[android] - add FileSource activation/deactivation to MapSnapshotter, handle multiple deactivate scenario in FileSource (#10556)

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/storage/FileSource.java

@@ -6,10 +6,8 @@ import android.content.pm.PackageManager;
 import android.content.res.AssetManager;
 import android.os.Environment;
 import android.support.annotation.NonNull;
-
 import com.mapbox.mapboxsdk.Mapbox;
 import com.mapbox.mapboxsdk.constants.MapboxConstants;
-
 import timber.log.Timber;
 
 /**
@@ -119,28 +117,14 @@ public class FileSource {
   }
 
   private long nativePtr;
-  private long activeCounter;
-  private boolean wasPaused;
 
   private FileSource(String cachePath, AssetManager assetManager) {
     initialize(Mapbox.getAccessToken(), cachePath, assetManager);
   }
 
-  public void activate() {
-    activeCounter++;
-    if (activeCounter == 1 && wasPaused) {
-      wasPaused = false;
-      resume();
-    }
-  }
+  public native void activate();
 
-  public void deactivate() {
-    activeCounter--;
-    if (activeCounter == 0) {
-      wasPaused = true;
-      pause();
-    }
-  }
+  public native void deactivate();
 
   public native void setAccessToken(@NonNull String accessToken);
 
@@ -148,10 +132,6 @@ public class FileSource {
 
   public native void setApiBaseUrl(String baseUrl);
 
-  private native void resume();
-
-  private native void pause();
-
   /**
    * Sets a callback for transforming URLs requested from the internet
    * <p>

platform/android/src/file_source.cpp

@@ -63,11 +63,22 @@ void FileSource::setResourceTransform(jni::JNIEnv& env, jni::Object<FileSource::
 }
 
 void FileSource::resume(jni::JNIEnv&) {
-    fileSource->resume();
+    if (!activationCounter) {
+        activationCounter = optional<int>(1) ;
+        return;
+    }
+
+    activationCounter.value()++;
+    if (activationCounter == 1) {
+       fileSource->resume();
+    }
 }
 
 void FileSource::pause(jni::JNIEnv&) {
-    fileSource->pause();
+    activationCounter.value()--;
+    if (activationCounter == 0) {
+        fileSource->pause();
+    }
 }
 
 jni::Class<FileSource> FileSource::javaClass;
@@ -100,8 +111,8 @@ void FileSource::registerNative(jni::JNIEnv& env) {
         METHOD(&FileSource::setAccessToken, "setAccessToken"),
         METHOD(&FileSource::setAPIBaseUrl, "setApiBaseUrl"),
         METHOD(&FileSource::setResourceTransform, "setResourceTransform"),
-        METHOD(&FileSource::resume, "resume"),
-        METHOD(&FileSource::pause, "pause")
+        METHOD(&FileSource::resume, "activate"),
+        METHOD(&FileSource::pause, "deactivate")
     );
 }
 

platform/android/src/file_source.hpp

@@ -54,6 +54,7 @@ public:
     static void registerNative(jni::JNIEnv&);
 
 private:
+    optional<int> activationCounter;
     std::unique_ptr<Actor<ResourceTransform>> resourceTransform;
     std::unique_ptr<mbgl::DefaultFileSource> fileSource;
 };

platform/android/src/snapshotter/map_snapshotter.cpp

@@ -15,7 +15,7 @@ namespace android {
 
 MapSnapshotter::MapSnapshotter(jni::JNIEnv& _env,
                                jni::Object<MapSnapshotter> _obj,
-                               jni::Object<FileSource> jFileSource,
+                               jni::Object<FileSource> _jFileSource,
                                jni::jfloat _pixelRatio,
                                jni::jint width,
                                jni::jint height,
@@ -34,16 +34,16 @@ MapSnapshotter::MapSnapshotter(jni::JNIEnv& _env,
         return;
     }
 
-    auto& fileSource = mbgl::android::FileSource::getDefaultFileSource(_env, jFileSource);
+    jFileSource = FileSource::getNativePeer(_env, _jFileSource);
+    auto& fileSource = mbgl::android::FileSource::getDefaultFileSource(_env, _jFileSource);
     auto size = mbgl::Size { static_cast<uint32_t>(width), static_cast<uint32_t>(height) };
     auto cameraOptions = position ? CameraPosition::getCameraOptions(_env, position) : CameraOptions();
     optional<mbgl::LatLngBounds> bounds;
     if (region) {
         bounds = LatLngBounds::getLatLngBounds(_env, region);
     }
-
+    
     showLogo = _showLogo;
-
     // Create the core snapshotter
     snapshotter = std::make_unique<mbgl::MapSnapshotter>(fileSource,
                                                          *threadPool,
@@ -58,8 +58,9 @@ MapSnapshotter::MapSnapshotter(jni::JNIEnv& _env,
 
 MapSnapshotter::~MapSnapshotter() = default;
 
-void MapSnapshotter::start(JNIEnv&) {
+void MapSnapshotter::start(JNIEnv& env) {
     MBGL_VERIFY_THREAD(tid);
+    activateFilesource(env);
 
     snapshotCallback = std::make_unique<Actor<mbgl::MapSnapshotter::Callback>>(
             *Scheduler::GetCurrent(),
@@ -79,17 +80,19 @@ void MapSnapshotter::start(JNIEnv&) {
             static auto onSnapshotReady = javaClass.GetMethod<void (jni::Object<MapSnapshot>)>(*_env, "onSnapshotReady");
             javaPeer->Call(*_env, onSnapshotReady, mapSnapshot);
         }
+
+        deactivateFilesource(*_env);
     });
 
     snapshotter->snapshot(snapshotCallback->self());
 }
 
-void MapSnapshotter::cancel(JNIEnv&) {
+void MapSnapshotter::cancel(JNIEnv& env) {
     MBGL_VERIFY_THREAD(tid);
     snapshotCallback.reset();
+    deactivateFilesource(env);
 }
 
-
 void MapSnapshotter::setStyleUrl(JNIEnv& env, jni::String styleURL) {
     snapshotter->setStyleURL(jni::Make<std::string>(env, styleURL));
 }
@@ -108,6 +111,22 @@ void MapSnapshotter::setRegion(JNIEnv& env, jni::Object<LatLngBounds> region) {
     snapshotter->setRegion(LatLngBounds::getLatLngBounds(env, region));
 }
 
+// Private methods //
+
+void MapSnapshotter::activateFilesource(JNIEnv& env) {
+    if (!activatedFilesource) {
+        activatedFilesource = true;
+        jFileSource->resume(env);
+    }
+}
+
+void MapSnapshotter::deactivateFilesource(JNIEnv& env) {
+    if (activatedFilesource) {
+        activatedFilesource = false;
+        jFileSource->pause(env);
+    }
+}
+
 // Static methods //
 
 jni::Class<MapSnapshotter> MapSnapshotter::javaClass;

platform/android/src/snapshotter/map_snapshotter.hpp

@@ -65,6 +65,11 @@ private:
     std::shared_ptr<mbgl::ThreadPool> threadPool;
     std::unique_ptr<Actor<mbgl::MapSnapshotter::Callback>> snapshotCallback;
     std::unique_ptr<mbgl::MapSnapshotter> snapshotter;
+
+    FileSource *jFileSource;
+    void activateFilesource(JNIEnv&);
+    void deactivateFilesource(JNIEnv&);
+    bool activatedFilesource = false;
 };
 
 } // namespace android