pagespeed/kernel/http/data_url.h

/*
 * 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.
 */

#ifndef PAGESPEED_KERNEL_HTTP_DATA_URL_H_
#define PAGESPEED_KERNEL_HTTP_DATA_URL_H_

#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"

namespace net_instaweb {
struct ContentType;

enum Encoding {
  UNKNOWN,  // Used only for output of ParseDataUrl.
  BASE64,
  //   LATIN1,  // TODO(jmaessen): implement non-BASE64 encodings.
  //   UTF8,
  PLAIN
};

// Create a data: url from the given content-type and content.  See:
// http://en.wikipedia.org/wiki/Data_URI_scheme
//
// The ENCODING indicates how to encode the content; for binary data
// this is UTF8, for ascii / Latin1 it's LATIN1.  If you have ascii
// without high bits or NULs, use LATIN1.  If you have alphanumeric data,
// use PLAIN (which doesn't encode at all).
//
// Note in particular that IE<=7 does not support this, so it makes us
// UserAgent-dependent.  It also pretty much requires outgoing content to be
// compressed as we tend to base64-encode the content.
void DataUrl(const ContentType& content_type, const Encoding encoding,
             const StringPiece& content, GoogleString* result);

// Determine if the given URL is a data: URL. Cheaper than ParseDataUrl.
bool IsDataUrl(const StringPiece url);

// Determine if the given URL is a data:image URL (aka an inlined image).
bool IsDataImageUrl(const StringPiece url);

// Dismantle a data: url into its component pieces, but do not decode the
// content.  Note that encoded_content will be a substring of the input url and
// shares its lifetime.  Invalidates all outputs if url does not parse.
bool ParseDataUrl(const StringPiece& url, const ContentType** content_type,
                  Encoding* encoding, StringPiece* encoded_content);

bool DecodeDataUrlContent(Encoding encoding, const StringPiece& encoded_content,
                          GoogleString* decoded_content);

}  // namespace net_instaweb

#endif  // PAGESPEED_KERNEL_HTTP_DATA_URL_H_