IDEA-131502 Show JSON arrays in structure view for deeply nested properties

Additionally hide nodes for objects and arrays if they do not contain properties
somewhere inside.

json/src/com/intellij/json/structureView/JsonStructureViewElement.java

@@ -4,6 +4,7 @@ import com.intellij.ide.structureView.StructureViewTreeElement;
 import com.intellij.ide.util.treeView.smartTree.TreeElement;
 import com.intellij.json.psi.*;
 import com.intellij.navigation.ItemPresentation;
+import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.util.ArrayUtil;
 import com.intellij.util.Function;
 import com.intellij.util.containers.ContainerUtil;
@@ -18,7 +19,7 @@ public class JsonStructureViewElement implements StructureViewTreeElement {
   private final JsonElement myElement;
 
   public JsonStructureViewElement(@NotNull JsonElement element) {
-    assert element instanceof JsonFile || element instanceof JsonProperty || element instanceof JsonObject;
+    assert PsiTreeUtil.instanceOf(element, JsonFile.class, JsonProperty.class, JsonObject.class, JsonArray.class);
     myElement = element;
   }
 
@@ -60,7 +61,7 @@ public class JsonStructureViewElement implements StructureViewTreeElement {
     else if (myElement instanceof JsonProperty) {
       value = ((JsonProperty)myElement).getValue();
     }
-    else if (myElement instanceof JsonObject) {
+    else if (PsiTreeUtil.instanceOf(myElement, JsonObject.class, JsonArray.class)) {
       value = myElement;
     }
     if (value instanceof JsonObject) {
@@ -77,7 +78,13 @@ public class JsonStructureViewElement implements StructureViewTreeElement {
       final List<TreeElement> childObjects = ContainerUtil.mapNotNull(array.getValueList(), new Function<JsonValue, TreeElement>() {
         @Override
         public TreeElement fun(JsonValue value) {
-          return value instanceof JsonObject ? new JsonStructureViewElement(value) : null;
+          if (value instanceof JsonObject && !((JsonObject)value).getPropertyList().isEmpty()) {
+            return new JsonStructureViewElement(value);
+          }
+          else if (value instanceof JsonArray && PsiTreeUtil.findChildOfType(value, JsonProperty.class) != null) {
+            return new JsonStructureViewElement(value);
+          }
+          return null;
         }
       });
       return ArrayUtil.toObjectArray(childObjects, TreeElement.class);

json/src/com/intellij/json/structureView/JsonStructureViewModel.java

@@ -3,6 +3,7 @@ package com.intellij.json.structureView;
 import com.intellij.ide.structureView.StructureViewModel;
 import com.intellij.ide.structureView.StructureViewModelBase;
 import com.intellij.ide.structureView.StructureViewTreeElement;
+import com.intellij.json.psi.JsonArray;
 import com.intellij.json.psi.JsonFile;
 import com.intellij.json.psi.JsonObject;
 import com.intellij.json.psi.JsonProperty;
@@ -18,7 +19,7 @@ public class JsonStructureViewModel extends StructureViewModelBase implements St
 
   public JsonStructureViewModel(@NotNull PsiFile psiFile, @Nullable Editor editor) {
     super(psiFile, editor, new JsonStructureViewElement((JsonFile)psiFile));
-    withSuitableClasses(JsonFile.class, JsonProperty.class, JsonObject.class);
+    withSuitableClasses(JsonFile.class, JsonProperty.class, JsonObject.class, JsonArray.class);
   }
 
   @Override

json/tests/test/com/intellij/json/JsonStructureViewTest.java

@@ -59,6 +59,18 @@ public class JsonStructureViewTest extends JsonTestCase {
            "    +object\n");
   }
 
+  // IDEA-131502
+  public void testArrayNodesAreShownIfNecessary() {
+    doTest("-ArrayNodesAreShownIfNecessary.json\n" +
+           " -array\n" +
+           "  -object\n" +
+           "   nestedObject\n" +
+           " -array\n" +
+           "  +array\n" +
+           " -object\n" +
+           "  siblingObject\n");
+  }
+
   // Moved from JavaScript
 
   public void testSimpleStructure() {

json/tests/testData/structureView/ArrayNodesAreShownIfNecessary.json

@@ -0,0 +1,20 @@
+[
+  [
+    {
+      "nestedObject" : true
+    }
+  ],
+  [
+    {
+      /* empty */
+    }
+  ],
+  [
+    [
+      {"deepNestedObject": true}
+    ]
+  ],
+  {
+    "siblingObject" : true
+  }
+]