Remove containing dir when empty (#676)

* remove containing dir when empty

* spotless

splunk-otel-android/src/main/java/com/splunk/rum/DefaultSpanStorage.java

@@ -31,7 +31,7 @@ public DefaultSpanStorage(FileUtils fileUtils, File rootDir) {
     }
 
     @Override
-    public File provideSpanFile() {
+    public File provideSpansDirectory() {
         File spansPath = fileUtils.getSpansDirectory(rootDir);
         if (spansPath.exists() || spansPath.mkdirs()) {
             return spansPath;
@@ -45,16 +45,16 @@ public File provideSpanFile() {
 
     @Override
     public Stream<File> getAllSpanFiles() {
-        return fileUtils.listSpanFiles(provideSpanFile());
+        return fileUtils.listSpanFiles(provideSpansDirectory());
     }
 
     @Override
     public long getTotalFileSizeInBytes() {
-        return fileUtils.getTotalFileSizeInBytes(provideSpanFile());
+        return fileUtils.getTotalFileSizeInBytes(provideSpansDirectory());
     }
 
     @Override
     public Stream<File> getPendingFiles() {
-        return fileUtils.listSpanFiles(provideSpanFile());
+        return fileUtils.listSpanFiles(provideSpansDirectory());
     }
 }

splunk-otel-android/src/main/java/com/splunk/rum/DeviceSpanStorageLimiter.java

@@ -52,7 +52,7 @@ private DeviceSpanStorageLimiter(Builder builder) {
     boolean ensureFreeSpace() {
         tryFreeingSpace();
         // play nice if disk is getting full
-        return fileProvider.provideSpanFile().getFreeSpace() > limitInBytes();
+        return fileProvider.provideSpansDirectory().getFreeSpace() > limitInBytes();
     }
 
     private void tryFreeingSpace() {

splunk-otel-android/src/main/java/com/splunk/rum/SpanStorage.java

@@ -26,10 +26,9 @@
 interface SpanStorage {
 
     /***
-     * Provide location of storing spans
-     * @return
+     * Returns the location where spans are buffered.
      */
-    File provideSpanFile();
+    File provideSpansDirectory();
 
     /***
      * @return all spans including those that can be sent or not

splunk-otel-android/src/main/java/com/splunk/rum/StartTypeAwareSpanStorage.java

@@ -19,6 +19,7 @@
 import static com.splunk.rum.SplunkRum.LOG_TAG;
 
 import android.util.Log;
+import androidx.annotation.VisibleForTesting;
 import io.opentelemetry.android.instrumentation.activity.VisibleScreenTracker;
 import java.io.File;
 import java.util.UUID;
@@ -29,7 +30,7 @@
  * If the app is brought to foreground and the same session ID still in use, the background spans are moved to /span for eventual sending.
  * If the app still in the background until process-kill, the background span files will eventually be deleted by the @DeviceSpanStorageLimiter.
  */
-public class StartTypeAwareSpanStorage implements SpanStorage {
+class StartTypeAwareSpanStorage implements SpanStorage {
 
     private final VisibleScreenTracker visibleScreenTracker;
     private final FileUtils fileUtils;
@@ -39,19 +40,37 @@ public class StartTypeAwareSpanStorage implements SpanStorage {
 
     static StartTypeAwareSpanStorage create(
             VisibleScreenTracker visibleScreenTracker, FileUtils fileUtils, File rootDir) {
+        File spansDir = fileUtils.getSpansDirectory(rootDir);
+        String uniqueId = UUID.randomUUID().toString();
+        return create(visibleScreenTracker, fileUtils, rootDir, spansDir, uniqueId);
+    }
+
+    @VisibleForTesting
+    static StartTypeAwareSpanStorage create(
+            VisibleScreenTracker visibleScreenTracker,
+            FileUtils fileUtils,
+            File rootDir,
+            File spansDir,
+            String uniqueId) {
         StartTypeAwareSpanStorage startTypeAwareSpanStorage =
-                new StartTypeAwareSpanStorage(visibleScreenTracker, fileUtils, rootDir);
+                new StartTypeAwareSpanStorage(
+                        visibleScreenTracker, fileUtils, rootDir, spansDir, uniqueId);
         startTypeAwareSpanStorage.cleanupUnsentBackgroundSpans();
         return startTypeAwareSpanStorage;
     }
 
