From 9ef40edc7521a5ba3380318adaad40797f9b7a63 Mon Sep 17 00:00:00 2001
From: Richard Zschech <richard@zschech.net>
Date: Fri, 22 Jul 2016 20:54:53 -0400
Subject: [PATCH] LOG4J2-1341 GC-free HighlightConverter and StyleConverter

---
 .../core/pattern/HighlightConverter.java      | 26 +++++++++++++------
 .../log4j/core/pattern/StyleConverter.java    | 24 +++++++++++------
 .../src/test/resources/gcFreeLogging.xml      | 10 +++----
 .../resources/gcFreeMixedSyncAsyncLogging.xml | 10 +++----
 log4j-core/src/test/resources/log4j-style.xml |  4 +--
 src/site/xdoc/manual/garbagefree.xml          | 10 ++++++-
 6 files changed, 55 insertions(+), 29 deletions(-)

diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/pattern/HighlightConverter.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/pattern/HighlightConverter.java
index 0e2f63dece3..a3a31ab22b1 100644
--- a/log4j-core/src/main/java/org/apache/logging/log4j/core/pattern/HighlightConverter.java
+++ b/log4j-core/src/main/java/org/apache/logging/log4j/core/pattern/HighlightConverter.java
@@ -193,6 +193,8 @@ public static HighlightConverter newInstance(final Configuration config, final S
 
     private final boolean noAnsi;
 
+    private final String defaultStyle;
+
     /**
      * Construct the converter.
      *
@@ -205,6 +207,7 @@ private HighlightConverter(final List<PatternFormatter> patternFormatters, final
         super("style", "style");
         this.patternFormatters = patternFormatters;
         this.levelStyles = levelStyles;
+        this.defaultStyle = AnsiEscape.getDefaultStyle();
         this.noAnsi = noAnsi;
     }
 
@@ -213,17 +216,24 @@ private HighlightConverter(final List<PatternFormatter> patternFormatters, final
      */
     @Override
     public void format(final LogEvent event, final StringBuilder toAppendTo) {
-        final StringBuilder buf = new StringBuilder();
-        for (final PatternFormatter formatter : patternFormatters) {
-            formatter.format(event, buf);
+        int start = 0;
+        int end = 0;
+        if (!noAnsi) {
+            start = toAppendTo.length();
+            toAppendTo.append(levelStyles.get(event.getLevel()));
+            end = toAppendTo.length();
+        }
+
+        //noinspection ForLoopReplaceableByForEach
+        for (int i = 0, size = patternFormatters.size(); i <  size; i++) {
+            patternFormatters.get(i).format(event, toAppendTo);
         }
 
-        if (buf.length() > 0) {
-            if (noAnsi) {
-                toAppendTo.append(buf.toString());
+        if (!noAnsi) {
+            if (toAppendTo.length() == end) {
+                toAppendTo.setLength(start);
             } else {
-                toAppendTo.append(levelStyles.get(event.getLevel())).append(buf.toString()).
-                    append(AnsiEscape.getDefaultStyle());
+                toAppendTo.append(defaultStyle);
             }
         }
     }
diff --git a/log4j-core/src/main/java/org/apache/logging/log4j/core/pattern/StyleConverter.java b/log4j-core/src/main/java/org/apache/logging/log4j/core/pattern/StyleConverter.java
index 202d77189d2..6d73b3b0eab 100644
--- a/log4j-core/src/main/java/org/apache/logging/log4j/core/pattern/StyleConverter.java
+++ b/log4j-core/src/main/java/org/apache/logging/log4j/core/pattern/StyleConverter.java
@@ -94,17 +94,25 @@ public static StyleConverter newInstance(final Configuration config, final Strin
      */
     @Override
     public void format(final LogEvent event, final StringBuilder toAppendTo) {
-        final StringBuilder buf = new StringBuilder();
-        for (final PatternFormatter formatter : patternFormatters) {
-            formatter.format(event, buf);
+        int start = 0;
+        int end = 0;
+        if (!noAnsi) {
+            start = toAppendTo.length();
+            toAppendTo.append(style);
+            end = toAppendTo.length();
         }
 
