[sf-newfe] Fix snapshot paths for recursive mirror paths

If we are mirroring a hierarchy that already contains a mirror
then we need to track all the mirror roots inorder to have
a unique path.

Test: presubmit
Test: can screenrecord magnifier
Test: dumpsys SurfaceFlinger --frontend
Bug: 238781169
Change-Id: Id2272981f6f6244f41328428b73184bccf5d1888

8 files changed, 112 insertions, 35 deletions

diff --git a/services/surfaceflinger/FrontEnd/LayerHierarchy.cpp b/services/surfaceflinger/FrontEnd/LayerHierarchy.cpp
index 962dc09680..1e5a6fbd1e 100644
--- a/services/surfaceflinger/FrontEnd/LayerHierarchy.cpp
+++ b/services/surfaceflinger/FrontEnd/LayerHierarchy.cpp
@@ -145,7 +145,8 @@ std::string LayerHierarchy::getDebugStringShort() const {
 }
 
 void LayerHierarchy::dump(std::ostream& out, const std::string& prefix,
-                          LayerHierarchy::Variant variant, bool isLastChild) const {
+                          LayerHierarchy::Variant variant, bool isLastChild,
+                          bool includeMirroredHierarchy) const {
     if (!mLayer) {
         out << " ROOT";
     } else {
@@ -153,8 +154,11 @@ void LayerHierarchy::dump(std::ostream& out, const std::string& prefix,
         if (variant == LayerHierarchy::Variant::Relative) {
             out << "(Relative) ";
         } else if (variant == LayerHierarchy::Variant::Mirror) {
-            out << "(Mirroring) " << *mLayer << "\n" + prefix + "   └─ ...";
-            return;
+            if (!includeMirroredHierarchy) {
+                out << "(Mirroring) " << *mLayer << "\n" + prefix + "   └─ ...";
+                return;
+            }
+            out << "(Mirroring) ";
         }
         out << *mLayer;
     }
@@ -168,7 +172,7 @@ void LayerHierarchy::dump(std::ostream& out, const std::string& prefix,
             childPrefix += (isLastChild ? "   " : "│  ");
         }
         out << "\n";
-        child->dump(out, childPrefix, childVariant, lastChild);
+        child->dump(out, childPrefix, childVariant, lastChild, includeMirroredHierarchy);
     }
     return;
 }
@@ -435,8 +439,11 @@ std::string LayerHierarchy::TraversalPath::toString() const {
     std::stringstream ss;
     ss << "TraversalPath{.id = " << id;
 
-    if (mirrorRootId != UNASSIGNED_LAYER_ID) {
-        ss << ", .mirrorRootId=" << mirrorRootId;
+    if (!mirrorRootIds.empty()) {
+        ss << ", .mirrorRootIds=";
+        for (auto rootId : mirrorRootIds) {
+            ss << rootId << ",";
+        }
     }
 
     if (!relativeRootIds.empty()) {
@@ -453,13 +460,6 @@ std::string LayerHierarchy::TraversalPath::toString() const {
     return ss.str();
 }
 
