java: ensure PSI/document compatibility for decompiled .class files

java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClassFileDecompiler.java

@@ -17,8 +17,6 @@ package com.intellij.psi.impl.compiled;
 
 import com.intellij.openapi.components.ServiceManager;
 import com.intellij.openapi.diagnostic.Logger;
-import com.intellij.openapi.editor.Document;
-import com.intellij.openapi.fileEditor.FileDocumentManager;
 import com.intellij.openapi.fileTypes.BinaryFileDecompiler;
 import com.intellij.openapi.project.DefaultProjectFactory;
 import com.intellij.openapi.vfs.VirtualFile;
@@ -54,17 +52,6 @@ public class ClassFileDecompiler implements BinaryFileDecompiler {
       if (result != null) return result;
     }
 
-    return decompileText(file);
-  }
-
-  @NotNull
-  public static CharSequence decompileText(@NotNull VirtualFile file) {
-    Document document = FileDocumentManager.getInstance().getCachedDocument(file);
-    if (document != null) {
-      return document.getImmutableCharSequence();
-    }
-
-    ClassFileDecompilers.Decompiler decompiler = ClassFileDecompilers.find(file);
     if (decompiler instanceof ClassFileDecompilers.Light) {
       try {
         return ((ClassFileDecompilers.Light)decompiler).getText(file);

java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsFileImpl.java

@@ -24,8 +24,10 @@ import com.intellij.lang.FileASTNode;
 import com.intellij.lang.java.JavaLanguage;
 import com.intellij.openapi.application.ApplicationManager;
 import com.intellij.openapi.diagnostic.Logger;
+import com.intellij.openapi.editor.Document;
 import com.intellij.openapi.extensions.Extensions;
 import com.intellij.openapi.extensions.PluginId;
+import com.intellij.openapi.fileEditor.FileDocumentManager;
 import com.intellij.openapi.fileTypes.FileType;
 import com.intellij.openapi.progress.ProgressManager;
 import com.intellij.openapi.project.DefaultProjectFactory;
@@ -33,6 +35,7 @@ import com.intellij.openapi.roots.FileIndexFacade;
 import com.intellij.openapi.ui.Queryable;
 import com.intellij.openapi.util.Comparing;
 import com.intellij.openapi.util.Computable;
+import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.ModificationTracker;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.pom.java.LanguageLevel;
@@ -77,6 +80,8 @@ public class ClsFileImpl extends ClsRepositoryPsiElement<PsiClassHolderFileStub>
                          implements PsiJavaFile, PsiFileWithStubSupport, PsiFileEx, Queryable, PsiClassOwnerEx, PsiCompiledFile {
   private static final Logger LOG = Logger.getInstance("#com.intellij.psi.impl.compiled.ClsFileImpl");
 
+  private static final Key<Document> CLS_DOCUMENT_LINK_KEY = Key.create("cls.document.link");
+
   /** NOTE: you absolutely MUST NOT hold PsiLock under the mirror lock */
   private final Object myMirrorLock = new Object();
   private final Object myStubLock = new Object();
@@ -342,7 +347,10 @@ public class ClsFileImpl extends ClsRepositoryPsiElement<PsiClassHolderFileStub>
   }
 
   private TreeElement trySetMirror(VirtualFile file, String fileName, boolean usePlugin) {
-    CharSequence mirrorText = ClassFileDecompiler.decompileText(file);
+    final Document document = FileDocumentManager.getInstance().getDocument(file);
+    assert document != null : file.getUrl();
+
+    CharSequence mirrorText = document.getImmutableCharSequence();
     PsiFileFactory factory = PsiFileFactory.getInstance(getManager().getProject());
     PsiFile mirror = factory.createFileFromText(fileName, JavaLanguage.INSTANCE, mirrorText, false, false);
     mirror.putUserData(PsiUtil.FILE_LANGUAGE_LEVEL_KEY, getLanguageLevel());
@@ -353,6 +361,7 @@ public class ClsFileImpl extends ClsRepositoryPsiElement<PsiClassHolderFileStub>
         @Override
         public void run() {
           setMirror(mirrorTreeElement);
+          putUserData(CLS_DOCUMENT_LINK_KEY, document);
         }
       });
     }
@@ -515,6 +524,7 @@ public class ClsFileImpl extends ClsRepositoryPsiElement<PsiClassHolderFileStub>
 
