Improve reliability of custom spelling dictionary file.

chrome/browser/spellchecker/spellcheck_custom_dictionary.h

 // 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.
 
 #ifndef CHROME_BROWSER_SPELLCHECKER_SPELLCHECK_CUSTOM_DICTIONARY_H_
 #define CHROME_BROWSER_SPELLCHECKER_SPELLCHECK_CUSTOM_DICTIONARY_H_
 
 #include <string>
 #include <vector>
 
 #include "base/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/observer_list.h"
 #include "chrome/browser/spellchecker/spellcheck_dictionary.h"
 #include "chrome/common/spellcheck_common.h"
 
 // Defines a custom dictionary which users can add their own words to.
 class SpellcheckCustomDictionary : public SpellcheckDictionary {
  public:
   class Observer {
    public:
     virtual void OnCustomDictionaryLoaded() = 0;
     virtual void OnCustomDictionaryWordAdded(const std::string& word) = 0;
@@ skipping 44 matching lines @@
   // The caller owns this new list.
   chrome::spellcheck_common::WordList* LoadDictionary();
 
   // The reply point for PostTaskAndReplyWithResult. Called when LoadDictionary
   // is finished reading words from custom dictionary file. Moves the strings
   // from the |custom_words| argument into the private member variable |words_|
   // and deletes the memory at |custom_words|.
   void SetCustomWordListAndDelete(
       chrome::spellcheck_common::WordList* custom_words);
 
+  // Loads the dictionary file into |custom_words|. If the dictionary checksum
+  // is not valid, but backup checksum is valid, then restores the backup and
+  // loads that into |custom_words| instead.

[groby-ooo-7-16, 2012/12/05 00:56:19]

"If the backup is invalid too, |custom_words| will be cleared"

[please use gerrit instead, 2012/12/05 16:51:26]

Done.

+  void LoadDictionaryFileReliably(
+      chrome::spellcheck_common::WordList* custom_words);
+
+  // Backs up the original dictionary and checksum files, saves |custom_words|

[groby-ooo-7-16, 2012/12/05 00:56:19]

- "and checksum files"

[please use gerrit instead, 2012/12/05 16:51:26]

Done.

+  // and its checksum into the dictionary file.
+  void SaveDictionaryFileReliably(
+      const chrome::spellcheck_common::WordList& custom_words);
+
+  // Extracts the checksum out of |contents| and truncates |contents| to exclude
+  // the checksum line. Returns an empty string if |contents| do not contain a
+  // checksum.
+  std::string GetChecksum(std::string* contents);
+
   // In-memory cache of the custom words file.
   chrome::spellcheck_common::WordList words_;
 
   // A path for custom dictionary per profile.
   FilePath custom_dictionary_path_;
 
   base::WeakPtrFactory<SpellcheckCustomDictionary> weak_ptr_factory_;
 
-  std::vector<Observer*> observers_;
+  ObserverList<Observer> observers_;
+
+  const FilePath::StringType backup_extension_;
+  const std::string checksum_prefix_;

[groby-ooo-7-16, 2012/12/05 00:56:19]

Why a member? It never changes its value, and it's only used in one function?

I'd suggest a constant in anon namespace and creating the string on the fly in
GetChecksum

(Ditto for backup_extension_)

[please use gerrit instead, 2012/12/05 16:51:26]

Done.

 
   DISALLOW_COPY_AND_ASSIGN(SpellcheckCustomDictionary);
 };
 
 #endif  // CHROME_BROWSER_SPELLCHECKER_SPELLCHECK_CUSTOM_DICTIONARY_H_