Adding SharedFileInputStream tests

Signed-off-by: Jorge Bescos Gascon <[email protected]>

api/src/main/java/jakarta/mail/util/SharedFileInputStream.java

@@ -76,7 +76,7 @@ public class SharedFileInputStream extends BufferedInputStream
      */
     static class SharedFile implements AutoCloseable {
         private int cnt;
-        private RandomAccessFile in;
+        RandomAccessFile in;
 
         SharedFile(String file) throws IOException {
             this.in = new RandomAccessFile(file, "r");
@@ -256,10 +256,10 @@ private int read1(byte[] b, int off, int len) throws IOException {
         int avail = count - pos;
         if (avail <= 0) {
             if (false) {
-	    /* If the requested length is at least as large as the buffer, and
-	       if there is no mark/reset activity, do not bother to copy the
-	       bytes into the local buffer.  In this way buffered streams will
-	       cascade harmlessly. */
+            /* If the requested length is at least as large as the buffer, and
+               if there is no mark/reset activity, do not bother to copy the
+               bytes into the local buffer.  In this way buffered streams will
+               cascade harmlessly. */
                 if (len >= buf.length && markpos < 0) {
                     // XXX - seek, update bufpos - how?
                     return in.read(b, off, len);
@@ -328,10 +328,10 @@ public synchronized long skip(long n) throws IOException {
 
         if (avail <= 0) {
             // If no mark position set then don't keep in buffer
-	    /*
+            /*
             if (markpos <0) 
                 return in.skip(n);
-	    */
+            */
 
             // Fill in buffer to save bytes for reset
             fill();
@@ -439,7 +439,7 @@ public void close() throws IOException {
     @Override
     public long getPosition() {
 //System.out.println("getPosition: start " + start + " pos " + pos 
-//	+ " bufpos " + bufpos + " = " + (bufpos + pos - start));
+//      + " bufpos " + bufpos + " = " + (bufpos + pos - start));
         if (in == null)
             throw new RuntimeException("Stream closed");
         return bufpos + pos - start;
@@ -473,18 +473,18 @@ public synchronized InputStream newStream(long start, long end) {
     // for testing...
     /*
     public static void main(String[] argv) throws Exception {
-	SharedFileInputStream is = new SharedFileInputStream(argv[0]);
-	java.util.Random r = new java.util.Random();
-	int b;
-	while ((b = is.read()) >= 0) {
-	    System.out.write(b);
-	    if (r.nextDouble() < 0.3) {
-		InputStream is2 = is.newStream(is.getPosition(), -1);
-		int b2;
-		while ((b2 = is2.read()) >= 0)
-		    ;
-	    }
-	}
+        SharedFileInputStream is = new SharedFileInputStream(argv[0]);
+        java.util.Random r = new java.util.Random();
+        int b;
+        while ((b = is.read()) >= 0) {
+            System.out.write(b);
+            if (r.nextDouble() < 0.3) {
+                InputStream is2 = is.newStream(is.getPosition(), -1);
+                int b2;
+                while ((b2 = is2.read()) >= 0)
+                    ;
+            }
+        }
     }
     */
 }

api/src/test/java/jakarta/mail/util/SharedFileInputStreamTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2023 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0, which is available at
@@ -16,13 +16,22 @@
 
 package jakarta.mail.util;
 
-import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+import jakarta.mail.util.SharedFileInputStream.SharedFile;
 
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.RandomAccessFile;
+import java.lang.ref.PhantomReference;
+import java.lang.ref.Reference;
+import java.lang.ref.ReferenceQueue;
+import java.lang.reflect.Field;
+import java.util.concurrent.TimeoutException;
 
-import static org.junit.Assert.fail;
+import org.junit.Test;
 
 /**
  * Please note:
@@ -62,4 +71,85 @@ public void testGrandChild() throws Exception {
             file.delete();
         }
     }
+
+    @Test
+    public void testOpenIfOneOpened() throws Exception {
+        File file = new File(SharedFileInputStreamTest.class.getResource("/jakarta/mail/util/sharedinputstream.txt").toURI());
+        SharedFileInputStream in0 = null;
+        SharedFileInputStream in1 = null;
+        try (SharedFileInputStream in = new SharedFileInputStream(file)) {
+            in0 = (SharedFileInputStream) in.newStream(0, 6);
+            in1 = (SharedFileInputStream) in.newStream(6, 12);
+        }
+        RandomAccessFile ra0 = getRandomAccessFile(in0);
+        RandomAccessFile ra1 = getRandomAccessFile(in1);
+        // It is the same instance
+        assertEquals(ra0, ra1);
+        // RandomAccessFile still be open
+        in1.close();
+        assertEquals(false, isClosed(ra1));
+        in0.close();
+        // All SharedFileInputStream are closed, so RandomAccessFile gets closed too
+        assertEquals(true, isClosed(ra1));
+    }
+
+    @Test
+    public void testGC() throws Exception {
+        File file = new File(SharedFileInputStreamTest.class.getResource("/jakarta/mail/util/sharedinputstream.txt").toURI());
+        SharedFileInputStream in = new SharedFileInputStream(file);
+        GCUtil gcUtil = new GCUtil(in);
+        SharedFileInputStream in0 = (SharedFileInputStream) in.newStream(0, 6);
+        in.close();
+        in = null;
+        gcUtil.waitTillGCed(1000);
+        gcUtil = new GCUtil(in0);
+        SharedFileInputStream in1 = (SharedFileInputStream) in0.newStream(6, 12);
+        assertEquals("test0\n", new String(in0.readAllBytes()));
+        in0.close();
+        in0 = null;
+        gcUtil.waitTillGCed(1000);
+        assertEquals("test1\n", new String(in1.readAllBytes()));
+        in1.close();
+    }
+
+    private RandomAccessFile getRandomAccessFile(SharedFileInputStream in) throws Exception {
+        Field f1 = SharedFileInputStream.class.getDeclaredField("sf");
+        f1.setAccessible(true);
+        SharedFile rin = (SharedFile) f1.get(in);
+        RandomAccessFile rf = rin.in;
+        return rf;
+    }
+
+    private boolean isClosed(RandomAccessFile rf) throws Exception {
+        try {
+            rf.readByte();
+            return false;
+        } catch (IOException e) {
+            return true;
+        }
+    }
+
+    private static class GCUtil {
+
+        private final ReferenceQueue<Object> rq = new ReferenceQueue<>();
+        private final PhantomReference<Object> phantomRef;
+
+        private GCUtil(Object ref) {
+            phantomRef = new PhantomReference<>(ref, rq);
+        }
+
+        private void waitTillGCed(long timeout) throws Exception {
+            Reference<? extends Object> gced;
+            long time = 0;
+            long sleep = 100;
+            while ((gced = rq.poll()) != phantomRef) {
+                Thread.sleep(sleep);
+                time = time + sleep;
+                if (time >= timeout) {
+                    throw new TimeoutException("Instance not GCed after " + timeout + " millis");
+                }
+                System.gc();
+            }
+        }
+    }
 }

api/src/test/resources/jakarta/mail/util/sharedinputstream.txt

@@ -0,0 +1,10 @@
+test0
+test1
+test2
+test3
+test4
+test5
+test6
+test7
+test8
+test9