Made Language.addFileExtension public, added a languageModified event…

…, made DocumentManager update document's languages as necessary

src/document/DocumentManager.js

@@ -1215,7 +1215,26 @@ define(function (require, exports, module) {
      */
     function _handleLanguageAdded(event, language) {
         CollectionUtils.forEach(_openDocuments, function (doc, key) {
-            doc._updateLanguage();
+            // No need to look at the new language if this document has one already
+            if (doc.getLanguage().isFallbackLanguage()) {
+                doc._updateLanguage();
+            }
+        });
+    }
+
+    /**
+     * @private
+     * Update document
+     */
+    function _handleLanguageModified(event, language) {
+        CollectionUtils.forEach(_openDocuments, function (doc, key) {
+            var docLanguage = doc.getLanguage();
+            // A modified language can affect a document
+            // - if its language was modified
+            // - if the document doesn't have a language yet and its file extension was added to the modified language
+            if (docLanguage === language || docLanguage.isFallbackLanguage()) {
+                doc._updateLanguage();
+            }
         });
     }
 
@@ -1255,4 +1274,5 @@ define(function (require, exports, module) {
 
     // Handle Language change events
     $(LanguageManager).on("languageAdded", _handleLanguageAdded);
+    $(LanguageManager).on("languageModified", _handleLanguageModified);
 });

src/language/LanguageManager.js

@@ -209,6 +209,27 @@ define(function (require, exports, module) {
         return _fallbackLanguage;
     }
 
+    /**
+     * @private
+     * Notify listeners when a language is added
+     * @param {!Language} language The new language
+     */
+    function _triggerLanguageAdded(language) {
+        // finally, store language to _language map
+        _languages[language.getId()] = language;
+        $(exports).triggerHandler("languageAdded", [language]);
+    }
+
+    /**
+     * @private
+     * Notify listeners when a language is modified
+     * @param {!Language} language The modified language
+     */
+    function _triggerLanguageModified(language) {
+        $(exports).triggerHandler("languageModified", [language]);
+    }
+
+
     /**
      * @constructor
      * Model for a language.
@@ -357,9 +378,8 @@ define(function (require, exports, module) {
      * Private for now since dependent code would need to by kept in sync with such changes.
      * See https://github.com/adobe/brackets/issues/2966 for plans to make this public.
      * @param {!string} extension A file extension used by this language
-     * @private
      */
-    Language.prototype._addFileExtension = function (extension) {
+    Language.prototype.addFileExtension = function (extension) {
         extension = _normalizeFileExtension(extension);
 
         if (this._fileExtensions.indexOf(extension) === -1) {
@@ -376,6 +396,8 @@ define(function (require, exports, module) {
                 // $(this).triggerHandler("fileExtensionAdded", [extension]);
                 // $(exports).triggerHandler("fileExtensionAdded", [extension, this]);
             }
+
+            this._wasModified();
         }
     };
 
@@ -468,17 +490,25 @@ define(function (require, exports, module) {
         }
         this._modeToLanguageMap[mode] = language;
     };
+
+    /**
+     * Determines whether this is the fallback language or not
+     * @return {boolean} True if this is the fallback language, false otherwise
+     */
+    Language.prototype.isFallbackLanguage = function () {
+        return this === _fallbackLanguage;
+    };
 
     /**
+     * Trigger the "languageModified" event if this language is registered already
+     * @see _triggerLanguageModified
      * @private
-     * Notify listeners when a language is added
-     * @param {!Language} language The new language
      */
-    function _triggerLanguageAdded(language) {
-        // finally, store language to _language map
-        _languages[language.getId()] = language;
-        $(exports).triggerHandler("languageAdded", [language]);
-    }
+    Language.prototype._wasModified = function () {
+        if (_languages[this._id]) {
+            _triggerLanguageModified(this);
+        }
+    };
 
     /**
      * Defines a language.
@@ -523,7 +553,7 @@ define(function (require, exports, module) {
             // register language file extensions after mode has loaded
             if (fileExtensions) {
                 for (i = 0; i < fileExtensions.length; i++) {
-                    language._addFileExtension(fileExtensions[i]);
+                    language.addFileExtension(fileExtensions[i]);
                 }
             }
 

test/spec/LanguageManager-test.js

@@ -404,6 +404,46 @@ define(function (require, exports, module) {
                 });
             });
 
+            it("should update the document's language when a language is modified", function () {
+                var unknown,
+                    doc,
+                    spy,
+                    modifiedLanguage,
+                    promise;
+
+                runs(function () {
+                    // Create a shell script file
+                    doc = SpecRunnerUtils.createMockActiveDocument({ filename: "test.foo" });
+
+                    // Initial language will be unknown (shell is not a default language)
+                    unknown = LanguageManager.getLanguage("unknown");
+
+                    // listen for event
+                    spy = jasmine.createSpy("languageChanged event handler");
+                    $(doc).on("languageChanged", spy);
+
+                    // sanity check language
+                    expect(doc.getLanguage()).toBe(unknown);
+
+                    // make active
+                    doc.addRef();
+
+                    modifiedLanguage = LanguageManager.getLanguage("html");
+                    modifiedLanguage.addFileExtension("foo");
+
+                    // language should change
+                    expect(doc.getLanguage()).toBe(modifiedLanguage);
+                    expect(spy).toHaveBeenCalled();
+                    expect(spy.callCount).toEqual(1);
+
+                    // check callback args (arg 0 is a jQuery event)
+                    expect(spy.mostRecentCall.args[1]).toBe(unknown);
+                    expect(spy.mostRecentCall.args[2]).toBe(modifiedLanguage);
+
+                    // cleanup
+                    doc.releaseRef();
+                });
+            });
         });
     });
 });