){
                        return NULL;
                }
                int *d = malloc(sizeof(int));
                memcpy(d, &ds, sizeof(ds));
                return d;
        `}

        # Free the socket
        fun destroy `{ free(self); `}

        # Close the socket in both read/write
        fun close: Int `{ return close(*self); `}

        # Get the FD related to `self`
        fun descriptor: Int `{ return *self; `}

        # Connect to another open socket
        #
        # SEE: C documentation for more details on the `connect` operation
        fun connect(addrIn: NativeSocketAddrIn): Int `{
                return connect(*self, (struct sockaddr*)addrIn, sizeof(*addrIn));
        `}

        # Write `length` bytes from `buffer`
        fun write(buffer: CString, length: Int): Int `{
                return write(*self, buffer, length);
        `}

        # Write `value` as a single byte
        fun write_byte(value: Int): Int `{
                unsigned char byt = (unsigned char)value;
                return write(*self, &byt, 1);
        `}

        # Read `length` bytes into `buffer`, returns the number of bytes read
        fun read(buffer: CString, length: Int): Int `{
                return read(*self, buffer, length);
        `}

        # Sets an option for the socket
        #
        # Returns `true` on success.
        fun setsockopt(level: NativeSocketOptLevels, option_name: NativeSocketOptNames, option_value: Int): Bool `{
                int err = setsockopt(*self, level, option_name, &option_value, sizeof(int));
                if(err != 0){
                        return 0;
                }
                return 1;
        `}

        # Bind the socket to a local address
        #
        # SEE: C documentation for more details on the bind operation
        fun bind(addrIn: NativeSocketAddrIn): Int `{ return bind(*self, (struct sockaddr*)addrIn, sizeof(*addrIn)); `}

        # Prepare for listening to incoming connections
        fun listen(size: Int): Int `{ return listen(*self, size); `}

        # Checks if the buffer is ready for any event specified when creating the pollfd structure
        fun socket_poll(filedesc: PollFD, timeout: Int): Array[NativeSocketPollValues]
        do
                var result = native_poll(filedesc.poll_struct, timeout)
                assert result != -1
                return filedesc.check_response(result)
        end

        # Poll this socket with `POLLHUP|POLLERR`
        #
        # A return value of 0 means there is no errors.
        fun poll_hup_err: Int `{
                struct pollfd fd = {*self, POLLHUP|POLLERR, 0};
                int res = poll(&fd, 1, 0);
                return res;
        `}

        # Call to the poll function of the C socket
        #
        # Signature:
        # int poll(struct pollfd fds[], nfds_t nfds, int timeout);
        #
        # Official documentation of the poll function:
        #
        # The poll() function provides applications with a mechanism for multiplexing input/output over a set of file descriptors.
        # For each member of the array pointed to by fds, poll() shall examine the given file descriptor for the event(s) specified in events.
        # The number of pollfd structures in the fds array is specified by nfds.
        # The poll() function shall identify those file descriptors on which an application can read or write data, or on which certain events have occurred.
        # The fds argument specifies the file descriptors to be examined and the events of interest for each file descriptor.
        # It is a pointer to an array with one member for each open file descriptor of interest.
        # The array's members are pollfd structures within which fd specifies an open file descriptor and events and revents are bitmasks constructed by
        # OR'ing a combination of the pollfd flags.
        private fun native_poll(filedesc: NativeSocketPollFD, timeout: Int): Int `{
                int poll_return = poll(filedesc, 1, timeout);
                return poll_return;
        `}

        private fun native_accept(addr_in: NativeSocketAddrIn): NativeSocket `{
                socklen_t s = sizeof(struct sockaddr);
                int socket = accept(*self, (struct sockaddr*)addr_in, &s);
                if (socket == -1) return NULL;

                int *ptr = malloc(sizeof(int));
                *ptr = socket;
                return ptr;
        `}

        # Accept a new connection on `self`
        #
        # Require the socket to be first bound and listening for connections
        fun accept: nullable SocketAcceptResult
        do
                var addrIn = new NativeSocketAddrIn
                var s = native_accept(addrIn)
                if s.address_is_null then return null
                return new SocketAcceptResult(s, addrIn)
        end

