Use SmartList in places where it is clear that memory may be saved (#32)

Author: jwren

third_party/src/main/java/com/jetbrains/lang/dart/analyzer/DartAnalysisServerService.java

@@ -2001,7 +2001,7 @@ public void execution_deleteContext(final @NotNull String contextId) {
                                                                                                                 @NotNull List<RuntimeCompletionExpression> expressions) {
     final AnalysisServer server = myServer;
     if (server == null) {
-      return new Pair<>(new ArrayList<>(), new ArrayList<>());
+      return new Pair<>(new SmartList<>(), new SmartList<>());
     }
 
     final String contextFileUri = getFileUri(contextFile);

third_party/src/main/java/com/jetbrains/lang/dart/analyzer/DartServerData.java

@@ -290,7 +290,7 @@ VirtualFile getNotLocalVirtualFile(@NotNull String fileUri) {
 
   @NotNull
   List<DartError> getErrors(final @NotNull SearchScope scope) {
-    final List<DartError> errors = new ArrayList<>();
+    final List<DartError> errors = new SmartList<>();
 
     synchronized (myErrorData) {
       for (Map.Entry<DartFileInfo, List<DartError>> entry : myErrorData.entrySet()) {

third_party/src/main/java/com/jetbrains/lang/dart/ide/hierarchy/call/DartCalleeTreeStructure.java

@@ -5,6 +5,7 @@
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFile;
+import com.intellij.util.SmartList;
 import com.jetbrains.lang.dart.analyzer.DartAnalysisServerService;
 import com.jetbrains.lang.dart.psi.DartComponent;
 import com.jetbrains.lang.dart.psi.DartComponentName;
@@ -81,7 +82,7 @@ private static PsiElement getDeclaration(DartNavigationTarget target, PsiElement
         return region.getTargets();
       }
     }
-    return new ArrayList<>(0);
+    return new SmartList<>();
   }
 
   @Override

third_party/src/main/java/com/jetbrains/lang/dart/ide/refactoring/introduce/DartServerExtractLocalVariableHandler.java

@@ -18,6 +18,7 @@
 import com.intellij.refactoring.ui.NameSuggestionsField;
 import com.intellij.refactoring.util.CommonRefactoringUtil;
 import com.intellij.util.ArrayUtil;
+import com.intellij.util.SmartList;
 import com.intellij.util.ui.JBUI;
 import com.jetbrains.lang.dart.DartBundle;
 import com.jetbrains.lang.dart.DartFileType;
@@ -35,7 +36,6 @@
 
 import javax.swing.*;
 import java.awt.*;
-import java.util.ArrayList;
 import java.util.List;
 
 public class DartServerExtractLocalVariableHandler implements RefactoringActionHandler {
@@ -89,9 +89,6 @@ public void perform() {
       final int[] offsets = refactoring.getCoveringExpressionOffsets();
       final int[] lengths = refactoring.getCoveringExpressionLengths();
       expressions = getDartExpressions(offsets, lengths);
-      if (expressions == null) {
-        return;
-      }
     }
     // select the expression to extract
     if (expressions.size() == 1 || ApplicationManager.getApplication().isUnitTestMode()) {
@@ -119,12 +116,13 @@ private void createRefactoring(int offset, int length) {
     return PsiTreeUtil.findElementOfClassAtRange(file, offset, offset + length, DartExpression.class);
   }
 
-  private @Nullable List<DartExpression> getDartExpressions(int[] offsets, int[] lengths) {
-    final List<DartExpression> expressions = new ArrayList<>();
+  @NotNull
+  private List<DartExpression> getDartExpressions(int[] offsets, int[] lengths) {
+    final List<DartExpression> expressions = new SmartList<>();
     for (int i = 0; i < offsets.length; i++) {
       final DartExpression expression = findExpressionWithRange(offsets[i], lengths[i]);
       if (expression == null) {
-        return null;
+        return expressions;
       }
       expressions.add(expression);
     }