-    private StartTypeAwareSpanStorage(
-            VisibleScreenTracker visibleScreenTracker, FileUtils fileUtils, File rootDir) {
+    @VisibleForTesting
+    StartTypeAwareSpanStorage(
+            VisibleScreenTracker visibleScreenTracker,
+            FileUtils fileUtils,
+            File rootDir,
+            File spansDir,
+            String uniqueId) {
         this.visibleScreenTracker = visibleScreenTracker;
         this.fileUtils = fileUtils;
         this.rootDir = rootDir;
-        this.spanDir = fileUtils.getSpansDirectory(rootDir);
-        this.uniqueId = UUID.randomUUID().toString();
+        this.spanDir = spansDir;
+        this.uniqueId = uniqueId;
     }
 
     @Override
@@ -80,7 +99,7 @@ private boolean isAppForeground() {
 
     private void moveBackgroundSpanToPendingSpan() {
         fileUtils
-                .listSpanFiles(getCurrentSessionBackgroundFile())
+                .listSpanFiles(getCurrentSessionBackgroundDirectory())
                 .forEach(
                         file -> {
                             File destinationFile = new File(spanDir, file.getName());
@@ -96,19 +115,19 @@ private void moveBackgroundSpanToPendingSpan() {
         cleanupUnsentBackgroundSpans();
     }
 
-    private File getCurrentSessionBackgroundFile() {
+    private File getCurrentSessionBackgroundDirectory() {
         return new File(spanDir, "background/" + uniqueId);
     }
 
     @Override
-    public File provideSpanFile() {
-        return ensureDirExist(getSpanFile());
+    public File provideSpansDirectory() {
+        return ensureDirExist(getSpansDirectory());
     }
 
-    private File getSpanFile() {
+    private File getSpansDirectory() {
         if (!isAppForeground()) {
             Log.d(LOG_TAG, "Creating background span " + uniqueId);
-            return getCurrentSessionBackgroundFile();
+            return getCurrentSessionBackgroundDirectory();
         }
         Log.d(LOG_TAG, "Creating foreground span " + uniqueId);
         return spanDir;
@@ -139,5 +158,9 @@ private void cleanupUnsentBackgroundSpans() {
                             fileUtils.listFilesRecursively(dir).forEach(fileUtils::safeDelete);
                             fileUtils.safeDelete(dir);
                         });
+        File backgroundDir = getCurrentSessionBackgroundDirectory();
+        if (!fileUtils.listFilesRecursively(backgroundDir).findAny().isPresent()) {
+            fileUtils.safeDelete(backgroundDir);
+        }
     }
 }

splunk-otel-android/src/main/java/com/splunk/rum/ZipkinToDiskSender.java

@@ -81,7 +81,7 @@ public Call<Void> sendSpans(List<byte[]> encodedSpans) {
     }
 
     private File createFilename(long now) {
-        return new File(spanStorage.provideSpanFile(), now + ".spans");
+        return new File(spanStorage.provideSpansDirectory(), now + ".spans");
     }
 
     static Builder builder() {

splunk-otel-android/src/test/java/com/splunk/rum/DeviceSpanStorageLimiterTest.java

@@ -56,7 +56,7 @@ void setup() {
     void ensureFreeSpace_littleUsageEnoughFreeSpace() {
         File mockFile = mock(File.class);
         when(spanStorage.getTotalFileSizeInBytes()).thenReturn(10 * 1024L);
-        when(spanStorage.provideSpanFile()).thenReturn(mockFile);
+        when(spanStorage.provideSpansDirectory()).thenReturn(mockFile);
         when(mockFile.getFreeSpace()).thenReturn(99L); // Disk is very full
         assertFalse(limiter.ensureFreeSpace());
         verify(fileUtils, never()).safeDelete(any());
@@ -66,7 +66,7 @@ void ensureFreeSpace_littleUsageEnoughFreeSpace() {
     void ensureFreeSpace_littleUsageButNotEnoughFreeSpace() {
         File mockFile = mock(File.class);
         when(spanStorage.getTotalFileSizeInBytes()).thenReturn(10 * 1024L);
-        when(spanStorage.provideSpanFile()).thenReturn(mockFile);
+        when(spanStorage.provideSpansDirectory()).thenReturn(mockFile);
         when(mockFile.getFreeSpace()).thenReturn(MAX_STORAGE_USE_BYTES * 99); // lots of room
         assertTrue(limiter.ensureFreeSpace());
         verify(fileUtils, never()).safeDelete(any());
@@ -75,7 +75,7 @@ void ensureFreeSpace_littleUsageButNotEnoughFreeSpace() {
     @Test
     void ensureFreeSpace_underLimit() {
         File mockFile = mock(File.class);
-        when(spanStorage.provideSpanFile()).thenReturn(mockFile);
+        when(spanStorage.provideSpansDirectory()).thenReturn(mockFile);
 
         when(spanStorage.getTotalFileSizeInBytes()).thenReturn(MAX_STORAGE_USE_BYTES - 1);
         when(mockFile.getFreeSpace()).thenReturn(MAX_STORAGE_USE_BYTES + 1);
@@ -91,7 +91,7 @@ void ensureFreeSpace_overLimitHappyDeletion() {
         File file3 = new File("newest");
 
