1 files changed, 186 insertions, 0 deletions
diff --git a/uriloader/exthandler/tests/unit/test_getTypeFromExtension_with_empty_Content_Type.js b/uriloader/exthandler/tests/unit/test_getTypeFromExtension_with_empty_Content_Type.js
new file mode 100644
index 000000000..1ae2a6fcf
--- /dev/null
+++ b/uriloader/exthandler/tests/unit/test_getTypeFromExtension_with_empty_Content_Type.js
@@ -0,0 +1,186 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Test for bug 484579 <https://bugzilla.mozilla.org/show_bug.cgi?id=484579>:
+ * nsIMIMEService.getTypeFromExtension may fail unexpectedly on Windows when
+ * "Content Type" is empty in the registry.
+ */
+function run_test() {
+  // --- Preliminary platform check ---
+
+  // If this test is not running on the Windows platform, stop now, before
+  // calling XPCOMUtils.generateQI during the MockWindowsRegKey declaration.
+  if (mozinfo.os != "win")
+    return;
+
+  // --- Modified nsIWindowsRegKey implementation ---
+
+  Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+
+  /**
+   * Constructs a new mock registry key by wrapping the provided object.
+   *
+   * This mock implementation is tailored for this test, and forces consumers
+   * of the readStringValue method to believe that the "Content Type" value of
+   * the ".txt" key under HKEY_CLASSES_ROOT is an empty string.
+   *
+   * The same value read from "HKEY_LOCAL_MACHINE\SOFTWARE\Classes" is not
+   * affected.
+   *
+   * @param aWrappedObject   An actual nsIWindowsRegKey implementation.
+   */
+  function MockWindowsRegKey(aWrappedObject) {
+    this._wrappedObject = aWrappedObject;
+
+    // This function creates a forwarding function for wrappedObject
+    function makeForwardingFunction(functionName) {
+      return function() {
+        return aWrappedObject[functionName].apply(aWrappedObject, arguments);
+      }
+    }
+
+    // Forward all the functions that are not explicitly overridden
+    for (var propertyName in aWrappedObject) {
+      if (!(propertyName in this)) {
+        if (typeof aWrappedObject[propertyName] == "function") {
+          this[propertyName] = makeForwardingFunction(propertyName);
+        } else {
+          this[propertyName] = aWrappedObject[propertyName];
+        }
+      }
+    }
+  }
+
+  MockWindowsRegKey.prototype = {
+    // --- Overridden nsISupports interface functions ---
+
+    QueryInterface: XPCOMUtils.generateQI([Ci.nsIWindowsRegKey]),
+
+    // --- Overridden nsIWindowsRegKey interface functions ---
+
+    open: function(aRootKey, aRelPath, aMode) {
+      // Remember the provided root key and path
+      this._rootKey = aRootKey;
+      this._relPath = aRelPath;
+
+      // Create the actual registry key
+      return this._wrappedObject.open(aRootKey, aRelPath, aMode);
+    },
+
+    openChild: function(aRelPath, aMode) {
+      // Open the child key and wrap it
+      var innerKey = this._wrappedObject.openChild(aRelPath, aMode);
+      var key = new MockWindowsRegKey(innerKey);
+
+      // Set the properties of the child key and return it
+      key._rootKey = this._rootKey;
+      key._relPath = this._relPath + aRelPath;
+      return key;
+    },
+
+    createChild: function(aRelPath, aMode) {
+      // Create the child key and wrap it
+      var innerKey = this._wrappedObject.createChild(aRelPath, aMode);
+      var key = new MockWindowsRegKey(innerKey);
+
+      // Set the properties of the child key and return it
+      key._rootKey = this._rootKey;
+      key._relPath = this._relPath + aRelPath;
+      return key;
+    },
+
+    get childCount() {
+      return this._wrappedObject.childCount;
+    },
+
+    get valueCount() {
+      return this._wrappedObject.valueCount;
+    },
+
+    readStringValue: function(aName) {
+      // If this is the key under test, return a fake value
+      if (this._rootKey == Ci.nsIWindowsRegKey.ROOT_KEY_CLASSES_ROOT &&
+          this._relPath.toLowerCase() == ".txt" &&
+          aName.toLowerCase() == "content type") {
+        return "";
+      }
+
+      // Return the real value in the registry
+      return this._wrappedObject.readStringValue(aName);
+    }
+  };
+
+  // --- Mock nsIWindowsRegKey factory ---
+
+  var componentRegistrar = Components.manager.
+                           QueryInterface(Ci.nsIComponentRegistrar);
+
+  var originalWindowsRegKeyCID;
+  var mockWindowsRegKeyFactory;
+
+  const kMockCID = Components.ID("{9b23dfe9-296b-4740-ba1c-d39c9a16e55e}");
+  const kWindowsRegKeyContractID = "@mozilla.org/windows-registry-key;1";
+  const kWindowsRegKeyClassName = "nsWindowsRegKey";
+
+  function registerMockWindowsRegKeyFactory() {
+    mockWindowsRegKeyFactory = {
+      createInstance: function(aOuter, aIid) {
+        if (aOuter != null)
+          throw Cr.NS_ERROR_NO_AGGREGATION;
+
+        var innerKey = originalWindowsRegKeyFactory.createInstance(null, aIid);
+        var key = new MockWindowsRegKey(innerKey);
+
+        return key.QueryInterface(aIid);
+      }
+    };
+
+    // Preserve the original factory
+    originalWindowsRegKeyCID = Cc[kWindowsRegKeyContractID].number;
+
+    // Register the mock factory
+    componentRegistrar.registerFactory(
+      kMockCID,
+      "Mock Windows Registry Key Implementation",
+      kWindowsRegKeyContractID,
+      mockWindowsRegKeyFactory
+    );
+  }
+
+  function unregisterMockWindowsRegKeyFactory() {
+    // Free references to the mock factory
+    componentRegistrar.unregisterFactory(
+      kMockCID,
+      mockWindowsRegKeyFactory
+    );
+
+    // Restore the original factory
+    componentRegistrar.registerFactory(
+      Components.ID(originalWindowsRegKeyCID),
+      "",
+      kWindowsRegKeyContractID,
+      null
+    );
+  }
+
+  // --- Test procedure ---
+
+  // Activate the override of the ".txt" file association data in the registry
+  registerMockWindowsRegKeyFactory();
+  try {
+    // Try and get the MIME type associated with the extension. If this
+    // operation does not throw an unexpected exception, the test succeeds.
+    var type = Cc["@mozilla.org/mime;1"].
+               getService(Ci.nsIMIMEService).
+               getTypeFromExtension(".txt");
+  } catch (e if (e instanceof Ci.nsIException &&
+                 e.result == Cr.NS_ERROR_NOT_AVAILABLE)) {
+    // This is an expected exception, thrown if the type can't be determined
+  } finally {
+    // Ensure we restore the original factory when the test is finished
+    unregisterMockWindowsRegKeyFactory();
+  }
+}