mspdebug/ui/input_async.c

183 lines
4.4 KiB
C

/* MSPDebug - debugging tool for MSP430 MCUs
* Copyright (C) 2009-2012 Daniel Beer
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include "input_async.h"
#include "util.h"
#include "ctrlc.h"
#include "thread.h"
#define MAX_LINE_LENGTH 1024
/* Mailbox state machine works as follows:
*
* BLOCKED: no data is requested by the main thread. The only
* transition from this state is to RECEIVING at the request of the
* main thread.
*
* RECEIVING: main thread is waiting for data. Reader thread may
* change state to either READY or EOF.
*
* READY: a line of text is ready to be picked up from the mailbox.
* The only transitions are to either BLOCKED or RECEIVING, at the
* request of the main thread.
*
* EOF: end of input. No transitions from this state.
*/
typedef enum {
STATE_BLOCKED,
STATE_RECEIVING,
STATE_READY,
STATE_EOF
} mailbox_state_t;
struct mailbox {
thread_lock_t lock;
thread_cond_t cond;
mailbox_state_t state;
char text[MAX_LINE_LENGTH];
};
static struct mailbox linebox;
static void handle_special(const char *text)
{
if (!strcmp(text, "break"))
ctrlc_raise();
}
static void handle_command(const char *text)
{
/* Deliver the command to the mailbox if it's receiving. */
thread_lock_acquire(&linebox.lock);
if (linebox.state == STATE_RECEIVING) {
strncpy(linebox.text, text, sizeof(linebox.text));
linebox.text[sizeof(linebox.text) - 1] = 0;
linebox.state = STATE_READY;
}
thread_lock_release(&linebox.lock);
thread_cond_notify(&linebox.cond);
}
static void io_worker(void *thread_arg)
{
char buf[MAX_LINE_LENGTH];
(void)thread_arg;
/* Read commands from stdin and dispatch them */
while (fgets(buf, sizeof(buf), stdin)) {
int len = strlen(buf);
while (len > 0 && isspace(buf[len - 1]))
len--;
buf[len] = 0;
if (buf[0] == '\\')
handle_special(buf + 1);
else if (buf[0] == ':')
handle_command(buf + 1);
else
handle_command(buf);
}
/* Wait for the next read request and deliver EOF */
thread_lock_acquire(&linebox.lock);
while (linebox.state != STATE_RECEIVING)
thread_cond_wait(&linebox.cond, &linebox.lock);
linebox.state = STATE_EOF;
thread_lock_release(&linebox.lock);
thread_cond_notify(&linebox.cond);
}
static int async_init(void)
{
thread_t thr;
thread_lock_init(&linebox.lock);
thread_cond_init(&linebox.cond);
linebox.state = STATE_BLOCKED;
if (thread_create(&thr, io_worker, NULL) < 0) {
fprintf(stderr, "async_init: failed to "
"start reader thread: %s\n", last_error());
return -1;
}
return 0;
}
static void async_exit(void) { }
static int async_read_command(char *buf, int max_len)
{
/* Upon entry to this function, the mailbox is either in the
* BLOCKED or EOF state. First, put us into the receiving
* state.
*/
thread_lock_acquire(&linebox.lock);
if (linebox.state == STATE_EOF) {
thread_lock_release(&linebox.lock);
return 1;
}
linebox.state = STATE_RECEIVING;
thread_lock_release(&linebox.lock);
thread_cond_notify(&linebox.cond);
/* Now wait for the reader thread to change the mailbox state to
* either READY or EOF.
*/
thread_lock_acquire(&linebox.lock);
while (linebox.state == STATE_RECEIVING)
thread_cond_wait(&linebox.cond, &linebox.lock);
if (linebox.state == STATE_EOF) {
thread_lock_release(&linebox.lock);
return 1;
}
strncpy(buf, linebox.text, max_len);
buf[max_len - 1] = 0;
linebox.state = STATE_BLOCKED;
thread_lock_release(&linebox.lock);
thread_cond_notify(&linebox.cond);
return 0;
}
static int async_prompt_abort(const char *message)
{
(void)message;
return 0;
}
const struct input_interface input_async = {
.init = async_init,
.exit = async_exit,
.read_command = async_read_command,
.prompt_abort = async_prompt_abort
};