         File mockFile = mock(File.class);
-        when(spanStorage.provideSpanFile()).thenReturn(mockFile);
+        when(spanStorage.provideSpansDirectory()).thenReturn(mockFile);
         when(spanStorage.getTotalFileSizeInBytes()).thenReturn(MAX_STORAGE_USE_BYTES + 1);
         when(fileUtils.getModificationTime(file1)).thenReturn(1000L);
         when(fileUtils.getModificationTime(file2)).thenReturn(1001L);

splunk-otel-android/src/test/java/com/splunk/rum/DiskToZipkinExporterTest.java

@@ -54,11 +54,14 @@ class DiskToZipkinExporterTest {
     @BeforeEach
     void setup() throws Exception {
         Mockito.reset(SPAN_STORAGE);
-        when(SPAN_STORAGE.provideSpanFile()).thenReturn(spanFilesPath);
-        file1 = new File(SPAN_STORAGE.provideSpanFile() + File.separator + "file1.spans");
-        file2 = new File(SPAN_STORAGE.provideSpanFile() + File.separator + "file2.spans");
+        when(SPAN_STORAGE.provideSpansDirectory()).thenReturn(spanFilesPath);
+        file1 = new File(SPAN_STORAGE.provideSpansDirectory() + File.separator + "file1.spans");
+        file2 = new File(SPAN_STORAGE.provideSpansDirectory() + File.separator + "file2.spans");
         imposter =
-                new File(SPAN_STORAGE.provideSpanFile() + File.separator + "someImposterFile.dll");
+                new File(
+                        SPAN_STORAGE.provideSpansDirectory()
+                                + File.separator
+                                + "someImposterFile.dll");
 
         when(currentNetworkProvider.refreshNetworkStatus()).thenReturn(currentNetwork);
         when(currentNetwork.isOnline()).thenReturn(true);

splunk-otel-android/src/test/java/com/splunk/rum/StartTypeAwareSpanStorageTest.java

@@ -21,49 +21,82 @@
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 import io.opentelemetry.android.instrumentation.activity.VisibleScreenTracker;
 import java.io.File;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.UUID;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.mockito.ArgumentCaptor;
 
-public class StartTypeAwareSpanStorageTest {
+class StartTypeAwareSpanStorageTest {
 
-    private final FileUtils fileUtils = mock();
-
-    private final File rootDir = new File("files/");
-    private final VisibleScreenTracker visibleScreenTracker = mock();
+    final File rootDir = new File("files/");
+    VisibleScreenTracker visibleScreenTracker;
+    FileUtils fileUtils;
 
     private StartTypeAwareSpanStorage fileProvider;
 
     @BeforeEach
     void setup() {
+        visibleScreenTracker = mock();
+        fileUtils = mock();
         when(fileUtils.getSpansDirectory(rootDir)).thenReturn(new File(rootDir, "spans"));
         fileProvider = StartTypeAwareSpanStorage.create(visibleScreenTracker, fileUtils, rootDir);
     }
 
     @Test
     void create_onNewId_shouldCleanOldBackgroundFiles() {
         File file = mock();
+        ArgumentCaptor<File> fileArgumentCaptor = ArgumentCaptor.forClass(File.class);
         when(file.getPath()).thenReturn("files/spans/background/123");
+
+        fileProvider = StartTypeAwareSpanStorage.create(visibleScreenTracker, fileUtils, rootDir);
+        fileUtils = mock(FileUtils.class);
         when(fileUtils.listDirectories(any())).thenReturn(Stream.of(file));
-        ArgumentCaptor<File> fileArgumentCaptor = ArgumentCaptor.forClass(File.class);
+        when(fileUtils.listFiles(file)).thenReturn(Stream.of(file));
 
         fileProvider = StartTypeAwareSpanStorage.create(visibleScreenTracker, fileUtils, rootDir);
 
