input/soup: new input plugin based on libsoup

To demonstrate the new I/O thread.  libsoup is well-integrated into
the GLib main loop, which made this plugin pretty easy to write.

As a side effect, we have to initialize the I/O thread in all debug
programs that use the input API.

1 files changed, 370 insertions, 0 deletions

diff --git a/src/input/soup_input_plugin.c b/src/input/soup_input_plugin.c
new file mode 100644
index 000000000..7ceabbc62
--- /dev/null
+++ b/src/input/soup_input_plugin.c
@@ -0,0 +1,370 @@
+/*
+ * Copyright (C) 2003-2011 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 "config.h"
+#include "input/soup_input_plugin.h"
+#include "input_plugin.h"
+#include "io_thread.h"
+#include "conf.h"
+
+#include <libsoup/soup-uri.h>
+#include <libsoup/soup-session-async.h>
+
+#include <assert.h>
+#include <string.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "input_soup"
+
+/**
+ * Do not buffer more than this number of bytes.  It should be a
+ * reasonable limit that doesn't make low-end machines suffer too
+ * much, but doesn't cause stuttering on high-latency lines.
+ */
+static const size_t SOUP_MAX_BUFFERED = 512 * 1024;
+
+static SoupURI *soup_proxy;
+static SoupSession *soup_session;
+
+struct input_soup {
+	struct input_stream base;
+
+	GMutex *mutex;
+	GCond *cond;
+
+	SoupMessage *msg;
+
+	GQueue *buffers;
+
+	size_t current_consumed;
+
+	size_t total_buffered;
+
+	bool alive, ready, pause, eof;
+};
+
+static inline GQuark
+soup_quark(void)
+{
+	return g_quark_from_static_string("soup");
+}
+
+static bool
+input_soup_init(const struct config_param *param, GError **error_r)
+{
+	assert(soup_proxy == NULL);
+	assert(soup_session == NULL);
+
+	g_type_init();
+
+	const char *proxy = config_get_block_string(param, "proxy", NULL);
+
+	if (proxy != NULL) {
+		soup_proxy = soup_uri_new(proxy);
+		if (soup_proxy == NULL) {
+			g_set_error(error_r, soup_quark(), 0,
+				    "failed to parse proxy setting");
+			return false;
+		}
+	}
+
+	soup_session =
+		soup_session_async_new_with_options(SOUP_SESSION_PROXY_URI,
+						    soup_proxy,
+						    SOUP_SESSION_ASYNC_CONTEXT,
+						    io_thread_context(),
+						    NULL);
+
+	return true;
+}
+
+static void
+input_soup_finish(void)
+{
+	assert(soup_session != NULL);
+
+	soup_session_abort(soup_session);
+	g_object_unref(G_OBJECT(soup_session));
+
+	if (soup_proxy != NULL)
+		soup_uri_free(soup_proxy);
+}
+
+static void
+input_soup_session_callback(G_GNUC_UNUSED SoupSession *session,
+			    G_GNUC_UNUSED SoupMessage *msg, gpointer user_data)
+{
+	struct input_soup *s = user_data;
+
+	assert(msg == s->msg);
+
+	g_mutex_lock(s->mutex);
+	s->alive = false;
+	g_cond_broadcast(s->cond);
+	g_mutex_unlock(s->mutex);
+}
+
+static void
+input_soup_got_headers(SoupMessage *msg, gpointer user_data)
+{
+	struct input_soup *s = user_data;
+
+	if (!SOUP_STATUS_IS_SUCCESSFUL(msg->status_code)) {
+		soup_session_cancel_message(soup_session, msg,
+					    SOUP_STATUS_CANCELLED);
+		return;
+	}
+
+	soup_message_body_set_accumulate(msg->response_body, false);
+
+	g_mutex_lock(s->mutex);
+	s->ready = true;
+	g_cond_broadcast(s->cond);
+	g_mutex_unlock(s->mutex);
+}
+
+static void
+input_soup_got_chunk(SoupMessage *msg, SoupBuffer *chunk, gpointer user_data)
+{
+	struct input_soup *s = user_data;
+
+	assert(msg == s->msg);
+
+	g_mutex_lock(s->mutex);
+
+	g_queue_push_tail(s->buffers, soup_buffer_copy(chunk));
+	s->total_buffered += chunk->length;
+
+	if (s->total_buffered >= SOUP_MAX_BUFFERED && !s->pause) {
+		s->pause = true;
+		soup_session_pause_message(soup_session, msg);
+	}
+
+	g_cond_broadcast(s->cond);
+	g_mutex_unlock(s->mutex);
+}
+
+static void
+input_soup_got_body(SoupMessage *msg, gpointer user_data)
+{
+	struct input_soup *s = user_data;
+
+	assert(msg == s->msg);
+
+	g_mutex_lock(s->mutex);
+
+	s->eof = true;
+	s->alive = false;
+
+	g_cond_broadcast(s->cond);
+	g_mutex_unlock(s->mutex);
+}
+
+static bool
+input_soup_wait_data(struct input_soup *s)
+{
+	while (true) {
+		if (s->eof)
+			return true;
+
+		if (!s->alive)
