module/mpd: monitors MPD

modules/mpd/mpd.c

@@ -0,0 +1,301 @@
+#include "mpd.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <poll.h>
+
+#include <mpd/client.h>
+
+#define LOG_MODULE "mpd"
+#define LOG_ENABLE_DBG 1
+#include "../../log.h"
+#include "../../bar.h"
+
+enum state {
+    STATE_OFFLINE = 1000,
+    STATE_STOP = MPD_STATE_STOP,
+    STATE_PAUSE = MPD_STATE_PAUSE,
+    STATE_PLAY = MPD_STATE_PLAY,
+};
+
+struct private {
+    char *host;
+    uint16_t port;
+    struct particle *label;
+
+    struct mpd_connection *conn;
+    enum state state;
+    char *album;
+    char *artist;
+    char *title;
+
+    unsigned elapsed;
+    unsigned duration;
+};
+
+static void
+destroy(struct module *mod)
+{
+    struct private *m = mod->private;
+    free(m->host);
+    free(m->album);
+    free(m->artist);
+    free(m->title);
+    assert(m->conn == NULL);
+
+    m->label->destroy(m->label);
+
+    free(m);
+    module_default_destroy(mod);
+}
+
+static struct exposable *
+content(struct module *mod)
+{
+    struct private *m = mod->private;
+
+    mtx_lock(&mod->lock);
+
+    const char *state_str = NULL;
+    switch (m->state) {
+    case STATE_OFFLINE: state_str = "offline"; break;
+    case STATE_STOP:    state_str = "stopped"; break;
+    case STATE_PAUSE:   state_str = "paused"; break;
+    case STATE_PLAY:    state_str = "playing"; break;
+    }
+
+    char pos[16], end[16];
+
+    if (m->elapsed >= 60 * 60)
+        snprintf(pos, sizeof(pos), "%02u:%02u:%02u",
+                 m->elapsed / (60 * 60),
+                 m->elapsed % (60 * 60) / 60,
+                 m->elapsed % 60);
+    else
+        snprintf(pos, sizeof(pos), "%02u:%02u",
+                 m->elapsed / 60, m->elapsed % 60);
+
+    if (m->duration >= 60 * 60)
+        snprintf(end, sizeof(end), "%02u:%02u:%02u",
+                 m->duration / (60 * 60),
+                 m->duration % (60 * 60) / 60,
+                 m->duration % 60);
+    else
+        snprintf(end, sizeof(end), "%02u:%02u",
+                 m->duration / 60, m->duration % 60);
+
+    struct tag_set tags = {
+        .tags = (struct tag *[]){
+            tag_new_string("state", state_str),
+            tag_new_string("album", m->album),
+            tag_new_string("artist", m->artist),
+            tag_new_string("title", m->title),
+            tag_new_string("pos", pos),
+            tag_new_string("end", end),
+            tag_new_int("duration", m->duration),
+            tag_new_int_range("elapsed", m->elapsed, 0, m->duration),
+        },
+        .count = 8,
+    };
+
+    mtx_unlock(&mod->lock);
+
+    struct exposable *exposable = m->label->instantiate(m->label, &tags);
+
+    tag_set_destroy(&tags);
+    return exposable;
+}
+
+static struct mpd_connection *
+connect_to_mpd(const struct module *mod)
+{
+    const struct private *m = mod->private;
+
+    struct mpd_connection *conn = mpd_connection_new(m->host, m->port, 0);
+    if (conn == NULL) {
+        LOG_ERR("failed to create MPD connection");
+        return NULL;
+    }
+
+    enum mpd_error merr = mpd_connection_get_error(conn);
+    if (merr != MPD_ERROR_SUCCESS) {
+        LOG_WARN("failed to connect to MPD: %s",
+                 mpd_connection_get_error_message(conn));
+        return NULL;
+    }
+
+    const unsigned *version = mpd_connection_get_server_version(conn);
+    LOG_INFO("connected to MPD %u.%u.%u", version[0], version[1], version[2]);
+
+    return conn;
+}
+
+static bool
+update_status(struct module *mod)
+{
+    struct private *m = mod->private;
+
+    struct mpd_status *status = mpd_run_status(m->conn);
+    if (status == NULL) {
+        LOG_ERR("failed to get status: %s",
+                mpd_connection_get_error_message(m->conn));
+        return false;
+    }
+
+    mtx_lock(&mod->lock);
+    m->state = mpd_status_get_state(status);
+    m->duration = mpd_status_get_total_time(status);
+    m->elapsed = mpd_status_get_elapsed_time(status);
+    mtx_unlock(&mod->lock);
+
+    mpd_status_free(status);
+
