Author: markt
Date: Fri Apr 13 16:33:33 2018
New Revision: 1829086
URL: http://svn.apache.org/viewvc?rev=1829086&view=rev
Log:
Fix a rare edge case that is unlikely to occur in real usage. This edge case
meant that writing long streams of UTF-8 characters to the HTTP response that
consisted almost entirely of surrogate pairs could result in one surrogate pair
being dropped.
Modified:
tomcat/trunk/java/org/apache/catalina/connector/OutputBuffer.java
tomcat/trunk/test/org/apache/catalina/connector/TestOutputBuffer.java
tomcat/trunk/webapps/docs/changelog.xml
Modified: tomcat/trunk/java/org/apache/catalina/connector/OutputBuffer.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/java/org/apache/catalina/connector/OutputBuffer.java?rev=1829086&r1=1829085&r2=1829086&view=diff
==============================================================================
--- tomcat/trunk/java/org/apache/catalina/connector/OutputBuffer.java (original)
+++ tomcat/trunk/java/org/apache/catalina/connector/OutputBuffer.java Fri Apr
13 16:33:33 2018
@@ -431,6 +431,16 @@ public class OutputBuffer extends Writer
}
if (from.remaining() > 0) {
flushByteBuffer();
+ } else if (conv.isUndeflow() && bb.limit() > bb.capacity() - 4) {
+ // Handle an edge case. There are no more chars to write at the
+ // moment but there is a leftover character in the converter
+ // which must be part of a surrogate pair. The byte buffer does
+ // not have enough space left to output the bytes for this pair
+ // once it is complete )it will require 4 bytes) so flush now
to
+ // prevent the bytes for the leftover char and the rest of the
+ // surrogate pair yet to be written from being lost.
+ // See TestOutputBuffer#testUtf8SurrogateBody()
+ flushByteBuffer();
}
}
Modified: tomcat/trunk/test/org/apache/catalina/connector/TestOutputBuffer.java
URL:
http://svn.apache.org/viewvc/tomcat/trunk/test/org/apache/catalina/connector/TestOutputBuffer.java?rev=1829086&r1=1829085&r2=1829086&view=diff
==============================================================================
--- tomcat/trunk/test/org/apache/catalina/connector/TestOutputBuffer.java
(original)
+++ tomcat/trunk/test/org/apache/catalina/connector/TestOutputBuffer.java Fri
Apr 13 16:33:33 2018
@@ -19,6 +19,7 @@ package org.apache.catalina.connector;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.Writer;
+import java.nio.charset.StandardCharsets;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
@@ -156,4 +157,58 @@ public class TestOutputBuffer extends To
w.write("OK");
}
}
+
+
+ @Test
+ public void testUtf8SurrogateBody() throws Exception {
+ // Create test data. This is carefully constructed to trigger the edge
+ // case. Small variations may cause the test to miss the edge case.
+ StringBuffer sb = new StringBuffer();
+ sb.append("a");
+
+ for (int i = 0x10000; i < 0x11000; i++) {
+ char[] chars = Character.toChars(i);
+ sb.append(chars);
+ }
+ String data = sb.toString();
+
+ Tomcat tomcat = getTomcatInstance();
+ Context root = tomcat.addContext("", TEMP_DIR);
+ Tomcat.addServlet(root, "Test", new Utf8WriteChars(data));
+ root.addServletMappingDecoded("/test", "Test");
+
+ tomcat.start();
+
+ ByteChunk bc = new ByteChunk();
+ getUrl("http://localhost:"; + getPort() + "/test", bc, null);
+
+ bc.setCharset(StandardCharsets.UTF_8);
+ Assert.assertEquals(data, bc.toString());
+ }
+
+
+ private static class Utf8WriteChars extends HttpServlet {
+
+ private static final long serialVersionUID = 1L;
+
+ private final char[] chars;
+
+ public Utf8WriteChars(String data) {
+ chars = data.toCharArray();
+ }
+
+ @Override
+ protected void doGet(HttpServletRequest req, HttpServletResponse resp)
+ throws ServletException, IOException {
+
+ resp.setCharacterEncoding("UTF-8");
+ resp.setContentType("text/plain");
+ Writer w = resp.getWriter();
+
+ for (int i = 0; i < chars.length; i++) {
+ w.write(chars[i]);
+ }
+ }
+ }
+
}
Modified: tomcat/trunk/webapps/docs/changelog.xml
URL:
http://svn.apache.org/viewvc/tomcat/trunk/webapps/docs/changelog.xml?rev=1829086&r1=1829085&r2=1829086&view=diff
==============================================================================
--- tomcat/trunk/webapps/docs/changelog.xml (original)
+++ tomcat/trunk/webapps/docs/changelog.xml Fri Apr 13 16:33:33 2018
@@ -62,6 +62,12 @@
type="javax.sql.XADataSource"</code>. Patch provided by Masafumi Miura.
(csutherl)
</fix>
+ <fix>
+ Fix a rare edge case that is unlikely to occur in real usage. This edge
+ case meant that writing long streams of UTF-8 characters to the HTTP
+ response that consisted almost entirely of surrogate pairs could result
+ in one surrogate pair being dropped. (markt)
+ </fix>
</changelog>
</subsection>
<subsection name="Coyote">
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