Move MIME type detection to mime package

Simple refactoring to move the MIME type utility code to its own package.

Change-Id: I2c1d8be7a2ca385d728974a0a443e35b4723dc96

gerrit-server/src/main/java/com/google/gerrit/server/mime/FileTypeRegistry.java

@@ -0,0 +1,47 @@
+// Copyright (C) 2009 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.mime;
+
+import eu.medsea.mimeutil.MimeType;
+import eu.medsea.mimeutil.MimeUtil2;
+
+public interface FileTypeRegistry {
+  /**
+   * Get the most specific MIME type available for a file.
+   *
+   * @param path name of the file. The base name (component after the last '/')
+   *        may be used to help determine the MIME type, such as by examining
+   *        the extension (portion after the last '.' if present).
+   * @param content the complete file content. If non-null the content may be
+   *        used to guess the MIME type by examining the beginning for common
+   *        file headers.
+   * @return the MIME type for this content. If the MIME type is not recognized
+   *         or cannot be determined, {@link MimeUtil2#UNKNOWN_MIME_TYPE} which
+   *         is an alias for {@code application/octet-stream}.
+   */
+  public abstract MimeType getMimeType(final String path, final byte[] content);
+
+  /**
+   * Is this content type safe to transmit to a browser directly?
+   *
+   * @param type the MIME type of the file content.
+   * @return true if the Gerrit administrator wants to permit this content to be
+   *         served as-is; false if the administrator does not trust this
+   *         content type and wants it to be protected (typically by wrapping
+   *         the data in a ZIP archive).
+   */
+  public abstract boolean isSafeInline(final MimeType type);
+
+}