Allow adding custom global search scopes

reference:
OC-9143 Add 'File added to Xcode project' scope
OC-3934 Add 'Files not added to Xcode project' scope to help find and add such files to the project.
CPP-505 Better CMake files overview in the project pane

platform/analysis-impl/src/com/intellij/psi/search/PredefinedSearchScopeProvider.java

@@ -1,18 +1,4 @@
-/*
- * Copyright 2000-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.psi.search;
 
 import com.intellij.openapi.actionSystem.DataContext;

platform/analysis-impl/src/com/intellij/psi/search/SearchScopeProvider.java

@@ -0,0 +1,16 @@
+// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+package com.intellij.psi.search;
+
+import com.intellij.openapi.extensions.ExtensionPointName;
+
+import java.util.List;
+
+public interface SearchScopeProvider {
+  ExtensionPointName<SearchScopeProvider> EP = ExtensionPointName.create("com.intellij.searchScopesProvider");
+
+  /**
+   * General project scopes are added after 'Project', 'Everything' but before 'Production', 'Tests', etc.
+   * @see PredefinedSearchScopeProvider
+   */
+  List<SearchScope> getGeneralProjectScopes();
+}

platform/lang-impl/src/com/intellij/psi/search/PredefinedSearchScopeProviderImpl.java

@@ -1,18 +1,4 @@
-/*
- * Copyright 2000-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.psi.search;
 
 import com.intellij.ide.IdeBundle;
@@ -27,6 +13,7 @@ import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.application.ReadAction;
 import com.intellij.openapi.editor.Editor;
 import com.intellij.openapi.editor.SelectionModel;
+import com.intellij.openapi.extensions.Extensions;
 import com.intellij.openapi.fileEditor.FileEditorManager;
 import com.intellij.openapi.module.*;
 import com.intellij.openapi.project.Project;
@@ -76,6 +63,10 @@ public class PredefinedSearchScopeProviderImpl extends PredefinedSearchScopeProv
       result.add(GlobalSearchScope.allScope(project));
     }
 
+    for (SearchScopeProvider each : Extensions.getExtensions(SearchScopeProvider.EP, project)) {
+      result.addAll(each.getGeneralProjectScopes());
+    }
+
     if (ModuleUtil.isSupportedRootType(project, JavaSourceRootType.TEST_SOURCE)) {
       result.add(GlobalSearchScopesCore.projectProductionScope(project));
       result.add(GlobalSearchScopesCore.projectTestScope(project));

platform/platform-resources/src/META-INF/LangExtensionPoints.xml

@@ -258,6 +258,7 @@
     <extensionPoint name="definitionsSearch" interface="com.intellij.util.QueryExecutor"/>
     <extensionPoint name="definitionsScopedSearch" interface="com.intellij.util.QueryExecutor"/>
 
+    <extensionPoint name="searchScopesProvider" interface="com.intellij.psi.search.SearchScopeProvider" area="IDEA_PROJECT"/>
     <extensionPoint name="searchScopeEnlarger" interface="com.intellij.psi.search.SearchScopeEnlarger"/>
     <extensionPoint name="useScopeEnlarger" interface="com.intellij.psi.search.UseScopeEnlarger"/>
     <extensionPoint name="resolveScopeEnlarger" interface="com.intellij.psi.ResolveScopeEnlarger"/>