-        if (buf.length() > 0) {
-            if (noAnsi) {
-                // faster to test and do this than setting style and defaultStyle to empty strings.
-                toAppendTo.append(buf.toString());
+        //noinspection ForLoopReplaceableByForEach
+        for (int i = 0, size = patternFormatters.size(); i <  size; i++) {
+            patternFormatters.get(i).format(event, toAppendTo);
+        }
+
+        if (!noAnsi) {
+            if (toAppendTo.length() == end) {
+                toAppendTo.setLength(start);
             } else {
-                toAppendTo.append(style).append(buf.toString()).append(defaultStyle);
+                // faster to test and do this than setting style and defaultStyle to empty strings.
+                toAppendTo.append(defaultStyle);
             }
         }
     }
diff --git a/log4j-core/src/test/resources/gcFreeLogging.xml b/log4j-core/src/test/resources/gcFreeLogging.xml
index f90d754b14d..889346693a6 100644
--- a/log4j-core/src/test/resources/gcFreeLogging.xml
+++ b/log4j-core/src/test/resources/gcFreeLogging.xml
@@ -6,13 +6,13 @@
     </Console>
     <File name="File" fileName="target/gcfreefile.log" bufferedIO="false">
       <PatternLayout>
-        <Pattern>%d %p %c{1.} [%t] %m%n</Pattern>
+        <Pattern>%highlight{%style{%d}{bright,cyan} %p %c{1.} [%t] %m%n}</Pattern>
       </PatternLayout>
     </File>
     <RollingFile name="RollingFile" fileName="target/gcfreeRollingFile.log"
         filePattern="target/gcfree-%d{MM-dd-yy-HH-mm-ss}.log.gz">
       <PatternLayout>
-        <Pattern>%d %p %c{1.} [%t] %m%n</Pattern>
+        <Pattern>%highlight{%style{%d}{bright,cyan} %p %c{1.} [%t] %m%n}</Pattern>
       </PatternLayout>
       <Policies>
         <SizeBasedTriggeringPolicy size="50M" />
@@ -20,7 +20,7 @@
     </RollingFile>
     <RandomAccessFile name="RandomAccessFile" fileName="target/gcfreeRAF.log" immediateFlush="false" append="false">
       <PatternLayout>
-        <Pattern>%d %p %c{1.} [%t] %X{aKey} %m %ex%n</Pattern>
+        <Pattern>%highlight{%style{%d}{bright,cyan} %p %c{1.} [%t] %X{aKey} %m %ex%n}</Pattern>
       </PatternLayout>
     </RandomAccessFile>
     <RollingRandomAccessFile name="RollingRandomAccessFile"
@@ -28,7 +28,7 @@
         filePattern="target/afterRollover-%i.log" append="false"
         immediateFlush="false">
       <PatternLayout>
-        <Pattern>%d %p %c{1.} [%t] %X{aKey} %m %location %ex%n</Pattern>
+        <Pattern>%highlight{%style{%d}{bright,cyan} %p %c{1.} [%t] %X{aKey} %m %location %ex%n}</Pattern>
       </PatternLayout>
       <Policies>
         <SizeBasedTriggeringPolicy size="50 M"/>
@@ -38,7 +38,7 @@
         fileName="target/gcfreemmap.log"
         immediateFlush="false" append="false">
       <PatternLayout>
-        <Pattern>%d %p %c{1.} [%t] %X{aKey} %m%ex%n</Pattern>
+        <Pattern>%highlight{%style{%d}{bright,cyan} %p %c{1.} [%t] %X{aKey} %m%ex%n}</Pattern>
       </PatternLayout>
     </MemoryMappedFile>
     <RandomAccessFile name="RandomAccessFileGelf" fileName="target/gcfree.json" immediateFlush="false" append="false">
diff --git a/log4j-core/src/test/resources/gcFreeMixedSyncAsyncLogging.xml b/log4j-core/src/test/resources/gcFreeMixedSyncAsyncLogging.xml
index e4c00009f17..50bff5780c7 100644
--- a/log4j-core/src/test/resources/gcFreeMixedSyncAsyncLogging.xml
+++ b/log4j-core/src/test/resources/gcFreeMixedSyncAsyncLogging.xml
@@ -6,13 +6,13 @@
     </Console>
     <File name="File" fileName="target/gcfreefileMixed.log" bufferedIO="false">