        # Set whether this socket is non blocking
        fun non_blocking=(value: Bool) `{
                int flags = fcntl(*self, F_GETFL, 0);
                if (flags == -1) flags = 0;

                if (value) {
                        flags = flags | O_NONBLOCK;
                } else if (flags & O_NONBLOCK) {
                        flags = flags - O_NONBLOCK;
                } else {
                        return;
                }
                fcntl(*self, F_SETFL, flags);
        `}

        # Send `len` bytes from `buf` to `dest_addr`
        fun sendto(buf: CString, len: Int, flags: Int, dest_addr: NativeSocketAddrIn): Int `{
                return sendto(*self, buf, len, flags, (struct sockaddr*)dest_addr, sizeof(struct sockaddr_in));
        `}

        # Receive a message into `buf` of maximum `len` bytes
        fun recv(buf: CString, len: Int, flags: Int): Int `{
                return recv(*self, buf, len, flags);
        `}

        # Receive a message into `buf` of maximum `len` bytes and store sender info into `src_addr`
        fun recvfrom(buf: CString, len: Int, flags: Int, src_addr: NativeSocketAddrIn): Int `{
                socklen_t srclen = sizeof(struct sockaddr_in);
                return recvfrom(*self, buf, len, flags, (struct sockaddr*)src_addr, &srclen);
        `}
end

# Result of a call to `NativeSocket::accept`
class SocketAcceptResult

        # Opened socket
        var socket: NativeSocket

        # Address of the remote client
        var addr_in: NativeSocketAddrIn
end

# Socket address in the Internet namespace, pointer to a `struct sockaddr_in`
extern class NativeSocketAddrIn `{ struct sockaddr_in* `}

        # `NULL` pointer
        new nul `{ return NULL; `}

        # `malloc` a new instance
        new `{
                struct sockaddr_in *sai = NULL;
                sai = malloc(sizeof(struct sockaddr_in));
                return sai;
        `}

        # Set `address` and `family` from `hostent` (to use with `Sys::gethostbyname`)
        fun fill_from_hostent(hostent: NativeSocketHostent) `{
                self->sin_family = hostent->h_addrtype;
                memcpy((char*)&self->sin_addr.s_addr,
                       (char*)hostent->h_addr,
                           hostent->h_length);
        `}

        # Internet address as then IPV4 numbers-and-dots notation
        fun address: CString `{ return (char*)inet_ntoa(self->sin_addr); `}

        # Set `address` to `INADDR_ANY`
        fun address_any `{ self->sin_addr.s_addr = INADDR_ANY; `}

        # Set `address` to `INADDR_BROADCAST`
        fun address_broadcast `{ self->sin_addr.s_addr = INADDR_BROADCAST; `}

        # Address family
        fun family: NativeSocketAddressFamilies `{ return self->sin_family; `}

        # Address family
        fun family=(value: NativeSocketAddressFamilies) `{ self->sin_family = value; `}

        # Port
        fun port: Int `{ return ntohs(self->sin_port); `}

        # Port
        fun port=(value: Int) `{ self->sin_port = htons(value); `}
end

# Host entry information, a pointer to a `struct hostent`
extern class NativeSocketHostent `{ struct hostent* `}
        private fun native_h_aliases(i: Int): CString `{
                return self->h_aliases[i];
        `}

        # Alternative names for the host
        fun h_aliases: Array[String]
        do
                var res = new Array[String]
                loop
                        var ha = native_h_aliases(res.length)
                        if ha.address_is_null then break
                        res.add ha.to_s
                end
                return res
        end

        # Host IPv4 address
        fun h_addr: CString `{
                return (char*)inet_ntoa(*(struct in_addr*)self->h_addr);
        `}

        # Host address type
        fun h_addrtype: Int `{ return self->h_addrtype; `}

        # Length in bytes of the addresses
        fun h_length: Int `{ return self->h_length; `}

        # Host name
        fun h_name: CString `{ return self->h_name; `}
end

# Time structure, with a microsecond resolution
extern class NativeTimeval `{ struct timeval* `}
        new (seconds: Int, microseconds: Int) `{
                struct timeval* tv = NULL;
                tv = malloc(sizeof(struct timeval));
                tv->tv_sec = seconds;
                tv->tv_usec = microseconds;
                return tv;
        `}