-LayerHierarchy::TraversalPath LayerHierarchy::TraversalPath::getMirrorRoot() const {
-    LLOG_ALWAYS_FATAL_WITH_TRACE_IF(!isClone(), "Cannot get mirror root of a non cloned node");
-    TraversalPath mirrorRootPath = *this;
-    mirrorRootPath.id = mirrorRootId;
-    return mirrorRootPath;
-}
-
 // Helper class to update a passed in TraversalPath when visiting a child. When the object goes out
 // of scope the TraversalPath is reset to its original state.
 LayerHierarchy::ScopedAddToTraversalPath::ScopedAddToTraversalPath(TraversalPath& traversalPath,
@@ -471,7 +471,7 @@ LayerHierarchy::ScopedAddToTraversalPath::ScopedAddToTraversalPath(TraversalPath
     traversalPath.id = layerId;
     traversalPath.variant = variant;
     if (variant == LayerHierarchy::Variant::Mirror) {
-        traversalPath.mirrorRootId = mParentPath.id;
+        traversalPath.mirrorRootIds.emplace_back(mParentPath.id);
     } else if (variant == LayerHierarchy::Variant::Relative) {
         if (std::find(traversalPath.relativeRootIds.begin(), traversalPath.relativeRootIds.end(),
                       layerId) != traversalPath.relativeRootIds.end()) {
@@ -486,7 +486,7 @@ LayerHierarchy::ScopedAddToTraversalPath::~ScopedAddToTraversalPath() {
     // Reset the traversal id to its original parent state using the state that was saved in
     // the constructor.
     if (mTraversalPath.variant == LayerHierarchy::Variant::Mirror) {
-        mTraversalPath.mirrorRootId = mParentPath.mirrorRootId;
+        mTraversalPath.mirrorRootIds.pop_back();
     } else if (mTraversalPath.variant == LayerHierarchy::Variant::Relative) {
         mTraversalPath.relativeRootIds.pop_back();
     }
diff --git a/services/surfaceflinger/FrontEnd/LayerHierarchy.h b/services/surfaceflinger/FrontEnd/LayerHierarchy.h
index 1e4838727b..ba2e262baf 100644
--- a/services/surfaceflinger/FrontEnd/LayerHierarchy.h
+++ b/services/surfaceflinger/FrontEnd/LayerHierarchy.h
@@ -57,25 +57,25 @@ public:
     // ├─ B {Traversal path id = 2}
     // │  ├─ C {Traversal path id = 3}
     // │  ├─ D {Traversal path id = 4}
-    // │  └─ E {Traversal path id = 5}
-    // ├─ F (Mirrors B) {Traversal path id = 6}
-    // └─ G (Mirrors F) {Traversal path id = 7}
+    // │  └─ E (Mirrors C) {Traversal path id = 5}
+    // └─ F (Mirrors B) {Traversal path id = 6}
     //
-    // C, D and E can be traversed via B or via F then B or via G then F then B.
+    // C can be traversed via B or E or F and or via F then E.
     // Depending on how the node is reached, its properties such as geometry or visibility might be
     // different. And we can uniquely identify the node by keeping track of the nodes leading up to
     // it. But to be more efficient we only need to track the nodes id and the top mirror root path.
     // So C for example, would have the following unique traversal paths:
     //  - {Traversal path id = 3}
-    //  - {Traversal path id = 3, mirrorRootId = 6}
-    //  - {Traversal path id = 3, mirrorRootId = 7}
+    //  - {Traversal path id = 3, mirrorRootIds = 5}
+    //  - {Traversal path id = 3, mirrorRootIds = 6}
+    //  - {Traversal path id = 3, mirrorRootIds = 6, 5}
 
     struct TraversalPath {
         uint32_t id;
         LayerHierarchy::Variant variant;
         // Mirrored layers can have a different geometry than their parents so we need to track
         // the mirror roots in the traversal.
-        uint32_t mirrorRootId = UNASSIGNED_LAYER_ID;
+        ftl::SmallVector<uint32_t, 5> mirrorRootIds;
         // Relative layers can be visited twice, once by their parent and then once again by
         // their relative parent. We keep track of the roots here to detect any loops in the
         // hierarchy. If a relative root already exists in the list while building the
@@ -93,11 +93,10 @@ public:
         // Returns true if the node or its parents are not Detached.
         bool isAttached() const { return !detached; }
         // Returns true if the node is a clone.
-        bool isClone() const { return mirrorRootId != UNASSIGNED_LAYER_ID; }
-        TraversalPath getMirrorRoot() const;
+        bool isClone() const { return !mirrorRootIds.empty(); }
 
         bool operator==(const TraversalPath& other) const {
-            return id == other.id && mirrorRootId == other.mirrorRootId;
+            return id == other.id && mirrorRootIds == other.mirrorRootIds;
         }
         std::string toString() const;
 
