Dedup the changed classes before hot reload (#345)

* Dedup the changed classes before hot reload

Signed-off-by: Jinbo Wang <[email protected]>

* Make checkstyle happy

Author: testforstephen

com.microsoft.java.debug.plugin/src/main/java/com/microsoft/java/debug/plugin/internal/JavaHotCodeReplaceProvider.java

@@ -26,10 +26,9 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
-import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
+import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
 import java.util.function.Consumer;
 import java.util.logging.Level;
@@ -101,9 +100,9 @@ public class JavaHotCodeReplaceProvider implements IHotCodeReplaceProvider, IRes
 
     private PublishSubject<HotCodeReplaceEvent> eventSubject = PublishSubject.<HotCodeReplaceEvent>create();
 
-    private Set<IResource> deltaResources = new LinkedHashSet<>();
+    private List<IResource> deltaResources = new ArrayList<>();
 
-    private Set<String> deltaClassNames = new LinkedHashSet<>();
+    private List<String> deltaClassNames = new ArrayList<>();
 
     /**
      * Visitor for resource deltas.
@@ -290,8 +289,23 @@ public void resourceChanged(IResourceChangeEvent event) {
                 List<IResource> resources = visitor.getChangedClassFiles();
                 List<String> classNames = visitor.getQualifiedNamesList();
                 synchronized (this) {
-                    deltaResources.addAll(resources);
-                    deltaClassNames.addAll(classNames);
+                    for (int i = 0; i < classNames.size(); i++) {
+                        String className = classNames.get(i);
+                        IResource resource = resources.get(i);
+                        boolean duplicate = false;
+                        for (int j = 0; j < deltaClassNames.size(); j++) {
+                            if (Objects.equals(deltaClassNames.get(j), className)
+                                && JdtUtils.isSameFile(deltaResources.get(j), resource)) {
+                                duplicate = true;
+                                break;
+                            }
+                        }
+
+                        if (!duplicate) {
+                            deltaClassNames.add(className);
+                            deltaResources.add(resource);
+                        }
+                    }
                 }
                 publishEvent(HotCodeReplaceEvent.EventType.BUILD_COMPLETE, "Build completed.");
             }
@@ -311,7 +325,7 @@ public CompletableFuture<List<String>> redefineClasses() {
             String errorMessage = null;
             synchronized (this) {
                 classNames.addAll(deltaClassNames);
-                errorMessage = doHotCodeReplace(new ArrayList<>(deltaResources), new ArrayList<>(deltaClassNames));
+                errorMessage = doHotCodeReplace(deltaResources, deltaClassNames);
                 deltaResources.clear();
                 deltaClassNames.clear();
             }

com.microsoft.java.debug.plugin/src/main/java/com/microsoft/java/debug/plugin/internal/JdtUtils.java

@@ -15,6 +15,7 @@
 import java.util.Arrays;
 import java.util.LinkedHashSet;
 import java.util.List;
+import java.util.Objects;
 import java.util.Set;
 
 import org.apache.commons.lang3.StringUtils;
@@ -399,4 +400,19 @@ private static String getTypeName(String genericTypeSignature) {
         }
         return name.toString();
     }
+
+    /**
+     * Check whether two resources point to the same physical file.
+     */
+    public static boolean isSameFile(IResource resource1, IResource resource2) {
+        if (resource1 == null || resource2 == null) {
+            return false;
+        }
+
+        if (Objects.equals(resource1, resource2)) {
+            return true;
+        }
+
+        return Objects.equals(resource1.getLocation(), resource2.getLocation());
+    }
 }