Fix spellchecker dictionary logic.

This fixes #6.

2 files changed, 118 insertions, 185 deletions

diff --git a/editor/composer/nsEditorSpellCheck.cpp b/editor/composer/nsEditorSpellCheck.cpp
index 7cae48c1f..790480034 100644
--- a/editor/composer/nsEditorSpellCheck.cpp
+++ b/editor/composer/nsEditorSpellCheck.cpp
@@ -594,45 +594,24 @@ nsEditorSpellCheck::SetCurrentDictionary(const nsAString& aDictionary)
     // Ignore pending dictionary fetchers by increasing this number.
     mDictionaryFetcherGroup++;
 
-    uint32_t flags = 0;
-    mEditor->GetFlags(&flags);
-    if (!(flags & nsIPlaintextEditor::eEditorMailMask)) {
-      if (!aDictionary.IsEmpty() && (mPreferredLang.IsEmpty() ||
-          !mPreferredLang.Equals(aDictionary,
-                                 nsCaseInsensitiveStringComparator()))) {
-        // When user sets dictionary manually, we store this value associated
-        // with editor url, if it doesn't match the document language exactly.
-        // For example on "en" sites, we need to store "en-GB", otherwise
-        // the language might jump back to en-US although the user explicitly
-        // chose otherwise.
-        StoreCurrentDictionary(mEditor, aDictionary);
-#ifdef DEBUG_DICT
-        printf("***** Writing content preferences for |%s|\n",
-               NS_ConvertUTF16toUTF8(aDictionary).get());
-#endif
-      } else {
-        // If user sets a dictionary matching the language defined by
-        // document, we consider content pref has been canceled, and we clear it.
-        ClearCurrentDictionary(mEditor);
-#ifdef DEBUG_DICT
-        printf("***** Clearing content preferences for |%s|\n",
-               NS_ConvertUTF16toUTF8(aDictionary).get());
-#endif
-      }
-
-      // Also store it in as a preference, so we can use it as a fallback.
-      // We don't want this for mail composer because it uses
-      // "spellchecker.dictionary" as a preference.
-      Preferences::SetString("spellchecker.dictionary", aDictionary);
-#ifdef DEBUG_DICT
-      printf("***** Storing spellchecker.dictionary |%s|\n",
-             NS_ConvertUTF16toUTF8(aDictionary).get());
-#endif
+    if (mPreferredLang.IsEmpty() || 
+        !mPreferredLang.Equals(aDictionary, nsCaseInsensitiveStringComparator())) {    
+      // When user sets dictionary manually, we store this value associated
+      // with editor url, if it doesn't match the document language exactly.
+      // For example on "en" sites, we need to store "en-GB", otherwise
+      // the language might jump back to en-US although the user explicitly
+      // chose otherwise.
+      StoreCurrentDictionary(mEditor, aDictionary);
+    } else {       
+      // If user sets a dictionary matching the language defined by
+      // document, we consider content pref has been canceled, and we clear it.
+      ClearCurrentDictionary(mEditor);
     }
   }
   return mSpellChecker->SetCurrentDictionary(aDictionary);
 }
 
+
 NS_IMETHODIMP
 nsEditorSpellCheck::UninitSpellChecker()
 {
@@ -771,23 +750,16 @@ nsEditorSpellCheck::DictionaryFetched(DictionaryFetcher* aFetcher)
 
   /*
    * We try to derive the dictionary to use based on the following priorities:
-   * 1) Content preference, so the language the user set for the site before.
-   *    (Introduced in bug 678842 and corrected in bug 717433.)
-   * 2) Language set by the website, or any other dictionary that partly
-   *    matches that. (Introduced in bug 338427.)
-   *    Eg. if the website is "en-GB", a user who only has "en-US" will get
-   *    that. If the website is generic "en", the user will get one of the
-   *    "en-*" installed, (almost) at random.
-   *    However, we prefer what is stored in "spellchecker.dictionary",
-   *    so if the user chose "en-AU" before, they will get "en-AU" on a plain
-   *    "en" site. (Introduced in bug 682564.)
-   * 3) The value of "spellchecker.dictionary" which reflects a previous
-   *    language choice of the user (on another site).
-   *    (This was the original behaviour before the aforementioned bugs
-   *    landed).
-   * 4) The user's locale.
-   * 5) Use the current dictionary that is currently set.
-   * 6) The content of the "LANG" environment variable (if set).
+   * 1) Content preference: the language the user set for the site before.
+   * 2) The value of "spellchecker.dictionary.override" which reflects a 
+   *    global choice of language explicitly set by the user.
+   * 3) Language set by the website, or any other dictionary that partly matches that.
+   *    Eg. if the website is "en-GB", a user who only has "en-US" will get that.
+   *    If the website is generic "en", the user will get one of the "en-*" installed,
+   *    pretty much at random.
+   * 4) The user's locale
+   * 5) Leave the current dictionary set.
+   * 6) The content of the "LANG" environment variable (if set)
    * 7) The first spell check dictionary installed.
    */
 