@@ -107,8 +106,8 @@ public:
     struct TraversalPathHash {
         std::size_t operator()(const LayerHierarchy::TraversalPath& key) const {
             uint32_t hashCode = key.id * 31;
-            if (key.mirrorRootId != UNASSIGNED_LAYER_ID) {
-                hashCode += key.mirrorRootId * 31;
+            for (uint32_t mirrorRootId : key.mirrorRootIds) {
+                hashCode += mirrorRootId * 31;
             }
             return std::hash<size_t>{}(hashCode);
         }
@@ -158,9 +157,17 @@ public:
     const LayerHierarchy* getParent() const;
     friend std::ostream& operator<<(std::ostream& os, const LayerHierarchy& obj) {
         std::string prefix = " ";
-        obj.dump(os, prefix, LayerHierarchy::Variant::Attached, /*isLastChild=*/false);
+        obj.dump(os, prefix, LayerHierarchy::Variant::Attached, /*isLastChild=*/false,
+                 /*includeMirroredHierarchy*/ false);
         return os;
     }
+    std::string dump() const {
+        std::string prefix = " ";
+        std::ostringstream os;
+        dump(os, prefix, LayerHierarchy::Variant::Attached, /*isLastChild=*/false,
+             /*includeMirroredHierarchy*/ true);
+        return os.str();
+    }
 
     std::string getDebugStringShort() const;
     // Traverse the hierarchy and return true if loops are found. The outInvalidRelativeRoot
@@ -178,7 +185,7 @@ private:
     void traverseInZOrder(const Visitor& visitor, LayerHierarchy::TraversalPath& parent) const;
     void traverse(const Visitor& visitor, LayerHierarchy::TraversalPath& parent) const;
     void dump(std::ostream& out, const std::string& prefix, LayerHierarchy::Variant variant,
-              bool isLastChild) const;
+              bool isLastChild, bool includeMirroredHierarchy) const;
 
     const RequestedLayerState* mLayer;
     LayerHierarchy* mParent = nullptr;
diff --git a/services/surfaceflinger/FrontEnd/LayerSnapshot.cpp b/services/surfaceflinger/FrontEnd/LayerSnapshot.cpp
index 80bedf4a39..899d2dedaf 100644
--- a/services/surfaceflinger/FrontEnd/LayerSnapshot.cpp
+++ b/services/surfaceflinger/FrontEnd/LayerSnapshot.cpp
@@ -294,8 +294,11 @@ std::string LayerSnapshot::getDebugString() const {
 
 std::ostream& operator<<(std::ostream& out, const LayerSnapshot& obj) {
     out << "Layer [" << obj.path.id;
-    if (obj.path.mirrorRootId != UNASSIGNED_LAYER_ID) {
-        out << " mirrored from " << obj.path.mirrorRootId;
+    if (!obj.path.mirrorRootIds.empty()) {
+        out << " mirrored from ";
+        for (auto rootId : obj.path.mirrorRootIds) {
+            out << rootId << ",";
+        }
     }
     out << "] " << obj.name << "\n    " << (obj.isVisible ? "visible" : "invisible")
         << " reason=" << obj.getIsVisibleReason();
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 9a5173ba9b..2bbfa42358 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -2648,7 +2648,7 @@ Region Layer::getVisibleRegion(const DisplayDevice* display) const {
 
 void Layer::setInitialValuesForClone(const sp<Layer>& clonedFrom, uint32_t mirrorRootId) {
     mSnapshot->path.id = clonedFrom->getSequence();
-    mSnapshot->path.mirrorRootId = mirrorRootId;
+    mSnapshot->path.mirrorRootIds.emplace_back(mirrorRootId);
 
     cloneDrawingState(clonedFrom.get());
     mClonedFrom = clonedFrom;
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 517dc96195..92e4881941 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -5823,6 +5823,7 @@ status_t SurfaceFlinger::doDump(int fd, const DumpArgs& args, bool asProto) {
                 {"--timestats"s, protoDumper(&SurfaceFlinger::dumpTimeStats)},
                 {"--vsync"s, dumper(&SurfaceFlinger::dumpVsync)},
                 {"--wide-color"s, dumper(&SurfaceFlinger::dumpWideColorInfo)},
+                {"--frontend"s, dumper(&SurfaceFlinger::dumpFrontEnd)},
         };
 
         const auto flag = args.empty() ? ""s : std::string(String8(args[0]));
@@ -6132,6 +6133,38 @@ void SurfaceFlinger::dumpHdrInfo(std::string& result) const {
     }
 }
 
