[WIP][DO NOT LAND] Componentize spellcheck

chrome/renderer/spellchecker/hunspell_engine.cc

-// Copyright (c) 2012 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.
-
-#include "chrome/renderer/spellchecker/hunspell_engine.h"
-
-#include <stddef.h>
-#include <algorithm>
-#include <iterator>
-#include <utility>
-
-#include "base/files/memory_mapped_file.h"
-#include "base/time/time.h"
-#include "chrome/common/spellcheck_common.h"
-#include "chrome/common/spellcheck_messages.h"
-#include "content/public/renderer/render_thread.h"
-#include "third_party/hunspell/src/hunspell/hunspell.hxx"
-
-using content::RenderThread;
-
-namespace {
-  // Maximum length of words we actually check.
-  // 64 is the observed limits for OSX system checker.
-  const size_t kMaxCheckedLen = 64;
-
-  // Maximum length of words we provide suggestions for.
-  // 24 is the observed limits for OSX system checker.
-  const size_t kMaxSuggestLen = 24;
-
-  static_assert(kMaxCheckedLen <= size_t(MAXWORDLEN),
-                "MaxCheckedLen too long");
-  static_assert(kMaxSuggestLen <= kMaxCheckedLen,
-                "MaxSuggestLen too long");
-}  // namespace
-
-#if !defined(USE_BROWSER_SPELLCHECKER)
-SpellingEngine* CreateNativeSpellingEngine() {
-  return new HunspellEngine();
-}
-#endif
-
-HunspellEngine::HunspellEngine()
-    : hunspell_enabled_(false),
-      initialized_(false),
-      dictionary_requested_(false) {
-  // Wait till we check the first word before doing any initializing.
-}
-
-HunspellEngine::~HunspellEngine() {
-}
-
-void HunspellEngine::Init(base::File file) {
-  initialized_ = true;
-  hunspell_.reset();
-  bdict_file_.reset();
-  file_ = std::move(file);
-  hunspell_enabled_ = file_.IsValid();
-  // Delay the actual initialization of hunspell until it is needed.
-}
-
-void HunspellEngine::InitializeHunspell() {
-  if (hunspell_.get())
-    return;
-
-  bdict_file_.reset(new base::MemoryMappedFile);
-
-  if (bdict_file_->Initialize(std::move(file_))) {
-    hunspell_.reset(new Hunspell(bdict_file_->data(), bdict_file_->length()));
-  } else {
-    NOTREACHED() << "Could not mmap spellchecker dictionary.";
-  }
-}
-
-bool HunspellEngine::CheckSpelling(const base::string16& word_to_check,
-                                   int tag) {
-  // Assume all words that cannot be checked are valid. Since Chrome can't
-  // offer suggestions on them, either, there's no point in flagging them to
-  // the user.
-  bool word_correct = true;
-  std::string word_to_check_utf8(base::UTF16ToUTF8(word_to_check));
-
-  // Limit the size of checked words.
-  if (word_to_check_utf8.length() <= kMaxCheckedLen) {
-    // If |hunspell_| is NULL here, an error has occurred, but it's better
-    // to check rather than crash.
-    if (hunspell_.get()) {
-      // |hunspell_->spell| returns 0 if the word is misspelled.
-      word_correct = (hunspell_->spell(word_to_check_utf8.c_str()) != 0);
-    }
-  }
-
-  return word_correct;
-}
-
-void HunspellEngine::FillSuggestionList(
-    const base::string16& wrong_word,
-    std::vector<base::string16>* optional_suggestions) {
-  std::string wrong_word_utf8(base::UTF16ToUTF8(wrong_word));
-  if (wrong_word_utf8.length() > kMaxSuggestLen)
-    return;
-
-  // If |hunspell_| is NULL here, an error has occurred, but it's better
-  // to check rather than crash.
-  // TODO(groby): Technically, it's not. We should track down the issue.
-  if (!hunspell_.get())
-    return;
-
-  char** suggestions = NULL;
-  int number_of_suggestions =
-      hunspell_->suggest(&suggestions, wrong_word_utf8.c_str());
-
-  // Populate the vector of WideStrings.
-  for (int i = 0; i < number_of_suggestions; ++i) {
-    if (i < chrome::spellcheck_common::kMaxSuggestions)
-      optional_suggestions->push_back(base::UTF8ToUTF16(suggestions[i]));
-    free(suggestions[i]);
-  }
-  if (suggestions != NULL)
-    free(suggestions);
-}
-
-bool HunspellEngine::InitializeIfNeeded() {
-  if (!initialized_ && !dictionary_requested_) {
-    // RenderThread will not exist in test.
-    if (RenderThread::Get())
-      RenderThread::Get()->Send(new SpellCheckHostMsg_RequestDictionary);
-    dictionary_requested_ = true;
-    return true;
-  }
-
-  // Don't initialize if hunspell is disabled.
-  if (file_.IsValid())
-    InitializeHunspell();
-
-  return !initialized_;
-}
-
-bool HunspellEngine::IsEnabled() {
-  return hunspell_enabled_;
-}