From 434f27a21978a7d26703d3e0d74e46ddd6a9d6e1 Mon Sep 17 00:00:00 2001
From: Matt Blair <blair1618@gmail.com>
Date: Mon, 14 Dec 2020 15:12:51 -0500
Subject: [PATCH] Don't throw when native pointers have long values < 0 (#2217)

* Don't throw when native pointers have long values < 0

Android 11 and certain ROMs use "tagged pointers" that set the high bits on pointers, causing them to become negative as a long.

* Fix more pointer check comparisons in MapController
---
 .../java/com/mapzen/tangram/MapController.java     | 14 ++++----------
 .../src/main/java/com/mapzen/tangram/MapData.java  |  2 +-
 .../main/java/com/mapzen/tangram/NativeMap.java    |  2 +-
 3 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/platforms/android/tangram/src/main/java/com/mapzen/tangram/MapController.java b/platforms/android/tangram/src/main/java/com/mapzen/tangram/MapController.java
index 4109541f12..f0127a1428 100644
--- a/platforms/android/tangram/src/main/java/com/mapzen/tangram/MapController.java
+++ b/platforms/android/tangram/src/main/java/com/mapzen/tangram/MapController.java
@@ -670,7 +670,7 @@ public MapData addDataLayer(final String name, final boolean generateCentroid) {
             return mapData;
         }
         final long pointer = nativeMap.addClientDataSource(name, generateCentroid);
-        if (pointer <= 0) {
+        if (pointer == 0) {
             throw new RuntimeException("Unable to create new data source");
         }
         mapData = new MapData(name, pointer, this);
@@ -684,7 +684,9 @@ public MapData addDataLayer(final String name, final boolean generateCentroid) {
      */
     void removeDataLayer(@NonNull final MapData mapData) {
         clientTileSources.remove(mapData.name);
-        checkPointer(mapData.pointer);
+        if (mapData.pointer == 0) {
+            throw new RuntimeException("Tried to remove a MapData that was already disposed");
+        }
         nativeMap.removeClientDataSource(mapData.pointer);
     }
 
@@ -1083,14 +1085,6 @@ void onLowMemory() {
         nativeMap.onLowMemory();
     }
 
-    void checkPointer(final long ptr) {
-        if (ptr <= 0) {
-            throw new RuntimeException("Tried to perform an operation on an invalid pointer!"
-                    + " This means you may have used an object that has been disposed and is no"
-                    + " longer valid.");
-        }
-    }
-
     void checkId(final long id) {
         if (id <= 0) {
             throw new RuntimeException("Tried to perform an operation on an invalid id!"
diff --git a/platforms/android/tangram/src/main/java/com/mapzen/tangram/MapData.java b/platforms/android/tangram/src/main/java/com/mapzen/tangram/MapData.java
index abeb8b0b3b..e2fac5b6e3 100644
--- a/platforms/android/tangram/src/main/java/com/mapzen/tangram/MapData.java
+++ b/platforms/android/tangram/src/main/java/com/mapzen/tangram/MapData.java
@@ -92,7 +92,7 @@ public void clear() {
     }
 
     private void checkPointer(final long ptr) {
-        if (ptr <= 0) {
+        if (ptr == 0) {
             throw new RuntimeException("Tried to perform an operation on an invalid pointer!"
                     + " This means you may have used a MapData that has already been removed.");
         }
diff --git a/platforms/android/tangram/src/main/java/com/mapzen/tangram/NativeMap.java b/platforms/android/tangram/src/main/java/com/mapzen/tangram/NativeMap.java
index 5725b9721c..46f023fd79 100644
--- a/platforms/android/tangram/src/main/java/com/mapzen/tangram/NativeMap.java
+++ b/platforms/android/tangram/src/main/java/com/mapzen/tangram/NativeMap.java
@@ -9,7 +9,7 @@ class NativeMap {
 
     NativeMap(MapController mapController, AssetManager assetManager) {
         nativePointer = init(mapController, assetManager);
-        if (nativePointer <= 0) {
+        if (nativePointer == 0) {
             throw new RuntimeException("Unable to create a native Map object! There may be insufficient memory available.");
         }
     }