3 files changed, 263 insertions, 0 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 045a08648..c7ce6c1a6 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -541,6 +541,8 @@ add_library(core STATIC
     hle/service/nvflinger/buffer_item.h
     hle/service/nvflinger/buffer_item_consumer.cpp
     hle/service/nvflinger/buffer_item_consumer.h
+    hle/service/nvflinger/buffer_queue_consumer.cpp
+    hle/service/nvflinger/buffer_queue_consumer.h
     hle/service/nvflinger/buffer_queue_defs.h
     hle/service/nvflinger/buffer_slot.h
     hle/service/nvflinger/buffer_transform_flags.h
diff --git a/src/core/hle/service/nvflinger/buffer_queue_consumer.cpp b/src/core/hle/service/nvflinger/buffer_queue_consumer.cpp
new file mode 100644
index 000000000..f0875eca3
--- /dev/null
+++ b/src/core/hle/service/nvflinger/buffer_queue_consumer.cpp
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright 2021 yuzu Emulator Project
+// Copyright 2014 The Android Open Source Project
+// Parts of this implementation were base on:
+// https://cs.android.com/android/platform/superproject/+/android-5.1.1_r38:frameworks/native/libs/gui/BufferQueueConsumer.cpp
+
+#include "common/logging/log.h"
+#include "core/hle/service/nvflinger/buffer_item.h"
+#include "core/hle/service/nvflinger/buffer_queue_consumer.h"
+#include "core/hle/service/nvflinger/buffer_queue_core.h"
+#include "core/hle/service/nvflinger/producer_listener.h"
+
+namespace android {
+
+BufferQueueConsumer::BufferQueueConsumer(std::shared_ptr<BufferQueueCore> core_)
+    : core{std::move(core_)}, slots{core->slots} {}
+
+BufferQueueConsumer::~BufferQueueConsumer() = default;
+
+Status BufferQueueConsumer::AcquireBuffer(BufferItem* out_buffer, s64 expected_presenst_ns,
+                                          u64 max_frame_number) {
+    s32 num_dropped_buffers{};
+
+    std::shared_ptr<IProducerListener> listener;
+    {
+        std::unique_lock lock(core->mutex);
+
+        // Check that the consumer doesn't currently have the maximum number of buffers acquired.
+        s32 num_acquired_buffers{};
+        for (const auto& slot : slots) {
+            if (slot.buffer_state == BufferState::Acquired) {
+                ++num_acquired_buffers;
+            }
+        }
+
+        if (num_acquired_buffers >= core->max_acquired_buffer_count + 1) {
+            LOG_ERROR(Service_NVFlinger, "max acquired buffer count reached: {} (max {})",
+                      num_acquired_buffers, core->max_acquired_buffer_count);
+            return Status::InvalidOperation;
+        }
+
+        // Check if the queue is empty.
+        if (core->queue.empty()) {
+            return Status::NoBufferAvailable;
+        }
+
+        auto front(core->queue.begin());
+
+        // If expected_presenst_ns is specified, we may not want to return a buffer yet.
+        if (expected_presenst_ns != 0) {
+            constexpr auto MAX_REASONABLE_NSEC = 1000000000LL; // 1 second
+
+            // The expected_presenst_ns argument indicates when the buffer is expected to be
+            // presented on-screen.
+            while (core->queue.size() > 1 && !core->queue[0].is_auto_timestamp) {
+                const auto& buffer_item{core->queue[1]};
+
+                // If dropping entry[0] would leave us with a buffer that the consumer is not yet
+                // ready for, don't drop it.
+                if (max_frame_number && buffer_item.frame_number > max_frame_number) {
+                    break;
+                }
+
+                // If entry[1] is timely, drop entry[0] (and repeat).
+                const auto desired_present = buffer_item.timestamp;
+                if (desired_present < expected_presenst_ns - MAX_REASONABLE_NSEC ||
+                    desired_present > expected_presenst_ns) {
+                    // This buffer is set to display in the near future, or desired_present is
+                    // garbage.
+                    LOG_DEBUG(Service_NVFlinger, "nodrop desire={} expect={}", desired_present,
+                              expected_presenst_ns);
+                    break;
+                }
+
+                LOG_DEBUG(Service_NVFlinger, "drop desire={} expect={} size={}", desired_present,
+                          expected_presenst_ns, core->queue.size());
+
+                if (core->StillTracking(&*front)) {
+                    // Front buffer is still in mSlots, so mark the slot as free
+                    slots[front->slot].buffer_state = BufferState::Free;
+                    core->free_buffers.push_back(front->slot);
+                    listener = core->connected_producer_listener;
+                    ++num_dropped_buffers;
+                }
+
+                core->queue.erase(front);
+                front = core->queue.begin();
+            }
+
+            // See if the front buffer is ready to be acquired.
+            const auto desired_present = front->timestamp;
+            const auto buffer_is_due = desired_present <= expected_presenst_ns ||
+                                       desired_present > expected_presenst_ns + MAX_REASONABLE_NSEC;
+            const auto consumer_is_ready =
+                max_frame_number > 0 ? front->frame_number <= max_frame_number : true;
+
+            if (!buffer_is_due || !consumer_is_ready) {
+                LOG_DEBUG(Service_NVFlinger, "defer desire={} expect={}", desired_present,
+                          expected_presenst_ns);
+                return Status::PresentLater;
+            }
+
+            LOG_DEBUG(Service_NVFlinger, "accept desire={} expect={}", desired_present,
+                      expected_presenst_ns);
+        }
+
+        const auto slot = front->slot;
+        *out_buffer = *front;
+
+        LOG_DEBUG(Service_NVFlinger, "acquiring slot={}", slot);
+
+        // If the front buffer is still being tracked, update its slot state
+        if (core->StillTracking(&*front)) {
+            slots[slot].acquire_called = true;
+            slots[slot].needs_cleanup_on_release = false;
+            slots[slot].buffer_state = BufferState::Acquired;
+            slots[slot].fence = Fence::NoFence();
+        }
+
+        // If the buffer has previously been acquired by the consumer, set graphic_buffer to nullptr
+        // to avoid unnecessarily remapping this buffer on the consumer side.
