prepareInitialInputBuffer : retry buffers

During flush, if all input buffers are still with component,
We retry to get buffers to proceed.

Bug: 291241758
Bug: 296988490

Test: atest android.media.decoder.cts.AdaptivePlaybackTest
Test: atest android.media.cts.MediaCodecTest
Test: atest android.mediav2.cts.CodecDecoderTest
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:ef235a9a63e1b20f7de24d900db5e834f24e1ddb)
Merged-In: I6326c4c8542844cf7edb4c22054cc16a596c0af2
Change-Id: I6326c4c8542844cf7edb4c22054cc16a596c0af2
diff --git a/media/codec2/sfplugin/CCodec.cpp b/media/codec2/sfplugin/CCodec.cpp
index a75ce70..1153fb6 100644
--- a/media/codec2/sfplugin/CCodec.cpp
+++ b/media/codec2/sfplugin/CCodec.cpp
@@ -2137,7 +2137,7 @@
     }
 
     std::map<size_t, sp<MediaCodecBuffer>> clientInputBuffers;
-    status_t err = mChannel->prepareInitialInputBuffers(&clientInputBuffers);
+    status_t err = mChannel->prepareInitialInputBuffers(&clientInputBuffers, true);
     if (err != OK) {
         if (err == NO_MEMORY) {
             // NO_MEMORY happens here when all the buffers are still
@@ -2160,7 +2160,6 @@
         const std::unique_ptr<Config> &config = *configLocked;
         return config->mBuffersBoundToCodec;
     }());
-
     {
         Mutexed<State>::Locked state(mState);
         if (state->get() != RESUMING) {
diff --git a/media/codec2/sfplugin/CCodecBufferChannel.cpp b/media/codec2/sfplugin/CCodecBufferChannel.cpp
index feca03d..08244bc 100644
--- a/media/codec2/sfplugin/CCodecBufferChannel.cpp
+++ b/media/codec2/sfplugin/CCodecBufferChannel.cpp
@@ -25,6 +25,8 @@
 #include <atomic>
 #include <list>
 #include <numeric>
+#include <thread>
+#include <chrono>
 
 #include <C2AllocatorGralloc.h>
 #include <C2PlatformSupport.h>
@@ -1614,22 +1616,31 @@
 }
 
 status_t CCodecBufferChannel::prepareInitialInputBuffers(
-        std::map<size_t, sp<MediaCodecBuffer>> *clientInputBuffers) {
+        std::map<size_t, sp<MediaCodecBuffer>> *clientInputBuffers, bool retry) {
     if (mInputSurface) {
         return OK;
     }
 
     size_t numInputSlots = mInput.lock()->numSlots;
-
-    {
-        Mutexed<Input>::Locked input(mInput);
-        while (clientInputBuffers->size() < numInputSlots) {
-            size_t index;
-            sp<MediaCodecBuffer> buffer;
-            if (!input->buffers->requestNewBuffer(&index, &buffer)) {
-                break;
+    int retryCount = 1;
+    for (; clientInputBuffers->empty() && retryCount >= 0; retryCount--) {
+        {
+            Mutexed<Input>::Locked input(mInput);
+            while (clientInputBuffers->size() < numInputSlots) {
+                size_t index;
+                sp<MediaCodecBuffer> buffer;
+                if (!input->buffers->requestNewBuffer(&index, &buffer)) {
+                    break;
+                }
+                clientInputBuffers->emplace(index, buffer);
             }
-            clientInputBuffers->emplace(index, buffer);
+        }
+        if (!retry || (retryCount <= 0)) {
+            break;
+        }
+        if (clientInputBuffers->empty()) {
+            // wait: buffer may be in transit from component.
+            std::this_thread::sleep_for(std::chrono::milliseconds(4));
         }
     }
     if (clientInputBuffers->empty()) {
diff --git a/media/codec2/sfplugin/CCodecBufferChannel.h b/media/codec2/sfplugin/CCodecBufferChannel.h
index 41f5ae2..f60b6fa 100644
--- a/media/codec2/sfplugin/CCodecBufferChannel.h
+++ b/media/codec2/sfplugin/CCodecBufferChannel.h
@@ -140,7 +140,8 @@
      *                                  initial input buffers.
      */
     status_t prepareInitialInputBuffers(
-            std::map<size_t, sp<MediaCodecBuffer>> *clientInputBuffers);
+            std::map<size_t, sp<MediaCodecBuffer>> *clientInputBuffers,
+            bool retry = false);
 
     /**
      * Request initial input buffers as prepared in clientInputBuffers.