Move BufferNode to libbufferhubservice

BufferNode is a server-side class and should be located in the service
folder. Also, making the old bufferhubd service depending on
libbufferhubservice could solve the dependency problem.

Test: "atest buffer_node-test", "atest buffer_hub-test" passed.
Bug: 118893702
Change-Id: I5fad37d3c0475d6cd4f4e0ed17f911b6777a6868
diff --git a/services/bufferhub/Android.bp b/services/bufferhub/Android.bp
index a9af22f..d03d833 100644
--- a/services/bufferhub/Android.bp
+++ b/services/bufferhub/Android.bp
@@ -23,6 +23,13 @@
     ],
     srcs: [
         "BufferHubService.cpp",
+        "BufferNode.cpp",
+    ],
+    header_libs: [
+        "libbufferhub_headers",
+        "libdvr_headers",
+        "libnativewindow_headers",
+        "libpdx_headers",
     ],
     shared_libs: [
         "android.frameworks.bufferhub@1.0",
@@ -30,6 +37,7 @@
         "libhidltransport",
         "libhwbinder",
         "liblog",
+        "libui",
         "libutils",
     ],
     export_include_dirs: [
@@ -49,6 +57,7 @@
         "libhidltransport",
         "libhwbinder",
         "liblog",
+        "libui",
         "libutils",
     ],
     cflags: [
diff --git a/services/bufferhub/BufferNode.cpp b/services/bufferhub/BufferNode.cpp
new file mode 100644
index 0000000..62583a6
--- /dev/null
+++ b/services/bufferhub/BufferNode.cpp
@@ -0,0 +1,100 @@
+#include <errno.h>
+
+#include <bufferhub/BufferNode.h>
+#include <private/dvr/buffer_hub_defs.h>
+#include <ui/GraphicBufferAllocator.h>
+
+namespace android {
+namespace frameworks {
+namespace bufferhub {
+namespace V1_0 {
+namespace implementation {
+
+void BufferNode::InitializeMetadata() {
+    // Using placement new here to reuse shared memory instead of new allocation
+    // Initialize the atomic variables to zero.
+    dvr::BufferHubDefs::MetadataHeader* metadata_header = metadata_.metadata_header();
+    buffer_state_ = new (&metadata_header->buffer_state) std::atomic<uint64_t>(0);
+    fence_state_ = new (&metadata_header->fence_state) std::atomic<uint64_t>(0);
+    active_clients_bit_mask_ =
+            new (&metadata_header->active_clients_bit_mask) std::atomic<uint64_t>(0);
+}
+
+// Allocates a new BufferNode.
+BufferNode::BufferNode(uint32_t width, uint32_t height, uint32_t layer_count, uint32_t format,
+                       uint64_t usage, size_t user_metadata_size) {
+    uint32_t out_stride = 0;
+    // graphicBufferId is not used in GraphicBufferAllocator::allocate
+    // TODO(b/112338294) After move to the service folder, stop using the
+    // hardcoded service name "bufferhub".