+			return false;
+
+		if (!g_queue_is_empty(s->buffers))
+			return true;
+
+		assert(s->current_consumed == 0);
+
+		g_cond_wait(s->cond, s->mutex);
+	}
+}
+
+static struct input_stream *
+input_soup_open(const char *uri, G_GNUC_UNUSED GError **error_r)
+{
+	if (strncmp(uri, "http://", 7) != 0)
+		return NULL;
+
+	struct input_soup *s = g_new(struct input_soup, 1);
+	input_stream_init(&s->base, &input_plugin_soup, uri);
+
+	s->mutex = g_mutex_new();
+	s->cond = g_cond_new();
+
+	s->buffers = g_queue_new();
+	s->current_consumed = 0;
+	s->total_buffered = 0;
+
+	s->msg = soup_message_new(SOUP_METHOD_GET, uri);
+	soup_message_set_flags(s->msg, SOUP_MESSAGE_NO_REDIRECT);
+
+	soup_message_headers_append(s->msg->request_headers, "User-Agent",
+				    "Music Player Daemon " VERSION);
+
+	g_signal_connect(s->msg, "got-headers",
+			 G_CALLBACK(input_soup_got_headers), s);
+	g_signal_connect(s->msg, "got-chunk",
+			 G_CALLBACK(input_soup_got_chunk), s);
+	g_signal_connect(s->msg, "got-body",
+			 G_CALLBACK(input_soup_got_body), s);
+
+	s->alive = true;
+	s->ready = false;
+	s->pause = false;
+	s->eof = false;
+
+	soup_session_queue_message(soup_session, s->msg,
+				   input_soup_session_callback, s);
+
+	return &s->base;
+}
+
+static void
+input_soup_close(struct input_stream *is)
+{
+	struct input_soup *s = (struct input_soup *)is;
+
+	g_mutex_lock(s->mutex);
+
+	if (s->alive) {
+		assert(s->msg != NULL);
+
+		soup_session_cancel_message(soup_session, s->msg,
+					    SOUP_STATUS_CANCELLED);
+		s->alive = false;
+	}
+
+	g_mutex_unlock(s->mutex);
+}
+
+static int
+input_soup_buffer(struct input_stream *is, GError **error_r)
+{
+	struct input_soup *s = (struct input_soup *)is;
+
+	g_mutex_lock(s->mutex);
+
+	if (s->pause) {
+		if (s->total_buffered >= SOUP_MAX_BUFFERED) {
+			g_mutex_unlock(s->mutex);
+			return 1;
+		}
+
+		s->pause = false;
+		soup_session_unpause_message(soup_session, s->msg);
+	}
+
+
+	bool success = input_soup_wait_data(s);
+	s->base.ready = s->ready;
+	g_mutex_unlock(s->mutex);
+
+	if (!success) {
+		g_set_error_literal(error_r, soup_quark(), 0, "HTTP failure");
+		return -1;
+	}
+
+	return 1;
+}
+
+static size_t
+input_soup_read(struct input_stream *is, void *ptr, size_t size,
+		G_GNUC_UNUSED GError **error_r)
+{
+	struct input_soup *s = (struct input_soup *)is;
+
+	g_mutex_lock(s->mutex);
+
+	if (!input_soup_wait_data(s)) {
+		assert(!s->alive);
+		g_mutex_unlock(s->mutex);
+
+		return 0;
+	}
+
+	s->base.ready = s->ready;
+
+	char *p0 = ptr, *p = p0, *p_end = p0 + size;
+
+	while (p < p_end) {
+		SoupBuffer *buffer = g_queue_pop_head(s->buffers);
+		if (buffer == NULL) {
+			assert(s->current_consumed == 0);
+			break;
+		}
+
+		assert(s->current_consumed < buffer->length);
+		assert(s->total_buffered >= buffer->length);
+
+		const char *q = buffer->data;
+		q += s->current_consumed;
+
+		size_t remaining = buffer->length - s->current_consumed;
+		size_t nbytes = p_end - p;
+		if (nbytes > remaining)
+			nbytes = remaining;
+
+		memcpy(p, q, nbytes);
+		p += nbytes;
+
+		s->current_consumed += remaining;
+		if (s->current_consumed >= buffer->length) {
+			/* done with this buffer */
+			s->total_buffered -= buffer->length;
+			soup_buffer_free(buffer);
+			s->current_consumed = 0;
+		} else {
+			/* partial read */
+			assert(p == p_end);
+
+			g_queue_push_head(s->buffers, buffer);
+		}
+	}
+
+	if (s->pause && s->total_buffered < SOUP_MAX_BUFFERED) {
+		s->pause = false;
+		soup_session_unpause_message(soup_session, s->msg);
+	}
+
+	size_t nbytes = p - p0;
+	s->base.offset += nbytes;
+
+	g_mutex_unlock(s->mutex);
+	return nbytes;
+}
+
+static bool
+input_soup_eof(G_GNUC_UNUSED struct input_stream *is)
+{
+	struct input_soup *s = (struct input_soup *)is;
+
+	return !s->alive && g_queue_is_empty(s->buffers);
+}
+
+const struct input_plugin input_plugin_soup = {
+	.name = "soup",
+	.init = input_soup_init,
+	.finish = input_soup_finish,
+
+	.open = input_soup_open,
+	.close = input_soup_close,
+	.buffer = input_soup_buffer,
+	.read = input_soup_read,
+	.eof = input_soup_eof,
+};