Commonise buffer interval list code

This will be reused for usagetracker.

app/src/main/cpp/skyline/common/interval_list.h

@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright © 2022 Skyline Team and Contributors (https://github.com/skyline-emu/)
+
+#pragma once
+
+#include "base.h"
+#include "span.h"
+
+namespace skyline {
+    /**
+     * @brief Stores a list of non-overlapping intervals
+     */
+    template<typename SizeType>
+    class IntervalList {
+      public:
+        using DifferenceType = decltype(std::declval<SizeType>() - std::declval<SizeType>());
+
+        struct Interval {
+            SizeType offset;
+            SizeType end;
+
+            Interval() = default;
+
+            Interval(SizeType offset, SizeType end) : offset{offset}, end{end} {}
+
+            Interval(span<u8> interval) : offset{interval.data()}, end{interval.data() + interval.size()} {}
+        };
+
+      private:
+        std::vector<Interval> intervals; //!< A list of intervals sorted by their end offset
+
+      public:
+        struct QueryResult {
+            bool enclosed; //!< If the given offset was enclosed by an interval
+            DifferenceType size; //!< Size of the interval starting from the query offset, or distance to the next interval if `enclosed` is false (if there is no next interval size is 0)
+        };
+
+        /**
+         * @brief Clears all inserted intervals from the map
+         */
+        void Clear() {
+            intervals.clear();
+        }
+
+        /**
+         * @brief Forces future accesses to the given interval to use the shadow copy
+        */
+        void Insert(Interval entry) {
+            auto firstIt{std::lower_bound(intervals.begin(), intervals.end(), entry, [](const auto &lhs, const auto &rhs) {
+                return lhs.end < rhs.offset;
+            })}; // Lowest offset entry that (maybe) overlaps with the new entry
+
+            if (firstIt == intervals.end() || firstIt->offset >= entry.end) {
+                intervals.insert(firstIt, entry);
+                return;
+            }
+            // Now firstIt will always overlap
+
+            auto lastIt{firstIt}; // Highest offset entry that overlaps with the new entry
+            while (std::next(lastIt) != intervals.end() && std::next(lastIt)->offset < entry.end)
+                lastIt++;
+
+            // Since firstIt and lastIt both are guaranteed to overlap, max them to get the new entry's end
+            SizeType end{std::max(std::max(firstIt->end, entry.end), lastIt->end)};
+
+            // Erase all overlapping entries but the first
+            auto eraseStartIt{std::next(firstIt)};
+            auto eraseEndIt{std::next(lastIt)};
+            if (eraseStartIt != eraseEndIt) {
+                lastIt = intervals.erase(eraseStartIt, eraseEndIt);
+                firstIt = std::prev(lastIt);
+            }
+
+            firstIt->offset = std::min(entry.offset, firstIt->offset);
+            firstIt->end = end;
+        }
+
+        /**
+         * @brief Merge the given interval into the list
+         */
+        void Merge(const IntervalList<SizeType> &list) {
+            for (auto &entry : list.intervals)
+                Insert(entry);
+        }
+
+        /**
+         * @return A struct describing the interval containing `offset`
+         */
+        QueryResult Query(SizeType offset) {
+            auto it{std::lower_bound(intervals.begin(), intervals.end(), offset, [](const auto &lhs, const auto &rhs) {
+                return lhs.end < rhs;
+            })}; // Lowest offset entry that (maybe) overlaps with the new entry
+
+            if (it == intervals.end()) // No overlaps past offset
+                return {false, {}};
+            else if (it->offset > offset) // No overlap, return the distance to the next possible overlap
+                return {false, it->offset - offset};
+            else // Overlap, return the distance to the end of the overlap
+                return {true, it->end - offset};
+        }
+
+        /**
+         * @return If the given interval intersects with any of the intervals in the list
+         */
+        bool Intersect(Interval interval) {
+            SizeType offset{interval.offset};
+            while (offset < interval.end) {
+                if (auto result{Query(offset)}; result.enclosed)
+                    return true;
+                else if (result.size)
+                    offset += result.size;
+                else
+                    return false;
+            }
+
+            return false;
+        }
+    };
+}

