gecko/toolkit/content/tests/browser/common/toolkitFunctions.js

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 *
 * The contents of this file are subject to the Mozilla Public License Version
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 * the License. You may obtain a copy of the License at
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 *
 * Software distributed under the License is distributed on an "AS IS" basis,
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 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla XUL Toolkit Testing Code.
 *
 * The Initial Developer of the Original Code is
 * Paolo Amadini <http://www.amadzone.org/>.
 * Portions created by the Initial Developer are Copyright (C) 2009
 * the Initial Developer. All Rights Reserved.
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 *
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/**
 * Provides a temporary save directory.
 *
 * @return
 *        nsIFile pointing to the new or existing directory.
 */
function createTemporarySaveDirectory() {
  var saveDir = Cc["@mozilla.org/file/directory_service;1"].
                getService(Ci.nsIProperties).get("TmpD", Ci.nsIFile);
  saveDir.append("testsavedir");
  if (!saveDir.exists())
    saveDir.create(Ci.nsIFile.DIRECTORY_TYPE, 0755);
  return saveDir;
}

/**
 * Calls the provided save function while replacing the file picker component
 * with a mock implementation that returns a temporary file path and custom
 * filters, and the download component with an implementation that does not
 * depend on the download manager.
 *
 * @param aSaveFunction
 *        The function to call. This is usually the subject of the entire test
 *        being run.
 */
function callSaveWithMockObjects(aSaveFunction) {
  // Call the provided function while the mock object factories are in place and
  // ensure that, even in case of exceptions during the function's execution,
  // the mock object factories are unregistered before proceeding with the other
  // tests in the suite.
  mockFilePickerRegisterer.register();
  try {
    mockTransferForContinuingRegisterer.register();
    try {
      aSaveFunction();
    }
    finally {
      mockTransferForContinuingRegisterer.unregister();
    }
  }
  finally {
    mockFilePickerRegisterer.unregister();
  }
}

/**
 * Reads the contents of the provided short file (up to 1 MiB).
 *
 * @param aFile
 *        nsIFile object pointing to the file to be read.
 *
 * @return
 *        String containing the raw octets read from the file.
 */
function readShortFile(aFile) {
  var inputStream = Cc["@mozilla.org/network/file-input-stream;1"].
                    createInstance(Ci.nsIFileInputStream);
  inputStream.init(aFile, -1, 0, 0);
  try {
    var scrInputStream = Cc["@mozilla.org/scriptableinputstream;1"].
                         createInstance(Ci.nsIScriptableInputStream);
    scrInputStream.init(inputStream);
    try {
      // Assume that the file is much shorter than 1 MiB.
      return scrInputStream.read(1048576);
    }
    finally {
      // Close the scriptable stream after reading, even if the operation
      // failed.
      scrInputStream.close();
    }
  }
  finally {
    // Close the stream after reading, if it is still open, even if the read
    // operation failed.
    inputStream.close();
  }
}