chrome/renderer/spellchecker/hunspell_engine.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/renderer/spellchecker/hunspell_engine.h"
   6
   7 #include <algorithm>
   8 #include <iterator>
   9
  10 #include "base/files/memory_mapped_file.h"
  11 #include "base/time/time.h"
  12 #include "chrome/common/spellcheck_common.h"
  13 #include "chrome/common/spellcheck_messages.h"
  14 #include "content/public/renderer/render_thread.h"
  15 #include "third_party/hunspell/src/hunspell/hunspell.hxx"
  16
  17 using content::RenderThread;
  18
  19 namespace {
  20   // Maximum length of words we actually check.
  21   // 64 is the observed limits for OSX system checker.
  22   const size_t kMaxCheckedLen = 64;
  23
  24   // Maximum length of words we provide suggestions for.
  25   // 24 is the observed limits for OSX system checker.
  26   const size_t kMaxSuggestLen = 24;
  27
  28   static_assert(kMaxCheckedLen <= size_t(MAXWORDLEN),
  29                 "MaxCheckedLen too long");
  30   static_assert(kMaxSuggestLen <= kMaxCheckedLen,
  31                 "MaxSuggestLen too long");
  32 }  // namespace
  33
  34 #if !defined(OS_MACOSX)
  35 SpellingEngine* CreateNativeSpellingEngine() {
  36   return new HunspellEngine();
  37 }
  38 #endif
  39
  40 HunspellEngine::HunspellEngine()
  41     : hunspell_enabled_(false),
  42       initialized_(false),
  43       dictionary_requested_(false) {
  44   // Wait till we check the first word before doing any initializing.
  45 }
  46
  47 HunspellEngine::~HunspellEngine() {
  48 }
  49
  50 void HunspellEngine::Init(base::File file) {
  51   initialized_ = true;
  52   hunspell_.reset();
  53   bdict_file_.reset();
  54   file_ = file.Pass();
  55   hunspell_enabled_ = file_.IsValid();
  56   // Delay the actual initialization of hunspell until it is needed.
  57 }
  58
  59 void HunspellEngine::InitializeHunspell() {
  60   if (hunspell_.get())
  61     return;
  62
  63   bdict_file_.reset(new base::MemoryMappedFile);
  64
  65   if (bdict_file_->Initialize(file_.Pass())) {
  66     hunspell_.reset(new Hunspell(bdict_file_->data(), bdict_file_->length()));
  67   } else {
  68     NOTREACHED() << "Could not mmap spellchecker dictionary.";
  69   }
  70 }
  71
  72 bool HunspellEngine::CheckSpelling(const base::string16& word_to_check,
  73                                    int tag) {
  74   // Assume all words that cannot be checked are valid. Since Chrome can't
  75   // offer suggestions on them, either, there's no point in flagging them to
  76   // the user.
  77   bool word_correct = true;
  78   std::string word_to_check_utf8(base::UTF16ToUTF8(word_to_check));
  79
  80   // Limit the size of checked words.
  81   if (word_to_check_utf8.length() <= kMaxCheckedLen) {
  82     // If |hunspell_| is NULL here, an error has occurred, but it's better
  83     // to check rather than crash.
  84     if (hunspell_.get()) {
  85       // |hunspell_->spell| returns 0 if the word is misspelled.
  86       word_correct = (hunspell_->spell(word_to_check_utf8.c_str()) != 0);
  87     }
  88   }
  89
  90   return word_correct;
  91 }
  92
  93 void HunspellEngine::FillSuggestionList(
  94     const base::string16& wrong_word,
  95     std::vector<base::string16>* optional_suggestions) {
  96   std::string wrong_word_utf8(base::UTF16ToUTF8(wrong_word));
  97   if (wrong_word_utf8.length() > kMaxSuggestLen)
  98     return;
  99
 100   // If |hunspell_| is NULL here, an error has occurred, but it's better
 101   // to check rather than crash.
 102   // TODO(groby): Technically, it's not. We should track down the issue.
 103   if (!hunspell_.get())
 104     return;
 105
 106   char** suggestions = NULL;
 107   int number_of_suggestions =
 108       hunspell_->suggest(&suggestions, wrong_word_utf8.c_str());
 109
 110   // Populate the vector of WideStrings.
 111   for (int i = 0; i < number_of_suggestions; ++i) {
 112     if (i < chrome::spellcheck_common::kMaxSuggestions)
 113       optional_suggestions->push_back(base::UTF8ToUTF16(suggestions[i]));
 114     free(suggestions[i]);
 115   }
 116   if (suggestions != NULL)
 117     free(suggestions);
 118 }
 119
 120 bool HunspellEngine::InitializeIfNeeded() {
 121   if (!initialized_ && !dictionary_requested_) {
 122     // RenderThread will not exist in test.
 123     if (RenderThread::Get())
 124       RenderThread::Get()->Send(new SpellCheckHostMsg_RequestDictionary);
 125     dictionary_requested_ = true;
 126     return true;
 127   }
 128
 129   // Don't initialize if hunspell is disabled.
 130   if (file_.IsValid())
 131     InitializeHunspell();
 132
 133   return !initialized_;
 134 }
 135
 136 bool HunspellEngine::IsEnabled() {
 137   return hunspell_enabled_;
 138 }