fix build breakage

1. Add a missing field and a function
2. Disable the deprecated attribute in Android temporarily to
   allow us to use "pcm_read/write" which are deprecated upstream
3. Remove an unused define and an include in mixer.h
4. Add mixer_ctl_event and copy the snd_ctl_event to mixer_ctl_event
5. Add pcm_ioctl function and mark as deprecated function

5 files changed, 87 insertions, 23 deletions

diff --git a/include/tinyalsa/attributes.h b/include/tinyalsa/attributes.h
index e33f46a..f465ba1 100644
--- a/include/tinyalsa/attributes.h
+++ b/include/tinyalsa/attributes.h
@@ -6,7 +6,12 @@
  * when the library is being used incorrectly.
  * */
 
-#ifdef __GNUC__
+// FIXME: Disable the deprecated attribute in Android temporarily. pcm_read/write are marked as
+//   deprecated functions in the latest tinyalsa in GitHub. However, there are lots of libraries in
+//   Android using these functions and building with -Werror flags. Besides build breakage, the
+//   behavior and interface of the successors, pcm_readi/writei, are also changed. Once all have
+//   been cleaned up, we will enable this again.
+#if defined(__GNUC__) && !defined(ANDROID)
 
 /** Issues a warning when a function is being
  * used that is now deprecated.
@@ -20,7 +25,7 @@
  * */
 #define TINYALSA_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
 
-#else /* __GNUC__ */
+#else /* __GNUC__ && !ANDROID */
 
 /** This is just a placeholder for compilers
  * that aren't GCC or Clang.
@@ -34,6 +39,6 @@
  * */
 #define TINYALSA_WARN_UNUSED_RESULT
 
-#endif /* __GNUC__ */
+#endif /* __GNUC__ && !ANDROID */
 
 #endif /* TINYALSA_ATTRIBUTES_H */
diff --git a/include/tinyalsa/mixer.h b/include/tinyalsa/mixer.h
index 77d5d01..7d0580f 100644
--- a/include/tinyalsa/mixer.h
+++ b/include/tinyalsa/mixer.h
@@ -37,19 +37,34 @@
 
 #include <sys/time.h>
 #include <stddef.h>
-#include <sound/asound.h>
 
 #if defined(__cplusplus)
 extern "C" {
 #endif
 
-/* TLV header size*/
-#define TLV_HEADER_SIZE sizeof(struct snd_ctl_tlv)
-
 struct mixer;
 
 struct mixer_ctl;
 
+// mixer_ctl_event is a mirroring structure of snd_ctl_event
+struct mixer_ctl_event {
+    int type;
+    union {
+        struct {
+            unsigned int mask;
+            struct {
+                unsigned int numid;
+                int iface;
+                unsigned int device;
+                unsigned int subdevice;
+                unsigned char name[44];
+                unsigned int index;
+            } id;
+        } element;
+        unsigned char data[60];
+    } data;
+};
+
 /** Mixer control type.
  * @ingroup libtinyalsa-mixer
  */
@@ -138,7 +153,7 @@ int mixer_ctl_get_range_min(const struct mixer_ctl *ctl);
 
 int mixer_ctl_get_range_max(const struct mixer_ctl *ctl);
 
-int mixer_read_event(struct mixer *mixer, struct snd_ctl_event *ev);
+int mixer_read_event(struct mixer *mixer, struct mixer_ctl_event *event);
 
 int mixer_consume_event(struct mixer *mixer);
 #if defined(__cplusplus)
diff --git a/include/tinyalsa/pcm.h b/include/tinyalsa/pcm.h
index cdc31a5..6569146 100644
--- a/include/tinyalsa/pcm.h
+++ b/include/tinyalsa/pcm.h
@@ -221,6 +221,8 @@ struct pcm_config {
     /** The number of frames to overwrite the playback buffer when the playback underrun is greater
      * than the silence threshold */
     unsigned int silence_size;
+
+    unsigned int avail_min;
 };
 