        # Number of seconds recorded
        fun seconds: Int `{ return self->tv_sec; `}

        # Number of microseconds recorded
        fun microseconds: Int `{ return self->tv_usec; `}

        # Destory `self`
        fun destroy `{ free(self); `}
end

# Structure used to register FDs for a Select
#
# FIXME: This should not be Socket-specific
# FIXME: This is Unix-specific
extern class NativeSocketSet `{ fd_set* `}
        new `{
                fd_set *f = NULL;
                f = malloc(sizeof(fd_set));
                return f;
        `}

        # Add a file descriptor to the set
        fun set(s: NativeSocket) `{ FD_SET(*s, self); `}

        # Check if `s` is in the set
        fun is_set(s: NativeSocket): Bool `{ return FD_ISSET(*s, self); `}

        # Clear the set
        fun zero `{ FD_ZERO(self); `}

        # Remove `s` from the set
        fun clear(s: NativeSocket) `{ FD_CLR(*s, self); `}

        # Free the set
        fun destroy `{ free(self); `}
end

# Socket observer
class NativeSocketObserver
        # FIXME this implementation is broken. `reads`, `write` and `except`
        # are boxed objects, passing them to a C function is illegal.
        fun select(max: NativeSocket, reads: nullable NativeSocketSet, write: nullable NativeSocketSet,
                         except: nullable NativeSocketSet, timeout: NativeTimeval): Int `{
                fd_set *rds = NULL,
                       *wts = NULL,
                       *exs = NULL;
                struct timeval *tm = NULL;
                if (reads != NULL) rds = (fd_set*)reads;
                if (write != NULL) wts = (fd_set*)write;
                if (except != NULL) exs = (fd_set*)except;
                if (timeout != NULL) tm = (struct timeval*)timeout;
                return select(*max, rds, wts, exs, tm);
        `}
end

# Socket types
extern class NativeSocketTypes `{ int `}
        # STREAM socket, used for sequential writes/reads
        new sock_stream `{ return SOCK_STREAM; `}
        # DGRAM socket, used for packet-oriented communication
        new sock_dgram `{ return SOCK_DGRAM; `}
        # RAW socket, access raw data, without it being handled by the IP stack
        new sock_raw `{ return SOCK_RAW; `}
        # SEQPACKET, packet-oriented communication with guarantees in packet order
        new sock_seqpacket `{ return SOCK_SEQPACKET; `}
end

# Socket families
extern class NativeSocketAddressFamilies `{ int `}
        # Unspecified
        new af_unspec `{ return AF_UNSPEC; `}

        # Local to host (pipes)
        new af_unix `{ return AF_UNIX; `}

        # For backward compatibility
        new af_local `{ return AF_LOCAL; `}

        # Internetwork: UDP, TCP, etc.
        new af_inet `{ return AF_INET; `}

        # IBM SNA
        new af_sna `{ return AF_SNA; `}

        # DECnet
        new af_decnet `{ return AF_DECnet; `}

        # Internal Routing Protocol
        new af_route `{ return AF_ROUTE; `}

        # Novell Internet Protocol
        new af_ipx `{ return AF_IPX; `}

        # IPv6
        new af_inet6 `{ return AF_INET6; `}

        # Maximum identifier for socket families
        new af_max `{ return AF_MAX; `}
end

# Socket protocol families
extern class NativeSocketProtocolFamilies `{ int `}
        # Unspecified
        new pf_unspec `{ return PF_UNSPEC; `}

