Implement DetachedBuffer::Promote

1/ This enables a BufferHub-backed DetachedBuffer to be promoted into
   the ProducerBuffer.
2/ Add DetachedBuffer::IsConnected in addition to
   DetachedBuffer::IsValid.
3/ Cleaned up some using pdx:: namespace statements.

Bug: 69982239
Bug: 69981968
Bug: 70046255
Test: buffer_hub-test
Change-Id: I6ee99507b190d142647455532cdce0c2c780b2b0
diff --git a/libs/vr/libbufferhub/buffer_hub-test.cpp b/libs/vr/libbufferhub/buffer_hub-test.cpp
index 2302828..e247398 100644
--- a/libs/vr/libbufferhub/buffer_hub-test.cpp
+++ b/libs/vr/libbufferhub/buffer_hub-test.cpp
@@ -19,18 +19,18 @@
     return result;                            \
   })()
 
-using android::sp;
 using android::GraphicBuffer;
+using android::sp;
 using android::dvr::BufferConsumer;
+using android::dvr::BufferProducer;
+using android::dvr::DetachedBuffer;
+using android::dvr::BufferHubDefs::IsBufferAcquired;
+using android::dvr::BufferHubDefs::IsBufferGained;
+using android::dvr::BufferHubDefs::IsBufferPosted;
+using android::dvr::BufferHubDefs::IsBufferReleased;
 using android::dvr::BufferHubDefs::kConsumerStateMask;
 using android::dvr::BufferHubDefs::kMetadataHeaderSize;
 using android::dvr::BufferHubDefs::kProducerStateBit;
-using android::dvr::BufferHubDefs::IsBufferGained;
-using android::dvr::BufferHubDefs::IsBufferPosted;
-using android::dvr::BufferHubDefs::IsBufferAcquired;
-using android::dvr::BufferHubDefs::IsBufferReleased;
-using android::dvr::BufferProducer;
-using android::dvr::DetachedBuffer;
 using android::pdx::LocalChannelHandle;
 using android::pdx::LocalHandle;
 using android::pdx::Status;
@@ -376,8 +376,8 @@
   EXPECT_EQ(0, p->PostAsync(&metadata, invalid_fence));
   EXPECT_TRUE(IsBufferPosted(p->buffer_state()));
   for (size_t i = 0; i < kMaxConsumerCount; i++) {
-    EXPECT_TRUE(IsBufferPosted(cs[i]->buffer_state(),
-                               cs[i]->buffer_state_bit()));
+    EXPECT_TRUE(
+        IsBufferPosted(cs[i]->buffer_state(), cs[i]->buffer_state_bit()));
     EXPECT_LT(0, RETRY_EINTR(cs[i]->Poll(kPollTimeoutMs)));
     EXPECT_EQ(0, cs[i]->AcquireAsync(&metadata, &invalid_fence));
     EXPECT_TRUE(IsBufferAcquired(p->buffer_state()));
@@ -792,6 +792,7 @@
   // Detached buffer handle can be use to construct a new DetachedBuffer object.
   auto d = DetachedBuffer::Import(std::move(handle));
   EXPECT_FALSE(handle.valid());
+  EXPECT_TRUE(d->IsConnected());
   EXPECT_TRUE(d->IsValid());
 
   ASSERT_TRUE(d->buffer() != nullptr);
@@ -801,10 +802,11 @@
 
 TEST_F(LibBufferHubTest, TestCreateDetachedBufferFails) {
   // Buffer Creation will fail: BLOB format requires height to be 1.
-  auto b1 = DetachedBuffer::Create(kWidth, /*height=2*/2, kLayerCount,
+  auto b1 = DetachedBuffer::Create(kWidth, /*height=2*/ 2, kLayerCount,
                                    /*format=*/HAL_PIXEL_FORMAT_BLOB, kUsage,
                                    kUserMetadataSize);
 
