Rewrite our build as modular maven components

This refactoring splits the code up into different components, with
their own per-component CLASSPATH.  By moving all of our classes
into isolated components we can better isolate the classpaths and
try to avoid unexpected dependency problems.  It also allows us to
more clearly define which components are used by the GWT UI and
thus must be compiled under GWT, and which components are run on
the server and can therefore use more of the J2SE API.

Change-Id: I833cc22bacc5655d1c9099ed7c2b0e0a5b08855a
Signed-off-by: Shawn O. Pearce <sop@google.com>

gerrit-server/src/main/java/com/google/gerrit/server/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;
+
+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);
+
+}