        # Local socket
        new pf_local `{ return PF_LOCAL; `}

        # Unix socket
        new pf_unix `{ return PF_UNIX; `}

        # Internet (IPv4) socket
        new pf_inet `{ return PF_INET; `}

        # SNA (IBM) socket
        new pf_sna `{ return PF_SNA; `}

        # DECnet socket
        new pf_decnet `{ return PF_DECnet; `}

        # Routing tables control
        new pf_route `{ return PF_ROUTE; `}

        # Novell internet protocol
        new pf_ipx `{ return PF_IPX; `}

        # Key management protocol
        new pf_key `{ return PF_KEY; `}

        # Internet (IPv6) socket
        new pf_inet6 `{ return PF_INET6; `}

        # Maximum identifier for socket families
        new pf_max `{ return PF_MAX; `}
end

# Level on which to set options
extern class NativeSocketOptLevels `{ int `}

        # Dummy for IP (As defined in C)
        new ip `{ return IPPROTO_IP;`}

        # Control message protocol
        new icmp `{ return IPPROTO_ICMP;`}

        # Use TCP
        new tcp `{ return IPPROTO_TCP; `}

        # Socket level options
        new socket `{ return SOL_SOCKET; `}
end

# Options for socket, use with setsockopt
extern class NativeSocketOptNames `{ int `}

        # Enables debugging information
        new debug `{ return SO_DEBUG; `}

        # Authorizes the broadcasting of messages
        new broadcast `{ return SO_BROADCAST; `}

        # Authorizes the reuse of the local address
        new reuseaddr `{ return SO_REUSEADDR; `}

        # Authorizes the use of keep-alive packets in a connection
        new keepalive `{ return SO_KEEPALIVE; `}

        # Disable the Nagle algorithm and send data as soon as possible, in smaller packets
        new tcp_nodelay `{ return TCP_NODELAY; `}
end

# Used for the poll function of a socket, mix several Poll values to check for events on more than one type of event
extern class NativeSocketPollValues `{ int `}

        # Data other than high-priority data may be read without blocking.
        new pollin `{ return POLLIN; `}

        # Normal data may be read without blocking.
        new pollrdnorm `{ return POLLRDNORM; `}

        # Priority data may be read without blocking.
        new pollrdband `{ return POLLRDBAND; `}

        # High-priority data may be read without blocking.
        new pollpri `{ return POLLPRI; `}

        # Normal data may be written without blocking.
        new pollout `{ return POLLOUT; `}

        # Equivalent to POLLOUT
        new pollwrnorm `{ return POLLWRNORM; `}

        # Priority data may be written.
        new pollwrband `{ return POLLWRBAND; `}

        # An error has occurred on the device or stream.
        #
        # This flag is only valid in the revents bitmask; it shall be ignored in the events member.
        new pollerr `{ return POLLERR; `}

        # The device has been disconnected.
        #
        # This event and POLLOUT are mutually-exclusive; a stream can never be
        # writable if a hangup has occurred. However, this event and POLLIN,
        # POLLRDNORM, POLLRDBAND, or POLLPRI are not mutually-exclusive.
        #
        # This flag is only valid in the revents bitmask; it shall be ignored in the events member.
        new pollhup `{ return POLLHUP; `}

        # The specified fd value is invalid.
        #
        # This flag is only valid in the revents member; it shall ignored in the events member.
        new pollnval `{ return POLLNVAL; `}

        # Combines two NativeSocketPollValues
        private fun +(other: NativeSocketPollValues): NativeSocketPollValues `{
                return self | other;
        `}
end

redef class Sys
        # Get network host entry
        fun gethostbyname(name: CString): NativeSocketHostent `{
                return gethostbyname(name);
        `}

        # Last error raised by `gethostbyname`
        fun h_errno: HErrno `{ return h_errno; `}
end

# Error code of `Sys::h_errno`
extern class HErrno `{ int `}
        # The specified host is unknown
        fun host_not_found: Bool `{ return self == HOST_NOT_FOUND; `}

        # The requested name is valid but does not have an IP address
        #
        # Same as `no_data`.
        fun no_address: Bool `{ return self == NO_ADDRESS; `}

        # The requested name is valid byt does not have an IP address
        #
        # Same as `no_address`.
        fun no_data: Bool `{ return self == NO_DATA; `}

        # A nonrecoverable name server error occurred
        fun no_recovery: Bool `{ return self == NO_RECOVERY; `}

        # A temporary error occurred on an authoritative name server, try again later
        fun try_again: Bool `{ return self == TRY_AGAIN; `}

        redef fun to_s
        do
                if host_not_found then
                        return "The specified host is unknown"
                else if no_address then
                        return "The requested name is valid but does not have an IP address"
                else if no_recovery then
                        return "A nonrecoverable name server error occurred"
                else if try_again then
                        return "A temporary error occurred on an authoritative name server, try again later"
                else
                        # This may happen if another call was made to `gethostbyname`
                        # before we fetch the error code.
                        return "Unknown error on `gethostbyname`"
                end
        end
end