From 0b07ef3834fac53c9ff774b68de0a6343a2bad12 Mon Sep 17 00:00:00 2001
From: Gary Gregory <garydgregory@gmail.com>
Date: Sun, 7 Jul 2024 16:24:10 -0400
Subject: [PATCH] CharSequenceInputStream.available() should return 0 after the
 stream is closed

BoundedInputStream.available() return 0 after the stream is closed
---
 src/changes/changes.xml                                |  2 ++
 .../commons/io/input/CharSequenceInputStream.java      |  2 +-
 .../commons/io/input/CloseShieldInputStream.java       |  2 +-
 .../org/apache/commons/io/input/ClosedInputStream.java |  2 +-
 .../commons/io/input/CharSequenceInputStreamTest.java  | 10 ++++++++++
 5 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 96379a3fcc7..a7ab44abcb0 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -64,6 +64,8 @@ The <action> type attribute can be add,update,fix,remove.
       <action dev="ggregory" type="add"                due-to="Gary Gregory">Avoid NullPointerException in ProxyInputStream.available() when the underlying input stream is null.</action>
       <action dev="ggregory" type="add"                due-to="Gary Gregory">BufferedFileChannelInputStream.available() returns 0 before any reads.</action>
       <action dev="ggregory" type="add"                due-to="Gary Gregory">BufferedFileChannelInputStream.available() should return 0 when the stream is closed instead of throwing an exception.</action>      
+      <action dev="ggregory" type="add"                due-to="Gary Gregory">CharSequenceInputStream.available() should return 0 after the stream is closed.</action>
+      <action dev="ggregory" type="add"                due-to="Gary Gregory">BoundedInputStream.available() should return 0 when the stream is closed.</action>
       <!-- UPDATE -->
       <action dev="ggregory" type="update"             due-to="Dependabot">Bump tests commons.bytebuddy.version from 1.14.13 to 1.14.17 #615, #621, #631, #635.</action>
       <action dev="ggregory" type="update"             due-to="Dependabot">Bump tests commons-codec:commons-codec from 1.16.1 to 1.17.0.</action>
diff --git a/src/main/java/org/apache/commons/io/input/CharSequenceInputStream.java b/src/main/java/org/apache/commons/io/input/CharSequenceInputStream.java
index c36d0d61670..020424620fc 100644
--- a/src/main/java/org/apache/commons/io/input/CharSequenceInputStream.java
+++ b/src/main/java/org/apache/commons/io/input/CharSequenceInputStream.java
@@ -247,7 +247,7 @@ public int available() throws IOException {
 
     @Override
     public void close() throws IOException {
-        // noop
+        bBuf.position(bBuf.limit());
     }
 
     /**
diff --git a/src/main/java/org/apache/commons/io/input/CloseShieldInputStream.java b/src/main/java/org/apache/commons/io/input/CloseShieldInputStream.java
index 059e3beba4f..be92f4ed8f2 100644
--- a/src/main/java/org/apache/commons/io/input/CloseShieldInputStream.java
+++ b/src/main/java/org/apache/commons/io/input/CloseShieldInputStream.java
@@ -34,7 +34,7 @@ public class CloseShieldInputStream extends ProxyInputStream {
      * Constructs a proxy that only shields {@link System#in} from closing.
      *
      * @param inputStream the candidate input stream.
-     * @return the given stream or a proxy on {@link System#in}. 
+     * @return the given stream or a proxy on {@link System#in}.
      * @since 2.17.0
      */
     public static InputStream systemIn(final InputStream inputStream) {
diff --git a/src/main/java/org/apache/commons/io/input/ClosedInputStream.java b/src/main/java/org/apache/commons/io/input/ClosedInputStream.java
index 00f7e3c7294..561965fdbf2 100644
--- a/src/main/java/org/apache/commons/io/input/ClosedInputStream.java
+++ b/src/main/java/org/apache/commons/io/input/ClosedInputStream.java
@@ -51,7 +51,7 @@ public class ClosedInputStream extends InputStream {
 
     /**
      * Returns {@link #INSTANCE} if the given InputStream is null, otherwise returns the given input stream.
-     * 
+     *
      * @param in the InputStream to test.
      * @return {@link #INSTANCE} if the given InputStream is null, otherwise returns the given input stream.
      */
diff --git a/src/test/java/org/apache/commons/io/input/CharSequenceInputStreamTest.java b/src/test/java/org/apache/commons/io/input/CharSequenceInputStreamTest.java
index 7c87f3c26d2..ef7cbc5adec 100644
--- a/src/test/java/org/apache/commons/io/input/CharSequenceInputStreamTest.java
+++ b/src/test/java/org/apache/commons/io/input/CharSequenceInputStreamTest.java
@@ -118,6 +118,16 @@ public void testAvailable(final String csName) throws Exception {
         }
     }
 
+    @Test
+    public void testAvailableAfterClose() throws Exception {
+        final InputStream shadow;
+        try (InputStream in = CharSequenceInputStream.builder().setCharSequence("Hi").get()) {
+            assertTrue(in.available() > 0);
+            shadow = in;
+        }
+        assertEquals(0, shadow.available());
+    }
+
     private void testAvailableRead(final String csName) throws Exception {
         final String input = "test";
         try (InputStream r = new CharSequenceInputStream(input, csName)) {