+        if (out_buffer->acquire_called) {
+            out_buffer->graphic_buffer = nullptr;
+        }
+
+        core->queue.erase(front);
+
+        // We might have freed a slot while dropping old buffers, or the producer  may be blocked
+        // waiting for the number of buffers in the queue to decrease.
+        core->SignalDequeueCondition();
+    }
+
+    if (listener != nullptr) {
+        for (s32 i = 0; i < num_dropped_buffers; ++i) {
+            listener->OnBufferReleased();
+        }
+    }
+
+    return Status::NoError;
+}
+
+Status BufferQueueConsumer::ReleaseBuffer(s32 slot, u64 frame_number, const Fence& release_fence) {
+    if (slot < 0 || slot >= BufferQueueDefs::NUM_BUFFER_SLOTS) {
+        LOG_ERROR(Service_NVFlinger, "slot {} out of range", slot);
+        return Status::BadValue;
+    }
+
+    std::shared_ptr<IProducerListener> listener;
+    {
+        std::unique_lock lock(core->mutex);
+
+        // If the frame number has changed because the buffer has been reallocated, we can ignore
+        // this ReleaseBuffer for the old buffer.
+        if (frame_number != slots[slot].frame_number) {
+            return Status::StaleBufferSlot;
+        }
+
+        // Make sure this buffer hasn't been queued while acquired by the consumer.
+        auto current(core->queue.begin());
+        while (current != core->queue.end()) {
+            if (current->slot == slot) {
+                LOG_ERROR(Service_NVFlinger, "buffer slot {} pending release is currently queued",
+                          slot);
+                return Status::BadValue;
+            }
+            ++current;
+        }
+
+        if (slots[slot].buffer_state == BufferState::Acquired) {
+            slots[slot].fence = release_fence;
+            slots[slot].buffer_state = BufferState::Free;
+
+            core->free_buffers.push_back(slot);
+
+            listener = core->connected_producer_listener;
+
+            LOG_DEBUG(Service_NVFlinger, "releasing slot {}", slot);
+        } else if (slots[slot].needs_cleanup_on_release) {
+            LOG_DEBUG(Service_NVFlinger, "releasing a stale buffer slot {} (state = {})", slot,
+                      slots[slot].buffer_state);
+
+            slots[slot].needs_cleanup_on_release = false;
+
+            return Status::StaleBufferSlot;
+        } else {
+            LOG_ERROR(Service_NVFlinger, "attempted to release buffer slot {} but its state was {}",
+                      slot, slots[slot].buffer_state);
+
+            return Status::BadValue;
+        }
+
+        core->dequeue_condition.notify_all();
+    }
+
+    // Call back without lock held
+    if (listener != nullptr) {
+        listener->OnBufferReleased();
+    }
+
+    return Status::NoError;
+}
+
+Status BufferQueueConsumer::Connect(std::shared_ptr<IConsumerListener> consumer_listener,
+                                    bool controlled_by_app) {
+    if (consumer_listener == nullptr) {
+        LOG_ERROR(Service_NVFlinger, "consumer_listener may not be nullptr");
+        return Status::BadValue;
+    }
+
+    LOG_DEBUG(Service_NVFlinger, "controlled_by_app={}", controlled_by_app);
+
+    BufferQueueCore::AutoLock lock(core);
+
+    if (core->is_abandoned) {
+        LOG_ERROR(Service_NVFlinger, "BufferQueue has been abandoned");
+        return Status::NoInit;
+    }
+
+    core->consumer_listener = consumer_listener;
+    core->consumer_controlled_by_app = controlled_by_app;
+
+    return Status::NoError;
+}
+
+} // namespace android
diff --git a/src/core/hle/service/nvflinger/buffer_queue_consumer.h b/src/core/hle/service/nvflinger/buffer_queue_consumer.h
new file mode 100644
index 000000000..fbeb8b8d7
--- /dev/null
+++ b/src/core/hle/service/nvflinger/buffer_queue_consumer.h
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright 2021 yuzu Emulator Project
+// Copyright 2014 The Android Open Source Project
+// Parts of this implementation were base on:
+// https://cs.android.com/android/platform/superproject/+/android-5.1.1_r38:frameworks/native/include/gui/BufferQueueConsumer.h
+
+#pragma once
+
+#include <memory>
+
+#include "common/common_types.h"
+#include "core/hle/service/nvflinger/buffer_queue_defs.h"
+#include "core/hle/service/nvflinger/status.h"
+
+namespace android {
+
+class BufferItem;
+class BufferQueueCore;
+class IConsumerListener;
+
+class BufferQueueConsumer final {
+public:
+    explicit BufferQueueConsumer(std::shared_ptr<BufferQueueCore> core_);
+    ~BufferQueueConsumer();
+
+    Status AcquireBuffer(BufferItem* out_buffer, s64 expected_presenst_ns,
+                         u64 max_frame_number = 0);
+    Status ReleaseBuffer(s32 slot, u64 frame_number, const Fence& release_fence);
+    Status Connect(std::shared_ptr<IConsumerListener> consumer_listener, bool controlled_by_app);
+
+private:
+    std::shared_ptr<BufferQueueCore> core;
+    BufferQueueDefs::SlotsType& slots;
+};
+
+} // namespace android