+void SurfaceFlinger::dumpFrontEnd(std::string& result) {
+    mScheduler
+            ->schedule([&]() FTL_FAKE_GUARD(mStateLock) FTL_FAKE_GUARD(kMainThreadContext) {
+                std::ostringstream out;
+                out << "\nComposition list\n";
+                ui::LayerStack lastPrintedLayerStackHeader = ui::INVALID_LAYER_STACK;
+                for (const auto& snapshot : mLayerSnapshotBuilder.getSnapshots()) {
+                    if (lastPrintedLayerStackHeader != snapshot->outputFilter.layerStack) {
+                        lastPrintedLayerStackHeader = snapshot->outputFilter.layerStack;
+                        out << "LayerStack=" << lastPrintedLayerStackHeader.id << "\n";
+                    }
+                    out << "  " << *snapshot << "\n";
+                }
+
+                out << "\nInput list\n";
+                lastPrintedLayerStackHeader = ui::INVALID_LAYER_STACK;
+                mLayerSnapshotBuilder.forEachInputSnapshot(
+                        [&](const frontend::LayerSnapshot& snapshot) {
+                            if (lastPrintedLayerStackHeader != snapshot.outputFilter.layerStack) {
+                                lastPrintedLayerStackHeader = snapshot.outputFilter.layerStack;
+                                out << "LayerStack=" << lastPrintedLayerStackHeader.id << "\n";
+                            }
+                            out << "  " << snapshot << "\n";
+                        });
+
+                out << "\nLayer Hierarchy\n"
+                    << mLayerHierarchyBuilder.getHierarchy().dump() << "\n\n";
+                result.append(out.str());
+            })
+            .get();
+}
+
 perfetto::protos::LayersProto SurfaceFlinger::dumpDrawingStateProto(uint32_t traceFlags) const {
     std::unordered_set<uint64_t> stackIdsToSkip;
 
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 59b1172edc..8fa5de7f30 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -1090,6 +1090,7 @@ private:
     void dumpRawDisplayIdentificationData(const DumpArgs&, std::string& result) const;
     void dumpWideColorInfo(std::string& result) const REQUIRES(mStateLock);
     void dumpHdrInfo(std::string& result) const REQUIRES(mStateLock);
+    void dumpFrontEnd(std::string& result);
 
     perfetto::protos::LayersProto dumpDrawingStateProto(uint32_t traceFlags) const;
     void dumpOffscreenLayersProto(perfetto::protos::LayersProto& layersProto,
diff --git a/services/surfaceflinger/tests/unittests/LayerHierarchyTest.cpp b/services/surfaceflinger/tests/unittests/LayerHierarchyTest.cpp
index e4f49e863b..95f19406b4 100644
--- a/services/surfaceflinger/tests/unittests/LayerHierarchyTest.cpp
+++ b/services/surfaceflinger/tests/unittests/LayerHierarchyTest.cpp
@@ -736,4 +736,22 @@ TEST_F(LayerHierarchyTest, removedRootLayerIsNoLongerMirrored) {
     EXPECT_EQ(getTraversalPath(hierarchyBuilder.getOffscreenHierarchy()), expected);
 }
 
