From 908f24e8eca6c37bca35e3c9ec9bae955b2e47a3 Mon Sep 17 00:00:00 2001
From: Ross Allan <ross@nallar.me>
Date: Sat, 9 Sep 2017 11:58:53 +0100
Subject: [PATCH] Always close the InputStreams returned from Jar.getResource
 (#46)

* Always close the InputStreams returned from Jar.getResource

* Tentative change to not open inputstream when checking if a resource exists
---
 src/main/java/net/md_5/specialsource/Jar.java | 31 +++++++++++++++----
 .../net/md_5/specialsource/SpecialSource.java | 16 ++++++++--
 .../net/md_5/specialsource/repo/JarRepo.java  | 22 +------------
 3 files changed, 40 insertions(+), 29 deletions(-)

diff --git a/src/main/java/net/md_5/specialsource/Jar.java b/src/main/java/net/md_5/specialsource/Jar.java
index 39c6c40..52f3ea8 100644
--- a/src/main/java/net/md_5/specialsource/Jar.java
+++ b/src/main/java/net/md_5/specialsource/Jar.java
@@ -75,12 +75,26 @@ public class Jar implements Closeable {
      * @return
      */
     public boolean containsClass(String clazz) {
-        try {
-            return contains.contains(clazz) ? true : getClass(clazz) != null;
-        } catch (IOException ex) {
-            // IO error - regardless we do not have access to the class, so we can ignore it and move on
-            return false;
+        if (contains.contains(clazz)) {
+            return true;
         }
+
+        if (containsResource(clazz + ".class")) {
+            contains.add(clazz);
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * Check if this jar contains the given resource.
+     *
+     * @param name The name of the resource
+     * @return true Whether a resource with the given name exists
+     */
+    public boolean containsResource(String name) {
+        JarFile jarFile = jarForResource.get(name);
+        return jarFile != null && jarFile.getEntry(name) != null;
     }
 
     /**
@@ -128,8 +142,13 @@ public class Jar implements Closeable {
         try {
             InputStream is = getClass(clazz);
             if (is != null) {
+                ClassReader cr;
                 // Process it
-                ClassReader cr = new ClassReader(is);
+                try {
+                    cr = new ClassReader(is);
+                } finally {
+                    is.close();
+                }
                 ClassNode node = new ClassNode();
                 cr.accept(node, 0);
 
diff --git a/src/main/java/net/md_5/specialsource/SpecialSource.java b/src/main/java/net/md_5/specialsource/SpecialSource.java
index a3dcba2..1f5fcde 100644
--- a/src/main/java/net/md_5/specialsource/SpecialSource.java
+++ b/src/main/java/net/md_5/specialsource/SpecialSource.java
@@ -299,8 +299,20 @@ public class SpecialSource {
         JarComparer visitor1 = visitors.first;
         JarComparer visitor2 = visitors.second;
 
-        ClassReader clazz1 = new ClassReader(jars.first.getClass(classes.first));
-        ClassReader clazz2 = new ClassReader(jars.second.getClass(classes.second));
+        ClassReader clazz1, clazz2;
+        InputStream first = null;
+        InputStream second = null;
+        try {
+            clazz1 = new ClassReader(first = jars.second.getClass(classes.first));
+            clazz2 = new ClassReader(second = jars.first.getClass(classes.second));
+        } finally {
+            if (first != null) {
+                first.close();
+            }
+            if (second != null) {
+                second.close();
+            }
+        }
         clazz1.accept(visitor1, 0);
         clazz2.accept(visitor2, 0);
 
diff --git a/src/main/java/net/md_5/specialsource/repo/JarRepo.java b/src/main/java/net/md_5/specialsource/repo/JarRepo.java
index 9ea42a6..5f61b4c 100644
--- a/src/main/java/net/md_5/specialsource/repo/JarRepo.java
+++ b/src/main/java/net/md_5/specialsource/repo/JarRepo.java
@@ -28,11 +28,8 @@
  */
 package net.md_5.specialsource.repo;
 
-import java.io.IOException;
-import java.io.InputStream;
 import lombok.RequiredArgsConstructor;
 import net.md_5.specialsource.Jar;
-import org.objectweb.asm.ClassReader;
 import org.objectweb.asm.tree.ClassNode;
 
 @RequiredArgsConstructor
@@ -42,23 +39,6 @@ public class JarRepo extends CachingRepo {
 
     @Override
     protected ClassNode findClass0(String internalName) {
-        ClassNode node = null;
-
-        try {
-            InputStream is = jar.getClass(internalName);
-
-            if (is != null) {
-                ClassReader reader = new ClassReader(is);
-                ClassNode node0 = new ClassNode();
-                reader.accept(node0, 0); // TODO
-                is.close();
-
-                node = node0;
-            }
-        } catch (IOException ex) {
-            ex.printStackTrace();
-        }
-
-        return node;
+        return jar.getNode(internalName);
     }
 }