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* Copyright 2010 Google Inc.
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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// Author: mdsteele@google.com (Matthew D. Steele)
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#ifndef PAGESPEED_KERNEL_HTML_COLLAPSE_WHITESPACE_FILTER_H_
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#define PAGESPEED_KERNEL_HTML_COLLAPSE_WHITESPACE_FILTER_H_
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#include "pagespeed/kernel/html/empty_html_filter.h"
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#include "pagespeed/kernel/html/html_name.h"
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#include "pagespeed/kernel/base/basictypes.h"
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namespace net_instaweb {
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class HtmlCharactersNode;
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// Reduce the size of the HTML by collapsing whitespace (except within certain
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// tags, e.g. <pre> and <script>). Note that this is a dangerous filter, as
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// CSS can be used to make the HTML whitespace-sensitive in unpredictable
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// places; thus, it should only be used for content that you are sure will not
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// TODO(mdsteele): Use the CSS parser (once it's finished) to try to
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// intelligently determine when the CSS "white-space: pre" property is in use;
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// that would make this filter much safer.
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class CollapseWhitespaceFilter : public EmptyHtmlFilter {
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explicit CollapseWhitespaceFilter(HtmlParse* html_parse);
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virtual ~CollapseWhitespaceFilter();
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virtual void StartDocument();
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virtual void StartElement(HtmlElement* element);
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virtual void EndElement(HtmlElement* element);
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virtual void Characters(HtmlCharactersNode* characters);
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virtual const char* Name() const { return "CollapseWhitespace"; }
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HtmlParse* html_parse_;
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std::vector<HtmlName::Keyword> keyword_stack_;
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DISALLOW_COPY_AND_ASSIGN(CollapseWhitespaceFilter);
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} // namespace net_instaweb
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#endif // PAGESPEED_KERNEL_HTML_COLLAPSE_WHITESPACE_FILTER_H_