Allow to retrieve documents as raw unformatted text

By setting the URL parameter 'raw' a document for which a formatter is
registered can be retrieved as raw unformatted text, e.g.:

  /xdocs/project/external%2Fopenssl/rev/stable-1.3/docs%2Ffaq.md?raw

The 'raw' parameter cannot be used for binary files.

Change-Id: I9579b4302b1fd5a8efdb1661bd03c206d01f96f3
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
diff --git a/src/main/java/com/googlesource/gerrit/plugins/xdocs/Resources.java b/src/main/java/com/googlesource/gerrit/plugins/xdocs/Resources.java
new file mode 100644
index 0000000..02e547b
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/xdocs/Resources.java
@@ -0,0 +1,50 @@
+// Copyright (C) 2014 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.googlesource.gerrit.plugins.xdocs;
+
+import com.google.gerrit.httpd.resources.Resource;
+import com.google.gwtexpui.server.CacheHeaders;
+
+import java.io.IOException;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+public class Resources {
+  public static final Resource METHOD_NOT_ALLOWED = new Resource() {
+    private static final long serialVersionUID = 1L;
+
+    @Override
+    public int weigh() {
+      return 0;
+    }
+
+    @Override
+    public void send(HttpServletRequest req, HttpServletResponse res)
+        throws IOException {
+      CacheHeaders.setNotCacheable(res);
+      res.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED);
+    }
+
+    @Override
+    public boolean isUnchanged(long latestModifiedDate) {
+      return false;
+    }
+
+    protected Object readResolve() {
+      return METHOD_NOT_ALLOWED;
+    }
+  };
+}
diff --git a/src/main/java/com/googlesource/gerrit/plugins/xdocs/XDocLoader.java b/src/main/java/com/googlesource/gerrit/plugins/xdocs/XDocLoader.java
index 9fd8ac1..3705f33 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/xdocs/XDocLoader.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/xdocs/XDocLoader.java
@@ -35,6 +35,7 @@
 import com.googlesource.gerrit.plugins.xdocs.formatter.Formatters;
 import com.googlesource.gerrit.plugins.xdocs.formatter.Formatters.FormatterProvider;
 
+import org.eclipse.jgit.diff.RawText;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectLoader;
 import org.eclipse.jgit.lib.Repository;
@@ -97,10 +98,14 @@
           }
           ObjectId objectId = tw.getObjectId(0);
           ObjectLoader loader = repo.open(objectId);
-          byte[] raw = loader.getBytes(Integer.MAX_VALUE);
+          byte[] bytes = loader.getBytes(Integer.MAX_VALUE);
+          if (formatter.getName().equals(Formatters.RAW_FORMATTER)
+              && RawText.isBinary(bytes)) {
+            return Resources.METHOD_NOT_ALLOWED;
+          }
           String html =
               formatter.get().format(formatterCfg,
-                  replaceMacros(key.getProject(), raw));
+                  replaceMacros(key.getProject(), bytes));
           return getAsHtmlResource(html, commit.getCommitTime());
         } finally {
           tw.release();
diff --git a/src/main/java/com/googlesource/gerrit/plugins/xdocs/XDocServlet.java b/src/main/java/com/googlesource/gerrit/plugins/xdocs/XDocServlet.java
index 70eb763..0c61366 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/xdocs/XDocServlet.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/xdocs/XDocServlet.java
@@ -125,13 +125,19 @@
       res.sendRedirect(getRedirectUrl(req, key, cfg));
       return;
     }
+
     MimeType mimeType = fileTypeRegistry.getMimeType(key.file, null);
-    FormatterProvider formatter = formatters.get(state, key.file);
-    if (formatter == null
-        && !("image".equals(mimeType.getMediaType())
-            && fileTypeRegistry.isSafeInline(mimeType))) {
-      Resource.NOT_FOUND.send(req, res);
-      return;
+    FormatterProvider formatter;
+    if (req.getParameter("raw") != null) {
+      formatter = formatters.getRawFormatter();
+    } else {
+      formatter = formatters.get(state, key.file);
+      if (formatter == null
+          && !("image".equals(mimeType.getMediaType())
+              && fileTypeRegistry.isSafeInline(mimeType))) {
+        Resource.NOT_FOUND.send(req, res);
+        return;
+      }
     }
 
     try {
diff --git a/src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/Formatters.java b/src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/Formatters.java
index efbde10..eb5f447 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/Formatters.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/xdocs/formatter/Formatters.java
@@ -43,6 +43,8 @@
 
 @Singleton
 public class Formatters {
+  public static final String RAW_FORMATTER = "RAW";
+
   private final String pluginName;
   private final PluginConfigFactory pluginCfgFactory;
   private final FileTypeRegistry fileTypeRegistry;
@@ -129,6 +131,11 @@
   }
 
   public FormatterProvider getByName(String formatterName) {
+    if (formatterName.equals(RAW_FORMATTER)) {
+      return new FormatterProvider(RAW_FORMATTER,
+          getByName(PlainTextFormatter.NAME).formatter);
+    }
+
     for (String pluginName : formatters.plugins()) {
       for (Entry<String, Provider<Formatter>> e :
           formatters.byPlugin(pluginName).entrySet()) {
@@ -140,6 +147,10 @@
     return null;
   }
 
+  public FormatterProvider getRawFormatter() {
+    return getByName(RAW_FORMATTER);
+  }
+
   public static class FormatterProvider {
     private final String name;
     private final Provider<Formatter> formatter;
diff --git a/src/main/resources/Documentation/about.md b/src/main/resources/Documentation/about.md
index 80195fb..531c7cc 100644
--- a/src/main/resources/Documentation/about.md
+++ b/src/main/resources/Documentation/about.md
@@ -18,6 +18,15 @@
 If the file name is omitted the plugin serves the `README.md` from the
 project if available.
 
+By setting the URL parameter `raw` the document will be returned as raw
+unformatted text.
+
+```
+  /@PLUGIN@/project/external%2Fopenssl/rev/stable-1.3/docs%2Ffaq.md?raw
+```
+
+The `raw` parameter cannot be used for binary files.
+
 *WARNING:* All HTML blocks as well as inline HTML tags are suppressed.
 Both will be accepted in the input but not be contained in the output.