[log] IDEA-132229 Optimize HashImpl serialization

* Read/write bytes, don't convert from/to String.
* Introduce VcsLogHashMap versioning, cleanup previous version on start.

platform/vcs-log/impl/src/com/intellij/vcs/log/data/VcsLogHashMap.java

@@ -54,18 +54,24 @@ public class VcsLogHashMap implements Disposable {
 
   private static final File LOG_CACHE_APP_DIR = new File(PathManager.getSystemPath(), "vcs-log");
   private static final Logger LOG = Logger.getInstance(VcsLogHashMap.class);
+  private static final int VERSION = 1;
 
   private final PersistentEnumerator<Hash> myPersistentEnumerator;
 
   VcsLogHashMap(@NotNull Project project, @NotNull Map<VirtualFile, VcsLogProvider> logProviders) throws IOException {
-    final File myMapFile = new File(LOG_CACHE_APP_DIR, calcLogId(project, logProviders));
+    String logId = calcLogId(project, logProviders);
+    final File mapFile = new File(LOG_CACHE_APP_DIR, logId + "." + VERSION);
+    if (!mapFile.exists()) {
+      IOUtil.deleteAllFilesStartingWith(new File(LOG_CACHE_APP_DIR, logId));
+    }
+
     Disposer.register(project, this);
     myPersistentEnumerator = IOUtil.openCleanOrResetBroken(new ThrowableComputable<PersistentEnumerator<Hash>, IOException>() {
       @Override
       public PersistentEnumerator<Hash> compute() throws IOException {
-        return new PersistentEnumerator<Hash>(myMapFile, new MyHashKeyDescriptor(), Page.PAGE_SIZE);
+        return new PersistentEnumerator<Hash>(mapFile, new MyHashKeyDescriptor(), Page.PAGE_SIZE);
       }
-    }, myMapFile);
+    }, mapFile);
   }
 
   @NotNull
@@ -189,12 +195,12 @@ public class VcsLogHashMap implements Disposable {
   private static class MyHashKeyDescriptor implements KeyDescriptor<Hash> {
     @Override
     public void save(@NotNull DataOutput out, Hash value) throws IOException {
-      out.writeUTF(value.asString());
+      ((HashImpl)value).write(out);
     }
 
     @Override
     public Hash read(@NotNull DataInput in) throws IOException {
-      return HashImpl.build(in.readUTF());
+      return HashImpl.read(in);
     }
 
     @Override

platform/vcs-log/impl/src/com/intellij/vcs/log/impl/HashImpl.java

@@ -15,9 +15,13 @@
  */
 package com.intellij.vcs.log.impl;
 
+import com.intellij.util.io.DataInputOutputUtil;
 import com.intellij.vcs.log.Hash;
 import org.jetbrains.annotations.NotNull;
 
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
 import java.util.Arrays;
 
 /**
@@ -37,6 +41,19 @@ public class HashImpl implements Hash {
     return new HashImpl(data);
   }
 
+  @NotNull
+  public static Hash read(@NotNull DataInput in) throws IOException {
+    int length = DataInputOutputUtil.readINT(in);
+    byte[] buf = new byte[length];
+    in.readFully(buf);
+    return new HashImpl(buf);
+  }
+
+  public void write(@NotNull DataOutput out) throws IOException {
+    DataInputOutputUtil.writeINT(out, myData.length);
+    out.write(myData);
+  }
+
   @NotNull
   private static byte[] buildData(@NotNull String inputStr) {
     // if length == 5, need 3 byte + 1 signal byte

platform/vcs-log/impl/test/com/intellij/vcs/log/impl/HashSerializeTest.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2000-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.vcs.log.impl;
+
+import com.intellij.openapi.util.io.FileUtil;
+import com.intellij.util.io.DataOutputStream;
+import org.jetbrains.annotations.NotNull;
+import org.junit.Test;
+
+import java.io.*;
+
+import static org.junit.Assert.assertEquals;
+
+public class HashSerializeTest {
+
+  @Test
+  public void full_hash() throws IOException {
+    HashImpl hash = (HashImpl)HashImpl.build("d35ee91fad4a04bce0ea91a762cc8f3bf3e1929f");
+    File file = writeToTempFile(hash);
+    HashImpl newHash = readFromFile(file);
+    assertEquals(hash, newHash);
+  }
+
+  @Test
+  public void short_hash() throws IOException {
+    HashImpl hash = (HashImpl)HashImpl.build("d35ee91");
+    File file = writeToTempFile(hash);
+    HashImpl newHash = readFromFile(file);
+    assertEquals(hash, newHash);
+  }
+
+  @NotNull
+  private static File writeToTempFile(@NotNull HashImpl hash) throws IOException {
+    File file = FileUtil.createTempFile("", "");
+    DataOutputStream out = new DataOutputStream(new FileOutputStream(file));
+    try {
+      hash.write(out);
+    }
+    finally {
+      out.close();
+    }
+    return file;
+  }
+
+  @NotNull
+  private static HashImpl readFromFile(@NotNull File file) throws IOException {
+    HashImpl newHash;
+    DataInputStream in = new DataInputStream(new FileInputStream(file));
+    try {
+      newHash = (HashImpl)HashImpl.read(in);
+    }
+    finally {
+      in.close();
+    }
+    return newHash;
+  }
+}