Enable syntax coloring for Go, BUCK and .gitmodules

Register a custom MimeDetector that identifies these
files and selects the content type known to CodeMirror.

Change-Id: I4335e79ebc9d5e89db6cd0e7040486bd97871b47

gerrit-server/src/main/java/com/google/gerrit/server/DefaultFileExtensionRegistry.java

@@ -0,0 +1,104 @@
+// Copyright (C) 2013 The Android Open Source Project
+//
+// 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.google.gerrit.server;
+
+import com.google.common.collect.ImmutableMap;
+
+import eu.medsea.mimeutil.MimeType;
+import eu.medsea.mimeutil.MimeUtil;
+import eu.medsea.mimeutil.detector.MimeDetector;
+
+import java.io.File;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.Collection;
+import java.util.Collections;
+
+public class DefaultFileExtensionRegistry extends MimeDetector {
+  private static final MimeType INI = newMimeType("text/x-ini", 2);
+  private static final MimeType PYTHON = newMimeType("text/x-python", 2);
+
+  private static final ImmutableMap<String, MimeType> TYPES = ImmutableMap.of(
+      ".gitmodules", INI,
+      "project.config", INI,
+      "BUCK", PYTHON,
+      "defs", newMimeType(PYTHON.toString(), 1),
+      "go", newMimeType("text/x-go", 1));
+
+  private static MimeType newMimeType(String type, final int specificity) {
+    return new MimeType(type) {
+      private static final long serialVersionUID = 1L;
+
+      @Override
+      public int getSpecificity() {
+        return specificity;
+      }
+    };
+  }
+
+  static {
+    for (MimeType type : TYPES.values()) {
+      MimeUtil.addKnownMimeType(type);
+    }
+  }
+
+  @Override
+  public String getDescription() {
+    return getClass().getName();
+  }
+
+  @Override
+  protected Collection<MimeType> getMimeTypesFileName(String name) {
+    int s = name.lastIndexOf('/');
+    if (s >= 0) {
+      name = name.substring(s + 1);
+    }
+
+    MimeType type = TYPES.get(name);
+    if (type != null) {
+      return Collections.singletonList(type);
+    }
+
+    int d = name.lastIndexOf('.');
+    if (0 < d) {
+      type = TYPES.get(name.substring(d + 1));
+      if (type != null) {
+        return Collections.singletonList(type);
+      }
+    }
+
+    return Collections.emptyList();
+  }
+
+  @Override
+  protected Collection<MimeType> getMimeTypesFile(File file) {
+    return getMimeTypesFileName(file.getName());
+  }
+
+  @Override
+  protected Collection<MimeType> getMimeTypesURL(URL url) {
+    return getMimeTypesFileName(url.getPath());
+  }
+
+  @Override
+  protected Collection<MimeType> getMimeTypesInputStream(InputStream arg0) {
+    return Collections.emptyList();
+  }
+
+  @Override
+  protected Collection<MimeType> getMimeTypesByteArray(byte[] arg0) {
+    return Collections.emptyList();
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/MimeUtilFileTypeRegistry.java

@@ -54,13 +54,13 @@ public class MimeUtilFileTypeRegistry implements FileTypeRegistry {
     if (HostPlatform.isWin32()) {
       register("eu.medsea.mimeutil.detector.WindowsRegistryMimeDetector");
     }
+    register(DefaultFileExtensionRegistry.class.getName());
   }
 
   private void register(String name) {
     mimeUtil.registerMimeDetector(name);
   }
 
-
   /**
    * Get specificity of mime types with generic types forced to low values
    *