From 228c172c32b5034781d915fa910a783cb5504e24 Mon Sep 17 00:00:00 2001
From: Roman Shevchenko <roman.shevchenko@jetbrains.com>
Date: Thu, 6 Sep 2012 18:02:48 +0400
Subject: [PATCH] IDEA-26980 (consider .jar length when updating mirror file)

Problem: Apply Patch action (which adds .jar file to a .jar directory) in a course of applicability check creates empty files in VFS. This triggers following event chain: VFS create file -> .jar directory update -> project root update -> .jar scan -> mirror file update, and leads to copying 0-length content into a .jar mirror. Subsequent VFS content change event doesn't caused mirror update as it usually takes less then 2 secs to apply patch completely.
---
 .../openapi/vfs/impl/jar/JarHandler.java      | 23 ++++++++++++-------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/platform/platform-impl/src/com/intellij/openapi/vfs/impl/jar/JarHandler.java b/platform/platform-impl/src/com/intellij/openapi/vfs/impl/jar/JarHandler.java
index 61cd1e63e740..9a31eb444904 100644
--- a/platform/platform-impl/src/com/intellij/openapi/vfs/impl/jar/JarHandler.java
+++ b/platform/platform-impl/src/com/intellij/openapi/vfs/impl/jar/JarHandler.java
@@ -25,6 +25,8 @@ import com.intellij.openapi.application.PathManager;
 import com.intellij.openapi.progress.ProgressIndicator;
 import com.intellij.openapi.progress.ProgressManager;
 import com.intellij.openapi.ui.Messages;
+import com.intellij.openapi.util.io.FileAttributes;
+import com.intellij.openapi.util.io.FileSystemUtil;
 import com.intellij.openapi.util.io.FileUtil;
 import com.intellij.openapi.vfs.JarFileSystem;
 import com.intellij.openapi.vfs.LocalFileSystem;
@@ -70,22 +72,27 @@ public class JarHandler extends JarHandlerBase implements FileSystemInterface {
 
   @Override
   public File getMirrorFile(File originalFile) {
-    if (!myFileSystem.isMakeCopyOfJar(originalFile) || !originalFile.exists()) return originalFile;
+    if (!myFileSystem.isMakeCopyOfJar(originalFile)) return originalFile;
 
-    String folderPath = getJarsDir();
+    final FileAttributes originalAttributes = FileSystemUtil.getAttributes(originalFile);
+    if (originalAttributes == null) return originalFile;
+
+    final String folderPath = getJarsDir();
     if (!new File(folderPath).exists() && !new File(folderPath).mkdirs()) {
       return originalFile;
     }
 
-    String fileName = originalFile.getName() + "." + Integer.toHexString(originalFile.getPath().hashCode());
-    File mirror = new File(folderPath, fileName);
+    final String mirrorName = originalFile.getName() + "." + Integer.toHexString(originalFile.getPath().hashCode());
+    final File mirrorFile = new File(folderPath, mirrorName);
+    final FileAttributes mirrorAttributes = FileSystemUtil.getAttributes(mirrorFile);
 
-    if (!mirror.exists() ||
-        Math.abs(originalFile.lastModified() - mirror.lastModified()) > 2000) {
-      return copyToMirror(originalFile, mirror);
+    if (mirrorAttributes == null ||
+        originalAttributes.length != mirrorAttributes.length ||
+        Math.abs(originalAttributes.lastModified - mirrorAttributes.lastModified) > 2000) {
+      return copyToMirror(originalFile, mirrorFile);
     }
 
-    return mirror;
+    return mirrorFile;
   }
 
   private static String getJarsDir() {