From ad3e32d93517612e438c1d1d857979c6c78c67c4 Mon Sep 17 00:00:00 2001
From: jrm <jrm@fb.com>
Date: Wed, 13 Apr 2016 16:06:40 -0700
Subject: [PATCH] Fix resource leak false positive with the resource wrapper
 java.io.DataInputStream

Summary:public
The code:

  DataInputStream in = new DataInputStream(new BufferedInputStream(new FileInputStream(file)));

creates a resource with `FileInputStream()` and wraps it twice as a field of `BufferedInputStream` and then as a field of `DataInputStream`. Then calling:

  in.close();

needs to go down the wrappers hierachy: `DataInputStream.close()` -> `FilterInputStream.close()` which then calls `BufferedInputStream.close()` -> `FilterInputStream.close()` -> `FileInputStream.close()`.

Going down the wrapper was not working before because `FilterInputStream.close()` was only going further when the type of field `in` was `FileInputStream` wheras it should also continue when the type of the field is any subtype of `FilterInputStream`, e.g. `DataInputStream` and `BufferedInputStream` like in the test example. This diff fixes this last aspect.

Reviewed By: sblackshear

Differential Revision: D3174822

fb-gh-sync-id: 3adbb7e
fbshipit-source-id: 3adbb7e
---
 infer/models/java/src/java/io/FilterInputStream.java |  8 ++++++--
 .../java/infer/FilterInputStreamLeaks.java           | 12 +++++++-----
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/infer/models/java/src/java/io/FilterInputStream.java b/infer/models/java/src/java/io/FilterInputStream.java
index 5cab86568..e682588f1 100644
--- a/infer/models/java/src/java/io/FilterInputStream.java
+++ b/infer/models/java/src/java/io/FilterInputStream.java
@@ -28,9 +28,13 @@ public class FilterInputStream extends InputStream {
     }
 
     public void close() throws IOException {
-        if (in != null)
-            if (in instanceof FileInputStream)
+        if (in != null) {
+            if (in instanceof FileInputStream) {
                 ((FileInputStream) in).close();
+            } else {
+                in.close();
+            }
+        }
     }
 
     public int read() throws IOException {
diff --git a/infer/tests/codetoanalyze/java/infer/FilterInputStreamLeaks.java b/infer/tests/codetoanalyze/java/infer/FilterInputStreamLeaks.java
index 1b12e0e80..351522c6d 100644
--- a/infer/tests/codetoanalyze/java/infer/FilterInputStreamLeaks.java
+++ b/infer/tests/codetoanalyze/java/infer/FilterInputStreamLeaks.java
@@ -10,11 +10,7 @@
 package codetoanalyze.java.infer;
 
 
-import java.io.BufferedInputStream;
-import java.io.DataInputStream;
-import java.io.FileInputStream;
-import java.io.IOException;
-import java.io.PushbackInputStream;
+import java.io.*;
 import java.security.DigestInputStream;
 import java.util.zip.CheckedInputStream;
 import java.util.zip.DeflaterInputStream;
@@ -263,4 +259,10 @@ public class FilterInputStreamLeaks {
       if (pms != null) pms.close();
     }
   }
+
+  public void twoLevelWrapperNoLeak(File file) throws IOException {
+    DataInputStream in = new DataInputStream(new BufferedInputStream(new FileInputStream(file)));
+    in.close();
+  }
+
 }