+    int ret = GraphicBufferAllocator::get().allocate(width, height, format, layer_count, usage,
+                                                     const_cast<const native_handle_t**>(
+                                                             &buffer_handle_),
+                                                     &out_stride,
+                                                     /*graphicBufferId=*/0,
+                                                     /*requestor=*/"bufferhub");
+
+    if (ret != OK || buffer_handle_ == nullptr) {
+        ALOGE("BufferNode::BufferNode: Failed to allocate buffer: %s", strerror(-ret));
+        return;
+    }
+
+    buffer_desc_.width = width;
+    buffer_desc_.height = height;
+    buffer_desc_.layers = layer_count;
+    buffer_desc_.format = format;
+    buffer_desc_.usage = usage;
+    buffer_desc_.stride = out_stride;
+
+    metadata_ = BufferHubMetadata::Create(user_metadata_size);
+    if (!metadata_.IsValid()) {
+        ALOGE("BufferNode::BufferNode: Failed to allocate metadata.");
+        return;
+    }
+    InitializeMetadata();
+}
+
+// Free the handle
+BufferNode::~BufferNode() {
+    if (buffer_handle_ != nullptr) {
+        status_t ret = GraphicBufferAllocator::get().free(buffer_handle_);
+        if (ret != OK) {
+            ALOGE("BufferNode::~BufferNode: Failed to free handle; Got error: %d", ret);
+        }
+    }
+}
+
+uint64_t BufferNode::GetActiveClientsBitMask() const {
+    return active_clients_bit_mask_->load(std::memory_order_acquire);
+}
+
+uint64_t BufferNode::AddNewActiveClientsBitToMask() {
+    uint64_t current_active_clients_bit_mask = GetActiveClientsBitMask();
+    uint64_t client_state_mask = 0ULL;
+    uint64_t updated_active_clients_bit_mask = 0ULL;
+    do {
+        client_state_mask = dvr::BufferHubDefs::FindNextAvailableClientStateMask(
+                current_active_clients_bit_mask);
+        if (client_state_mask == 0ULL) {
+            ALOGE("BufferNode::AddNewActiveClientsBitToMask: reached the maximum "
+                  "mumber of channels per buffer node: 32.");
+            errno = E2BIG;
+            return 0ULL;
+        }
+        updated_active_clients_bit_mask = current_active_clients_bit_mask | client_state_mask;
+    } while (!(active_clients_bit_mask_->compare_exchange_weak(current_active_clients_bit_mask,
+                                                               updated_active_clients_bit_mask,
+                                                               std::memory_order_acq_rel,
+                                                               std::memory_order_acquire)));
+    return client_state_mask;
+}
+
+void BufferNode::RemoveClientsBitFromMask(const uint64_t& value) {
+    active_clients_bit_mask_->fetch_and(~value);
+}
+
+} // namespace implementation
+} // namespace V1_0
+} // namespace bufferhub
+} // namespace frameworks
+} // namespace android
diff --git a/services/bufferhub/include/bufferhub/BufferNode.h b/services/bufferhub/include/bufferhub/BufferNode.h
new file mode 100644
index 0000000..ffeacac
--- /dev/null
+++ b/services/bufferhub/include/bufferhub/BufferNode.h
@@ -0,0 +1,84 @@
+#ifndef ANDROID_FRAMEWORKS_BUFFERHUB_V1_0_BUFFER_NODE_H_
+#define ANDROID_FRAMEWORKS_BUFFERHUB_V1_0_BUFFER_NODE_H_
+
+#include <android/hardware_buffer.h>
+#include <ui/BufferHubMetadata.h>
+
+namespace android {
+namespace frameworks {
+namespace bufferhub {
+namespace V1_0 {
+namespace implementation {
+
+class BufferNode {
+public:
+    // Allocates a new BufferNode.
+    BufferNode(uint32_t width, uint32_t height, uint32_t layer_count, uint32_t format,
+               uint64_t usage, size_t user_metadata_size);
+
+    ~BufferNode();
+
+    // Returns whether the object holds a valid metadata.
+    bool IsValid() const { return metadata_.IsValid(); }
+
+    size_t user_metadata_size() const { return metadata_.user_metadata_size(); }
+
+    // Accessors of the buffer description and handle
+    const native_handle_t* buffer_handle() const { return buffer_handle_; }
+    const AHardwareBuffer_Desc& buffer_desc() const { return buffer_desc_; }
+
+    // Accessors of metadata.
+    const BufferHubMetadata& metadata() const { return metadata_; }
+
+    // Gets the current value of active_clients_bit_mask in metadata_ with
+    // std::memory_order_acquire, so that all previous releases of
+    // active_clients_bit_mask from all threads will be returned here.
+    uint64_t GetActiveClientsBitMask() const;
+
+    // Find and add a new client_state_mask to active_clients_bit_mask in
+    // metadata_.
+    // Return the new client_state_mask that is added to active_clients_bit_mask.
