[performance for 143] make somewhat less intrusive but more public way of reusing loaded file content

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

@@ -16,7 +16,6 @@
 package com.intellij.psi.impl.compiled;
 
 import com.intellij.openapi.diagnostic.Logger;
-import com.intellij.openapi.util.Key;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.compiled.ClassFileDecompilers;
 import com.intellij.psi.stubs.BinaryFileStubBuilder;
@@ -40,7 +39,6 @@ public class ClassFileStubBuilder implements BinaryFileStubBuilder {
   private static final Logger LOG = Logger.getInstance("#com.intellij.psi.impl.compiled.ClassFileStubBuilder");
 
   public static final int STUB_VERSION = 12;
-  public static final Key<byte[]> ourCompiledClassContentHintKey = Key.create("compiled.class.content.hint");
 
   @Override
   public boolean acceptsFile(@NotNull VirtualFile file) {
@@ -53,7 +51,7 @@ public class ClassFileStubBuilder implements BinaryFileStubBuilder {
     byte[] content = fileContent.getContent();
 
     try {
-      file.putUserData(ourCompiledClassContentHintKey, content);
+      file.setForcedContentHint(content);
       ClassFileDecompilers.Decompiler decompiler = ClassFileDecompilers.find(file);
       if (decompiler instanceof Full) {
         return ((Full)decompiler).getStubBuilder().buildFileStub(fileContent);
@@ -63,7 +61,7 @@ public class ClassFileStubBuilder implements BinaryFileStubBuilder {
       LOG.debug(e);
     }
     finally {
-      file.putUserData(ourCompiledClassContentHintKey, null);
+      file.setForcedContentHint(null);
     }
 
     try {

platform/core-api/src/com/intellij/openapi/vfs/VirtualFile.java

@@ -750,4 +750,7 @@ public abstract class VirtualFile extends UserDataHolderBase implements Modifica
   public CharSequence getNameSequence() {
     return getName();
   }
+
+  public void setForcedContentHint(byte[] forcedContent) {
+  }
 }

platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/impl/VirtualFileImpl.java

@@ -19,17 +19,20 @@
  */
 package com.intellij.openapi.vfs.newvfs.impl;
 
+import com.intellij.openapi.util.Key;
 import com.intellij.openapi.vfs.VfsUtilCore;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.openapi.vfs.newvfs.NewVirtualFile;
 import com.intellij.openapi.vfs.newvfs.NewVirtualFileSystem;
 import com.intellij.util.LineSeparator;
 import com.intellij.util.containers.ContainerUtil;
+import com.intellij.util.io.UnsyncByteArrayInputStream;
 import com.intellij.util.keyFMap.KeyFMap;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
+import java.io.DataInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -90,10 +93,24 @@ public class VirtualFileImpl extends VirtualFileSystemEntry {
     return false;
   }
 
+  private static final Key<byte[]> ourForcedContentKey = Key.create("forced.content.key");
+
+  @Override
+  public void setForcedContentHint(byte[] forcedContent) {
+    putUserData(ourForcedContentKey, forcedContent);
+  }
+
   @Override
   @NotNull
   public InputStream getInputStream() throws IOException {
-    return VfsUtilCore.inputStreamSkippingBOM(ourPersistence.getInputStream(this), this);
+    final byte[] forcedContent = getUserData(ourForcedContentKey);
+
+    return VfsUtilCore.inputStreamSkippingBOM(
+      forcedContent == null ?
+        ourPersistence.getInputStream(this):
+        new DataInputStream(new UnsyncByteArrayInputStream(forcedContent)),
+      this
+    );
   }
 
   @Override
@@ -105,6 +122,8 @@ public class VirtualFileImpl extends VirtualFileSystemEntry {
   @NotNull
   @Override
   public byte[] contentsToByteArray(boolean cacheContent) throws IOException {
+    final byte[] forcedContent = getUserData(ourForcedContentKey);
+    if (forcedContent != null) return forcedContent;
     return ourPersistence.contentsToByteArray(this, cacheContent);
   }