@@ -795,131 +767,100 @@ nsEditorSpellCheck::DictionaryFetched(DictionaryFetcher* aFetcher)
   // https://html.spec.whatwg.org/#attr-lang
   // This is used in SetCurrentDictionary.
   mPreferredLang.Assign(aFetcher->mRootContentLang);
-#ifdef DEBUG_DICT
-  printf("***** mPreferredLang (element) |%s|\n",
-         NS_ConvertUTF16toUTF8(mPreferredLang).get());
-#endif
 
   // If no luck, try the "Content-Language" header.
   if (mPreferredLang.IsEmpty()) {
     mPreferredLang.Assign(aFetcher->mRootDocContentLang);
-#ifdef DEBUG_DICT
-    printf("***** mPreferredLang (content-language) |%s|\n",
-           NS_ConvertUTF16toUTF8(mPreferredLang).get());
-#endif
   }
-
-  // Auxiliary status.
-  nsresult rv2;
-
-  // We obtain a list of available dictionaries.
-  nsTArray<nsString> dictList;
-  rv2 = mSpellChecker->GetDictionaryList(&dictList);
-  NS_ENSURE_SUCCESS(rv2, rv2);
-
+  
   // Priority 1:
+  // Get language from content prefs, if set.
   // If we successfully fetched a dictionary from content prefs, do not go
   // further. Use this exact dictionary.
-  // Don't use content preferences for editor with eEditorMailMask flag.
   nsAutoString dictName;
-  uint32_t flags;
-  mEditor->GetFlags(&flags);
-  if (!(flags & nsIPlaintextEditor::eEditorMailMask)) {
-    dictName.Assign(aFetcher->mDictionary);
-    if (!dictName.IsEmpty()) {
-      if (NS_SUCCEEDED(TryDictionary(dictName, dictList, DICT_NORMAL_COMPARE))) {
-#ifdef DEBUG_DICT
-        printf("***** Assigned from content preferences |%s|\n",
-               NS_ConvertUTF16toUTF8(dictName).get());
-#endif
-
-        // We take an early exit here, so let's not forget to clear the word
-        // list.
-        DeleteSuggestedWordList();
-        return NS_OK;
-      }
-      // May be dictionary was uninstalled ?
-      // Clear the content preference and continue.
-      ClearCurrentDictionary(mEditor);
+  dictName.Assign(aFetcher->mDictionary);
+  if (!dictName.IsEmpty()) {
+    if (NS_SUCCEEDED(SetCurrentDictionary(dictName))) {
+      // We take an early exit here, so clear the suggested word list.
+      DeleteSuggestedWordList();
+      return NS_OK;
     }
+    // Maybe the dictionary was uninstalled ?
+    // Clear the content preference and continue.
+    ClearCurrentDictionary(mEditor);  
   }
-
+ 
   // Priority 2:
-  // After checking the content preferences, we use the language of the element
-  // or document.
-  dictName.Assign(mPreferredLang);
-#ifdef DEBUG_DICT
-  printf("***** Assigned from element/doc |%s|\n",
-         NS_ConvertUTF16toUTF8(dictName).get());
-#endif
-
-  // Get the preference value.
+  // Get global preferred language from preferences, if set.
   nsAutoString preferredDict;
-  preferredDict = Preferences::GetLocalizedString("spellchecker.dictionary");
+  preferredDict = Preferences::GetLocalizedString("spellchecker.dictionary.override");
+  if (!preferredDict.IsEmpty()) {
+    dictName.Assign(preferredDict);
+  }
 
