From 6416b2dac6905c1ee48df75fdf42d3f6929785db Mon Sep 17 00:00:00 2001
From: Thomas White <taw@physics.org>
Date: Sat, 19 Jun 2021 11:35:30 +0200
Subject: Basic REPL I/O

---
 src/repl-connection.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 176 insertions(+)
 create mode 100644 src/repl-connection.c

(limited to 'src/repl-connection.c')

diff --git a/src/repl-connection.c b/src/repl-connection.c
new file mode 100644
index 0000000..622e260
--- /dev/null
+++ b/src/repl-connection.c
@@ -0,0 +1,176 @@
+/*
+ * repl-connection.c
+ *
+ * Copyright © 2019-2021 Thomas White <taw@bitwiz.me.uk>
+ *
+ * This file is part of Starlet.
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <glib.h>
+#include <gio/gio.h>
+#include <gio/gunixsocketaddress.h>
+
+#include <libintl.h>
+#define _(x) gettext(x)
+
+#include "repl-connection.h"
+
+struct _replconnection
+{
+	GSocketConnection *conn;
+	char inbuf[1024];
+	char input[2048];
+};
+
+
+static char *strip_crap(const char *line_orig)
+{
+	size_t len;
+	char *line;
+	size_t outptr;
+	int i;
+	int escape_seq;
+
+	len = strlen(line_orig);
+
+	line = malloc(len+1);
+	if ( line == NULL ) return NULL;
+
+	/* Remove non-ASCII characters and ANSI escape sequences */
+	outptr = 0;
+	escape_seq = 0;
+	for ( i=0; i<len; i++ ) {
+		char ch = line_orig[i];
+		if ( (ch >= 0x1f ) && (ch < 0xff) && !escape_seq ) {
+			line[outptr++] = ch;
+		}
+		if ( ch == 0x1b ) escape_seq = 1;
+		if ( escape_seq && ch == 'm' ) escape_seq = 0;
+	}
+	line[outptr] = '\0';
+
+	return line;
+}
+
+
+static void process_line(const char *line_orig, ReplConnection *repl)
+{
+	char *line = strip_crap(line_orig);
+	printf("%p: '%s'\n", repl, line);
+	free(line);
+}
+
+
+static void input_ready(GObject *source, GAsyncResult *res, gpointer vp)
+{
+	GError *error = NULL;
+	ReplConnection *repl = vp;
+	size_t len;
+	int i;
+	char *nl_pos;
+	char *remaining;
+
+	len = g_input_stream_read_finish(G_INPUT_STREAM(source), res, &error);
+	repl->inbuf[len] = '\0';
+
+	for ( i=0; i<len; i++ ) {
+		if ( repl->inbuf[i] == '\0' ) {
+			repl->inbuf[i] = ' ';
+			fprintf(stderr, "Zero byte found in REPL output\n");
+		}
+	}
+
+	if ( strlen(repl->input) + len + 1 >= 2048 ) {
+		fprintf(stderr, "Too much input!\n");
+	} else {
+		strcat(repl->input, repl->inbuf);
+	}
+
+	nl_pos = strchr(repl->input, '\n');
+	while ( nl_pos != NULL ) {
+
+		size_t len_remaining = strlen(nl_pos);
+
+		nl_pos[0] = '\0';
+		process_line(repl->input, repl);
+
+		memmove(repl->input, nl_pos+1, len_remaining);
+		nl_pos = strchr(repl->input, '\n');
+	}
+
+	remaining = strip_crap(repl->input);
+	if ( strcmp(remaining, "scheme@(guile-user)> ") == 0 ) {
+		printf("Prompt!\n");
+		repl->input[0] = '\0';
+	}
+	free(remaining);
+
+	g_input_stream_read_async(g_io_stream_get_input_stream(G_IO_STREAM(repl->conn)),
+	                          repl->inbuf, 1023, G_PRIORITY_DEFAULT, NULL,
+	                          input_ready, repl);
+}
+
+
+ReplConnection *repl_connection_new(const char *socket)
+{
+	ReplConnection *repl;
+	GSocketClient *client;
+	GSocketAddress *addr;
+	GError *error = NULL;
+
+	repl = malloc(sizeof(struct _replconnection));
+	if ( repl == NULL ) return NULL;
+
+	addr = g_unix_socket_address_new(socket);
+	if ( addr == NULL ) return NULL;
+
+	client = g_socket_client_new();
+	repl->conn = g_socket_client_connect(client, G_SOCKET_CONNECTABLE(addr),
+	                                     NULL, &error);
+	if ( repl->conn == NULL ) {
+		fprintf(stderr, "Couldn't connect: %s\n", error->message);
+		return NULL;
+	}
+
+	repl->input[0] = '\0';
+
+	g_input_stream_read_async(g_io_stream_get_input_stream(G_IO_STREAM(repl->conn)),
+	                          repl->inbuf, 1023, G_PRIORITY_DEFAULT, NULL,
+	                          input_ready, repl);
+
+	return repl;
+}
+
+
+int repl_send(ReplConnection *repl, const char *line)
+{
+	GError *error = NULL;
+	GOutputStream *out = g_io_stream_get_output_stream(G_IO_STREAM(repl->conn));
+	if ( g_output_stream_write(out, line, strlen(line), NULL, &error) == -1 ) {
+		fprintf(stderr, "Couldn't send: %s\n", error->message);
+		return 1;
+	}
+	if ( g_output_stream_write(out, "\n", 1, NULL, &error) == -1 ) {
+		fprintf(stderr, "Couldn't send newline: %s\n", error->message);
+		return 1;
+	}
+	return 0;
+}
-- 
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