src/net/instaweb/rewriter/public/css_url_counter.h

/*
 * Copyright 2012 Google Inc.
 *
 * 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.
 */

// Author: sligocki@google.com (Shawn Ligocki)

#ifndef NET_INSTAWEB_REWRITER_PUBLIC_CSS_URL_COUNTER_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_CSS_URL_COUNTER_H_

#include "net/instaweb/rewriter/public/css_tag_scanner.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"

namespace net_instaweb {

class GoogleUrl;
class MessageHandler;

// "Transformer" that records the URLs it sees (with counts) instead of
// applying any transformation.
class CssUrlCounter : public CssTagScanner::Transformer {
 public:
  // base_url and handler must live longer than CssUrlCounter.
  CssUrlCounter(const GoogleUrl* base_url, MessageHandler* handler)
      : base_url_(base_url), handler_(handler) {}
  virtual ~CssUrlCounter();

  // Record and count URLs in in_text. Does not reset url_counts_, so if you
  // call this multiple times it will accumulate url_counts_ over all inputs.
  // Returns False if CssUrlCounter found unparseable URLs.
  bool Count(const StringPiece& in_text);

  // Access URL occurrence counts after you've scanned a CSS file.
  const StringIntMap& url_counts() const { return url_counts_; }

 private:
  // CssTagScanner::Transform interface. Called indirectly by Count().
  virtual TransformStatus Transform(GoogleString* str);

  // Counts for how many times each URL was found in the CSS file.
  StringIntMap url_counts_;

  // Base URL for CSS file, needed to absolutify URLs in Transform.
  const GoogleUrl* base_url_;

  MessageHandler* handler_;

  DISALLOW_COPY_AND_ASSIGN(CssUrlCounter);
};

}  // namespace net_instaweb

#endif  // NET_INSTAWEB_REWRITER_PUBLIC_CSS_URL_COUNTER_H_