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   COMPILE_ASSERT(kMaxCheckedLen <= size_t(MAXWORDLEN), MaxCheckedLen_too_long);
  29   COMPILE_ASSERT(kMaxSuggestLen <= kMaxCheckedLen, MaxSuggestLen_too_long);
  30 }  // namespace
  31
  32 #if !defined(OS_MACOSX)
  33 SpellingEngine* CreateNativeSpellingEngine() {
  34   return new HunspellEngine();
  35 }
  36 #endif
  37
  38 HunspellEngine::HunspellEngine()
  39     : hunspell_enabled_(false),
  40       initialized_(false),
  41       dictionary_requested_(false) {
  42   // Wait till we check the first word before doing any initializing.
  43 }
  44
  45 HunspellEngine::~HunspellEngine() {
  46 }
  47
  48 void HunspellEngine::Init(base::File file) {
  49   initialized_ = true;
  50   hunspell_.reset();
  51   bdict_file_.reset();
  52   file_ = file.Pass();
  53   hunspell_enabled_ = file_.IsValid();
  54   // Delay the actual initialization of hunspell until it is needed.
  55 }
  56
  57 void HunspellEngine::InitializeHunspell() {
  58   if (hunspell_.get())
  59     return;
  60
  61   bdict_file_.reset(new base::MemoryMappedFile);
  62
  63   if (bdict_file_->Initialize(file_.Pass())) {
  64     hunspell_.reset(new Hunspell(bdict_file_->data(), bdict_file_->length()));
  65   } else {
  66     NOTREACHED() << "Could not mmap spellchecker dictionary.";
  67   }
  68 }
  69
  70 bool HunspellEngine::CheckSpelling(const base::string16& word_to_check,
  71                                    int tag) {
  72   // Assume all words that cannot be checked are valid. Since Chrome can't
  73   // offer suggestions on them, either, there's no point in flagging them to
  74   // the user.
  75   bool word_correct = true;
  76   std::string word_to_check_utf8(base::UTF16ToUTF8(word_to_check));
  77
  78   // Limit the size of checked words.
  79   if (word_to_check_utf8.length() <= kMaxCheckedLen) {
  80     // If |hunspell_| is NULL here, an error has occurred, but it's better
  81     // to check rather than crash.
  82     if (hunspell_.get()) {
  83       // |hunspell_->spell| returns 0 if the word is misspelled.
  84       word_correct = (hunspell_->spell(word_to_check_utf8.c_str()) != 0);
  85     }
  86   }
  87
  88   return word_correct;
  89 }
  90
  91 void HunspellEngine::FillSuggestionList(
  92     const base::string16& wrong_word,
  93     std::vector<base::string16>* optional_suggestions) {
  94   std::string wrong_word_utf8(base::UTF16ToUTF8(wrong_word));
  95   if (wrong_word_utf8.length() > kMaxSuggestLen)
  96     return;
  97
  98   // If |hunspell_| is NULL here, an error has occurred, but it's better
  99   // to check rather than crash.
 100   // TODO(groby): Technically, it's not. We should track down the issue.
 101   if (!hunspell_.get())
 102     return;
 103
 104   char** suggestions = NULL;
 105   int number_of_suggestions =
 106       hunspell_->suggest(&suggestions, wrong_word_utf8.c_str());
 107
 108   // Populate the vector of WideStrings.
 109   for (int i = 0; i < number_of_suggestions; ++i) {
 110     if (i < chrome::spellcheck_common::kMaxSuggestions)
 111       optional_suggestions->push_back(base::UTF8ToUTF16(suggestions[i]));
 112     free(suggestions[i]);
 113   }
 114   if (suggestions != NULL)
 115     free(suggestions);
 116 }
 117
 118 bool HunspellEngine::InitializeIfNeeded() {
 119   if (!initialized_ && !dictionary_requested_) {
 120     // RenderThread will not exist in test.
 121     if (RenderThread::Get())
 122       RenderThread::Get()->Send(new SpellCheckHostMsg_RequestDictionary);
 123     dictionary_requested_ = true;
 124     return true;
 125   }
 126
 127   // Don't initialize if hunspell is disabled.
 128   if (file_.IsValid())
 129     InitializeHunspell();
 130
 131   return !initialized_;
 132 }
 133
 134 bool HunspellEngine::IsEnabled() {
 135   return hunspell_enabled_;
 136 }