libui: Add std::hash support for Rects/Region

Adds support for std::hash to Rect, FloatRect, and Region.

Bug: 158790260
Test: libui unit tests
Change-Id: I593bad1d3111d9b28984de5c2d80695c124e30b6

6 files changed, 78 insertions, 0 deletions

diff --git a/libs/ui/Android.bp b/libs/ui/Android.bp
index 714ee3e909..a8d476250b 100644
--- a/libs/ui/Android.bp
+++ b/libs/ui/Android.bp
@@ -220,9 +220,11 @@ cc_library_headers {
     },
     header_libs: [
         "libnativewindow_headers",
+        "libmath_headers",
     ],
     export_header_lib_headers: [
         "libnativewindow_headers",
+        "libmath_headers",
     ],
     min_sdk_version: "29",
 }
diff --git a/libs/ui/include/ui/FloatRect.h b/libs/ui/include/ui/FloatRect.h
index bec2552fde..69cadfe32e 100644
--- a/libs/ui/include/ui/FloatRect.h
+++ b/libs/ui/include/ui/FloatRect.h
@@ -16,6 +16,7 @@
 
 #pragma once
 
+#include <math/HashCombine.h>
 #include <ostream>
 
 namespace android {
@@ -60,3 +61,13 @@ static inline void PrintTo(const FloatRect& rect, ::std::ostream* os) {
 }
 
 }  // namespace android
+
+namespace std {
+
+template <>
+struct hash<android::FloatRect> {
+    size_t operator()(const android::FloatRect& rect) const {
+        return android::hashCombine(rect.left, rect.top, rect.right, rect.bottom);
+    }
+};
+} // namespace std
diff --git a/libs/ui/include/ui/Rect.h b/libs/ui/include/ui/Rect.h
index 58323e553e..9e24a077ff 100644
--- a/libs/ui/include/ui/Rect.h
+++ b/libs/ui/include/ui/Rect.h
@@ -24,6 +24,7 @@
 #include <utils/Log.h>
 #include <utils/TypeHelpers.h>
 
+#include <math/HashCombine.h>
 #include <ui/FloatRect.h>
 #include <ui/Point.h>
 #include <ui/Size.h>
@@ -234,4 +235,13 @@ ANDROID_BASIC_TYPES_TRAITS(Rect)
 
 }; // namespace android
 
+namespace std {
+template <>
+struct hash<android::Rect> {
+    size_t operator()(const android::Rect& rect) const {
+        return android::hashCombine(rect.left, rect.top, rect.right, rect.bottom);
+    }
+};
+} // namespace std
+
 #endif // ANDROID_UI_RECT
diff --git a/libs/ui/include/ui/Region.h b/libs/ui/include/ui/Region.h
index 6bb7b8d21c..927c334c85 100644
--- a/libs/ui/include/ui/Region.h
+++ b/libs/ui/include/ui/Region.h
@@ -21,6 +21,7 @@
 #include <sys/types.h>
 #include <ostream>
 
+#include <math/HashCombine.h>
 #include <ui/Rect.h>
 #include <utils/Flattenable.h>
 
@@ -234,4 +235,17 @@ static inline void PrintTo(const Region& region, ::std::ostream* os) {
 // ---------------------------------------------------------------------------
 }; // namespace android
 
+namespace std {
+template <>
+struct hash<android::Region> {
+    size_t operator()(const android::Region& region) const {
+        size_t hash = 0;
+        for (const android::Rect& rect : region) {
+            android::hashCombineSingle(hash, rect);
+        }
+        return hash;
+    }
+};
+} // namespace std
+
 #endif // ANDROID_UI_REGION_H
diff --git a/libs/ui/tests/Rect_test.cpp b/libs/ui/tests/Rect_test.cpp
index 5499a5b507..9cc36bb15b 100644
--- a/libs/ui/tests/Rect_test.cpp
+++ b/libs/ui/tests/Rect_test.cpp
@@ -259,4 +259,33 @@ TEST(RectTest, toFloatRect) {
     EXPECT_EQ(FloatRect(10.f, 20.f, 50.f, 60.f), floatRect);
 }
 
+TEST(RectTest, RectHash) {
+    const std::vector<Rect> rects = {
+            Rect(10, 20, 50, 60), Rect(11, 20, 50, 60), Rect(11, 21, 50, 60),
+            Rect(11, 21, 51, 60), Rect(11, 21, 51, 61),
+    };
+
+    for (const auto& a : rects) {
+        for (const auto& b : rects) {
+            const bool hashEq = std::hash<Rect>{}(a) == std::hash<Rect>{}(b);
+            EXPECT_EQ(a == b, hashEq);
+        }
+    }
+}
+
+TEST(RectTest, FloatRectHash) {
+    const std::vector<FloatRect> floatRects = {
+            Rect(10, 20, 50, 60).toFloatRect(), Rect(11, 20, 50, 60).toFloatRect(),
+            Rect(11, 21, 50, 60).toFloatRect(), Rect(11, 21, 51, 60).toFloatRect(),
+            Rect(11, 21, 51, 61).toFloatRect(),
+    };
+
+    for (const auto& a : floatRects) {
+        for (const auto& b : floatRects) {
+            const bool hashEq = std::hash<FloatRect>{}(a) == std::hash<FloatRect>{}(b);
+            EXPECT_EQ(a == b, hashEq);
+        }
+    }
+}
+
 } // namespace android::ui
diff --git a/libs/ui/tests/Region_test.cpp b/libs/ui/tests/Region_test.cpp
index c6b826d66e..74924bdce8 100644
--- a/libs/ui/tests/Region_test.cpp
+++ b/libs/ui/tests/Region_test.cpp
@@ -167,5 +167,17 @@ TEST_F(RegionTest, EqualsToSelf) {
     ASSERT_TRUE(touchableRegion.contains(50, 50));
 }
 
+TEST_F(RegionTest, RegionHash) {
+    Region region1;
+    region1.addRectUnchecked(10, 20, 30, 40);
+    region1.addRectUnchecked(40, 30, 20, 10);
+
+    Region region2;
+    region2.addRectUnchecked(11, 20, 30, 40);
+    region2.addRectUnchecked(40, 31, 20, 10);
+
+    EXPECT_NE(std::hash<Region>{}(region1), std::hash<Region>{}(region2));
+}
+
 }; // namespace android