-  // The following will be driven by this status. Once we were able to set a
+  // Priority 3:
+  // Get language from element/doc, if set.
+  if (dictName.IsEmpty() && !mPreferredLang.IsEmpty()) {
+    dictName.Assign(mPreferredLang);
+  }
+ 
+  // Auxiliary status value
+  nsresult rv2;
+ 
+  // Obtain a list of available dictionaries to check against.
+  nsTArray<nsString> dictList;
+  rv2 = mSpellChecker->GetDictionaryList(&dictList);
+  NS_ENSURE_SUCCESS(rv2, rv2);
+  int32_t i, dictCount = dictList.Length();
+  
+  // The following will be driven by this status. Once we are able to set a
   // dictionary successfully, we're done. So we start with a "failed" status.
-  nsresult rv = NS_ERROR_NOT_AVAILABLE;
-
+  nsresult rv = NS_ERROR_FAILURE;
+  
   if (!dictName.IsEmpty()) {
-    // RFC 5646 explicitly states that matches should be case-insensitive.
-    rv = TryDictionary (dictName, dictList, DICT_COMPARE_CASE_INSENSITIVE);
-
-    if (NS_FAILED(rv)) {
-#ifdef DEBUG_DICT
-      printf("***** Setting of |%s| failed (or it wasn't available)\n",
-             NS_ConvertUTF16toUTF8(dictName).get());
-#endif
+    for (i = 0; i < dictCount; i++) {
+      nsAutoString dictStr(dictList.ElementAt(i));
+      if (dictName.Equals(dictStr, nsCaseInsensitiveStringComparator())) {
+        // First let's correct any problems due to non-matching case.
+        // This applies to both a user-set override and document language.
+        // RFC 5646 explicitly states that matches should be case-insensitive.
+        dictName.Assign(dictStr);
+        // Try to set it. Doing this inside this loop avoids trying to set a
+        // dictionary that isn't available.
+        rv = SetCurrentDictionary(dictName);
+        break;
+      }
+    }
 
+    if (NS_FAILED(rv)) {      
       // Required dictionary was not available. Try to get a dictionary
-      // matching at least language part of dictName.
+      // matching at least the language part of dictName:
       nsAutoString langCode;
       int32_t dashIdx = dictName.FindChar('-');
-      if (dashIdx != -1) {
+      if (dashIdx != -1) { 
         langCode.Assign(Substring(dictName, 0, dashIdx));
       } else {
         langCode.Assign(dictName);
       }
 
-      // Try dictionary.spellchecker preference, if it starts with langCode,
-      // so we don't just get any random dictionary matching the language.
-      if (!preferredDict.IsEmpty() &&
-          nsStyleUtil::DashMatchCompare(preferredDict, langCode, nsDefaultStringComparator())) {
-#ifdef DEBUG_DICT
-        printf("***** Trying preference value |%s| since it matches language code\n",
-               NS_ConvertUTF16toUTF8(preferredDict).get());
-#endif
-        rv = TryDictionary (preferredDict, dictList,
-                            DICT_COMPARE_CASE_INSENSITIVE);
-      }
+      nsDefaultStringComparator comparator;
 
-      if (NS_FAILED(rv)) {
-        // Use any dictionary with the required language.
-#ifdef DEBUG_DICT
-        printf("***** Trying to find match for language code |%s|\n",
-               NS_ConvertUTF16toUTF8(langCode).get());
-#endif
-        rv = TryDictionary (langCode, dictList, DICT_COMPARE_DASHMATCH);
+      // Loop over available dictionaries; if we find one with the required
+      // language, use it.
+      for (i = 0; i < dictCount; i++) {
+        nsAutoString dictStr(dictList.ElementAt(i));
+        if (nsStyleUtil::DashMatchCompare(dictStr, langCode, comparator) &&
+            NS_SUCCEEDED(rv = SetCurrentDictionary(dictStr))) {
+          break;
+        }
       }
     }
   }
-
-  // Priority 3:
-  // If the document didn't supply a dictionary or the setting failed,
-  // try the user preference next.
-  if (NS_FAILED(rv)) {
-    if (!preferredDict.IsEmpty()) {
-#ifdef DEBUG_DICT
-      printf("***** Trying preference value |%s|\n",
-             NS_ConvertUTF16toUTF8(preferredDict).get());
-#endif
-      rv = TryDictionary (preferredDict, dictList, DICT_NORMAL_COMPARE);
-    }
-  }
-
+  
   // Priority 4:
-  // As next fallback, try the current locale.
-  if (NS_FAILED(rv)) {
+  // Content prefs, override and document didn't give us a valid dictionary
+  // name, so we just get the current locale and try to use that.
+  if (NS_FAILED (rv)) {
     nsCOMPtr<nsIXULChromeRegistry> packageRegistry =
       mozilla::services::GetXULChromeRegistryService();
 
