src/com/google/enterprise/adaptor/fs/HtmlResponseWriter.java - plexi/fs - Git at Google

 // Copyright 2013 Google Inc. All Rights Reserved.
 //
 // 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.enterprise.adaptor.fs;

 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Strings;
 import com.google.enterprise.adaptor.DocId;
 import com.google.enterprise.adaptor.DocIdEncoder;

 import java.io.Closeable;
 import java.io.IOException;
 import java.io.Writer;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.text.MessageFormat;
 import java.util.Locale;
 import java.util.logging.Level;
 import java.util.logging.Logger;

 class HtmlResponseWriter implements Closeable {
   private static final Logger log
       = Logger.getLogger(HtmlResponseWriter.class.getName());

   private enum State {
     /** Initial state after construction. */
     INITIAL,
     /**
      * {@link #start} was just called, so the HTML header is in place, but no
      * other content.
      */
     STARTED,
     /** {@link #finish} has been called, so the HTML footer has been written. */
     FINISHED,
     /** The writer has been closed. */
     CLOSED,
   }

   private final Writer writer;
   private final DocIdEncoder docIdEncoder;
   private final Locale locale;
   private DocId docId;
   private URI docUri;
   private State state = State.INITIAL;

   public HtmlResponseWriter(Writer writer, DocIdEncoder docIdEncoder,
       Locale locale) {
     if (writer == null) {
       throw new NullPointerException();
     }
     if (docIdEncoder == null) {
       throw new NullPointerException();
     }
     if (locale == null) {
       throw new NullPointerException();
     }
     this.writer = writer;
     this.docIdEncoder = docIdEncoder;
     this.locale = locale;
   }

   /**
    * Start writing HTML document.
    *
    * @param docId the DocId for the document being written out
    * @param label possibly-{@code null} title or name of {@code docId}
    */
   public void start(DocId docId, String label)
       throws IOException {
     if (state != State.INITIAL) {
       throw new IllegalStateException("In unexpected state: " + state);
     }
     this.docId = docId;
     this.docUri = docIdEncoder.encodeDocId(docId);
     // TODO(ejona): Localize.
     String header = MessageFormat.format("{0} {1}",
         "Folder", computeLabel(label, docId));
     writer.write("<!DOCTYPE html>\n<html><head><title>");
     writer.write(escapeContent(header));
     writer.write("</title></head><body><h1>");
     writer.write(escapeContent(header));
     writer.write("</h1>");
     state = State.STARTED;
   }

   /**
    * @param docId docId to add as a link in the document
    * @param label possibly-{@code null} title or description of {@code docId}
    */
   public void addLink(DocId doc, String label) throws IOException {
     if (state != State.STARTED) {
       throw new IllegalStateException("In unexpected state: " + state);
     }
     if (doc == null) {
       throw new NullPointerException();
     }
     writer.write("<li><a href=\"");
     writer.write(escapeAttributeValue(encodeDocId(doc)));
     writer.write("\">");
     writer.write(escapeContent(computeLabel(label, doc)));
     writer.write("</a></li>");
   }

   /**
    * Complete HTML body and flush.
    */
   public void finish() throws IOException {
     log.entering("HtmlResponseWriter", "finish");
     if (state != State.STARTED) {
       throw new IllegalStateException("In unexpected state: " + state);
     }
     writer.write("</body></html>");
     writer.flush();
     state = State.FINISHED;
     log.exiting("HtmlResponseWriter", "finish");
   }

   /**
    * Close underlying writer. You will generally want to call {@link #finish}
    * first.
    */
   @Override
   public void close() throws IOException {
     log.entering("HtmlResponseWriter", "close");
     writer.close();
     state = State.CLOSED;
     log.exiting("HtmlResponseWriter", "close");
   }

   /**
    * Encodes a DocId into a URI formatted as a string.
    */
   private String encodeDocId(DocId doc) {
     log.entering("HtmlResponseWriter", "encodeDocId", doc);
     URI uri = docIdEncoder.encodeDocId(doc);
     uri = relativize(docUri, uri);
     String encoded = uri.toASCIIString();
     log.exiting("HtmlResponseWriter", "encodeDocId", encoded);
     return encoded;
   }

   /**
    * Produce a relative URI from {@code uri} relative to {@code base}, assuming
    * both URIs are hierarchial. If possible, a relative URI will be returned
    * that can be resolved from {@code base}, otherwise {@code uri} will be
    * returned.
    *
    * <p>Necessary since {@link URI#relativize} is broken when considering
    * http://host/path vs http://host/path/ as the base URI. See
    * <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6226081">
    * Bug 6226081</a> for more information. In addition, this version uses
    * {@code ..} when possible unlike {@link URI#relativize}.
    */
   @VisibleForTesting
   static URI relativize(URI base, URI uri) {
     if (base.getScheme() == null || !base.getScheme().equals(uri.getScheme())
         || base.getAuthority() == null
         || !base.getAuthority().equals(uri.getAuthority())) {
       return uri;
     }
     if (base.equals(uri)) {
       return URI.create("#");
     }
     // These paths are known to start with a / or be the empty string; since the
     // URIs have a scheme, we know they are absolute.
     String basePath = base.getPath();
     String uriPath = uri.getPath();

