diff options
Diffstat (limited to 'Modules/_multiprocessing/socket_connection.c')
-rw-r--r-- | Modules/_multiprocessing/socket_connection.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/Modules/_multiprocessing/socket_connection.c b/Modules/_multiprocessing/socket_connection.c new file mode 100644 index 0000000..a6ff9dd --- /dev/null +++ b/Modules/_multiprocessing/socket_connection.c @@ -0,0 +1,180 @@ +/* + * A type which wraps a socket + * + * socket_connection.c + * + * Copyright (c) 2006-2008, R Oudkerk --- see COPYING.txt + */ + +#include "multiprocessing.h" + +#ifdef MS_WINDOWS +# define WRITE(h, buffer, length) send((SOCKET)h, buffer, length, 0) +# define READ(h, buffer, length) recv((SOCKET)h, buffer, length, 0) +# define CLOSE(h) closesocket((SOCKET)h) +#else +# define WRITE(h, buffer, length) write(h, buffer, length) +# define READ(h, buffer, length) read(h, buffer, length) +# define CLOSE(h) close(h) +#endif + +/* + * Send string to file descriptor + */ + +static Py_ssize_t +_conn_sendall(HANDLE h, char *string, size_t length) +{ + char *p = string; + Py_ssize_t res; + + while (length > 0) { + res = WRITE(h, p, length); + if (res < 0) + return MP_SOCKET_ERROR; + length -= res; + p += res; + } + + return MP_SUCCESS; +} + +/* + * Receive string of exact length from file descriptor + */ + +static Py_ssize_t +_conn_recvall(HANDLE h, char *buffer, size_t length) +{ + size_t remaining = length; + Py_ssize_t temp; + char *p = buffer; + + while (remaining > 0) { + temp = READ(h, p, remaining); + if (temp <= 0) { + if (temp == 0) + return remaining == length ? + MP_END_OF_FILE : MP_EARLY_END_OF_FILE; + else + return temp; + } + remaining -= temp; + p += temp; + } + + return MP_SUCCESS; +} + +/* + * Send a string prepended by the string length in network byte order + */ + +static Py_ssize_t +conn_send_string(ConnectionObject *conn, char *string, size_t length) +{ + /* The "header" of the message is a 32 bit unsigned number (in + network order) which specifies the length of the "body". If + the message is shorter than about 16kb then it is quicker to + combine the "header" and the "body" of the message and send + them at once. */ + if (length < (16*1024)) { + char *message; + int res; + + message = PyMem_Malloc(length+4); + if (message == NULL) + return MP_MEMORY_ERROR; + + *(UINT32*)message = htonl((UINT32)length); + memcpy(message+4, string, length); + res = _conn_sendall(conn->handle, message, length+4); + PyMem_Free(message); + return res; + } else { + UINT32 lenbuff; + + if (length > MAX_MESSAGE_LENGTH) + return MP_BAD_MESSAGE_LENGTH; + + lenbuff = htonl((UINT32)length); + return _conn_sendall(conn->handle, (char*)&lenbuff, 4) || + _conn_sendall(conn->handle, string, length); + } +} + +/* + * Attempts to read into buffer, or failing that into *newbuffer + * + * Returns number of bytes read. + */ + +static Py_ssize_t +conn_recv_string(ConnectionObject *conn, char *buffer, + size_t buflength, char **newbuffer, size_t maxlength) +{ + int res; + UINT32 ulength; + + *newbuffer = NULL; + + res = _conn_recvall(conn->handle, (char*)&ulength, 4); + if (res < 0) + return res; + + ulength = ntohl(ulength); + if (ulength > maxlength) + return MP_BAD_MESSAGE_LENGTH; + + if (ulength <= buflength) { + res = _conn_recvall(conn->handle, buffer, (size_t)ulength); + return res < 0 ? res : ulength; + } else { + *newbuffer = PyMem_Malloc((size_t)ulength); + if (*newbuffer == NULL) + return MP_MEMORY_ERROR; + res = _conn_recvall(conn->handle, *newbuffer, (size_t)ulength); + return res < 0 ? (Py_ssize_t)res : (Py_ssize_t)ulength; + } +} + +/* + * Check whether any data is available for reading -- neg timeout blocks + */ + +static int +conn_poll(ConnectionObject *conn, double timeout) +{ + int res; + fd_set rfds; + + FD_ZERO(&rfds); + FD_SET((SOCKET)conn->handle, &rfds); + + if (timeout < 0.0) { + res = select((int)conn->handle+1, &rfds, NULL, NULL, NULL); + } else { + struct timeval tv; + tv.tv_sec = (long)timeout; + tv.tv_usec = (long)((timeout - tv.tv_sec) * 1e6 + 0.5); + res = select((int)conn->handle+1, &rfds, NULL, NULL, &tv); + } + + if (res < 0) { + return MP_SOCKET_ERROR; + } else if (FD_ISSET(conn->handle, &rfds)) { + return TRUE; + } else { + assert(res == 0); + return FALSE; + } +} + +/* + * "connection.h" defines the Connection type using defs above + */ + +#define CONNECTION_NAME "Connection" +#define CONNECTION_TYPE ConnectionType + +#include "connection.h" |