Remove duplicate words from custom spelling dictionary on load

chrome/browser/spellchecker/spellcheck_custom_dictionary.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/browser/spellchecker/spellcheck_custom_dictionary.h"
 
 #include <functional>
 
 #include "base/file_util.h"
 #include "base/string_split.h"
@@ skipping 39 matching lines @@
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 
   std::string contents;
   file_util::ReadFileToString(custom_dictionary_path_, &contents);
   if (contents.empty()) {
     custom_words->clear();
     return;
   }
 
   base::SplitString(contents, '\n', custom_words);
+
+  // Erase duplicates.
+  std::sort(custom_words->begin(), custom_words->end());
+  custom_words->erase(std::unique(custom_words->begin(), custom_words->end()),
+                      custom_words->end());
+
   // Clear out empty words.
   custom_words->erase(remove_if(custom_words->begin(), custom_words->end(),
     mem_fun_ref(&std::string::empty)), custom_words->end());
+
+  // Write out the clean file.
+  std::stringstream ss;
+  for (WordList::iterator it = custom_words->begin();
+       it != custom_words->end();
+       ++it) {
+    ss << *it << '\n';
+  }
+  contents = ss.str();
+  file_util::WriteFile(custom_dictionary_path_,
+                       contents.c_str(),
+                       contents.length());
 }
 
 void SpellcheckCustomDictionary::SetCustomWordList(WordList* custom_words) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   words_.clear();
   if (custom_words)
     std::swap(words_, *custom_words);
 
   std::vector<Observer*>::iterator it;
@@ skipping 90 matching lines @@
 }
 
 void SpellcheckCustomDictionary::EraseWordFromCustomDictionary(
     const std::string& word) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   DCHECK(IsStringUTF8(word));
 
   WordList custom_words;
   LoadDictionaryIntoCustomWordList(&custom_words);
 
-  char empty[] = {'\0'};
-  char separator[] = {'\n', '\0'};
+  const char empty[] = {'\0'};
+  const char separator[] = {'\n', '\0'};
   file_util::WriteFile(custom_dictionary_path_, empty, 0);
   for (WordList::iterator it = custom_words.begin();
       it != custom_words.end();
       ++it) {
     std::string word_to_add = *it;
     if (word.compare(word_to_add) != 0) {
       file_util::AppendToFile(custom_dictionary_path_, word_to_add.c_str(),
           word_to_add.length());
       file_util::AppendToFile(custom_dictionary_path_, separator, 1);
     }
@@ skipping 24 matching lines @@
   return custom_words;
 }
 
 void SpellcheckCustomDictionary::SetCustomWordListAndDelete(
     WordList* custom_words) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   SetCustomWordList(custom_words);
   delete custom_words;
 }