Componentize safe_browsing [X+1] : move the renderer part to component.

chrome/renderer/safe_browsing/phishing_term_feature_extractor.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// PhishingTermFeatureExtractor handles computing term features from the text
-// of a web page for the client-side phishing detection model.  To do this, it
-// takes a list of terms that appear in the model, and scans through the page
-// text looking for them.  Any terms that appear will cause a corresponding
-// features::kPageTerm feature to be added to the FeatureMap.
-//
-// To make it harder for a phisher to enumerate all of the relevant terms in
-// the model, the terms are provided as SHA-256 hashes, rather than plain text.
-//
-// There is one PhishingTermFeatureExtractor per RenderView.
-
-#ifndef CHROME_RENDERER_SAFE_BROWSING_PHISHING_TERM_FEATURE_EXTRACTOR_H_
-#define CHROME_RENDERER_SAFE_BROWSING_PHISHING_TERM_FEATURE_EXTRACTOR_H_
-
-#include <stddef.h>
-#include <stdint.h>
-
-#include <memory>
-#include <set>
-#include <string>
-
-#include "base/callback.h"
-#include "base/containers/hash_tables.h"
-#include "base/macros.h"
-#include "base/memory/weak_ptr.h"
-#include "base/strings/string16.h"
-#include "base/strings/string_piece.h"
-
-namespace safe_browsing {
-class FeatureExtractorClock;
-class FeatureMap;
-
-class PhishingTermFeatureExtractor {
- public:
-  // Callback to be run when feature extraction finishes.  The callback
-  // argument is true if extraction was successful, false otherwise.
-  typedef base::Callback<void(bool)> DoneCallback;
-
-  // Creates a PhishingTermFeatureExtractor which will extract features for
-  // all of the terms whose SHA-256 hashes are in |page_term_hashes|.  These
-  // terms may be multi-word n-grams, with at most |max_words_per_term| words.
-  //
-  // |page_word_hashes| contains the murmur3 hashes for all of the individual
-  // words that make up the terms.  Both sets of strings are UTF-8 encoded and
-  // lowercased prior to hashing.  The caller owns both sets of strings, and
-  // must ensure that they are valid until the PhishingTermFeatureExtractor is
-  // destroyed.
-  //
-  // In addition to extracting page terms, we will also extract text shingling
-  // sketch, which consists of hashes of N-gram-words (referred to as shingles)
-  // in the page. |shingle_size| defines N, and |max_shingles_per_page| defines
-  // the maximum number of unique shingle hashes we extracted per page.
-  //
-  // |clock| is used for timing feature extractor operations, and may be mocked
-  // for testing.  The caller keeps ownership of the clock.
-  PhishingTermFeatureExtractor(
-      const base::hash_set<std::string>* page_term_hashes,
-      const base::hash_set<uint32_t>* page_word_hashes,
-      size_t max_words_per_term,
-      uint32_t murmurhash3_seed,
-      size_t max_shingles_per_page,
-      size_t shingle_size,
-      FeatureExtractorClock* clock);
-  ~PhishingTermFeatureExtractor();
-
-  // Begins extracting features from |page_text| into the given FeatureMap.
-  // |page_text| should contain the plain text of a web page, including any
-  // subframes, as returned by RenderView::CaptureText().
-  //
-  // To avoid blocking the render thread for too long, the feature extractor
-  // may run in several chunks of work, posting a task to the current
-  // MessageLoop to continue processing.  Once feature extraction is complete,
-  // |done_callback| is run on the current thread.
-  // PhishingTermFeatureExtractor takes ownership of the callback.
-  //
-  // |page_text|, |features|, and |shingle_hashes| are owned by the caller,
-  // and must not be destroyed until either |done_callback| is run or
-  // CancelPendingExtraction() is called.
-  void ExtractFeatures(const base::string16* page_text,
-                       FeatureMap* features,
-                       std::set<uint32_t>* shingle_hashes,
-                       const DoneCallback& done_callback);
-
-  // Cancels any pending feature extraction.  The DoneCallback will not be run.
-  // Must be called if there is a feature extraction in progress when the page
-  // is unloaded or the PhishingTermFeatureExtractor is destroyed.
-  void CancelPendingExtraction();
-
- private:
-  struct ExtractionState;
-
-  // The maximum amount of wall time that we will spend on a single extraction
-  // iteration before pausing to let other MessageLoop tasks run.
-  static const int kMaxTimePerChunkMs;
-
-  // The number of words that we will process before checking to see whether
-  // kMaxTimePerChunkMs has elapsed.  Since checking the current time can be
-  // slow, we don't do this on every word processed.
-  static const int kClockCheckGranularity;
-
-  // The maximum total amount of time that the feature extractor will run
-  // before giving up on the current page.
-  static const int kMaxTotalTimeMs;
-
-  // Does the actual work of ExtractFeatures.  ExtractFeaturesWithTimeout runs
-  // until a predefined maximum amount of time has elapsed, then posts a task
-  // to the current MessageLoop to continue extraction.  When extraction
-  // finishes, calls RunCallback().
-  void ExtractFeaturesWithTimeout();
-
-  // Handles a single word in the page text.
-  void HandleWord(const base::StringPiece16& word);
-
-  // Helper to verify that there is no pending feature extraction.  Dies in
-  // debug builds if the state is not as expected.  This is a no-op in release
-  // builds.
-  void CheckNoPendingExtraction();
-
-  // Runs |done_callback_| and then clears all internal state.
-  void RunCallback(bool success);
-
-  // Clears all internal feature extraction state.
-  void Clear();
-
-  // All of the term hashes that we are looking for in the page.
-  const base::hash_set<std::string>* page_term_hashes_;
-
-  // Murmur3 hashes of all the individual words in page_term_hashes_.  If
-  // page_term_hashes_ included (hashed) "one" and "one two", page_word_hashes_
-  // would contain (hashed) "one" and "two".  We do this so that we can have a
-  // quick out in the common case that the current word we are processing
-  // doesn't contain any part of one of our terms.
-  const base::hash_set<uint32_t>* page_word_hashes_;
-
-  // The maximum number of words in an n-gram.
-  const size_t max_words_per_term_;
-
-  // The seed for murmurhash3.
-  const uint32_t murmurhash3_seed_;
-
-  // The maximum number of unique shingle hashes we extract in a page.
-  const size_t max_shingles_per_page_;
-
-  // The number of words in a shingle.
-  const size_t shingle_size_;
-
-  // Non-owned pointer to our clock.
-  FeatureExtractorClock* clock_;
-
-  // The output parameters from the most recent call to ExtractFeatures().
-  const base::string16* page_text_;  // The caller keeps ownership of this.
-  FeatureMap* features_;  // The caller keeps ownership of this.
-  std::set<uint32_t>* shingle_hashes_;
-  DoneCallback done_callback_;
-
-  // Stores the current state of term extraction from |page_text_|.
-  std::unique_ptr<ExtractionState> state_;
-
-  // Used in scheduling ExtractFeaturesWithTimeout tasks.
-  // These pointers are invalidated if extraction is cancelled.
-  base::WeakPtrFactory<PhishingTermFeatureExtractor> weak_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(PhishingTermFeatureExtractor);
-};
-
-}  // namespace safe_browsing
-
-#endif  // CHROME_RENDERER_SAFE_BROWSING_PHISHING_TERM_FEATURE_EXTRACTOR_H_