audio: utils: Add flush() and size() methods to MonoPipe

Add two new methods to the MonoPipe class:

- flush(): Flushes the audio frames available in the pipe.
  It should be called when te pipe is already in shutdown
  state to ensure that no more new data is pushed.

- size(): Queries the pipe size.

Change-Id: Ia8c2ac287a475bd3e72f48368d297fc544b19eed
Signed-off-by: Misael Lopez Cruz <misael.lopez@ti.com>

2 files changed, 49 insertions, 0 deletions

diff --git a/audio/utils/include/tiaudioutils/MonoPipe.h b/audio/utils/include/tiaudioutils/MonoPipe.h
index 7fcef8c..8445ddc 100644
--- a/audio/utils/include/tiaudioutils/MonoPipe.h
+++ b/audio/utils/include/tiaudioutils/MonoPipe.h
@@ -139,6 +139,27 @@ class MonoPipe {
     virtual int availableToWrite() const;
 
     /**
+     * \brief Query the size of the pipe
+     *
+     * Queries the size of the pipe. It might be different to the requested
+     * number of frames if the pipe implementation relies does size rounding.
+     *
+     * \return Size of the pipe (in frames)
+     */
+    virtual size_t size() const;
+
+    /**
+     * \brief Flush the pipe
+     *
+     * Flushes all frames present in the pipe. It should be called when the
+     * pipe is in shutdown state to ensure no new data is written to the
+     * pipe.
+     *
+     * \return 0 on success, otherwise negative error code
+     */
+    virtual int flush();
+
+    /**
      * \brief Shut down the pipe
      *
      * Shuts down the pipe, causing any blocking write() calls to unblock
diff --git a/audio/utils/src/MonoPipe.cpp b/audio/utils/src/MonoPipe.cpp
index e463f79..be021f1 100644
--- a/audio/utils/src/MonoPipe.cpp
+++ b/audio/utils/src/MonoPipe.cpp
@@ -110,6 +110,34 @@ int MonoPipe::availableToWrite() const
     return mSink->availableToWrite();
 }
 
+size_t MonoPipe::size() const
+{
+    return mSink->maxFrames();
+}
+
+int MonoPipe::flush()
+{
+    ALOGW_IF(!isShutdown(), "MonoPipe: flushing while not in shutdown state");
+
+    int avail = availableToRead();
+    int16_t buffer[mParams.channels * avail];
+
+    /* Read all frames still present in the pipe */
+    while (avail > 0) {
+        int ret = read(buffer, avail);
+        if (ret < 0) {
+            ALOGE("MonoPipe: failed to flush the pipe %d", ret);
+            return ret;
+        }
+        avail -= ret;
+    }
+
+    avail = availableToRead();
+    ALOGW_IF(avail, "MonoPipe: %d frames were not flushed", avail);
+
+    return 0;
+}
+
 void MonoPipe::shutdown(bool state)
 {
     mSink->shutdown(state);