From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Date: Mon, 18 Nov 2019 04:22:44 +0000 (+0900)
Subject: rawmidi: stream_pair: add an API to create GSource
X-Git-Tag: v0.1.0~171
X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=4e0e683fdcbfc5468e240bc1aebbdc58ffa814a7;p=alsa-gobject.git

rawmidi: stream_pair: add an API to create GSource

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---

diff --git a/src/rawmidi/alsarawmidi.map b/src/rawmidi/alsarawmidi.map
index 9f81ab1..dc74eb6 100644
--- a/src/rawmidi/alsarawmidi.map
+++ b/src/rawmidi/alsarawmidi.map
@@ -21,6 +21,7 @@ ALSA_GOBJECT_0_0_0 {
     "alsarawmidi_stream_pair_write_to_substream";
     "alsarawmidi_stream_pair_drain_substream";
     "alsarawmidi_stream_pair_drop_substream";
+    "alsarawmidi_stream_pair_create_source";
 
     "alsarawmidi_substream_params_get_type";
     "alsarawmidi_substream_params_new";
diff --git a/src/rawmidi/stream-pair.c b/src/rawmidi/stream-pair.c
index 265e0c2..e085425 100644
--- a/src/rawmidi/stream-pair.c
+++ b/src/rawmidi/stream-pair.c
@@ -17,6 +17,12 @@ struct _ALSARawmidiStreamPairPrivate {
 };
 G_DEFINE_TYPE_WITH_PRIVATE(ALSARawmidiStreamPair, alsarawmidi_stream_pair, G_TYPE_OBJECT)
 
+typedef struct {
+    GSource src;
+    ALSARawmidiStreamPair *self;
+    gpointer tag;
+} RawmidiStreamPairSource;
+
 enum rawmidi_stream_pair_prop_type {
     RAWMIDI_STREAM_PAIR_PROP_DEVNODE = 1,
     RAWMIDI_STREAM_PAIR_PROP_COUNT,
@@ -347,3 +353,92 @@ void alsarawmidi_stream_pair_drop_substream(ALSARawmidiStreamPair *self,
     if (ioctl(priv->fd, SNDRV_RAWMIDI_IOCTL_DROP, &direction) < 0)
         generate_error(error, errno);
 }
+
+static gboolean rawmidi_stream_pair_check_src(GSource *gsrc)
+{
+    RawmidiStreamPairSource *src = (RawmidiStreamPairSource *)gsrc;
+    GIOCondition condition;
+
+    // Don't go to dispatch if nothing available. As an exception, return TRUE
+    // for POLLERR to call .dispatch for internal destruction.
+    condition = g_source_query_unix_fd(gsrc, src->tag);
+    return !!(condition & (G_IO_IN | G_IO_ERR));
+}
+
+static gboolean rawmidi_stream_pair_dispatch_src(GSource *gsrc, GSourceFunc cb,
+                                                 gpointer user_data)
+{
+    RawmidiStreamPairSource *src = (RawmidiStreamPairSource *)gsrc;
+    ALSARawmidiStreamPair *self = src->self;
+    ALSARawmidiStreamPairPrivate *priv;
+    GIOCondition condition;
+
+    priv = alsarawmidi_stream_pair_get_instance_private(self);
+    if (priv->fd < 0)
+        return G_SOURCE_REMOVE;
+
+    condition = g_source_query_unix_fd(gsrc, src->tag);
+    if (condition & G_IO_ERR)
+        return G_SOURCE_REMOVE;
+
+    // Just be sure to continue to process this source.
+    return G_SOURCE_CONTINUE;
+}
+
+static void rawmidi_stream_pair_finalize_src(GSource *gsrc)
+{
+    RawmidiStreamPairSource *src = (RawmidiStreamPairSource *)gsrc;
+
+    g_object_unref(src->self);
+}
+
+/**
+ * alsarawmidi_stream_pair_create_source:
+ * @self: A #ALSARawmidiStreamPair.
+ * @gsrc: (out): A #GSource to handle events from ALSA rawmidi character device.
+ * @error: A #GError.
+ *
+ * Allocate GSource structure to handle events from ALSA rawmidi character
+ * device for input substream.
+ */
+void alsarawmidi_stream_pair_create_source(ALSARawmidiStreamPair *self,
+                                           GSource **gsrc, GError **error)
+{
+    static GSourceFuncs funcs = {
+            .check          = rawmidi_stream_pair_check_src,
+            .dispatch       = rawmidi_stream_pair_dispatch_src,
+            .finalize       = rawmidi_stream_pair_finalize_src,
+    };
+    ALSARawmidiStreamPairPrivate *priv;
+    RawmidiStreamPairSource *src;
+    int access_modes;
+
+    g_return_if_fail(ALSARAWMIDI_IS_STREAM_PAIR(self));
+    priv = alsarawmidi_stream_pair_get_instance_private(self);
+
+    if (priv->fd < 0) {
+        generate_error(error, ENXIO);
+        return;
+    }
+
+    access_modes = fcntl(priv->fd, F_GETFL);
+    if (access_modes < 0) {
+        generate_error(error, errno);
+        return;
+    }
+
+    if (!(access_modes & O_RDWR) && !(access_modes & O_WRONLY)) {
+        generate_error(error, ENOTSUP);
+        return;
+    }
+
+    *gsrc = g_source_new(&funcs, sizeof(RawmidiStreamPairSource));
+    src = (RawmidiStreamPairSource *)(*gsrc);
+
+    g_source_set_name(*gsrc, "ALSARawmidiStreamPair");
+    g_source_set_priority(*gsrc, G_PRIORITY_HIGH_IDLE);
+    g_source_set_can_recurse(*gsrc, TRUE);
+
+    src->self = g_object_ref(self);
+    src->tag = g_source_add_unix_fd(*gsrc, priv->fd, G_IO_IN);
+}
diff --git a/src/rawmidi/stream-pair.h b/src/rawmidi/stream-pair.h
index 79a4d8e..f25c8f3 100644
--- a/src/rawmidi/stream-pair.h
+++ b/src/rawmidi/stream-pair.h
@@ -87,6 +87,9 @@ void alsarawmidi_stream_pair_drop_substream(ALSARawmidiStreamPair *self,
                                         ALSARawmidiStreamDirection direction,
                                         GError **error);
 
+void alsarawmidi_stream_pair_create_source(ALSARawmidiStreamPair *self,
+                                           GSource **gsrc, GError **error);
+
 G_END_DECLS
 
 #endif
diff --git a/tests/alsarawmidi-stream-pair b/tests/alsarawmidi-stream-pair
index 3002461..b31a095 100644
--- a/tests/alsarawmidi-stream-pair
+++ b/tests/alsarawmidi-stream-pair
@@ -23,6 +23,7 @@ methods = (
     'write_to_substream',
     'drain_substream',
     'drop_substream',
+    'create_source',
 )
 signals = ()