       <PatternLayout>
-        <Pattern>%d %p %c{1.} [%t] %m%n</Pattern>
+        <Pattern>%highlight{%style{%d}{bright,cyan} %p %c{1.} [%t] %m%n}</Pattern>
       </PatternLayout>
     </File>
     <RollingFile name="RollingFile" fileName="target/gcfreeRollingFileMixed.log"
         filePattern="target/gcfree-%d{MM-dd-yy-HH-mm-ss}.log.gz">
       <PatternLayout>
-        <Pattern>%d %p %c{1.} [%t] %m%n</Pattern>
+        <Pattern>%highlight{%style{%d}{bright,cyan} %p %c{1.} [%t] %m%n}</Pattern>
       </PatternLayout>
       <Policies>
         <SizeBasedTriggeringPolicy size="50M" />
@@ -20,7 +20,7 @@
     </RollingFile>
     <RandomAccessFile name="RandomAccessFile" fileName="target/gcfreeRAFMixed.log" immediateFlush="false" append="false">
       <PatternLayout>
-        <Pattern>%d %p %c{1.} [%t] %X{aKey} %m %ex%n</Pattern>
+        <Pattern>%highlight{%style{%d}{bright,cyan} %p %c{1.} [%t] %X{aKey} %m %ex%n}</Pattern>
       </PatternLayout>
     </RandomAccessFile>
     <RollingRandomAccessFile name="RollingRandomAccessFile"
@@ -28,7 +28,7 @@
         filePattern="target/afterRollover-%i.log" append="false"
         immediateFlush="false">
       <PatternLayout>
-        <Pattern>%d %p %c{1.} [%t] %X{aKey} %m %location %ex%n</Pattern>
+        <Pattern>%highlight{%style{%d}{bright,cyan} %p %c{1.} [%t] %X{aKey} %m %location %ex%n}</Pattern>
       </PatternLayout>
       <Policies>
         <SizeBasedTriggeringPolicy size="50 M"/>
@@ -38,7 +38,7 @@
         fileName="target/gcfreemmapMixed.log"
         immediateFlush="false" append="false">
       <PatternLayout>
-        <Pattern>%d %p %c{1.} [%t] %X{aKey} %m%ex%n</Pattern>
+        <Pattern>%highlight{%style{%d}{bright,cyan} %p %c{1.} [%t] %X{aKey} %m%ex%n}</Pattern>
       </PatternLayout>
     </MemoryMappedFile>
     <RandomAccessFile name="RandomAccessFileGelf" fileName="target/gcfreeMixed.json" immediateFlush="false" append="false">
diff --git a/log4j-core/src/test/resources/log4j-style.xml b/log4j-core/src/test/resources/log4j-style.xml
index 9b18b37c460..6acf8730a45 100644
--- a/log4j-core/src/test/resources/log4j-style.xml
+++ b/log4j-core/src/test/resources/log4j-style.xml
@@ -20,7 +20,7 @@
   <Appenders>
     <List name="List">
        <PatternLayout>
-         <Pattern>%d %highlight{%p} %style{%logger}{bright,cyan} %C{1.} %msg%n</Pattern>
+         <Pattern>%d %highlight{%p} %style{%logger}{bright,cyan}%style{}{bright,cyan} %C{1.} %msg%n</Pattern>
       </PatternLayout>
     </List>
   </Appenders>
@@ -31,4 +31,4 @@
     </Root>
   </Loggers>
 
-</Configuration>
\ No newline at end of file
+</Configuration>
diff --git a/src/site/xdoc/manual/garbagefree.xml b/src/site/xdoc/manual/garbagefree.xml
index 58ca1d045cf..969a947ac88 100644
--- a/src/site/xdoc/manual/garbagefree.xml
+++ b/src/site/xdoc/manual/garbagefree.xml
@@ -233,6 +233,14 @@
                 </table>
               </td>
             </tr>
+            <tr>
+              <td>%hightlight{pattern}{style}</td>
+              <td>Adds ANSI colors (unless child pattern is not garbage free)</td>
+            </tr>
+            <tr>
+              <td>style{pattern}{ANSI style}</td>
+              <td>Style the message (unless child pattern is not garbage free)</td>
+            </tr>
             <tr>
               <td>%m, %msg, %message</td>
               <td>Log message (unless message text contains '${')</td>
@@ -501,4 +509,4 @@ public void garbageFree() {
       </subsection>
     </section>
   </body>
-</document>
\ No newline at end of file
+</document>