v0.6.5

app/src/main/kotlin/com/looker/droidify/database/QueryLoader.kt

@@ -0,0 +1,94 @@
+package com.looker.droidify.database
+
+import android.content.Context
+import android.database.Cursor
+import android.os.CancellationSignal
+import android.os.OperationCanceledException
+import androidx.loader.content.AsyncTaskLoader
+
+class QueryLoader(context: Context, private val query: (CancellationSignal) -> Cursor?) :
+    AsyncTaskLoader<Cursor>(context) {
+    private val observer = ForceLoadContentObserver()
+    private var cancellationSignal: CancellationSignal? = null
+    private var cursor: Cursor? = null
+
+    override fun loadInBackground(): Cursor? {
+        val cancellationSignal = synchronized(this) {
+            if (isLoadInBackgroundCanceled) {
+                throw OperationCanceledException()
+            }
+            val cancellationSignal = CancellationSignal()
+            this.cancellationSignal = cancellationSignal
+            cancellationSignal
+        }
+        try {
+            val cursor = query(cancellationSignal)
+            if (cursor != null) {
+                try {
+                    cursor.count // Ensure the cursor window is filled
+                    cursor.registerContentObserver(observer)
+                } catch (e: Exception) {
+                    cursor.close()
+                    throw e
+                }
+            }
+            return cursor
+        } finally {
+            synchronized(this) {
+                this.cancellationSignal = null
+            }
+        }
+    }
+
+    override fun cancelLoadInBackground() {
+        super.cancelLoadInBackground()
+
+        synchronized(this) {
+            cancellationSignal?.cancel()
+        }
+    }
+
+    override fun deliverResult(data: Cursor?) {
+        if (isReset) {
+            data?.close()
+        } else {
+            val oldCursor = cursor
+            cursor = data
+            if (isStarted) {
+                super.deliverResult(data)
+            }
+            if (oldCursor != data) {
+                oldCursor.closeIfNeeded()
+            }
+        }
+    }
+
+    override fun onStartLoading() {
+        cursor?.let(this::deliverResult)
+        if (takeContentChanged() || cursor == null) {
+            forceLoad()
+        }
+    }
+
+    override fun onStopLoading() {
+        cancelLoad()
+    }
+
+    override fun onCanceled(data: Cursor?) {
+        data.closeIfNeeded()
+    }
+
+    override fun onReset() {
+        super.onReset()
+
+        stopLoading()
+        cursor.closeIfNeeded()
+        cursor = null
+    }
+
+    private fun Cursor?.closeIfNeeded() {
+        if (this != null && !isClosed) {
+            close()
+        }
+    }
+}