+  EXPECT_FALSE(b1->IsConnected());
   EXPECT_FALSE(b1->IsValid());
   EXPECT_TRUE(b1->buffer() == nullptr);
 
@@ -813,6 +815,7 @@
       kWidth, kHeight, kLayerCount, kFormat, kUsage,
       /*user_metadata_size=*/std::numeric_limits<size_t>::max());
 
+  EXPECT_FALSE(b2->IsConnected());
   EXPECT_FALSE(b2->IsValid());
   EXPECT_TRUE(b2->buffer() == nullptr);
 
@@ -822,6 +825,7 @@
       /*user_metadata_size=*/std::numeric_limits<size_t>::max() -
           kMetadataHeaderSize);
 
+  EXPECT_FALSE(b3->IsConnected());
   EXPECT_FALSE(b3->IsValid());
   EXPECT_TRUE(b3->buffer() == nullptr);
 }
@@ -831,6 +835,7 @@
                                    kUsage, kUserMetadataSize);
   int b1_id = b1->id();
 
+  EXPECT_TRUE(b1->IsConnected());
   EXPECT_TRUE(b1->IsValid());
   ASSERT_TRUE(b1->buffer() != nullptr);
   EXPECT_NE(b1->id(), 0);
@@ -843,6 +848,7 @@
   ASSERT_TRUE(g1 != nullptr);
   EXPECT_TRUE(g1->isDetachedBuffer());
 
+  EXPECT_FALSE(b1->IsConnected());
   EXPECT_FALSE(b1->IsValid());
   EXPECT_TRUE(b1->buffer() == nullptr);
 
@@ -856,6 +862,7 @@
 
   auto b2 = DetachedBuffer::Import(std::move(h1->handle()));
   ASSERT_FALSE(h1->isValid());
+  EXPECT_TRUE(b2->IsConnected());
   EXPECT_TRUE(b2->IsValid());
 