+TEST_F(LayerHierarchyTest, canMirrorDisplayWithMirrors) {
+    LayerHierarchyBuilder hierarchyBuilder(mLifecycleManager.getLayers());
+    reparentLayer(12, UNASSIGNED_LAYER_ID);
+    mirrorLayer(/*layer*/ 14, /*parent*/ 1, /*layerToMirror*/ 11);
+    UPDATE_AND_VERIFY(hierarchyBuilder);
+
+    createDisplayMirrorLayer(3, ui::LayerStack::fromValue(0));
+    setLayerStack(3, 1);
+    UPDATE_AND_VERIFY(hierarchyBuilder);
+
+    std::vector<uint32_t> expected = {1, 11, 111, 13, 14, 11, 111, 2, 3,
+                                      1, 11, 111, 13, 14, 11, 111, 2};
+    EXPECT_EQ(getTraversalPath(hierarchyBuilder.getHierarchy()), expected);
+    EXPECT_EQ(getTraversalPathInZOrder(hierarchyBuilder.getHierarchy()), expected);
+    expected = {12, 121, 122, 1221};
+    EXPECT_EQ(getTraversalPath(hierarchyBuilder.getOffscreenHierarchy()), expected);
+}
+
 } // namespace android::surfaceflinger::frontend
diff --git a/services/surfaceflinger/tests/unittests/LayerSnapshotTest.cpp b/services/surfaceflinger/tests/unittests/LayerSnapshotTest.cpp
index 23534802cc..1227b994dd 100644
--- a/services/surfaceflinger/tests/unittests/LayerSnapshotTest.cpp
+++ b/services/surfaceflinger/tests/unittests/LayerSnapshotTest.cpp
@@ -410,8 +410,8 @@ TEST_F(LayerSnapshotTest, mirrorLayerGetsCorrectLayerStack) {
     std::vector<uint32_t> expected = {1,  11, 111, 13, 2,  3,   1,  11, 111,
                                       13, 2,  4,   1,  11, 111, 13, 2};
     UPDATE_AND_VERIFY(mSnapshotBuilder, expected);
-    EXPECT_EQ(getSnapshot({.id = 111, .mirrorRootId = 3})->outputFilter.layerStack.id, 3u);
-    EXPECT_EQ(getSnapshot({.id = 111, .mirrorRootId = 4})->outputFilter.layerStack.id, 4u);
+    EXPECT_EQ(getSnapshot({.id = 111, .mirrorRootIds = 3u})->outputFilter.layerStack.id, 3u);
+    EXPECT_EQ(getSnapshot({.id = 111, .mirrorRootIds = 4u})->outputFilter.layerStack.id, 4u);
 }
 
 // ROOT (DISPLAY 0)
@@ -435,7 +435,7 @@ TEST_F(LayerSnapshotTest, mirrorLayerTouchIsCroppedByMirrorRoot) {
     UPDATE_AND_VERIFY(mSnapshotBuilder, expected);
     EXPECT_TRUE(getSnapshot({.id = 111})->inputInfo.touchableRegion.hasSameRects(touch));
     Region touchCroppedByMirrorRoot{Rect{0, 0, 50, 50}};
-    EXPECT_TRUE(getSnapshot({.id = 111, .mirrorRootId = 3})
+    EXPECT_TRUE(getSnapshot({.id = 111, .mirrorRootIds = 3u})
                         ->inputInfo.touchableRegion.hasSameRects(touchCroppedByMirrorRoot));
 }
 
@@ -462,6 +462,21 @@ TEST_F(LayerSnapshotTest, cleanUpUnreachableSnapshotsAfterMirroring) {
     EXPECT_EQ(startingNumSnapshots, mSnapshotBuilder.getSnapshots().size());
 }
 
+TEST_F(LayerSnapshotTest, canMirrorDisplayWithMirrors) {
+    reparentLayer(12, UNASSIGNED_LAYER_ID);
+    mirrorLayer(/*layer*/ 14, /*parent*/ 1, /*layerToMirror*/ 11);
+    std::vector<uint32_t> expected = {1, 11, 111, 13, 14, 11, 111, 2};
+    UPDATE_AND_VERIFY(mSnapshotBuilder, expected);
+
+    createDisplayMirrorLayer(3, ui::LayerStack::fromValue(0));
+    setLayerStack(3, 3);
+    expected = {1, 11, 111, 13, 14, 11, 111, 2, 3, 1, 11, 111, 13, 14, 11, 111, 2};
+    UPDATE_AND_VERIFY(mSnapshotBuilder, expected);
+    EXPECT_EQ(getSnapshot({.id = 11, .mirrorRootIds = 14u})->outputFilter.layerStack.id, 0u);
+    EXPECT_EQ(getSnapshot({.id = 11, .mirrorRootIds = 3u})->outputFilter.layerStack.id, 3u);
+    EXPECT_EQ(getSnapshot({.id = 11, .mirrorRootIds = 3u, 14u})->outputFilter.layerStack.id, 3u);
+}
+
 // Rel z doesn't create duplicate snapshots but this is for completeness
 TEST_F(LayerSnapshotTest, cleanUpUnreachableSnapshotsAfterRelZ) {
     size_t startingNumSnapshots = mSnapshotBuilder.getSnapshots().size();