+    // Return 0ULL if there are already 32 bp clients of the buffer.
+    uint64_t AddNewActiveClientsBitToMask();
+
+    // Removes the value from active_clients_bit_mask in metadata_ with
+    // std::memory_order_release, so that the change will be visible to any
+    // acquire of active_clients_bit_mask_ in any threads after the succeed of
+    // this operation.
+    void RemoveClientsBitFromMask(const uint64_t& value);
+
+private:
+    // Helper method for constructors to initialize atomic metadata header
+    // variables in shared memory.
+    void InitializeMetadata();
+
+    // Gralloc buffer handles.
+    native_handle_t* buffer_handle_;
+    AHardwareBuffer_Desc buffer_desc_;
+
+    // Metadata in shared memory.
+    BufferHubMetadata metadata_;
+
+    // The following variables are atomic variables in metadata_ that are visible
+    // to Bn object and Bp objects. Please find more info in
+    // BufferHubDefs::MetadataHeader.
+
+    // buffer_state_ tracks the state of the buffer. Buffer can be in one of these
+    // four states: gained, posted, acquired, released.
+    std::atomic<uint64_t>* buffer_state_ = nullptr;
+
+    // TODO(b/112012161): add comments to fence_state_.
+    std::atomic<uint64_t>* fence_state_ = nullptr;
+
+    // active_clients_bit_mask_ tracks all the bp clients of the buffer. It is the
+    // union of all client_state_mask of all bp clients.
+    std::atomic<uint64_t>* active_clients_bit_mask_ = nullptr;
+};
+
+} // namespace implementation
+} // namespace V1_0
+} // namespace bufferhub
+} // namespace frameworks
+} // namespace android
+
+#endif // ANDROID_FRAMEWORKS_BUFFERHUB_V1_0_BUFFER_NODE_H_
diff --git a/services/bufferhub/tests/Android.bp b/services/bufferhub/tests/Android.bp
new file mode 100644
index 0000000..cef31f6
--- /dev/null
+++ b/services/bufferhub/tests/Android.bp
@@ -0,0 +1,24 @@
+cc_test {
+    name: "BufferNode_test",
+    srcs: ["BufferNode_test.cpp"],
+    cflags: [
+        "-DLOG_TAG=\"BufferNode_test\"",
+        "-DTRACE=0",
+        "-DATRACE_TAG=ATRACE_TAG_GRAPHICS",
+    ],
+    header_libs: [
+        "libbufferhub_headers",
+        "libdvr_headers",
+        "libnativewindow_headers",
+        "libpdx_headers",
+    ],
+    shared_libs: [
+        "libbufferhubservice",
+        "libui",
+    ],
+    static_libs: [
+        "libgmock",
+    ],
+    // TODO(b/117568153): Temporarily opt out using libcrt.
+    no_libcrt: true,
+}
\ No newline at end of file
diff --git a/services/bufferhub/tests/BufferNode_test.cpp b/services/bufferhub/tests/BufferNode_test.cpp
new file mode 100644
index 0000000..df31d78
--- /dev/null
+++ b/services/bufferhub/tests/BufferNode_test.cpp
@@ -0,0 +1,110 @@
+#include <bufferhub/BufferNode.h>
+#include <errno.h>
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <ui/GraphicBufferMapper.h>
+
+namespace android {
+namespace frameworks {
+namespace bufferhub {
+namespace V1_0 {
+namespace implementation {
+
+namespace {
+
+using testing::NotNull;
+
+const uint32_t kWidth = 640;
+const uint32_t kHeight = 480;
+const uint32_t kLayerCount = 1;
+const uint32_t kFormat = 1;
+const uint64_t kUsage = 0;
+const size_t kUserMetadataSize = 0;
+const size_t kMaxClientsCount = dvr::BufferHubDefs::kMaxNumberOfClients;
+
+class BufferNodeTest : public ::testing::Test {
+protected:
+    void SetUp() override {
+        buffer_node =
