3 files changed, 235 insertions, 0 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index c7ce6c1a6..5ba9b6c09 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -543,6 +543,8 @@ add_library(core STATIC
     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_core.cpp
+    hle/service/nvflinger/buffer_queue_core.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_core.cpp b/src/core/hle/service/nvflinger/buffer_queue_core.cpp
new file mode 100644
index 000000000..a6ff46aa9
--- /dev/null
+++ b/src/core/hle/service/nvflinger/buffer_queue_core.cpp
@@ -0,0 +1,135 @@
+// 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/BufferQueueCore.cpp
+
+#include "common/assert.h"
+
+#include "core/hle/service/nvflinger/buffer_queue_core.h"
+
+namespace android {
+
+BufferQueueCore::BufferQueueCore() : lock{mutex} {
+    // This is locked on creation, so unlock.
+    lock.unlock();
+
+    for (s32 slot = 0; slot < BufferQueueDefs::NUM_BUFFER_SLOTS; ++slot) {
+        free_slots.insert(slot);
+    }
+}
+
+void BufferQueueCore::NotifyShutdown() {
+    std::unique_lock<std::mutex> lk(mutex);
+
+    is_shutting_down = true;
+
+    SignalDequeueCondition();
+}
+
+void BufferQueueCore::SignalDequeueCondition() {
+    dequeue_condition.notify_all();
+}
+
+bool BufferQueueCore::WaitForDequeueCondition() {
+    if (is_shutting_down) {
+        return false;
+    }
+
+    dequeue_condition.wait(lock);
+
+    return true;
+}
+
+s32 BufferQueueCore::GetMinUndequeuedBufferCountLocked(bool async) const {
+    // If DequeueBuffer is allowed to error out, we don't have to add an extra buffer.
+    if (!use_async_buffer) {
+        return max_acquired_buffer_count;
+    }
+
+    if (dequeue_buffer_cannot_block || async) {
+        return max_acquired_buffer_count + 1;
+    }
+
+    return max_acquired_buffer_count;
+}
+
+s32 BufferQueueCore::GetMinMaxBufferCountLocked(bool async) const {
+    return GetMinUndequeuedBufferCountLocked(async) + 1;
+}
+
+s32 BufferQueueCore::GetMaxBufferCountLocked(bool async) const {
+    const auto min_buffer_count = GetMinMaxBufferCountLocked(async);
+    auto max_buffer_count = std::max(default_max_buffer_count, min_buffer_count);
+
+    if (override_max_buffer_count != 0) {
+        ASSERT(override_max_buffer_count >= min_buffer_count);
+        max_buffer_count = override_max_buffer_count;
+    }
+
+    // Any buffers that are dequeued by the producer or sitting in the queue waiting to be consumed
+    // need to have their slots preserved.
+    for (s32 slot = max_buffer_count; slot < BufferQueueDefs::NUM_BUFFER_SLOTS; ++slot) {
+        const auto state = slots[slot].buffer_state;
+        if (state == BufferState::Queued || state == BufferState::Dequeued) {
+            max_buffer_count = slot + 1;
+        }
+    }
+
+    return max_buffer_count;
+}
+
+s32 BufferQueueCore::GetPreallocatedBufferCountLocked() const {
+    return static_cast<s32>(std::count_if(slots.begin(), slots.end(),
+                                          [](const auto& slot) { return slot.is_preallocated; }));
+}
+
+void BufferQueueCore::FreeBufferLocked(s32 slot) {
+    LOG_DEBUG(Service_NVFlinger, "slot {}", slot);
+
+    const auto had_buffer = slots[slot].graphic_buffer != nullptr;
+
+    slots[slot].graphic_buffer.reset();
+
+    if (slots[slot].buffer_state == BufferState::Acquired) {
+        slots[slot].needs_cleanup_on_release = true;
+    }
+
+    if (slots[slot].buffer_state != BufferState::Free) {
+        free_slots.insert(slot);
+    } else if (had_buffer) {
+        // If the slot was FREE, but we had a buffer, we need to move this slot from the free
+        // buffers list to the the free slots list.
