optionally use lz4java for compression

.idea/libraries/lz4_java.xml

@@ -0,0 +1,11 @@
+<component name="libraryTable">
+  <library name="lz4-java">
+    <CLASSES>
+      <root url="jar://$PROJECT_DIR$/lib/lz4-java-1.3.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES>
+      <root url="jar://$PROJECT_DIR$/lib/src/lz4-java-1.3-src.jar!/" />
+    </SOURCES>
+  </library>
+</component>

platform/build-scripts/groovy/org/jetbrains/intellij/build/CommunityLibraryLicenses.groovy

@@ -243,6 +243,8 @@ class CommunityLibraryLicenses {
                        url: "http://logging.apache.org/log4j/1.2/index.html", licenseUrl: "http://www.apache.org/licenses/LICENSE-2.0"),
     new LibraryLicense(name: "Lombok AST", libraryName: "lombok-ast", version: "0.2.1", license: "MIT", url: "http://projectlombok.org/",
                        licenseUrl: "http://opensource.org/licenses/mit-license.php"),
+    new LibraryLicense(name: "lz4-java", libraryName: "lz4-java", version: "1.3", license: "Apache 2.0", url: "https://github.com/lz4/lz4-java",
+                       licenseUrl: "https://github.com/lz4/lz4-java/blob/master/LICENSE.txt"),
     new LibraryLicense(name: "markdown4j", libraryName: "markdown4j-2.2", version: "2.2", license: "New BSD",
                        url: "https://code.google.com/p/markdown4j/", licenseUrl: "http://opensource.org/licenses/BSD-3-Clause"),
     new LibraryLicense(name: "markdownj", attachedTo: "tasks-core", version: "", license: "BSD", url: "https://github.com/myabc/markdownj",

platform/util/src/com/intellij/openapi/application/PathManager.java

@@ -28,6 +28,7 @@ import com.intellij.util.io.URLUtil;
 import com.sun.jna.TypeMapper;
 import com.sun.jna.platform.FileUtils;
 import gnu.trove.THashSet;
+import net.jpountz.lz4.LZ4Factory;
 import org.apache.log4j.Appender;
 import org.apache.oro.text.regex.PatternMatcher;
 import org.intellij.lang.annotations.Flow;
@@ -515,6 +516,7 @@ public class PathManager {
       FileUtils.class,              // JNA (jna-platform)
       PatternMatcher.class,         // OROMatcher
       Snappy.class,                 // Snappy
+      LZ4Factory.class,                 // Snappy
     };
 
     final Set<String> classPath = new HashSet<String>();

platform/util/src/com/intellij/util/CompressionUtil.java

@@ -19,6 +19,8 @@ import com.intellij.openapi.util.ThreadLocalCachedByteArray;
 import com.intellij.util.io.DataInputOutputUtil;
 import com.intellij.util.io.DataOutputStream;
 import com.intellij.util.text.StringFactory;
+import net.jpountz.lz4.LZ4Compressor;
+import net.jpountz.lz4.LZ4Factory;
 import org.iq80.snappy.CorruptionException;
 import org.iq80.snappy.Snappy;
 import org.jetbrains.annotations.NotNull;
@@ -60,12 +62,22 @@ public class CompressionUtil {
   private static final AtomicLong mySizeAfterCompression = new AtomicLong();
 
   public static final boolean DUMP_COMPRESSION_STATS = SystemProperties.getBooleanProperty("idea.dump.compression.stats", false);
+  public static final boolean USE_SNAPPY = SystemProperties.getBooleanProperty("idea.use.snappy", true);
 
   public static int writeCompressedWithoutOriginalBufferLength(@NotNull DataOutput out, @NotNull byte[] bytes, int length) throws IOException {
     long started = DUMP_COMPRESSION_STATS ? System.nanoTime() : 0;
 
-    final byte[] compressedOutputBuffer = spareBufferLocal.getBuffer(Snappy.maxCompressedLength(length));
-    int compressedSize = Snappy.compress(bytes, 0, length, compressedOutputBuffer, 0);
+    final byte[] compressedOutputBuffer;
+    int compressedSize;
+
+    if (USE_SNAPPY) {
+      compressedOutputBuffer = spareBufferLocal.getBuffer(Snappy.maxCompressedLength(length));
+      compressedSize = Snappy.compress(bytes, 0, length, compressedOutputBuffer, 0);
+    } else {
+      LZ4Compressor compressor = LZ4Factory.fastestJavaInstance().fastCompressor();
+      compressedOutputBuffer = spareBufferLocal.getBuffer(compressor.maxCompressedLength(length));
+      compressedSize = compressor.compress(bytes, 0, length, compressedOutputBuffer, 0);
+    }
 
     final long time = (DUMP_COMPRESSION_STATS ? System.nanoTime() : 0) - started;
     mySizeAfterCompression.addAndGet(compressedSize);
@@ -93,7 +105,13 @@ public class CompressionUtil {
     int decompressedRequests = myDecompressionRequests.incrementAndGet();
     long started = DUMP_COMPRESSION_STATS ? System.nanoTime() : 0;
 
-    byte[] decompressedResult = Snappy.uncompress(bytes, 0, size);
+    final byte[] decompressedResult;
+
+    if (USE_SNAPPY) {
+      decompressedResult = Snappy.uncompress(bytes, 0, size);
+    } else {
+      decompressedResult = LZ4Factory.fastestJavaInstance().fastDecompressor().decompress(bytes, 0, 32768);
+    }
 
     long doneTime = (DUMP_COMPRESSION_STATS ? System.nanoTime() : 0) - started;
     long decompressedSize = myDecompressedSize.addAndGet(size);

platform/util/util.iml

@@ -24,6 +24,7 @@
     <orderEntry type="library" name="imgscalr" level="project" />
     <orderEntry type="library" name="xmlgraphics-commons" level="project" />
     <orderEntry type="library" name="batik" level="project" />
+    <orderEntry type="library" name="lz4-java" level="project" />
   </component>
   <component name="copyright">
     <Base>