Rework mediaplayer support to use mpd

Rework the mediaplayer support to replace the stubbed out app
framework agl-service-mediaplayer binding use with driving mpd
(Media Player Daemon) via the libmpdclient library.  Local file
playback behavior should be equivalent to before in an image
with mpd present and suitably configured.  Bluetooth AVRCP
support is still stubbed out, and will be re-implemented with
followup changes.

Bug-AGL: SPEC-4182

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: Ifdf092b472c271460d0f5e9a8c7d2353904411b2

1 files changed, 309 insertions, 0 deletions

diff --git a/mediaplayer/MpdEventHandler.cpp b/mediaplayer/MpdEventHandler.cpp
new file mode 100644
index 0000000..40d2999
--- /dev/null
+++ b/mediaplayer/MpdEventHandler.cpp
@@ -0,0 +1,309 @@
+/*
+ * Copyright (C) 2022 Konsulko Group
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <QDebug>
+#include "MpdEventHandler.h"
+
+MpdEventHandler::MpdEventHandler(QObject *parent) :
+	QObject(parent)
+{
+	// NOTE: Not specifying a timeout here as it is assumed to be long
+	//       enough that we won't timeout in the brief intervals when
+	//       switching in and out of idle mode.
+	struct mpd_connection *conn = mpd_connection_new(NULL, 0, 0);
+	if (!conn) {
+		qFatal("Could not create MPD connection");
+	}
+	if (mpd_connection_get_error(conn) != MPD_ERROR_SUCCESS) {
+		qFatal("%s", mpd_connection_get_error_message(conn));
+	}
+	m_mpd_conn = conn;
+}
+
+MpdEventHandler::~MpdEventHandler()
+{
+	mpd_connection_free(m_mpd_conn);
+}
+
+void MpdEventHandler::handleEvents(void)
+{
+	bool done = false;
+	enum mpd_idle mask = (enum mpd_idle)(MPD_IDLE_DATABASE|MPD_IDLE_QUEUE|MPD_IDLE_PLAYER);
+	enum mpd_idle events;
+	while (!done) {
+		// Wait for an event
+		events = mpd_run_idle_mask(m_mpd_conn, mask);
+
+		// NOTE: Realistically should be checking the result of
+		//       mpd_connection_get_error here, but handling it will
+		//       complicate things significantly.
+
+		// handle the events
+		if (events & MPD_IDLE_DATABASE) {
+			handleDatabaseEvent();
+		}
+		else if (events & MPD_IDLE_QUEUE) {
+			handleQueueEvent();
+		}
+		else if (events & MPD_IDLE_PLAYER) {
+			handlePlayerEvent();
+		}
+	}
+
+	qDebug() << "MpdEventHandler::handleEvents: exit";
+}
+
+void MpdEventHandler::handleDatabaseEvent(void)
+{
+	// Maybe clear queue here?
+	//mpd_run_delete_range(m_mpd_con, 0, UINT_MAX);
+
+	if(!mpd_run_add(m_mpd_conn, "/")) {
+		qWarning() << "mpd_run_add failed";
+	}
+}
+
+void MpdEventHandler::handleQueueEvent(void)
+{
+	QVariantList playlist;
+	bool done = false;
+	struct mpd_entity *entity;
+	mpd_send_list_queue_meta(m_mpd_conn);
+	do {
+		entity = mpd_recv_entity(m_mpd_conn);
+		if (!entity) {
+			enum mpd_error error = mpd_connection_get_error(m_mpd_conn);
+			if (error == MPD_ERROR_SUCCESS)
+				done = true;
+			break;
+		}
+		if (mpd_entity_get_type(entity) != MPD_ENTITY_TYPE_SONG) {
+			mpd_entity_free(entity);
+			continue;
+		}
+		const struct mpd_song *song = mpd_entity_get_song(entity);
+		QString title(mpd_song_get_tag(song, MPD_TAG_TITLE, 0));
+		QString artist(mpd_song_get_tag(song, MPD_TAG_ARTIST, 0));
+		QString album(mpd_song_get_tag(song, MPD_TAG_ALBUM, 0));
+		QString genre(mpd_song_get_tag(song, MPD_TAG_GENRE, 0));
+		QString uri(mpd_song_get_uri(song));
+		int pos = mpd_song_get_pos(song);
+		//qDebug() << "Queue[" << pos << "]: " << artist << " - " << title << " / " << album << ", genre " << genre;
+
+		QVariantMap track;
+		track["title"] = title;
+		track["artist"] = artist;
+		track["album"] = album;
+		track["genre"] = genre;
+		track["index"] = pos;
+		track["duration"] = mpd_song_get_duration_ms(song);
+		track["path"] = uri;
+		playlist.append(track);
+
+		mpd_entity_free(entity);
+	} while(!done);
+
+	if (done) {
+		QVariantMap metadata;
+		metadata["list"] = playlist;
+
+		emit playlistUpdate(metadata);
+	}
+}
+
+void MpdEventHandler::handlePlayerEvent(void)
+{
+	int pos = -1;
+	QString uri;
+	QVariantMap track;
+	QVariantMap metadata;
+	struct mpd_song* song = mpd_run_current_song(m_mpd_conn);
+	if (song) {
+		QString title(mpd_song_get_tag(song, MPD_TAG_TITLE, 0));
+		QString artist(mpd_song_get_tag(song, MPD_TAG_ARTIST, 0));
+		QString album(mpd_song_get_tag(song, MPD_TAG_ALBUM, 0));
+		QString genre(mpd_song_get_tag(song, MPD_TAG_GENRE, 0));
+		pos = mpd_song_get_pos(song);
+		uri = mpd_song_get_uri(song);
+		//qDebug() << "Current song[" << pos << "]: " << artist << " - " << title << " / " << album << ", genre " << genre;
+
+		track["title"] = title;