+                new BufferNode(kWidth, kHeight, kLayerCount, kFormat, kUsage, kUserMetadataSize);
+        ASSERT_TRUE(buffer_node->IsValid());
+    }
+
+    void TearDown() override {
+        if (buffer_node != nullptr) {
+            delete buffer_node;
+        }
+    }
+
+    BufferNode* buffer_node = nullptr;
+};
+
+TEST_F(BufferNodeTest, TestCreateBufferNode) {
+    EXPECT_EQ(buffer_node->user_metadata_size(), kUserMetadataSize);
+    // Test the handle just allocated is good (i.e. able to be imported)
+    GraphicBufferMapper& mapper = GraphicBufferMapper::get();
+    const native_handle_t* outHandle;
+    status_t ret =
+            mapper.importBuffer(buffer_node->buffer_handle(), buffer_node->buffer_desc().width,
+                                buffer_node->buffer_desc().height,
+                                buffer_node->buffer_desc().layers,
+                                buffer_node->buffer_desc().format, buffer_node->buffer_desc().usage,
+                                buffer_node->buffer_desc().stride, &outHandle);
+    EXPECT_EQ(ret, OK);
+    EXPECT_THAT(outHandle, NotNull());
+}
+
+TEST_F(BufferNodeTest, TestAddNewActiveClientsBitToMask_twoNewClients) {
+    uint64_t new_client_state_mask_1 = buffer_node->AddNewActiveClientsBitToMask();
+    EXPECT_EQ(buffer_node->GetActiveClientsBitMask(), new_client_state_mask_1);
+
+    // Request and add a new client_state_mask again.
+    // Active clients bit mask should be the union of the two new
+    // client_state_masks.
+    uint64_t new_client_state_mask_2 = buffer_node->AddNewActiveClientsBitToMask();
+    EXPECT_EQ(buffer_node->GetActiveClientsBitMask(),
+              new_client_state_mask_1 | new_client_state_mask_2);
+}
+
+TEST_F(BufferNodeTest, TestAddNewActiveClientsBitToMask_32NewClients) {
+    uint64_t new_client_state_mask = 0ULL;
+    uint64_t current_mask = 0ULL;
+    uint64_t expected_mask = 0ULL;
+
+    for (int i = 0; i < kMaxClientsCount; ++i) {
+        new_client_state_mask = buffer_node->AddNewActiveClientsBitToMask();
+        EXPECT_NE(new_client_state_mask, 0);
+        EXPECT_FALSE(new_client_state_mask & current_mask);
+        expected_mask = current_mask | new_client_state_mask;
+        current_mask = buffer_node->GetActiveClientsBitMask();
+        EXPECT_EQ(current_mask, expected_mask);
+    }
+
+    // Method should fail upon requesting for more than maximum allowable clients.
+    new_client_state_mask = buffer_node->AddNewActiveClientsBitToMask();
+    EXPECT_EQ(new_client_state_mask, 0ULL);
+    EXPECT_EQ(errno, E2BIG);
+}
+
+TEST_F(BufferNodeTest, TestRemoveActiveClientsBitFromMask) {
+    buffer_node->AddNewActiveClientsBitToMask();
+    uint64_t current_mask = buffer_node->GetActiveClientsBitMask();
+    uint64_t new_client_state_mask = buffer_node->AddNewActiveClientsBitToMask();
+    EXPECT_NE(buffer_node->GetActiveClientsBitMask(), current_mask);
+
+    buffer_node->RemoveClientsBitFromMask(new_client_state_mask);
+    EXPECT_EQ(buffer_node->GetActiveClientsBitMask(), current_mask);
+
+    // Remove the test_mask again to the active client bit mask should not modify
+    // the value of active clients bit mask.
+    buffer_node->RemoveClientsBitFromMask(new_client_state_mask);
+    EXPECT_EQ(buffer_node->GetActiveClientsBitMask(), current_mask);
+}
+
+} // namespace
+
+} // namespace implementation
+} // namespace V1_0
+} // namespace bufferhub
+} // namespace frameworks
+} // namespace android