Merge branch 'improved-overflow-support/richer-active-watch' into improved-overflow-support/event-handlers-with-active-watch

Author: sungshik

src/main/java/engineering/swat/watch/ActiveWatch.java

@@ -36,30 +36,8 @@
  */
 public interface ActiveWatch extends Closeable {
 
-    /**
-     * Handles `event`. The purpose of this method is to trigger the event
-     * handler of this watch "from the outside" (in addition to having native
-     * file system libraries trigger the event handler "from the inside"). This
-     * is useful to report synthetic events (e.g., while handling overflows).
-     */
-    void handleEvent(WatchEvent event);
-
     /**
      * Gets the path watched by this watch.
      */
     Path getPath();
-
-    /**
-     * Relativizes the full path of `event` against the path watched by this
-     * watch (as per `getPath()`). Returns a new event whose root path and
-     * relative path are set in accordance with the relativization.
-     */
-    default WatchEvent relativize(WatchEvent event) {
-        var fullPath = event.calculateFullPath();
-
-        var kind = event.getKind();
-        var rootPath = getPath();
-        var relativePath = rootPath.relativize(fullPath);
-        return new WatchEvent(kind, rootPath, relativePath);
-    }
 }

src/main/java/engineering/swat/watch/WatchEvent.java

@@ -28,6 +28,8 @@
 
 import java.nio.file.Path;
 
+import org.checkerframework.checker.nullness.qual.Nullable;
+
 /**
  * The library publishes these events to all subscribers, they are immutable and safe to share around.
  */
@@ -67,13 +69,13 @@ public enum Kind {
     private final Path relativePath;
 
     public WatchEvent(Kind kind, Path rootPath) {
-        this(kind, rootPath, Path.of(""));
+        this(kind, rootPath, null);
     }
 
-    public WatchEvent(Kind kind, Path rootPath, Path relativePath) {
+    public WatchEvent(Kind kind, Path rootPath, @Nullable Path relativePath) {
         this.kind = kind;
         this.rootPath = rootPath;
-        this.relativePath = relativePath;
+        this.relativePath = relativePath == null ? Path.of("") : relativePath;
     }
 
     public Kind getKind() {

src/main/java/engineering/swat/watch/impl/EventHandlingWatch.java

@@ -0,0 +1,55 @@
+/*
+ * BSD 2-Clause License
+ *
+ * Copyright (c) 2023, Swat.engineering
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package engineering.swat.watch.impl;
+
+import engineering.swat.watch.ActiveWatch;
+import engineering.swat.watch.WatchEvent;
+
+public interface EventHandlingWatch extends ActiveWatch {
+
+    /**
+     * Handles `event`. The purpose of this method is to trigger the event
+     * handler of this watch "from the outside" (in addition to having native
+     * file system libraries trigger the event handler "from the inside"). This
+     * is useful to report synthetic events (e.g., while handling overflows).
+     */
+    void handleEvent(WatchEvent event);
+
+    /**
+     * Relativizes the full path of `event` against the path watched by this
+     * watch (as per `getPath()`). Returns a new event whose root path and
+     * relative path are set in accordance with the relativization.
+     */
+    default WatchEvent relativize(WatchEvent event) {
+        var fullPath = event.calculateFullPath();
+
+        var kind = event.getKind();
+        var rootPath = getPath();
+        var relativePath = rootPath.relativize(fullPath);
+        return new WatchEvent(kind, rootPath, relativePath);
+    }
+}

src/main/java/engineering/swat/watch/impl/jdk/JDKBaseWatch.java

@@ -37,10 +37,10 @@
 import org.apache.logging.log4j.Logger;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
-import engineering.swat.watch.ActiveWatch;
 import engineering.swat.watch.WatchEvent;
+import engineering.swat.watch.impl.EventHandlingWatch;
 
-public abstract class JDKBaseWatch implements ActiveWatch {
+public abstract class JDKBaseWatch implements EventHandlingWatch {
     private final Logger logger = LogManager.getLogger();
 
     protected final Path path;
@@ -90,12 +90,9 @@ protected boolean startIfFirstTime() throws IOException {
     }
 
     protected WatchEvent translate(java.nio.file.WatchEvent<?> jdkEvent) {
-        var jdkKind = jdkEvent.kind();
-        var context = jdkKind == StandardWatchEventKinds.OVERFLOW ? null : jdkEvent.context();
-
-        var kind = translate(jdkKind);
+        var kind = translate(jdkEvent.kind());
         var rootPath = path;
-        var relativePath = context == null ? Path.of("") : (Path) context;
+        var relativePath = kind == WatchEvent.Kind.OVERFLOW ? null : (@Nullable Path) jdkEvent.context();
 
         var event = new WatchEvent(kind, rootPath, relativePath);
         logger.trace("Translated: {} to {}", jdkEvent, event);
@@ -119,7 +116,7 @@ private WatchEvent.Kind translate(java.nio.file.WatchEvent.Kind<?> jdkKind) {
         throw new IllegalArgumentException("Unexpected watch kind: " + jdkKind);
     }
 
-    // -- ActiveWatch --
+    // -- EventHandlingWatch --
 
     @Override
     public void handleEvent(WatchEvent e) {

src/main/java/engineering/swat/watch/impl/jdk/JDKRecursiveDirectoryWatch.java

@@ -299,8 +299,8 @@ private void detectedMissingEntries(Path dir, ArrayList<WatchEvent> events, Hash
     // -- JDKBaseWatch --
 
     @Override
-    public void handleEvent(WatchEvent ev) {
-        processEvents(ev);
+    public void handleEvent(WatchEvent event) {
+        processEvents(event);
     }
 
     @Override

src/test/java/engineering/swat/watch/impl/EventHandlingWatchTests.java

@@ -0,0 +1,67 @@
+/*
+ * BSD 2-Clause License
+ *
+ * Copyright (c) 2023, Swat.engineering
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package engineering.swat.watch.impl;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.IOException;
+import java.nio.file.Path;
+
+import org.junit.jupiter.api.Test;
+
+import engineering.swat.watch.WatchEvent;
+
+class EventHandlingWatchTests {
+
+    private static EventHandlingWatch emptyWatch(Path path) {
+        return new EventHandlingWatch() {
+            @Override
+            public void handleEvent(WatchEvent event) {
+                // Nothing to handle
+            }
+
+            @Override
+            public void close() throws IOException {
+                // Nothing to close
+            }
+
+            @Override
+            public Path getPath() {
+                return path;
+            }
+        };
+    }
+
+    @Test
+    void relativizeTest() {
+        var e1 = new WatchEvent(WatchEvent.Kind.OVERFLOW, Path.of("foo"), Path.of("bar", "baz.txt"));
+        var e2 = new WatchEvent(WatchEvent.Kind.OVERFLOW, Path.of("foo", "bar", "baz.txt"));
+        var e3 = emptyWatch(Path.of("foo")).relativize(e2);
+        assertEquals(e1.getRootPath(), e3.getRootPath());
+        assertEquals(e1.getRelativePath(), e3.getRelativePath());
+    }
+}