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

4 files changed, 346 insertions, 0 deletions

diff --git a/src/java/org/apache/fop/util/ColorSpaceCache.java b/src/java/org/apache/fop/util/ColorSpaceCache.java
new file mode 100644
index 000000000..92dcf8d55
--- /dev/null
+++ b/src/java/org/apache/fop/util/ColorSpaceCache.java
@@ -0,0 +1,110 @@
+/*
+ * 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.awt.color.ColorSpace;
+import java.awt.color.ICC_ColorSpace;
+import java.awt.color.ICC_Profile;
+import java.util.Collections;
+import java.util.Map;
+
+import javax.xml.transform.Source;
+import javax.xml.transform.URIResolver;
+import javax.xml.transform.stream.StreamSource;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * Map with cached ICC based ColorSpace objects.
+ */
+public class ColorSpaceCache {
+    /** logger instance */
+    private static Log log = LogFactory.getLog(ColorSpaceCache.class);
+
+    private URIResolver resolver;
+    private Map colorSpaceMap = Collections.synchronizedMap(new java.util.HashMap());
+
+    /**
+     * Default constructor
+     * @param resolver uri resolver
+     */
+    public ColorSpaceCache(URIResolver resolver) {
+        this.resolver = resolver;
+    }
+    
+    /**
+     * Create (if needed) and return an ICC ColorSpace instance.
+     * 
+     * The ICC profile source is taken from the src attribute of the color-profile FO element.
+     * If the ICC ColorSpace is not yet in the cache a new one is created and stored in the cache.
+     * 
+     * The FOP URI resolver is used to try and locate the ICC file. 
+     * If that fails null is returned.
+     * 
+     * @param base a base URI to resolve relative URIs
+     * @param iccProfileSrc ICC Profile source to return a ColorSpace for
+     * @return ICC ColorSpace object or null if ColorSpace could not be created 
+     */
+    public ColorSpace get(String base, String iccProfileSrc) {
+        ColorSpace colorSpace = null;
+        if (!colorSpaceMap.containsKey(base + iccProfileSrc)) {
+            try {
+                ICC_Profile iccProfile = null;
+                // First attempt to use the FOP URI resolver to locate the ICC
+                // profile
+                Source src = resolver.resolve(iccProfileSrc, base);
+                if (src != null && src instanceof StreamSource) {
+                    // FOP URI resolver found ICC profile - create ICC profile
+                    // from the Source
+                    iccProfile = ICC_Profile.getInstance(((StreamSource) src)
+                            .getInputStream());
+                } else {
+                    // TODO - Would it make sense to fall back on VM ICC
+                    // resolution
+                    // Problem is the cache might be more difficult to maintain
+                    // 
+                    // FOP URI resolver did not find ICC profile - perhaps the
+                    // Java VM can find it?
+                    // iccProfile = ICC_Profile.getInstance(iccProfileSrc);
+                }
+                if (iccProfile != null) {
+                    colorSpace = new ICC_ColorSpace(iccProfile);
+                }
+            } catch (Exception e) {
+                // Ignore exception - will be logged a bit further down
+                // (colorSpace == null case)
+            }
+
+            if (colorSpace != null) {
+                // Put in cache (not when VM resolved it as we can't control
+                colorSpaceMap.put(base + iccProfileSrc, colorSpace);
+            } else {
+                // TODO To avoid an excessive amount of warnings perhaps
+                // register a null ColorMap in the colorSpaceMap
+                log.warn("Color profile '" + iccProfileSrc + "' not found.");
+            }
+        } else {
+            colorSpace = (ColorSpace)colorSpaceMap.get(base
+                    + iccProfileSrc);
+        }
+        return colorSpace;
+    }        
+}
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));
+        }
+    }
+
+}
diff --git a/src/java/org/apache/fop/util/DataURLUtil.java b/src/java/org/apache/fop/util/DataURLUtil.java
new file mode 100644
index 000000000..03236dd45
--- /dev/null
+++ b/src/java/org/apache/fop/util/DataURLUtil.java
@@ -0,0 +1,67 @@
+/*
+ * 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.IOException;
+import java.io.InputStream;
+import java.io.StringWriter;
+import java.io.Writer;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.xmlgraphics.util.io.Base64EncodeStream;
+
+/**
+ * Utility classes for generating RFC 2397 data URLs.
+ */
+public class DataURLUtil {
+
+    /**
+     * Creates a new data URL and returns it as a String.
+     * @param in the InputStream to read the data from
+     * @param mediatype the MIME type of the content, or null
+     * @return the newly created data URL
+     * @throws IOException if an I/O error occurs
+     */
+    public static String createDataURL(InputStream in, String mediatype) throws IOException {
+        StringWriter writer = new StringWriter();
+        writeDataURL(in, mediatype, writer);
+        return writer.toString();
+    }
+    
+    /**
+     * Generates a data URL and writes it to a Writer.
+     * @param in the InputStream to read the data from
+     * @param mediatype the MIME type of the content, or null
+     * @param writer the Writer to write to
+     * @throws IOException if an I/O error occurs
+     */
+    public static void writeDataURL(InputStream in, String mediatype, Writer writer)
+            throws IOException {
+        writer.write("data:");
+        if (mediatype != null) {
+            writer.write(mediatype);
+        }
+        writer.write(";base64,");
+        Base64EncodeStream out = new Base64EncodeStream(
+                new WriterOutputStream(writer, "US-ASCII"));
+        IOUtils.copy(in, out);
+        out.flush();
+    }
+}
diff --git a/src/java/org/apache/fop/util/WriterOutputStream.java b/src/java/org/apache/fop/util/WriterOutputStream.java
new file mode 100644
index 000000000..d1908996a
--- /dev/null
+++ b/src/java/org/apache/fop/util/WriterOutputStream.java
@@ -0,0 +1,91 @@
+/*
+ * 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.IOException;
+import java.io.OutputStream;
+import java.io.Writer;
+
+/**
+ * An OutputStream wrapper for a Writer. 
+ */
+public class WriterOutputStream extends OutputStream {
+
+    private Writer writer;
+    private String encoding;
+
+    /**
+     * Creates a new WriterOutputStream.
+     * @param writer the Writer to write to
+     */
+    public WriterOutputStream(Writer writer) {
+        this(writer, null);
+    }
+
+    /**
+     * Creates a new WriterOutputStream.
+     * @param writer the Writer to write to
+     * @param encoding the encoding to use, or null if the default encoding should be used
+     */
+    public WriterOutputStream(Writer writer, String encoding) {
+        this.writer = writer;
+        this.encoding = encoding;
+    }
+
+    /**
+     * @see java.io.OutputStream#close()
+     */
+    public void close() throws IOException {
+        writer.close();
+    }
+
+    /**
+     * @see java.io.OutputStream#flush()
+     */
+    public void flush() throws IOException {
+        writer.flush();
+    }
+
+    /**
+     * @see java.io.OutputStream#write(byte[], int, int)
+     */
+    public void write(byte[] buf, int offset, int length) throws IOException {
+        if (encoding != null) {
+            writer.write(new String(buf, offset, length, encoding));
+        } else {
+            writer.write(new String(buf, offset, length));
+        }
+    }
+
+    /**
+     * @see java.io.OutputStream#write(byte[])
+     */
+    public void write(byte[] buf) throws IOException {
+        write(buf, 0, buf.length);
+    }
+
+    /**
+     * @see java.io.OutputStream#write(int)
+     */
+    public void write(int b) throws IOException {
+        write(new byte[] {(byte)b});
+    }
+
+}