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149 lines
3.2 KiB
C
149 lines
3.2 KiB
C
/*
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* A type which wraps a pipe handle in message oriented mode
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*
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* pipe_connection.c
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*
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* Copyright (c) 2006-2008, R Oudkerk --- see COPYING.txt
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*/
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#include "multiprocessing.h"
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#define CLOSE(h) CloseHandle(h)
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/*
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* Send string to the pipe; assumes in message oriented mode
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*/
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static Py_ssize_t
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conn_send_string(ConnectionObject *conn, char *string, size_t length)
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{
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DWORD amount_written;
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BOOL ret;
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Py_BEGIN_ALLOW_THREADS
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ret = WriteFile(conn->handle, string, length, &amount_written, NULL);
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Py_END_ALLOW_THREADS
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if (ret == 0 && GetLastError() == ERROR_NO_SYSTEM_RESOURCES) {
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PyErr_Format(PyExc_ValueError, "Cannnot send %" PY_FORMAT_SIZE_T "d bytes over connection", length);
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return MP_STANDARD_ERROR;
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}
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return ret ? MP_SUCCESS : MP_STANDARD_ERROR;
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}
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/*
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* Attempts to read into buffer, or if buffer too small into *newbuffer.
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*
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* Returns number of bytes read. Assumes in message oriented mode.
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*/
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static Py_ssize_t
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conn_recv_string(ConnectionObject *conn, char *buffer,
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size_t buflength, char **newbuffer, size_t maxlength)
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{
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DWORD left, length, full_length, err;
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BOOL ret;
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*newbuffer = NULL;
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Py_BEGIN_ALLOW_THREADS
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ret = ReadFile(conn->handle, buffer, MIN(buflength, maxlength),
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&length, NULL);
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Py_END_ALLOW_THREADS
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if (ret)
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return length;
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err = GetLastError();
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if (err != ERROR_MORE_DATA) {
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if (err == ERROR_BROKEN_PIPE)
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return MP_END_OF_FILE;
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return MP_STANDARD_ERROR;
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}
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if (!PeekNamedPipe(conn->handle, NULL, 0, NULL, NULL, &left))
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return MP_STANDARD_ERROR;
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full_length = length + left;
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if (full_length > maxlength)
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return MP_BAD_MESSAGE_LENGTH;
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*newbuffer = PyMem_Malloc(full_length);
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if (*newbuffer == NULL)
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return MP_MEMORY_ERROR;
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memcpy(*newbuffer, buffer, length);
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Py_BEGIN_ALLOW_THREADS
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ret = ReadFile(conn->handle, *newbuffer+length, left, &length, NULL);
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Py_END_ALLOW_THREADS
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if (ret) {
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assert(length == left);
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return full_length;
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} else {
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PyMem_Free(*newbuffer);
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return MP_STANDARD_ERROR;
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}
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}
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/*
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* Check whether any data is available for reading
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*/
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static int
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conn_poll(ConnectionObject *conn, double timeout, PyThreadState *_save)
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{
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DWORD bytes, deadline, delay;
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int difference, res;
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BOOL block = FALSE;
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if (!PeekNamedPipe(conn->handle, NULL, 0, NULL, &bytes, NULL))
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return MP_STANDARD_ERROR;
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if (timeout == 0.0)
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return bytes > 0;
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if (timeout < 0.0)
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block = TRUE;
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else
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/* XXX does not check for overflow */
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deadline = GetTickCount() + (DWORD)(1000 * timeout + 0.5);
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Sleep(0);
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for (delay = 1 ; ; delay += 1) {
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if (!PeekNamedPipe(conn->handle, NULL, 0, NULL, &bytes, NULL))
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return MP_STANDARD_ERROR;
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else if (bytes > 0)
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return TRUE;
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if (!block) {
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difference = deadline - GetTickCount();
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if (difference < 0)
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return FALSE;
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if ((int)delay > difference)
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delay = difference;
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}
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if (delay > 20)
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delay = 20;
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Sleep(delay);
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/* check for signals */
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Py_BLOCK_THREADS
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res = PyErr_CheckSignals();
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Py_UNBLOCK_THREADS
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if (res)
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return MP_EXCEPTION_HAS_BEEN_SET;
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}
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}
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/*
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* "connection.h" defines the PipeConnection type using the definitions above
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*/
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#define CONNECTION_NAME "PipeConnection"
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#define CONNECTION_TYPE PipeConnectionType
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#include "connection.h"
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