+		track["artist"] = artist;
+		track["album"] = album;
+		track["genre"] = genre;
+		track["index"] = pos;
+		track["duration"] = mpd_song_get_duration_ms(song);
+		track["path"] = uri;
+		mpd_song_free(song);
+
+		metadata["track"] = track;
+	}
+	// NOTE:
+	// It may make sense to check status first, and then try to handle the
+	// no song + stopped case at the end of the queue to trigger a move to
+	// the top of the playlist in the UI if that is deemed desirable (the
+	// old binding does not seem to).  However, this may prove a bit
+	// complicated if triggering stop instead of pause is done to trigger
+	// corking in WirePlumber...
+
+	struct mpd_status *status = mpd_run_status(m_mpd_conn);
+
+	int elapsed_ms = mpd_status_get_elapsed_ms(status);
+	metadata["position"] = elapsed_ms;
+
+	int volume = mpd_status_get_volume(status);
+	metadata["volume"] = volume == -1 ? 0 : volume;
+
+	// NOTE: current UI client user does not care about paused vs stopped,
+	//       and the old binding did not differentiate in its responses,
+	//       so do not do so either for now.
+	enum mpd_state state = mpd_status_get_state(status);
+	QString status_name("stopped");
+	if (state ==  MPD_STATE_PLAY)
+		status_name = "playing";
+	metadata["status"] = status_name;
+
+	mpd_status_free(status);
+
+	// For UI
+	emit metadataUpdate(metadata);
+
+	// For backend state tracking
+	emit playbackStateUpdate(pos, elapsed_ms, (state == MPD_STATE_PLAY));
+
+	if (uri.size()) {
+		// Send album art to UI as a separate update.
+		// This avoids things being out of sync than delaying while
+		// the art is is read.
+		// NOTE: Some form of caching might be desirable here.
+		QByteArray buffer;
+		QString mime_type;
+		if (getSongArt(uri, buffer, mime_type) && mime_type.size()) {
+			QString image_base64(buffer.toBase64());
+			QString mime_type_header("data:");
+			mime_type_header += mime_type;
+			mime_type_header += ";base64,";
+			image_base64.prepend(mime_type_header);
+
+			// Re-use metadata map...
+			track["image"] = image_base64;
+			metadata["track"] = track;
+
+			// ...but clear out the ephemeral metadata
+			metadata.remove("position");
+			metadata.remove("status");
+			metadata.remove("volume");
+
+			// Update UI
+			emit metadataUpdate(metadata);
+		}
+	}
+}
+
+bool MpdEventHandler::getSongArt(const QString &path, QByteArray &buffer, QString &type)
+{
+	bool rc = false;
+	unsigned pic_offset = 0;
+	unsigned pic_size = 0;
+
+	QByteArray path_ba = path.toLocal8Bit();
+	const char *path_cstr = path_ba.data();
+
+	bool first = true;
+	do {
+		QString pic_offset_str = QString::number(pic_offset);
+		QByteArray pic_offset_ba = pic_offset_str.toLocal8Bit();
+		const char *pic_offset_cstr = pic_offset_ba.data();
+
+		if (!mpd_send_command(m_mpd_conn, "readpicture", path_cstr, pic_offset_cstr, NULL)) {
+			if (mpd_connection_get_error(m_mpd_conn) != MPD_ERROR_SUCCESS)
+				goto conn_error;
+		}
+		struct mpd_pair *pair = mpd_recv_pair_named(m_mpd_conn, "size");
+		if (!pair) {
+			if (first) {
+				// No art, exit
+				break;
+			}
+
+			if (mpd_connection_get_error(m_mpd_conn) != MPD_ERROR_SUCCESS)
+				goto conn_error;
+		}
+		pic_size = QString(pair->value).toInt();
+		mpd_return_pair(m_mpd_conn, pair);
+
+		pair = mpd_recv_pair_named(m_mpd_conn, "type");
+		if (!pair) {
+			// check for error
+		}
+		QString mime_type(pair->value);
+		mpd_return_pair(m_mpd_conn, pair);
+		if (first) {
+			if (mime_type.size()) {
+				type = mime_type;
+			} else {
+				break;
+			}
+			first = false;
+		}
+
+		pair = mpd_recv_pair_named(m_mpd_conn, "binary");
+		if (!pair) {
+			if (mpd_connection_get_error(m_mpd_conn) != MPD_ERROR_SUCCESS)
+				goto conn_error;
+		}
+
+		unsigned chunk_size = QString(pair->value).toInt();
+		mpd_return_pair(m_mpd_conn, pair);
+
+		if (!chunk_size)
+			break;
+
+		char *buf = new (std::nothrow) char[chunk_size];
+		if (!buf)
+			goto conn_error;
+
+		if (!mpd_recv_binary(m_mpd_conn, buf, chunk_size)) {
+			if (mpd_connection_get_error(m_mpd_conn) != MPD_ERROR_SUCCESS) {
+				delete[] buf;
+				goto conn_error;
+			}
+		}
+
+		if (!mpd_response_finish(m_mpd_conn)) {
+			if (mpd_connection_get_error(m_mpd_conn) != MPD_ERROR_SUCCESS) {
+				delete[] buf;
+				goto conn_error;
+			}
+		}
+
+		buffer.append(buf, chunk_size);
+		delete[] buf;
+
+		pic_offset += chunk_size;
+
+	} while (pic_offset < pic_size);
+
+conn_error:
+	if (pic_offset == pic_size) {
+		rc = true;
+	} else {
+		// Don't pass garbage to caller
+		buffer.clear();
+	}
+
+	return rc;
+}