+    struct mpd_song *song = mpd_run_current_song(m->conn);
+    if (song == NULL && mpd_connection_get_error(m->conn) != MPD_ERROR_SUCCESS) {
+        LOG_ERR("failed to get current song: %s",
+                mpd_connection_get_error_message(m->conn));
+        return false;
+    }
+
+    if (song == NULL) {
+        mtx_lock(&mod->lock);
+        free(m->album); m->album = NULL;
+        free(m->artist); m->artist = NULL;
+        free(m->title); m->title = NULL;
+        mtx_unlock(&mod->lock);
+    } else {
+        const char *album = mpd_song_get_tag(song, MPD_TAG_ALBUM, 0);
+        const char *artist = mpd_song_get_tag(song, MPD_TAG_ARTIST, 0);
+        const char *title = mpd_song_get_tag(song, MPD_TAG_TITLE, 0);
+
+        mtx_lock(&mod->lock);
+        m->album = strdup(album);
+        m->artist = strdup(artist);
+        m->title = strdup(title);
+        mtx_unlock(&mod->lock);
+
+        mpd_song_free(song);
+    }
+
+    return true;
+}
+
+static int
+run(struct module_run_context *ctx)
+{
+    module_signal_ready(ctx);
+
+    struct module *mod = ctx->module;
+    const struct bar *bar = mod->bar;
+    struct private *m = mod->private;
+
+    bool aborted = false;
+
+    while (!aborted) {
+
+        if (m->conn != NULL) {
+            mpd_connection_free(m->conn);
+            m->conn = NULL;
+        }
+
+        /* Reset state */
+        mtx_lock(&mod->lock);
+        free(m->album); m->album = NULL;
+        free(m->artist); m->artist = NULL;
+        free(m->title); m->title = NULL;
+        m->state = STATE_OFFLINE;
+        m->elapsed = m->duration = 0;
+        mtx_unlock(&mod->lock);
+
+        /* Keep trying to connect, until we succeed */
+        while (!aborted) {
+            m->conn = connect_to_mpd(mod);
+            if (m->conn != NULL)
+                break;
+
+            struct pollfd fds[] = {{.fd = ctx->abort_fd, .events = POLLIN}};
+            int res = poll(fds, 1, 1 * 1000);
+
+            if (res == 1) {
+                assert(fds[0].revents & POLLIN);
+                aborted = true;
+            }
+        }
+
+        if (aborted)
+            break;
+
+        /* Initial state (after establishing a connection) */
+        assert(m->conn != NULL);
+        if (!update_status(mod))
+            continue;
+
+        bar->refresh(bar);
+
+        /* Monitor for events from MPD */
+        while (true) {
+            struct pollfd fds[] = {
+                {.fd = ctx->abort_fd, .events = POLLIN},
+                {.fd = mpd_connection_get_fd(m->conn), .events = POLLIN},
+            };
+
+            if (!mpd_send_idle(m->conn)) {
+                LOG_ERR("failed to send IDLE command: %s",
+                        mpd_connection_get_error_message(m->conn));
+                break;
+            }
+
+            poll(fds, 2, -1);
+
+            if (fds[0].revents & POLLIN) {
+                aborted = true;
+                break;
+            }
+
+            if (fds[1].revents & POLLHUP) {
+                LOG_WARN("disconnected from MPD daemon");
+                break;
+            }
+
+            enum mpd_idle idle = mpd_recv_idle(m->conn, true);
+            LOG_DBG("IDLE mask: %d", idle);
+
+            if (!update_status(mod))
+                break;
+
+            bar->refresh(bar);
+        }
+    }
+
+    if (m->conn != NULL) {
+        mpd_connection_free(m->conn);
+        m->conn = NULL;
+    }
+
+    return 0;
+}
+
+struct module *
+module_mpd(const char *host, uint16_t port, struct particle *label)
+{
+    struct private *priv = malloc(sizeof(*priv));
+    priv->host = strdup(host);
+    priv->port = port;
+    priv->label = label;
+    priv->conn = NULL;
+    priv->state = STATE_OFFLINE;
+    priv->album = NULL;
+    priv->artist = NULL;
+    priv->title = NULL;
+    priv->elapsed = 0;
+    priv->duration = 0;
+
+    struct module *mod = module_common_new();
+    mod->private = priv;
+    mod->run = &run;
+    mod->destroy = &destroy;
+    mod->content = &content;
+    return mod;
+}