 /** Enumeration of a PCM's hardware parameters.
@@ -361,6 +363,8 @@ int pcm_wait(struct pcm *pcm, int timeout);
 
 long pcm_get_delay(struct pcm *pcm);
 
+int pcm_ioctl(struct pcm *pcm, int code, ...) TINYALSA_DEPRECATED;
+
 #if defined(__cplusplus)
 }  /* extern "C" */
 #endif
diff --git a/src/mixer.c b/src/mixer.c
index fe590e8..a45502e 100644
--- a/src/mixer.c
+++ b/src/mixer.c
@@ -553,39 +553,61 @@ exit:
  * further events can be alerted.
  *
  * @param mixer A mixer handle.
- * @returns 0 on success.  -errno on failure.
+ * @returns 1 on success. 0, if no pending event. -errno on failure.
  * @ingroup libtinyalsa-mixer
  */
 int mixer_consume_event(struct mixer *mixer)
 {
-    struct snd_ctl_event ev;
+    struct mixer_ctl_event ev;
 
     return mixer_read_event(mixer, &ev);
 }
 
-int mixer_read_event(struct mixer *mixer, struct snd_ctl_event *ev)
+/** Read a mixer control event.
+ * Try to read an control event from mixer.
+ *
+ * @param mixer A mixer handle.
+ * @param event Output parameter. If there is an event read form the mixer, this function will fill
+ * the event data into it.
+ * @returns 1 on success. 0, if no pending event. -errno on failure.
+ * @ingroup libtinyalsa-mixer
+ */
+int mixer_read_event(struct mixer *mixer, struct mixer_ctl_event *event)
 {
-    struct mixer_ctl_group *grp;
-    ssize_t count = 0;
+    struct mixer_ctl_group *grp = NULL;
+    struct snd_ctl_event ev;
+    ssize_t bytes = 0;
+
+    if (!mixer || !event) {
+        return -EINVAL;
+    }
 
     if (mixer->h_grp) {
-        grp = mixer->h_grp;
-        if (grp->event_cnt) {
-            grp->event_cnt--;
-            count = grp->ops->read_event(grp->data, ev, sizeof(*ev));
-            return (count >= 0) ? 0 : -errno;
+        if (mixer->h_grp->event_cnt > 0) {
+            grp = mixer->h_grp;
         }
     }
 #ifdef TINYALSA_USES_PLUGINS
     if (mixer->v_grp) {
-        grp = mixer->v_grp;
-        if (grp->event_cnt) {
-            grp->event_cnt--;
-            count = grp->ops->read_event(grp->data, ev, sizeof(*ev));
-            return (count >= 0) ? 0 : -errno;
+        if (mixer->v_grp->event_cnt > 0) {
+            grp = mixer->v_grp;
         }
     }
 #endif
+    if (grp) {
+        grp->event_cnt--;
+        bytes = grp->ops->read_event(grp->data, &ev, sizeof(ev));
+
+        if (bytes < 0) {
+            return -errno;
+        }
+
+        if (bytes == sizeof(*event)) {
+            memcpy(event, &ev, sizeof(*event));
+            return 1;
+        }
+    }
+
     return 0;
 }
 
diff --git a/src/pcm.c b/src/pcm.c
index 352ddc6..98ca9eb 100644
--- a/src/pcm.c
+++ b/src/pcm.c
@@ -1750,3 +1750,21 @@ long pcm_get_delay(struct pcm *pcm)
 
     return pcm->pcm_delay;
 }
+
+// TODO: Currently in Android, there are some libraries using this function to control the driver.
+//   We should remove this function as soon as possible.
+int pcm_ioctl(struct pcm *pcm, int request, ...)
+{
+    va_list ap;
+    void * arg;
+
+    if (!pcm_is_ready(pcm))
+        return -1;
+
+    va_start(ap, request);
+    arg = va_arg(ap, void *);
+    va_end(ap);
+
+    // FIXME Does not handle plugins
+    return ioctl(pcm->fd, request, arg);
+}