app/src/main/cpp/skyline/gpu/buffer.cpp

@@ -116,49 +116,6 @@ namespace skyline::gpu {
         });
     }
 
-    void Buffer::InsertWriteIntervalDirect(WriteTrackingInterval entry) {
-        auto firstIt{std::lower_bound(directTrackedWrites.begin(), directTrackedWrites.end(), entry, [](const auto &lhs, const auto &rhs) {
-            return lhs.end < rhs.offset;
-        })}; // Lowest offset entry that (maybe) overlaps with the new entry
-
-        if (firstIt == directTrackedWrites.end() || firstIt->offset >= entry.end) {
-            directTrackedWrites.insert(firstIt, entry);
-            return;
-        }
-        // Now firstIt will always overlap
-        
-        auto lastIt{firstIt}; // Highest offset entry that overlaps with the new entry
-        while (std::next(lastIt) != directTrackedWrites.end() && std::next(lastIt)->offset < entry.end)
-            lastIt++;
-
-        // Since firstIt and lastIt both are guaranteed to overlap, max them to get the new entry's end
-        size_t end{std::max(std::max(firstIt->end, entry.end), lastIt->end)};
-
-        // Erase all overlapping entries but the first
-        auto eraseStartIt{std::next(firstIt)};
-        auto eraseEndIt{std::next(lastIt)};
-        if (eraseStartIt != eraseEndIt) {
-            lastIt = directTrackedWrites.erase(eraseStartIt, eraseEndIt);
-            firstIt = std::prev(lastIt);
-        }
-
-        firstIt->offset = std::min(entry.offset, firstIt->offset);
-        firstIt->end = end;
-    }
-
-    Buffer::QueryIntervalResult Buffer::QueryWriteIntervalDirect(u64 offset) {
-        auto it{std::lower_bound(directTrackedWrites.begin(), directTrackedWrites.end(), offset, [](const auto &lhs, const auto &rhs) {
-            return lhs.end < rhs;
-        })}; // Lowest offset entry that (maybe) overlaps with the new entry
-
-        if (it == directTrackedWrites.end()) // No overlaps for the entire rest of buffer
-            return {false, mirror.size() - offset};
-        else if (it->offset > offset) // No overlap, return the distance to the next possible overlap
-            return {false, it->offset - offset};
-        else // Overlap, return the distance to the end of the overlap
-            return {true, it->end - offset};
-    }
-
     void Buffer::EnableTrackedShadowDirect() {
         if (!directTrackedShadowActive) {
             directTrackedShadow.resize(guest->size());
@@ -168,7 +125,7 @@ namespace skyline::gpu {
 
     span<u8> Buffer::BeginWriteCpuSequencedDirect(size_t offset, size_t size) {
         EnableTrackedShadowDirect();
-        InsertWriteIntervalDirect({offset, offset + size});
+        directTrackedWrites.Insert({offset, offset + size});
         return {directTrackedShadow.data() + offset, size};
     }
 
@@ -180,7 +137,7 @@ namespace skyline::gpu {
                 directTrackedShadow.clear();
                 directTrackedShadow.shrink_to_fit();
             }
-            directTrackedWrites.clear();
+            directTrackedWrites.Clear();
         }
         
         return readsActive;
@@ -352,8 +309,8 @@ namespace skyline::gpu {
         if (directTrackedShadowActive && RefreshGpuReadsActiveDirect()) {
             size_t curOffset{offset};
             while (curOffset != data.size() + offset) {
-                auto result{QueryWriteIntervalDirect(curOffset)};
-                auto srcData{result.useShadow ? directTrackedShadow.data() : mirror.data()};
+                auto result{directTrackedWrites.Query(curOffset)};
+                auto srcData{result.enclosed ? directTrackedShadow.data() : mirror.data()};
                 std::memcpy(data.data() + curOffset - offset, srcData + curOffset, result.size);
                 curOffset += result.size;
             }

app/src/main/cpp/skyline/gpu/buffer.h

@@ -49,14 +49,7 @@ namespace skyline::gpu {
         size_t id;
         bool isDirect{}; //!< Indicates if a buffer is directly mapped from the guest
 
-        /**
-         * @brief Interval struct used to track which part of the buffer should be accessed through the shadow
-         */
-        struct WriteTrackingInterval {
-            size_t offset;
-            size_t end;
-        };
-        std::vector<WriteTrackingInterval> directTrackedWrites; //!< (Direct) A vector of write tracking intervals for the buffer, this is used to determine when to read from `directTrackedShadow`
+        IntervalList<size_t> directTrackedWrites; //!< (Direct) A list of tracking intervals for the buffer, this is used to determine when to read from `directTrackedShadow`
         std::vector<u8> directTrackedShadow; //!< (Direct) Temporary mirror used to track any CPU-side writes to the buffer while it's being read by the GPU
         bool directTrackedShadowActive{}; //!< (Direct) If `directTrackedShadow` is currently being used to track writes
 
@@ -116,11 +109,6 @@ namespace skyline::gpu {
         void ResetMegabufferState();
 
       private:
-        struct QueryIntervalResult {
-            bool useShadow; //!< If the shadow should be used for buffer accesses within the interval
-            u64 size; //!< Size of the interval starting from the query offset
-        };
-
         BufferDelegate *delegate;
 
         friend BufferView;
@@ -128,16 +116,6 @@ namespace skyline::gpu {
 
         void SetupStagedTraps();
 
-        /**
-         * @brief Forces future accesses to the given interval to use the shadow copy
-         */
-        void InsertWriteIntervalDirect(WriteTrackingInterval interval);
-
-        /**
-         * @return A struct describing the interval containing `offset`
-         */
-        QueryIntervalResult QueryWriteIntervalDirect(u64 offset);
-
         /**
          * @brief Enables the shadow buffer used for sequencing buffer contents independently of the GPU on the CPU
          */

app/src/main/cpp/skyline/gpu/buffer_manager.cpp

@@ -130,8 +130,7 @@ namespace skyline::gpu {
                 } else if (srcBuffer->directTrackedShadowActive) {
                     newBuffer->EnableTrackedShadowDirect();
                     copyBuffer(*newBuffer->guest, *srcBuffer->guest, newBuffer->directTrackedShadow.data(), srcBuffer->directTrackedShadow.data());
-                    for (const auto &interval : srcBuffer->directTrackedWrites)
-                        newBuffer->InsertWriteIntervalDirect(interval);
+                    newBuffer->directTrackedWrites.Merge(srcBuffer->directTrackedWrites);
                 }
             }