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

/*
 * Copyright 2010 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: mdsteele@google.com (Matthew D. Steele)

#ifndef NET_INSTAWEB_REWRITER_PUBLIC_JS_INLINE_FILTER_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_JS_INLINE_FILTER_H_

#include <cstddef>

#include "net/instaweb/rewriter/public/common_filter.h"
#include "net/instaweb/rewriter/public/resource.h"
#include "net/instaweb/rewriter/public/rewrite_driver.h"
#include "net/instaweb/rewriter/public/rewrite_options.h"
#include "net/instaweb/rewriter/public/script_tag_scanner.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/http/semantic_type.h"

namespace net_instaweb {
class HtmlElement;
class HtmlCharactersNode;
class Statistics;
class Variable;

// Inline small Javascript files.
class JsInlineFilter : public CommonFilter {
 public:
  static const char kNumJsInlined[];
  explicit JsInlineFilter(RewriteDriver* driver);
  virtual ~JsInlineFilter();

  virtual void StartDocumentImpl();
  virtual void EndDocument();
  virtual void StartElementImpl(HtmlElement* element);
  virtual void EndElementImpl(HtmlElement* element);
  virtual void Characters(HtmlCharactersNode* characters);
  virtual const char* Name() const { return "InlineJs"; }
  // Inlining javascript from unauthorized domains into HTML is considered
  // safe because it does not cause any new content to be executed compared
  // to the unoptimized page.
  virtual RewriteDriver::InlineAuthorizationPolicy AllowUnauthorizedDomain()
      const {
    return driver()->options()->HasInlineUnauthorizedResourceType(
               semantic_type::kScript) ?
           RewriteDriver::kInlineUnauthorizedResources :
           RewriteDriver::kInlineOnlyAuthorizedResources;
  }
  virtual bool IntendedForInlining() const { return true; }

  static void InitStats(Statistics* statistics);

 private:
  class Context;
  friend class Context;

  bool ShouldInline(const ResourcePtr& resource, GoogleString* reason) const;
  void RenderInline(const ResourcePtr& resource, const StringPiece& text,
                    HtmlElement* element);

  const size_t size_threshold_bytes_;
  ScriptTagScanner script_tag_scanner_;

  // This is set to true during StartElement() for a <script> tag that we
  // should maybe inline, but may be set back to false by Characters().  If it
  // is still true when we hit the corresponding EndElement(), then we'll
  // inline the script (and set it back to false).  It should never be true
  // outside of <script> and </script>.
  bool should_inline_;

  Variable* num_js_inlined_;

  DISALLOW_COPY_AND_ASSIGN(JsInlineFilter);
};

}  // namespace net_instaweb

#endif  // NET_INSTAWEB_REWRITER_PUBLIC_JS_INLINE_FILTER_H_