     String[] basePathParts = basePath.split("/", -1);
     String[] uriPathParts = uriPath.split("/", -1);
     int i = 0;
     // Remove common folders. Since we are looking at folders, we don't compare
     // the last elements in the array, because they were after the last '/' in
     // the URIs.
     for (; i < basePathParts.length - 1 && i < uriPathParts.length - 1; i++) {
       if (!basePathParts[i].equals(uriPathParts[i])) {
         break;
       }
     }
     StringBuilder pathBuilder = new StringBuilder();
     for (int j = i; j < basePathParts.length - 1; j++) {
       pathBuilder.append("../");
     }
     for (; i < uriPathParts.length; i++) {
       pathBuilder.append(uriPathParts[i]);
       pathBuilder.append("/");
     }
     String path = pathBuilder.substring(0, pathBuilder.length() - 1);
     int colonLocation = path.indexOf(":");
     int slashLocation = path.indexOf("/");
     if (colonLocation != -1
         && (slashLocation == -1 || colonLocation < slashLocation)) {
       // If there is a colon before the first slash, then it is easy to confuse
       // this relative URI for an absolute URI. Thus, we prepend a ./ so that
       // the beginning is obviously not a scheme.
       path = "./" + path;
     }
     try {
       return new URI(null, null, path, uri.getQuery(), uri.getFragment());
     } catch (URISyntaxException ex) {
       throw new AssertionError(ex);
     }
   }

   private String computeLabel(String label, DocId doc) {
     if (Strings.isNullOrEmpty(label)) {
       // Use the last part of the URL if an item doesn't have a title. The last
       // part of the URL will generally be a filename in this case.
       String[] parts = doc.getUniqueId().split("/", 0);
       label = parts[parts.length - 1];
     }
     return label;
   }

   private String escapeContent(String raw) {
     return raw.replace("&", "&amp;").replace("<", "&lt;");
   }

   private String escapeAttributeValue(String raw) {
     return escapeContent(raw).replace("\"", "&quot;").replace("'", "&apos;");
   }
 }
	// Copyright 2013 Google Inc. All Rights Reserved.
	//
	// 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.enterprise.adaptor.fs;

	import com.google.common.annotations.VisibleForTesting;
	import com.google.common.base.Strings;
	import com.google.enterprise.adaptor.DocId;
	import com.google.enterprise.adaptor.DocIdEncoder;

	import java.io.Closeable;
	import java.io.IOException;
	import java.io.Writer;
	import java.net.URI;
	import java.net.URISyntaxException;
	import java.text.MessageFormat;
	import java.util.Locale;
	import java.util.logging.Level;
	import java.util.logging.Logger;

	class HtmlResponseWriter implements Closeable {
	private static final Logger log
	= Logger.getLogger(HtmlResponseWriter.class.getName());

	private enum State {
	/** Initial state after construction. */
	INITIAL,
	/**
	* {@link #start} was just called, so the HTML header is in place, but no
	* other content.
	*/
	STARTED,
	/** {@link #finish} has been called, so the HTML footer has been written. */
	FINISHED,
	/** The writer has been closed. */
	CLOSED,
	}

	private final Writer writer;
	private final DocIdEncoder docIdEncoder;
	private final Locale locale;
	private DocId docId;
	private URI docUri;
	private State state = State.INITIAL;

	public HtmlResponseWriter(Writer writer, DocIdEncoder docIdEncoder,
	Locale locale) {
	if (writer == null) {
	throw new NullPointerException();
	}
	if (docIdEncoder == null) {
	throw new NullPointerException();
	}
	if (locale == null) {
	throw new NullPointerException();
	}
	this.writer = writer;
	this.docIdEncoder = docIdEncoder;
	this.locale = locale;
	}

	/**
	* Start writing HTML document.
	*
	* @param docId the DocId for the document being written out
	* @param label possibly-{@code null} title or name of {@code docId}
	*/
	public void start(DocId docId, String label)
	throws IOException {
	if (state != State.INITIAL) {
	throw new IllegalStateException("In unexpected state: " + state);
	}
	this.docId = docId;
	this.docUri = docIdEncoder.encodeDocId(docId);
	// TODO(ejona): Localize.
	String header = MessageFormat.format("{0} {1}",
	"Folder", computeLabel(label, docId));
	writer.write("<!DOCTYPE html>\n<html><head><title>");
	writer.write(escapeContent(header));
	writer.write("</title></head><body><h1>");
	writer.write(escapeContent(header));
	writer.write("</h1>");
	state = State.STARTED;
	}

