/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: NPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Netscape Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code.
 *
 * The Initial Developer of the Original Code is 
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 * Brian Nesse <bnesse@netscape.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or 
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the NPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the NPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsSafeSaveFile.h"

nsresult nsSafeSaveFile::Init(nsIFile *aTargetFile, nsIFile **aTempFile)
{
  NS_ASSERTION(aTargetFile, "null pointer");
  NS_ASSERTION(aTempFile, "null pointer");
  *aTempFile = nsnull;
  
  nsresult rv;
  
  rv = aTargetFile->Exists(&mTargetFileExists);
  if (NS_FAILED(rv)) {
    NS_ERROR("Can't tell if target file exists");
    mTargetFileExists = PR_TRUE; // Safer to assume it exists - we just do more work.
  }
  
  nsCOMPtr<nsIFile> tempResult;
  rv = aTargetFile->Clone(getter_AddRefs(tempResult));
  if (NS_SUCCEEDED(rv) && mTargetFileExists) {
    PRUint32 perm;
    if (NS_FAILED(aTargetFile->GetPermissions(&perm))) {
      NS_ERROR("Can't get permissions of target file");
      perm = 0700;
    }
    rv = tempResult->CreateUnique(nsIFile::NORMAL_FILE_TYPE, perm);
  }
  if (NS_SUCCEEDED(rv)) {
    NS_ADDREF(*aTempFile = tempResult);
    mTargetFile = aTargetFile;
    mTempFile = tempResult;
  }
  return rv;  
}

nsresult nsSafeSaveFile::OnSaveFinished(PRBool aSaveSucceeded, PRBool aBackupTarget)
{
  nsresult rv = NS_OK;
  
  if (aSaveSucceeded) {
    NS_ENSURE_STATE(mTargetFile && mTempFile);

    if (!mTargetFileExists) {
      // If the target file did not exist when we were initialized, then the
      // temp file we gave out was actually a reference to the target file.
      // since we succeeded in writing to the temp file (and hence succeeded
      // in writing to the target file), there is nothing more to do.
#ifdef DEBUG      
      PRBool equal;
      if (NS_FAILED(mTargetFile->Equals(mTempFile, &equal)) || !equal)
        NS_ERROR("mTempFile not equal to mTargetFile");
#endif
      return NS_OK;      
    }

    nsCAutoString targetFilename;
    rv = mTargetFile->GetNativeLeafName(targetFilename);
    
    if (aBackupTarget) {
      // Create a copy of the target before we overwrite it
      nsCAutoString backupFilename(targetFilename);
      PRInt32 pos = backupFilename.RFindChar('.');
      if (pos != -1)
        backupFilename.Truncate(pos);
      backupFilename.Append(NS_LITERAL_CSTRING(".bak"));
      
      // Find a unique name for the backup by using CreateUnique
      nsCOMPtr<nsIFile> uniqueFile;
      rv = mTargetFile->Clone(getter_AddRefs(uniqueFile));
      if (NS_SUCCEEDED(rv)) {
        rv = uniqueFile->SetNativeLeafName(backupFilename);
        if (NS_SUCCEEDED(rv)) {
          rv = uniqueFile->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0600);
          if (NS_SUCCEEDED(rv)) {
            uniqueFile->GetNativeLeafName(backupFilename);
            uniqueFile->Remove(PR_FALSE);
            // Finally, move the target to the backup
            mTargetFile->MoveToNative(nsnull, backupFilename);
          }
        }
      }
    }
    
    if (NS_SUCCEEDED(rv))
        rv = mTempFile->MoveToNative(nsnull, targetFilename); // This will replace target
  }
  else {
    NS_ENSURE_STATE(mTempFile);
    rv = mTempFile->Remove(PR_FALSE);
  }
  return rv;
}
