client: splitted client.c into several pieces

The soure file client.c has nearly 1000 lines, time for splitting it
into smaller pieces to improve readability.

src/client_write.c

@@ -0,0 +1,270 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "client_internal.h"
+
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+
+static size_t
+client_write_deferred_buffer(struct client *client,
+			     const struct deferred_buffer *buffer)
+{
+	GError *error = NULL;
+	GIOStatus status;
+	gsize bytes_written;
+
+	assert(client != NULL);
+	assert(client->channel != NULL);
+	assert(buffer != NULL);
+
+	status = g_io_channel_write_chars
+		(client->channel, buffer->data, buffer->size,
+		 &bytes_written, &error);
+	switch (status) {
+	case G_IO_STATUS_NORMAL:
+		return bytes_written;
+
+	case G_IO_STATUS_AGAIN:
+		return 0;
+
+	case G_IO_STATUS_EOF:
+		/* client has disconnected */
+
+		client_set_expired(client);
+		return 0;
+
+	case G_IO_STATUS_ERROR:
+		/* I/O error */
+
+		client_set_expired(client);
+		g_warning("failed to flush buffer for %i: %s",
+			  client->num, error->message);
+		g_error_free(error);
+		return 0;
+	}
+
+	/* unreachable */
+	return 0;
+}
+
+void
+client_write_deferred(struct client *client)
+{
+	size_t ret;
+
+	while (!g_queue_is_empty(client->deferred_send)) {
+		struct deferred_buffer *buf =
+			g_queue_peek_head(client->deferred_send);
+
+		assert(buf->size > 0);
+		assert(buf->size <= client->deferred_bytes);
+
+		ret = client_write_deferred_buffer(client, buf);
+		if (ret == 0)
+			break;
+
+		if (ret < buf->size) {
+			assert(client->deferred_bytes >= (size_t)ret);
+			client->deferred_bytes -= ret;
+			buf->size -= ret;
+			memmove(buf->data, buf->data + ret, buf->size);
+			break;
+		} else {
+			size_t decr = sizeof(*buf) -
+				sizeof(buf->data) + buf->size;
+
+			assert(client->deferred_bytes >= decr);
+			client->deferred_bytes -= decr;
+			g_free(buf);
+			g_queue_pop_head(client->deferred_send);
+		}
+
+		g_timer_start(client->last_activity);
+	}
+
+	if (g_queue_is_empty(client->deferred_send)) {
+		g_debug("[%u] buffer empty %lu", client->num,
+			(unsigned long)client->deferred_bytes);
+		assert(client->deferred_bytes == 0);
+	}
+}
+
+static void client_defer_output(struct client *client,
+				const void *data, size_t length)
+{
+	size_t alloc;
+	struct deferred_buffer *buf;
+
+	assert(length > 0);
+
+	alloc = sizeof(*buf) - sizeof(buf->data) + length;
+	client->deferred_bytes += alloc;
+	if (client->deferred_bytes > client_max_output_buffer_size) {
+		g_warning("[%u] output buffer size (%lu) is "
+			  "larger than the max (%lu)",
+			  client->num,
+			  (unsigned long)client->deferred_bytes,
+			  (unsigned long)client_max_output_buffer_size);
+		/* cause client to close */
+		client_set_expired(client);
+		return;
+	}
+
+	buf = g_malloc(alloc);
+	buf->size = length;
+	memcpy(buf->data, data, length);
+
+	g_queue_push_tail(client->deferred_send, buf);
+}
+
+static void client_write_direct(struct client *client,
+				const char *data, size_t length)
+{
+	GError *error = NULL;
+	GIOStatus status;
+	gsize bytes_written;
+
+	assert(client != NULL);
+	assert(client->channel != NULL);
+	assert(data != NULL);
+	assert(length > 0);
+	assert(g_queue_is_empty(client->deferred_send));
+
+	status = g_io_channel_write_chars(client->channel, data, length,
+					  &bytes_written, &error);
+	switch (status) {
+	case G_IO_STATUS_NORMAL:
+	case G_IO_STATUS_AGAIN:
+		break;
+
+	case G_IO_STATUS_EOF:
+		/* client has disconnected */
+
+		client_set_expired(client);
+		return;
+
+	case G_IO_STATUS_ERROR:
+		/* I/O error */
+
+		client_set_expired(client);
+		g_warning("failed to write to %i: %s",
+			  client->num, error->message);
+		g_error_free(error);
+		return;
+	}
+
+	if (bytes_written < length)
+		client_defer_output(client, data + bytes_written,
+				    length - bytes_written);
+
+	if (!g_queue_is_empty(client->deferred_send))
+		g_debug("[%u] buffer created", client->num);
+}
+
+void
+client_write_output(struct client *client)
+{
+	if (client_is_expired(client) || !client->send_buf_used)
+		return;
+
+	if (!g_queue_is_empty(client->deferred_send)) {
+		client_defer_output(client, client->send_buf,
+				    client->send_buf_used);
+
+		if (client_is_expired(client))
+			return;
+
+		/* try to flush the deferred buffers now; the current
+		   server command may take too long to finish, and
+		   meanwhile try to feed output to the client,
+		   otherwise it will time out.  One reason why
+		   deferring is slow might be that currently each
+		   client_write() allocates a new deferred buffer.
+		   This should be optimized after MPD 0.14. */
+		client_write_deferred(client);
+	} else
+		client_write_direct(client, client->send_buf,
+				    client->send_buf_used);
+
+	client->send_buf_used = 0;
+}
+
+/**
+ * Write a block of data to the client.
+ */
+static void client_write(struct client *client, const char *buffer, size_t buflen)
+{
+	/* if the client is going to be closed, do nothing */
+	if (client_is_expired(client))
+		return;
+
+	while (buflen > 0 && !client_is_expired(client)) {
+		size_t copylen;
+
+		assert(client->send_buf_used < sizeof(client->send_buf));
+
+		copylen = sizeof(client->send_buf) - client->send_buf_used;
+		if (copylen > buflen)
+			copylen = buflen;
+
+		memcpy(client->send_buf + client->send_buf_used, buffer,
+		       copylen);
+		buflen -= copylen;
+		client->send_buf_used += copylen;
+		buffer += copylen;
+		if (client->send_buf_used >= sizeof(client->send_buf))
+			client_write_output(client);
+	}
+}
+
+void client_puts(struct client *client, const char *s)
+{
+	client_write(client, s, strlen(s));
+}
+
+void client_vprintf(struct client *client, const char *fmt, va_list args)
+{
+	va_list tmp;
+	int length;
+	char *buffer;
+
+	va_copy(tmp, args);
+	length = vsnprintf(NULL, 0, fmt, tmp);
+	va_end(tmp);
+
+	if (length <= 0)
+		/* wtf.. */
+		return;
+
+	buffer = g_malloc(length + 1);
+	vsnprintf(buffer, length + 1, fmt, args);
+	client_write(client, buffer, length);
+	g_free(buffer);
+}
+
+G_GNUC_PRINTF(2, 3) void client_printf(struct client *client, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	client_vprintf(client, fmt, args);
+	va_end(args);
+}