+        verify(fileUtils, times(2)).safeDelete(fileArgumentCaptor.capture());
+        assertEquals(file, fileArgumentCaptor.getAllValues().get(0));
+        assertEquals(
+                fileProvider.provideSpansDirectory(), fileArgumentCaptor.getAllValues().get(1));
+    }
+
+    @Test
+    void create_cleanDoesntRemoveDirIfNotEmpty() {
+        String uniqueId = UUID.randomUUID().toString();
+        File spansDir = new File("files/spans");
+        File file = mock();
+        File file2 = mock();
+        fileUtils = mock(FileUtils.class);
+
+        ArgumentCaptor<File> fileArgumentCaptor = ArgumentCaptor.forClass(File.class);
+        when(file.getPath()).thenReturn("files/spans/background/123");
+
+        when(fileUtils.listDirectories(any())).thenReturn(Stream.of(file));
+        when(fileUtils.listFiles(file)).thenReturn(Stream.of(file));
+        when(fileUtils.listFilesRecursively(new File(spansDir, "background/" + uniqueId)))
+                .thenReturn(Stream.of(file2));
+
+        fileProvider =
+                StartTypeAwareSpanStorage.create(
+                        visibleScreenTracker, fileUtils, rootDir, spansDir, uniqueId);
+
         verify(fileUtils).safeDelete(fileArgumentCaptor.capture());
-        assertEquals(file.getPath(), fileArgumentCaptor.getValue().getPath());
+        assertEquals(file, fileArgumentCaptor.getAllValues().get(0));
     }
 
     @Test
-    void getPendingFiles_givenInBackground_shouldReturnForegoundOnlySpan() {
+    void getPendingFiles_givenInBackground_shouldReturnForegroundOnlySpan() {
         when(visibleScreenTracker.getPreviouslyVisibleScreen()).thenReturn(null);
         when(visibleScreenTracker.getCurrentlyVisibleScreen()).thenReturn("unknown");
         List<File> spans = fileProvider.getPendingFiles().collect(Collectors.toList());
@@ -72,7 +105,7 @@ void getPendingFiles_givenInBackground_shouldReturnForegoundOnlySpan() {
 
     @Test
     void
-            getPendingFiles_givenPrevouslyInBackground_shouldMoveBackgroundSpanToForegroundSpanForSending() {
+            getPendingFiles_givenPreviouslyInBackground_shouldMoveBackgroundSpanToForegroundSpanForSending() {
         when(visibleScreenTracker.getPreviouslyVisibleScreen()).thenReturn("LauncherActivity");
         when(visibleScreenTracker.getCurrentlyVisibleScreen()).thenReturn("MainActivity");
 
@@ -104,7 +137,7 @@ void getSpanPath_givenInBackground_shouldReturnBackgroundSpanPath() {
         when(visibleScreenTracker.getPreviouslyVisibleScreen()).thenReturn(null);
         when(visibleScreenTracker.getCurrentlyVisibleScreen()).thenReturn("unknown");
 
-        File path = fileProvider.provideSpanFile();
+        File path = fileProvider.provideSpansDirectory();
 
         assertTrue(path.getPath().startsWith("files/spans/background/"));
     }
@@ -114,7 +147,7 @@ void getSpanPath_givenInForeground_shouldReturnForegroundSpanPath() {
         when(visibleScreenTracker.getPreviouslyVisibleScreen()).thenReturn("LauncherActivity");
         when(visibleScreenTracker.getCurrentlyVisibleScreen()).thenReturn("MainActivity");
 
-        File path = fileProvider.provideSpanFile();
+        File path = fileProvider.provideSpansDirectory();
 
         assertFalse(path.getPath().startsWith("files/spans/background/"));
     }

splunk-otel-android/src/test/java/com/splunk/rum/ZipkinToDiskSenderTest.java

@@ -63,7 +63,7 @@ void setup() {
 
     @Test
     void testHappyPath() throws Exception {
-        when(spanStorage.provideSpanFile()).thenReturn(path);
+        when(spanStorage.provideSpansDirectory()).thenReturn(path);
 
         ZipkinToDiskSender sender =
                 ZipkinToDiskSender.builder()
@@ -91,7 +91,7 @@ void testEmptyListDoesNotWriteFile() {
 
     @Test
     void testWriteFails() throws Exception {
-        when(spanStorage.provideSpanFile()).thenReturn(path);
+        when(spanStorage.provideSpansDirectory()).thenReturn(path);
         doThrow(new IOException("boom")).when(fileUtils).writeAsLines(finalPath, spans);
 
         ZipkinToDiskSender sender =