   ASSERT_TRUE(b2->buffer() != nullptr);
@@ -865,3 +872,76 @@
   EXPECT_EQ(b2->id(), b1_id);
   EXPECT_FALSE(b2->buffer()->isDetachedBuffer());
 }
+
+TEST_F(LibBufferHubTest, TestPromoteDetachedBuffer) {
+  auto b1 = DetachedBuffer::Create(kWidth, kHeight, kLayerCount, kFormat,
+                                   kUsage, kUserMetadataSize);
+  int b1_id = b1->id();
+  EXPECT_TRUE(b1->IsValid());
+
+  auto status_or_handle = b1->Promote();
+  EXPECT_TRUE(status_or_handle);
+
+  // The detached buffer should have hangup.
+  EXPECT_GT(RETRY_EINTR(b1->Poll(kPollTimeoutMs)), 0);
+  auto status_or_int = b1->GetEventMask(POLLHUP);
+  EXPECT_TRUE(status_or_int.ok());
+  EXPECT_EQ(status_or_int.get(), POLLHUP);
+
+  // The buffer client is still considered as connected but invalid.
+  EXPECT_TRUE(b1->IsConnected());
+  EXPECT_FALSE(b1->IsValid());
+
+  // Gets the channel handle for the producer.
+  LocalChannelHandle h1 = status_or_handle.take();
+  EXPECT_TRUE(h1.valid());
+
+  std::unique_ptr<BufferProducer> p1 = BufferProducer::Import(std::move(h1));
+  EXPECT_FALSE(h1.valid());
+  ASSERT_TRUE(p1 != nullptr);
+  int p1_id = p1->id();
+
+  // A newly promoted ProducerBuffer should inherit the same buffer id.
+  EXPECT_EQ(b1_id, p1_id);
+  EXPECT_TRUE(IsBufferGained(p1->buffer_state()));
+}
+
+TEST_F(LibBufferHubTest, TestDetachThenPromote) {
+  std::unique_ptr<BufferProducer> p1 = BufferProducer::Create(
+      kWidth, kHeight, kFormat, kUsage, sizeof(uint64_t));
+  ASSERT_TRUE(p1.get() != nullptr);
+  int p1_id = p1->id();
+
+  // Detached the producer.
+  auto status_or_handle = p1->Detach();
+  EXPECT_TRUE(status_or_handle.ok());
+  LocalChannelHandle h1 = status_or_handle.take();
+  EXPECT_TRUE(h1.valid());
+
+  // Detached buffer handle can be use to construct a new DetachedBuffer object.
+  auto b1 = DetachedBuffer::Import(std::move(h1));
+  EXPECT_FALSE(h1.valid());
+  EXPECT_TRUE(b1->IsValid());
+  int b1_id = b1->id();
+  EXPECT_EQ(b1_id, p1_id);
+
+  // Promote the detached buffer.
+  status_or_handle = b1->Promote();
+  // The buffer client is still considered as connected but invalid.
+  EXPECT_TRUE(b1->IsConnected());
+  EXPECT_FALSE(b1->IsValid());
+  EXPECT_TRUE(status_or_handle.ok());
+
+  // Gets the channel handle for the producer.
+  LocalChannelHandle h2 = status_or_handle.take();
+  EXPECT_TRUE(h2.valid());
+
+  std::unique_ptr<BufferProducer> p2 = BufferProducer::Import(std::move(h2));
+  EXPECT_FALSE(h2.valid());
+  ASSERT_TRUE(p2 != nullptr);
+  int p2_id = p2->id();
+
+  // A newly promoted ProducerBuffer should inherit the same buffer id.
+  EXPECT_EQ(b1_id, p2_id);
+  EXPECT_TRUE(IsBufferGained(p2->buffer_state()));
+}
diff --git a/libs/vr/libbufferhub/detached_buffer.cpp b/libs/vr/libbufferhub/detached_buffer.cpp
index 1d59cf3..6fae16d 100644
--- a/libs/vr/libbufferhub/detached_buffer.cpp
+++ b/libs/vr/libbufferhub/detached_buffer.cpp
@@ -3,7 +3,11 @@
 #include <pdx/file_handle.h>
 #include <ui/DetachedBufferHandle.h>
 
+#include <poll.h>
+
+using android::pdx::LocalChannelHandle;
 using android::pdx::LocalHandle;
+using android::pdx::Status;
 
 namespace android {
 namespace dvr {
@@ -78,9 +82,26 @@
   return 0;
 }
 
-std::unique_ptr<BufferProducer> DetachedBuffer::Promote() {
-  ALOGE("DetachedBuffer::Promote: Not implemented.");
-  return nullptr;
+int DetachedBuffer::Poll(int timeout_ms) {
+  ATRACE_NAME("DetachedBuffer::Poll");
+  pollfd p = {client_.event_fd(), POLLIN, 0};
+  return poll(&p, 1, timeout_ms);
+}
+
+Status<LocalChannelHandle> DetachedBuffer::Promote() {
+  ATRACE_NAME("DetachedBuffer::Promote");
+  ALOGD_IF(TRACE, "DetachedBuffer::Promote: id=%d.", id_);
+
+  auto status_or_handle =
+      client_.InvokeRemoteMethod<DetachedBufferRPC::Promote>();
+  if (status_or_handle.ok()) {
+    // Invalidate the buffer.
+    buffer_ = {};
+  } else {
+    ALOGE("DetachedBuffer::Promote: Failed to promote buffer (id=%d): %s.", id_,
+          status_or_handle.GetErrorMessage().c_str());
+  }
+  return status_or_handle;
 }
 
 sp<GraphicBuffer> DetachedBuffer::TakeGraphicBuffer() {
diff --git a/libs/vr/libbufferhub/include/private/dvr/buffer_hub_client.h b/libs/vr/libbufferhub/include/private/dvr/buffer_hub_client.h
index c1cc7f3..0ea77c8 100644
--- a/libs/vr/libbufferhub/include/private/dvr/buffer_hub_client.h
+++ b/libs/vr/libbufferhub/include/private/dvr/buffer_hub_client.h
@@ -18,17 +18,17 @@
 