@@ -929,69 +870,57 @@ nsEditorSpellCheck::DictionaryFetched(DictionaryFetcher* aFetcher)
                                                false, utf8DictName);
       dictName.Assign(EmptyString());
       AppendUTF8toUTF16(utf8DictName, dictName);
-#ifdef DEBUG_DICT
-      printf("***** Trying locale |%s|\n",
-             NS_ConvertUTF16toUTF8(dictName).get());
-#endif
-      rv = TryDictionary (dictName, dictList, DICT_COMPARE_CASE_INSENSITIVE);
+      // Try to set it, if it's in the list.
+      for (i = 0; i < dictCount; i++) {
+        nsAutoString dictStr(dictList.ElementAt(i));
+        if (dictStr.Equals(dictName)) {
+          rv = SetCurrentDictionary(dictName);
+          break;
+        }
+      }
     }
   }
-
+   
   if (NS_FAILED(rv)) {
-  // Still no success.
+    // Still no success. Further fallback attempts required.
 
-  // Priority 5:
-  // If we have a current dictionary, don't try anything else.
+    // Priority 5:
+    // If we have a current dictionary, don't try anything else.  
     nsAutoString currentDictionary;
     rv2 = GetCurrentDictionary(currentDictionary);
-#ifdef DEBUG_DICT
-    if (NS_SUCCEEDED(rv2)) {
-        printf("***** Retrieved current dict |%s|\n",
-               NS_ConvertUTF16toUTF8(currentDictionary).get());
-    }
-#endif
-
+       
     if (NS_FAILED(rv2) || currentDictionary.IsEmpty()) {
+      // We don't have a current dictionary.
       // Priority 6:
       // Try to get current dictionary from environment variable LANG.
-      // LANG = language[_territory][.charset]
+      // LANG = language[_territory][.codeset]
       char* env_lang = getenv("LANG");
-      if (env_lang) {
+      if (env_lang != nullptr) {
         nsString lang = NS_ConvertUTF8toUTF16(env_lang);
+      
         // Strip trailing charset, if there is any.
         int32_t dot_pos = lang.FindChar('.');
         if (dot_pos != -1) {
           lang = Substring(lang, 0, dot_pos);
         }
-
+      
+        // Convert underscore to dash.
         int32_t underScore = lang.FindChar('_');
         if (underScore != -1) {
           lang.Replace(underScore, 1, '-');
-#ifdef DEBUG_DICT
-          printf("***** Trying LANG from environment |%s|\n",
-                 NS_ConvertUTF16toUTF8(lang).get());
-#endif
-          nsAutoString lang2;
-          lang2.Assign(lang);
-          rv = TryDictionary(lang2, dictList, DICT_COMPARE_CASE_INSENSITIVE);
+          // Only attempt to set if a _territory is present.
+          rv = SetCurrentDictionary(lang);
         }
       }
-
+    
       // Priority 7:
-      // If it does not work, pick the first one.
-      if (NS_FAILED(rv) && !dictList.IsEmpty()) {
-        nsAutoString firstInList;
-        firstInList.Assign(dictList[0]);
-        rv = TryDictionary(firstInList, dictList, DICT_NORMAL_COMPARE);
-#ifdef DEBUG_DICT
-        printf("***** Trying first of list |%s|\n",
-               NS_ConvertUTF16toUTF8(dictList[0]).get());
-        if (NS_SUCCEEDED(rv)) {
-          printf ("***** Setting worked.\n");
+      // If LANG does not work either, pick the first one.
+      if (NS_FAILED(rv)) {
+        if (dictList.Length() > 0) {
+          rv = SetCurrentDictionary(dictList[0]);
         }
-#endif
       }
-    }
+    } 
   }
 
   // If an error was thrown while setting the dictionary, just
@@ -999,6 +928,7 @@ nsEditorSpellCheck::DictionaryFetched(DictionaryFetcher* aFetcher)
   // up. The user can manually reset the language to their choice on
   // the dialog if it is wrong.
 
+  // Dictionary has changed, so delete the suggested word list.
   DeleteSuggestedWordList();
 
   return NS_OK;
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 67c632e71..62aedead2 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1117,6 +1117,9 @@ pref("print.print_via_parent", false);
 // in a document.
 pref("extensions.spellcheck.inline.max-misspellings", 500);
 
+// Predefined convenience pref for overriding the dictionary
+pref("spellchecker.dictionary.override", "");
+
 // Prefs used by libeditor. Prefs specific to seamonkey composer
 // belong in comm-central/editor/ui/composer.js