Bugzilla #42278:

Refactoring of color map cache and uri/fo resolution from FopFactory
Submitted by: Adrian Cumiskey <fop-dev@cumiskey.com>

Changes in addition to the patch by jeremias:
- Moved the color map cache to the util package so it doesn't clutter the API (apps) package.
- Factored out the data URL resolution into its own URIResolver class which can now be used separately.
- Added a utility class for generating RFC2397 data URLs.
- Added a unit test for data URL handling.

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@551874 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 78 insertions, 0 deletions

diff --git a/src/java/org/apache/fop/util/DataURIResolver.java b/src/java/org/apache/fop/util/DataURIResolver.java
new file mode 100644
index 000000000..4ae4be156
--- /dev/null
+++ b/src/java/org/apache/fop/util/DataURIResolver.java
@@ -0,0 +1,78 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+
+/* $Id$ */
+
+package org.apache.fop.util;
+
+import java.io.ByteArrayInputStream;
+
+import javax.xml.transform.Source;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.URIResolver;
+import javax.xml.transform.stream.StreamSource;
+
+// base64 support for "data" urls
+import org.apache.xmlgraphics.util.io.Base64DecodeStream;
+
+/**
+ * Resolves data URLs (described in RFC 2397) returning its data as a StreamSource.
+ * 
+ * @see javax.xml.transform.URIResolver
+ * @see <a href="http://www.ietf.org/rfc/rfc2397">RFC 2397</a>
+ */
+public class DataURIResolver implements URIResolver {
+
+    /**
+     * @see javax.xml.transform.URIResolver#resolve(java.lang.String, java.lang.String)
+     */
+    public Source resolve(String href, String base) throws TransformerException {
+        if (href.startsWith("data:")) {
+            return parseDataURI(href);
+        } else {
+            return null;
+        }
+    }
+
+    /**
+     * Parses inline data URIs as generated by MS Word's XML export and FO
+     * stylesheet.
+     * 
+     * @see <a href="http://www.ietf.org/rfc/rfc2397">RFC 2397</a>
+     */
+    private Source parseDataURI(String href) {
+        int commaPos = href.indexOf(',');
+        // header is of the form data:[<mediatype>][;base64]
+        String header = href.substring(0, commaPos);
+        String data = href.substring(commaPos + 1);
+        if (header.endsWith(";base64")) {
+            byte[] bytes = data.getBytes();
+            ByteArrayInputStream encodedStream = new ByteArrayInputStream(bytes);
+            Base64DecodeStream decodedStream = new Base64DecodeStream(
+                    encodedStream);
+            return new StreamSource(decodedStream);
+        } else {
+            // Note that this is not quite the full story here. But since we are
+            // only interested
+            // in base64-encoded binary data, the next line will probably never
+            // be called.
+            //TODO Handle un-escaping of special URL chars like %20
+            return new StreamSource(new java.io.StringReader(data));
+        }
+    }
+
+}