	/**
	* @param docId docId to add as a link in the document
	* @param label possibly-{@code null} title or description of {@code docId}
	*/
	public void addLink(DocId doc, String label) throws IOException {
	if (state != State.STARTED) {
	throw new IllegalStateException("In unexpected state: " + state);
	}
	if (doc == null) {
	throw new NullPointerException();
	}
	writer.write("<li><a href=\"");
	writer.write(escapeAttributeValue(encodeDocId(doc)));
	writer.write("\">");
	writer.write(escapeContent(computeLabel(label, doc)));
	writer.write("</a></li>");
	}

	/**
	* Complete HTML body and flush.
	*/
	public void finish() throws IOException {
	log.entering("HtmlResponseWriter", "finish");
	if (state != State.STARTED) {
	throw new IllegalStateException("In unexpected state: " + state);
	}
	writer.write("</body></html>");
	writer.flush();
	state = State.FINISHED;
	log.exiting("HtmlResponseWriter", "finish");
	}

	/**
	* Close underlying writer. You will generally want to call {@link #finish}
	* first.
	*/
	@Override
	public void close() throws IOException {
	log.entering("HtmlResponseWriter", "close");
	writer.close();
	state = State.CLOSED;
	log.exiting("HtmlResponseWriter", "close");
	}

	/**
	* Encodes a DocId into a URI formatted as a string.
	*/
	private String encodeDocId(DocId doc) {
	log.entering("HtmlResponseWriter", "encodeDocId", doc);
	URI uri = docIdEncoder.encodeDocId(doc);
	uri = relativize(docUri, uri);
	String encoded = uri.toASCIIString();
	log.exiting("HtmlResponseWriter", "encodeDocId", encoded);
	return encoded;
	}

	/**
	* Produce a relative URI from {@code uri} relative to {@code base}, assuming
	* both URIs are hierarchial. If possible, a relative URI will be returned
	* that can be resolved from {@code base}, otherwise {@code uri} will be
	* returned.
	*
	* <p>Necessary since {@link URI#relativize} is broken when considering
	* http://host/path vs http://host/path/ as the base URI. See
	* <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6226081">
	* Bug 6226081</a> for more information. In addition, this version uses
	* {@code ..} when possible unlike {@link URI#relativize}.
	*/
	@VisibleForTesting
	static URI relativize(URI base, URI uri) {
	if (base.getScheme() == null \|\| !base.getScheme().equals(uri.getScheme())
	\|\| base.getAuthority() == null
	\|\| !base.getAuthority().equals(uri.getAuthority())) {
	return uri;
	}
	if (base.equals(uri)) {
	return URI.create("#");
	}
	// These paths are known to start with a / or be the empty string; since the
	// URIs have a scheme, we know they are absolute.
	String basePath = base.getPath();
	String uriPath = uri.getPath();

	String[] basePathParts = basePath.split("/", -1);
	String[] uriPathParts = uriPath.split("/", -1);
	int i = 0;
	// Remove common folders. Since we are looking at folders, we don't compare
	// the last elements in the array, because they were after the last '/' in
	// the URIs.
	for (; i < basePathParts.length - 1 && i < uriPathParts.length - 1; i++) {
	if (!basePathParts[i].equals(uriPathParts[i])) {
	break;
	}
	}
	StringBuilder pathBuilder = new StringBuilder();
	for (int j = i; j < basePathParts.length - 1; j++) {
	pathBuilder.append("../");
	}
	for (; i < uriPathParts.length; i++) {
	pathBuilder.append(uriPathParts[i]);
	pathBuilder.append("/");
	}
	String path = pathBuilder.substring(0, pathBuilder.length() - 1);
	int colonLocation = path.indexOf(":");
	int slashLocation = path.indexOf("/");
	if (colonLocation != -1
	&& (slashLocation == -1 \|\| colonLocation < slashLocation)) {
	// If there is a colon before the first slash, then it is easy to confuse
	// this relative URI for an absolute URI. Thus, we prepend a ./ so that
	// the beginning is obviously not a scheme.
	path = "./" + path;
	}
	try {
	return new URI(null, null, path, uri.getQuery(), uri.getFragment());
	} catch (URISyntaxException ex) {
	throw new AssertionError(ex);
	}
	}

	private String computeLabel(String label, DocId doc) {
	if (Strings.isNullOrEmpty(label)) {
	// Use the last part of the URL if an item doesn't have a title. The last
	// part of the URL will generally be a filename in this case.
	String[] parts = doc.getUniqueId().split("/", 0);
	label = parts[parts.length - 1];
	}
	return label;
	}

	private String escapeContent(String raw) {
	return raw.replace("&", "&").replace("<", "<");
	}

	private String escapeAttributeValue(String raw) {
	return escapeContent(raw).replace("\"", """).replace("'", "'");
	}
	}