     ClsPackageStatementImpl packageStatement = new ClsPackageStatementImpl(this);
     synchronized (myMirrorLock) {
+      putUserData(CLS_DOCUMENT_LINK_KEY, null);
       myMirrorFileElement = null;
       myPackageStatement = packageStatement;
     }

java/java-tests/testSrc/com/intellij/psi/ClsMirrorBuildingTest.java

@@ -17,10 +17,12 @@ package com.intellij.psi;
 
 import com.intellij.JavaTestUtil;
 import com.intellij.ide.highlighter.JavaFileType;
+import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.fileEditor.FileDocumentManager;
+import com.intellij.openapi.util.io.FileUtil;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.openapi.vfs.StandardFileSystems;
 import com.intellij.openapi.vfs.VirtualFile;
-import com.intellij.openapi.vfs.VirtualFileSystem;
 import com.intellij.psi.codeStyle.CodeStyleSettingsManager;
 import com.intellij.psi.codeStyle.CommonCodeStyleSettings;
 import com.intellij.psi.impl.compiled.ClsFileImpl;
@@ -31,6 +33,7 @@ import com.intellij.testFramework.LightIdeaTestCase;
 import com.intellij.testFramework.PlatformTestUtil;
 import org.jetbrains.org.objectweb.asm.ClassReader;
 
+import java.io.File;
 import java.io.IOException;
 
 public class ClsMirrorBuildingTest extends LightIdeaTestCase {
@@ -107,6 +110,34 @@ public class ClsMirrorBuildingTest extends LightIdeaTestCase {
     new ClassReader(file.contentsToByteArray()).accept(visitor, ClassReader.SKIP_FRAMES);
   }
 
+  public void testDocumentReuse() throws IOException {
+    File classFile = new File(FileUtil.getTempDirectory(), "ReuseTest.class");
+    assertTrue(classFile.getPath(), classFile.createNewFile());
+    VirtualFile vFile = StandardFileSystems.local().findFileByPath(classFile.getPath());
+    assertNotNull(classFile.getPath(), vFile);
+    PsiFile psiFile = PsiManager.getInstance(getProject()).findFile(vFile);
+    assertNotNull(psiFile);
+    String testDir = JavaTestUtil.getJavaTestDataPath() + "/psi/cls/mirror/";
+
+    FileUtil.copy(new File(testDir, "pkg/ReuseTestV1.class"), classFile);
+    vFile.refresh(false, false);
+    String text1 = psiFile.getText();
+    assertTrue(text1, text1.contains("private int f1"));
+    assertFalse(text1, text1.contains("private int f2"));
+    Document doc1 = FileDocumentManager.getInstance().getCachedDocument(vFile);
+    assertNotNull(doc1);
+    assertSame(doc1, PsiDocumentManager.getInstance(getProject()).getDocument(psiFile));
+
+    FileUtil.copy(new File(testDir, "pkg/ReuseTestV2.class"), classFile);
+    vFile.refresh(false, false);
+    String text2 = psiFile.getText();
+    assertTrue(text2, text2.contains("private int f1"));
+    assertTrue(text2, text2.contains("private int f2"));
+    Document doc2 = FileDocumentManager.getInstance().getCachedDocument(vFile);
+    assertNotNull(doc2);
+    assertSame(doc2, PsiDocumentManager.getInstance(getProject()).getDocument(psiFile));
+  }
+
   private void doTest() {
     doTest(getTestName(false));
   }
@@ -117,8 +148,7 @@ public class ClsMirrorBuildingTest extends LightIdeaTestCase {
   }
 
   private static void doTest(String clsPath, String txtPath) {
-    VirtualFileSystem fs = clsPath.contains("!/") ? StandardFileSystems.jar() : StandardFileSystems.local();
-    VirtualFile file = fs.findFileByPath(clsPath);
+    VirtualFile file = (clsPath.contains("!/") ? StandardFileSystems.jar() : StandardFileSystems.local()).findFileByPath(clsPath);
     assertNotNull(clsPath, file);
 
     String expected;
@@ -126,8 +156,7 @@ public class ClsMirrorBuildingTest extends LightIdeaTestCase {
       expected = StringUtil.trimTrailing(PlatformTestUtil.loadFileText(txtPath));
     }
     catch (IOException e) {
-      fail(e.getMessage());
-      return;
+      throw new RuntimeException(e);
     }
 
     assertEquals(expected, ClsFileImpl.decompile(file).toString());