From d978ed6d8104e83cf37da73eb76ed92317cf521d Mon Sep 17 00:00:00 2001
From: "Maxim.Mossienko" <Maxim.Mossienko@jetbrains.com>
Date: Wed, 5 Jul 2017 19:58:24 +0200
Subject: [PATCH] [performance] Speed-up resource loading via classloader:

Avoid eager loading jar resource bytes.
---
 .../src/com/intellij/util/lang/JarLoader.java | 50 +++++++++++++++++--
 1 file changed, 46 insertions(+), 4 deletions(-)

diff --git a/platform/util/src/com/intellij/util/lang/JarLoader.java b/platform/util/src/com/intellij/util/lang/JarLoader.java
index d95963035c3b..9c54f0ba0a1f 100644
--- a/platform/util/src/com/intellij/util/lang/JarLoader.java
+++ b/platform/util/src/com/intellij/util/lang/JarLoader.java
@@ -19,12 +19,11 @@ import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.util.Pair;
 import com.intellij.openapi.util.io.FileUtil;
 import com.intellij.reference.SoftReference;
+import com.intellij.util.ArrayUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import java.io.File;
-import java.io.IOException;
-import java.io.InputStream;
+import java.io.*;
 import java.net.URL;
 import java.util.*;
 import java.util.jar.Attributes;
@@ -131,7 +130,7 @@ class JarLoader extends Loader {
       try {
         ZipEntry entry = zipFile.getEntry(name);
         if (entry != null) {
-          return MemoryResource.load(getBaseURL(), zipFile, entry, myAttributes);
+          return new MyResource(getBaseURL(), entry);
         }
       }
       finally {
@@ -144,6 +143,49 @@ class JarLoader extends Loader {
 
     return null;
   }
+  
+  private class MyResource extends Resource {
+    private final URL myUrl;
+    private final ZipEntry myEntry;
+
+    public MyResource(URL url, ZipEntry entry) throws IOException {
+      myUrl = new URL(url, entry.getName());
+      myEntry = entry;
+    }
+
+    @Override
+    public URL getURL() {
+      return myUrl;
+    }
+
+    @Override
+    public InputStream getInputStream() throws IOException {
+      return new ByteArrayInputStream(getBytes());
+    }
+
+    @Override
+    public byte[] getBytes() throws IOException {
+      byte[] result = ArrayUtil.EMPTY_BYTE_ARRAY;
+      try {
+        ZipFile file = getZipFile();
+        try {
+          result = FileUtil.loadBytes(file.getInputStream(myEntry), (int)myEntry.getSize());
+        } finally {
+          releaseZipFile(file);
+        }
+      }
+      catch (Exception e) {
+        error("file: " + myCanonicalFile, e);
+      }
+      
+      return result;
+    }
+
+    @Override
+    public String getValue(Attribute key) {
+      return myAttributes != null ? myAttributes.get(key) : null;
+    }
+  }
 
   protected void error(String message, Throwable t) {
     Logger.getInstance(JarLoader.class).error(message, t);