+        free_buffers.remove(slot);
+        free_slots.insert(slot);
+    }
+
+    slots[slot].buffer_state = BufferState::Free;
+    slots[slot].acquire_called = false;
+    slots[slot].frame_number = 0;
+    slots[slot].fence = Fence::NoFence();
+}
+
+void BufferQueueCore::FreeAllBuffersLocked() {
+    queue.clear();
+    buffer_has_been_queued = false;
+
+    for (s32 slot = 0; slot < BufferQueueDefs::NUM_BUFFER_SLOTS; ++slot) {
+        FreeBufferLocked(slot);
+    }
+}
+
+bool BufferQueueCore::StillTracking(const BufferItem* item) const {
+    const BufferSlot& slot = slots[item->slot];
+
+    return (slot.graphic_buffer != nullptr) && (item->graphic_buffer == slot.graphic_buffer);
+}
+
+void BufferQueueCore::WaitWhileAllocatingLocked() const {
+    while (is_allocating) {
+        std::unique_lock<std::mutex> lk(mutex);
+        is_allocating_condition.wait(lk);
+    }
+}
+
+} // namespace android
diff --git a/src/core/hle/service/nvflinger/buffer_queue_core.h b/src/core/hle/service/nvflinger/buffer_queue_core.h
new file mode 100644
index 000000000..8019b7024
--- /dev/null
+++ b/src/core/hle/service/nvflinger/buffer_queue_core.h
@@ -0,0 +1,98 @@
+// 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/BufferQueueCore.h
+
+#pragma once
+
+#include <condition_variable>
+#include <list>
+#include <memory>
+#include <mutex>
+#include <set>
+#include <vector>
+
+#include "core/hle/service/nvflinger/buffer_item.h"
+#include "core/hle/service/nvflinger/buffer_queue_defs.h"
+#include "core/hle/service/nvflinger/pixel_format.h"
+#include "core/hle/service/nvflinger/status.h"
+#include "core/hle/service/nvflinger/window.h"
+
+namespace android {
+
+class IConsumerListener;
+class IProducerListener;
+
+class BufferQueueCore final {
+    friend class BufferQueueProducer;
+    friend class BufferQueueConsumer;
+
+public:
+    static constexpr s32 INVALID_BUFFER_SLOT = BufferItem::INVALID_BUFFER_SLOT;
+
+    BufferQueueCore();
+
+    void NotifyShutdown();
+
+private:
+    void SignalDequeueCondition();
+    bool WaitForDequeueCondition();
+
+    s32 GetMinUndequeuedBufferCountLocked(bool async) const;
+    s32 GetMinMaxBufferCountLocked(bool async) const;
+    s32 GetMaxBufferCountLocked(bool async) const;
+    s32 GetPreallocatedBufferCountLocked() const;
+    void FreeBufferLocked(s32 slot);
+    void FreeAllBuffersLocked();
+    bool StillTracking(const BufferItem* item) const;
+    void WaitWhileAllocatingLocked() const;
+
+private:
+    class AutoLock final {
+    public:
+        AutoLock(std::shared_ptr<BufferQueueCore>& core_) : core{core_} {
+            core->lock.lock();
+        }
+
+        ~AutoLock() {
+            core->lock.unlock();
+        }
+
+    private:
+        std::shared_ptr<BufferQueueCore>& core;
+    };
+
+private:
+    mutable std::mutex mutex;
+    mutable std::unique_lock<std::mutex> lock;
+    bool is_abandoned{};
+    bool consumer_controlled_by_app{};
+    std::shared_ptr<IConsumerListener> consumer_listener;
+    u32 consumer_usage_bit{};
+    NativeWindowApi connected_api{NativeWindowApi::NoConnectedApi};
+    std::shared_ptr<IProducerListener> connected_producer_listener;
+    BufferQueueDefs::SlotsType slots{};
+    std::vector<BufferItem> queue;
+    std::set<s32> free_slots;
+    std::list<s32> free_buffers;
+    s32 override_max_buffer_count{};
+    mutable std::condition_variable dequeue_condition;
+    const bool use_async_buffer{}; // This is always disabled on HOS
+    bool dequeue_buffer_cannot_block{};
+    PixelFormat default_buffer_format{PixelFormat::Rgba8888};
+    u32 default_width{1};
+    u32 default_height{1};
+    s32 default_max_buffer_count{2};
+    const s32 max_acquired_buffer_count{}; // This is always zero on HOS
+    bool buffer_has_been_queued{};
+    u64 frame_counter{};
+    u32 transform_hint{};
+    bool is_allocating{};
+    mutable std::condition_variable is_allocating_condition;
+    bool allow_allocation{true};
+    u64 buffer_age{};
+    bool is_shutting_down{};
+};
+
+} // namespace android