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windows: Revise management of WaitCommEvent() operations. 

This fixes (at least parts of) bug #341.
This commit is contained in:
Martin Ling 2015-03-25 18:03:17 +00:00 committed by Uwe Hermann
parent 6c6aebe78c
commit 47fcf8ec85
2 changed files with 72 additions and 30 deletions
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1
libserialport_internal.h
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@ -109,6 +109,7 @@ struct sp_port {
DWORD events;
BYTE pending_byte;
BOOL writing;
BOOL wait_running;
#else
int fd;
#endif

101
serialport.c
View File

@ -399,6 +399,43 @@ SP_API void sp_free_port_list(struct sp_port **list)
CHECK_PORT_HANDLE(); \
} while (0)
#ifdef WIN32
/** To be called after port receive buffer is emptied. */
static enum sp_return restart_wait(struct sp_port *port)
{
DWORD wait_result;
if (port->wait_running) {
/* Check status of running wait operation. */
if (GetOverlappedResult(port->hdl, &port->wait_ovl,
&wait_result, FALSE)) {
DEBUG("Previous wait completed");
port->wait_running = FALSE;
} else if (GetLastError() == ERROR_IO_INCOMPLETE) {
DEBUG("Previous wait still running");
RETURN_OK();
} else {
RETURN_FAIL("GetOverlappedResult() failed");
}
}
if (!port->wait_running) {
/* Start new wait operation. */
if (WaitCommEvent(port->hdl, &port->events,
&port->wait_ovl)) {
DEBUG("New wait returned, events already pending");
} else if (GetLastError() == ERROR_IO_PENDING) {
DEBUG("New wait running in background");
port->wait_running = TRUE;
} else {
RETURN_FAIL("WaitCommEvent() failed");
}
}
RETURN_OK();
}
#endif
SP_API enum sp_return sp_open(struct sp_port *port, enum sp_mode flags)
{
struct port_data data;
@ -472,16 +509,15 @@ SP_API enum sp_return sp_open(struct sp_port *port, enum sp_mode flags)
RETURN_FAIL("SetCommMask() failed");
}
/* Start background operation for RX and error events. */
if (WaitCommEvent(port->hdl, &port->events, &port->wait_ovl) == 0) {
if (GetLastError() != ERROR_IO_PENDING) {
sp_close(port);
RETURN_FAIL("WaitCommEvent() failed");
}
}
port->writing = FALSE;
port->wait_running = FALSE;
ret = restart_wait(port);
if (ret < 0) {
sp_close(port);
RETURN_CODEVAL(ret);
}
#else
int flags_local = O_NONBLOCK | O_NOCTTY;
@ -623,6 +659,9 @@ SP_API enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers)
/* Returns non-zero upon success, 0 upon failure. */
if (PurgeComm(port->hdl, flags) == 0)
RETURN_FAIL("PurgeComm() failed");
if (buffers & SP_BUF_INPUT)
TRY(restart_wait(port));
#else
int flags = 0;
if (buffers == SP_BUF_BOTH)
@ -894,7 +933,8 @@ SP_API enum sp_return sp_blocking_read(struct sp_port *port, void *buf,
#ifdef _WIN32
DWORD bytes_read = 0;
DWORD wait_result = 0;
DWORD bytes_remaining;
int ret;
/* Set timeout. */
port->timeouts.ReadIntervalTimeout = 0;
@ -916,16 +956,16 @@ SP_API enum sp_return sp_blocking_read(struct sp_port *port, void *buf,
bytes_read = count;
}
/* Restart wait operation if needed. */
if (GetOverlappedResult(port->hdl, &port->wait_ovl, &wait_result, FALSE)) {
/* Previous wait completed, start a new one. */
if (WaitCommEvent(port->hdl, &port->events, &port->wait_ovl) == 0) {
if (GetLastError() != ERROR_IO_PENDING)
RETURN_FAIL("WaitCommEvent() failed");
}
} else if (GetLastError() != ERROR_IO_INCOMPLETE) {
RETURN_FAIL("GetOverlappedResult() failed");
}
ret = sp_input_waiting(port);
if (ret < 0)
RETURN_CODEVAL(ret);
bytes_remaining = ret;
/* Restart wait operation if buffer was emptied. */
if (bytes_read > 0 && bytes_remaining == 0)
TRY(restart_wait(port));
RETURN_INT(bytes_read);
@ -1005,7 +1045,8 @@ SP_API enum sp_return sp_nonblocking_read(struct sp_port *port, void *buf,
#ifdef _WIN32
DWORD bytes_read;
DWORD wait_result;
DWORD bytes_remaining;
int ret;
/* Set timeout. */
port->timeouts.ReadIntervalTimeout = MAXDWORD;
@ -1021,16 +1062,16 @@ SP_API enum sp_return sp_nonblocking_read(struct sp_port *port, void *buf,
if (GetOverlappedResult(port->hdl, &port->read_ovl, &bytes_read, TRUE) == 0)
RETURN_FAIL("GetOverlappedResult() failed");
/* Restart wait operation if needed. */
if (GetOverlappedResult(port->hdl, &port->wait_ovl, &wait_result, FALSE)) {
/* Previous wait completed, start a new one. */
if (WaitCommEvent(port->hdl, &port->events, &port->wait_ovl) == 0) {
if (GetLastError() != ERROR_IO_PENDING)
RETURN_FAIL("WaitCommEvent() failed");
}
} else if (GetLastError() != ERROR_IO_INCOMPLETE) {
RETURN_FAIL("GetOverlappedResult() failed");
}
ret = sp_input_waiting(port);
if (ret < 0)
RETURN_CODEVAL(ret);
bytes_remaining = ret;
/* Restart wait operation if buffer was emptied. */
if (bytes_read > 0 && bytes_remaining == 0)
TRY(restart_wait(port));
RETURN_INT(bytes_read);
#else