Fix paging issue where DataStatus was not updated on insert.

paging/lib/src/main/java/org/signal/paging/DataStatus.java

@@ -13,7 +13,8 @@ class DataStatus {
   private static final Pools.Pool<BitSet> POOL = new Pools.SynchronizedPool<>(1);
 
   private final BitSet state;
-  private final int    size;
+
+  private int size;
 
   public static DataStatus obtain(int size) {
     BitSet bitset = POOL.acquire();
@@ -31,6 +32,10 @@ class DataStatus {
     this.state = bitset;
   }
 
+  void mark(int position) {
+    state.set(position, true);
+  }
+
   void markRange(int startInclusive, int endExclusive) {
     state.set(startInclusive, endExclusive, true);
   }
@@ -53,6 +58,24 @@ class DataStatus {
     return -1;
   }
 
+  boolean get(int position) {
+    return state.get(position);
+  }
+
+  void insertState(int position, boolean value) {
+    if (position < 0 || position > size + 1) {
+      throw new IndexOutOfBoundsException();
+    }
+
+    for (int i = size; i > position; i--) {
+      state.set(i, state.get(i - 1));
+    }
+
+    state.set(position, value);
+
+    this.size = size + 1;
+  }
+
   int size() {
     return size;
   }

paging/lib/src/main/java/org/signal/paging/FixedSizePagingController.java

@@ -62,6 +62,10 @@ class FixedSizePagingController<Key, Data> implements PagingController<Key> {
       return;
     }
 
+    final int loadStart;
+    final int loadEnd;
+
+    synchronized (loadState) {
       if (loadState.size() == 0) {
         liveData.postValue(Collections.emptyList());
         return;
@@ -74,14 +78,14 @@ class FixedSizePagingController<Key, Data> implements PagingController<Key> {
       int leftLoadBoundary  = Math.max(0, leftPageBoundary - buffer);
       int rightLoadBoundary = Math.min(loadState.size(), rightPageBoundary + buffer);
 
-    int loadStart = loadState.getEarliestUnmarkedIndexInRange(leftLoadBoundary, rightLoadBoundary);
+      loadStart = loadState.getEarliestUnmarkedIndexInRange(leftLoadBoundary, rightLoadBoundary);
 
       if (loadStart < 0) {
         if (DEBUG) Log.i(TAG, buildLog(aroundIndex, "loadStart < 0"));
         return;
       }
 
-    int loadEnd = loadState.getLatestUnmarkedIndexInRange(Math.max(leftLoadBoundary, loadStart), rightLoadBoundary) + 1;
+      loadEnd = loadState.getLatestUnmarkedIndexInRange(Math.max(leftLoadBoundary, loadStart), rightLoadBoundary) + 1;
 
       if (loadEnd <= loadStart) {
         if (DEBUG) Log.i(TAG, buildLog(aroundIndex, "loadEnd <= loadStart, loadEnd: " + loadEnd + ", loadStart: " + loadStart));
@@ -93,6 +97,7 @@ class FixedSizePagingController<Key, Data> implements PagingController<Key> {
       loadState.markRange(loadStart, loadEnd);
 
       if (DEBUG) Log.i(TAG, buildLog(aroundIndex, "start: " + loadStart + ", end: " + loadEnd + ", totalSize: " + totalSize));
+    }
 
     FETCH_EXECUTOR.execute(() -> {
       if (invalidated) {
@@ -147,6 +152,10 @@ class FixedSizePagingController<Key, Data> implements PagingController<Key> {
         return;
       }
 
+      synchronized (loadState) {
+        loadState.mark(position);
+      }
+
       Data item = dataSource.load(key);
 
       if (item == null) {
@@ -180,6 +189,10 @@ class FixedSizePagingController<Key, Data> implements PagingController<Key> {
         return;
       }
 
+      synchronized (loadState) {
+        loadState.insertState(position, true);
+      }
+
       Data item = dataSource.load(key);
 
       if (item == null) {

paging/lib/src/test/java/org/signal/paging/DataStatusTest.java

@@ -0,0 +1,58 @@
+package org.signal.paging;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class DataStatusTest {
+
+  @Test
+  public void insertState_initiallyEmpty_InsertAtZero() {
+    DataStatus subject = DataStatus.obtain(0);
+    subject.insertState(0, true);
+
+    assertEquals(1, subject.size());
+    assertTrue(subject.get(0));
+  }
+
+  @Test
+  public void insertState_someData_InsertAtZero() {
+    DataStatus subject = DataStatus.obtain(2);
+    subject.mark(1);
+
+    subject.insertState(0, true);
+
+    assertEquals(3, subject.size());
+    assertTrue(subject.get(0));
+    assertFalse(subject.get(1));
+    assertTrue(subject.get(2));
+  }
+
+  @Test
+  public void insertState_someData_InsertAtOne() {
+    DataStatus subject = DataStatus.obtain(3);
+    subject.mark(1);
+
+    subject.insertState(1, true);
+
+    assertEquals(4, subject.size());
+    assertFalse(subject.get(0));
+    assertTrue(subject.get(1));
+    assertTrue(subject.get(2));
+    assertFalse(subject.get(3));
+  }
+
+  @Test(expected = IndexOutOfBoundsException.class)
+  public void insertState_negativeThrows() {
+    DataStatus subject = DataStatus.obtain(0);
+    subject.insertState(-1, true);
+  }
+
+  @Test(expected = IndexOutOfBoundsException.class)
+  public void insertState_largerThanSizePlusOneThrows() {
+    DataStatus subject = DataStatus.obtain(0);
+    subject.insertState(2, true);
+  }
+}