introduce LanguageUtil.getLanguageForPsi

platform/core-api/src/com/intellij/lang/LanguageUtil.java

@@ -19,10 +19,12 @@ package com.intellij.lang;
 import com.intellij.lexer.Lexer;
 import com.intellij.openapi.fileTypes.FileType;
 import com.intellij.openapi.fileTypes.LanguageFileType;
+import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Condition;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.FileViewProvider;
+import com.intellij.psi.LanguageSubstitutors;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFile;
 import com.intellij.psi.templateLanguages.TemplateLanguage;
@@ -47,6 +49,13 @@ public final class LanguageUtil {
   };
 
 
+  @Nullable
+  public static Language getLanguageForPsi(@NotNull Project project, @Nullable VirtualFile file) {
+    Language language = getFileLanguage(file);
+    if (language == null) return null;
+    return LanguageSubstitutors.INSTANCE.substituteLanguage(language, file, project);
+  }
+
   @Nullable
   public static Language getFileLanguage(@Nullable VirtualFile file) {
     return file == null ? null : getFileTypeLanguage(file.getFileType());

platform/core-impl/src/com/intellij/psi/SingleRootFileViewProvider.java

@@ -19,6 +19,7 @@ import com.google.common.util.concurrent.Atomics;
 import com.intellij.injected.editor.DocumentWindow;
 import com.intellij.lang.Language;
 import com.intellij.lang.LanguageParserDefinitions;
+import com.intellij.lang.LanguageUtil;
 import com.intellij.lang.ParserDefinition;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.command.undo.UndoConstants;
@@ -28,7 +29,6 @@ import com.intellij.openapi.fileEditor.FileDocumentManager;
 import com.intellij.openapi.fileEditor.impl.LoadTextUtil;
 import com.intellij.openapi.fileTypes.FileType;
 import com.intellij.openapi.fileTypes.FileTypeRegistry;
-import com.intellij.openapi.fileTypes.LanguageFileType;
 import com.intellij.openapi.fileTypes.PlainTextLanguage;
 import com.intellij.openapi.progress.ProcessCanceledException;
 import com.intellij.openapi.project.Project;
@@ -134,11 +134,9 @@ public class SingleRootFileViewProvider extends UserDataHolderBase implements Fi
     if (fileType.isBinary()) return Language.ANY;
     if (isTooLargeForIntelligence(file)) return PlainTextLanguage.INSTANCE;
 
-    if (fileType instanceof LanguageFileType) {
-      return LanguageSubstitutors.INSTANCE.substituteLanguage(((LanguageFileType)fileType).getLanguage(), file, project);
-    }
+    Language language = LanguageUtil.getLanguageForPsi(project, file);
 
-    return PlainTextLanguage.INSTANCE;
+    return language == null ? null : PlainTextLanguage.INSTANCE;
   }
 
   @Override

platform/lang-impl/src/com/intellij/ide/scratch/ScratchFileActions.java

@@ -17,6 +17,7 @@ package com.intellij.ide.scratch;
 
 import com.intellij.featureStatistics.FeatureUsageTracker;
 import com.intellij.lang.Language;
+import com.intellij.lang.LanguageUtil;
 import com.intellij.lang.PerFileMappings;
 import com.intellij.lang.StdLanguages;
 import com.intellij.lang.injection.InjectedLanguageManager;
@@ -196,7 +197,7 @@ public class ScratchFileActions {
         @Override
         public Language fun(VirtualFile file) {
           Language lang = fileService.getScratchesMapping().getMapping(file);
-          return lang != null ? lang : ScratchUtil.getLanguage(project, file);
+          return lang != null ? lang : LanguageUtil.getLanguageForPsi(project, file);
         }
       };
     }

platform/lang-impl/src/com/intellij/ide/scratch/ScratchFileServiceImpl.java

@@ -224,7 +224,7 @@ public class ScratchFileServiceImpl extends ScratchFileService implements Persis
     public SyntaxHighlighter create(@NotNull FileType fileType, @Nullable Project project, @Nullable VirtualFile file) {
       if (project == null || file == null || !(fileType instanceof ScratchFileType)) return null;
 
-      Language language = ScratchUtil.getLanguage(project, file);
+      Language language = LanguageUtil.getLanguageForPsi(project, file);
       return language == null ? null : SyntaxHighlighterFactory.getSyntaxHighlighter(language, project, file);
     }
   }

platform/lang-impl/src/com/intellij/ide/scratch/ScratchUtil.java

@@ -15,12 +15,7 @@
  */
 package com.intellij.ide.scratch;
 
-import com.intellij.lang.Language;
-import com.intellij.lang.LanguageUtil;
-import com.intellij.openapi.project.Project;
 import com.intellij.openapi.vfs.VirtualFile;
-import com.intellij.psi.LanguageSubstitutors;
-import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 /**
@@ -38,11 +33,4 @@ public class ScratchUtil {
   public static boolean isScratch(@Nullable VirtualFile file) {
     return file != null && file.getFileType() == ScratchFileType.INSTANCE;
   }
-
-  @Nullable
-  public static Language getLanguage(@NotNull Project project, @Nullable VirtualFile file) {
-    Language language = LanguageUtil.getFileLanguage(file);
-    if (language == null) return null;
-    return LanguageSubstitutors.INSTANCE.substituteLanguage(language, file, project);
-  }
 }

python/src/com/jetbrains/python/debugger/PyLineBreakpointType.java

@@ -16,6 +16,7 @@
 package com.jetbrains.python.debugger;
 
 import com.intellij.ide.scratch.ScratchUtil;
+import com.intellij.lang.LanguageUtil;
 import com.intellij.openapi.editor.Document;
 import com.intellij.openapi.fileEditor.FileDocumentManager;
 import com.intellij.openapi.project.Project;
@@ -70,7 +71,7 @@ public class PyLineBreakpointType extends XLineBreakpointTypeBase {
   }
 
   private static boolean isPythonScratch(@NotNull Project project, @NotNull VirtualFile file) {
-    return ScratchUtil.isScratch(file) && ScratchUtil.getLanguage(project, file) == PythonLanguage.INSTANCE;
+    return ScratchUtil.isScratch(file) && LanguageUtil.getLanguageForPsi(project, file) == PythonLanguage.INSTANCE;
   }
 
   private static boolean notStoppableElementType(IElementType elementType) {