 class BufferHubClient : public pdx::Client {
  public:
-  using LocalChannelHandle = pdx::LocalChannelHandle;
-
   BufferHubClient();
-  explicit BufferHubClient(LocalChannelHandle channel_handle);
+  explicit BufferHubClient(pdx::LocalChannelHandle channel_handle);
 
   bool IsValid() const;
-  LocalChannelHandle TakeChannelHandle();
+  pdx::LocalChannelHandle TakeChannelHandle();
 
   using pdx::Client::Close;
+  using pdx::Client::GetChannel;
   using pdx::Client::InvokeRemoteMethod;
   using pdx::Client::IsConnected;
+  using pdx::Client::event_fd;
 };
 
 class BufferHubBuffer : public pdx::Client {
diff --git a/libs/vr/libbufferhub/include/private/dvr/detached_buffer.h b/libs/vr/libbufferhub/include/private/dvr/detached_buffer.h
index 73e895d..6d0b502 100644
--- a/libs/vr/libbufferhub/include/private/dvr/detached_buffer.h
+++ b/libs/vr/libbufferhub/include/private/dvr/detached_buffer.h
@@ -8,8 +8,6 @@
 
 class DetachedBuffer {
  public:
-  using LocalChannelHandle = pdx::LocalChannelHandle;
-
   // Allocates a standalone DetachedBuffer not associated with any producer
   // consumer set.
   static std::unique_ptr<DetachedBuffer> Create(uint32_t width, uint32_t height,
@@ -22,7 +20,7 @@
 
   // Imports the given channel handle to a DetachedBuffer, taking ownership.
   static std::unique_ptr<DetachedBuffer> Import(
-      LocalChannelHandle channel_handle) {
+      pdx::LocalChannelHandle channel_handle) {
     return std::unique_ptr<DetachedBuffer>(
         new DetachedBuffer(std::move(channel_handle)));
   }
@@ -33,12 +31,31 @@
   const sp<GraphicBuffer>& buffer() const { return buffer_.buffer(); }
 
   int id() const { return id_; }
-  bool IsValid() const { return client_.IsValid(); }
+
+  // Returns true if the buffer holds an open PDX channels towards bufferhubd.
+  bool IsConnected() const { return client_.IsValid(); }
+
+  // Returns true if the buffer holds an valid gralloc buffer handle that's
+  // availble for the client to read from and/or write into.
+  bool IsValid() const { return buffer_.IsValid(); }
+
+  // Returns the event mask for all the events that are pending on this buffer
+  // (see sys/poll.h for all possible bits).
+  pdx::Status<int> GetEventMask(int events) {
+    if (auto* channel = client_.GetChannel()) {
+      return channel->GetEventMask(events);
+    } else {
+      return pdx::ErrorStatus(EINVAL);
+    }
+  }
+
+  // Polls the fd for |timeout_ms| milliseconds (-1 for infinity).
+  int Poll(int timeout_ms);
 
   // Promotes a DetachedBuffer to become a ProducerBuffer. Once promoted the
   // DetachedBuffer channel will be closed automatically on successful IPC
   // return. Further IPCs towards this channel will return error.
-  std::unique_ptr<BufferProducer> Promote();
+  pdx::Status<pdx::LocalChannelHandle> Promote();
 
   // Takes the underlying graphic buffer out of this DetachedBuffer. This call
   // immediately invalidates this DetachedBuffer object and transfers the
@@ -49,7 +66,7 @@
   DetachedBuffer(uint32_t width, uint32_t height, uint32_t layer_count,
                  uint32_t format, uint64_t usage, size_t user_metadata_size);
 
-  DetachedBuffer(LocalChannelHandle channel_handle);
+  DetachedBuffer(pdx::LocalChannelHandle channel_handle);
 
   int ImportGraphicBuffer();