/// <summary>
/// Will create an DocumentStream backed by a tempoary file.
/// </summary>
/// <remarks>
/// We prefer to create the temporary file in the same location as the
/// source to inherit the folders attributes and security.
///
/// If we can not we will use a system generated file.
/// </remarks>
/// <param name="copyoriginal">When true we will copy the source file if
/// possible. You must check for a non-zero result on the returning stream
/// to determin success.</param>
/// <returns>An DocumentStream.</returns>
internal DocumentStream CreateTemporary(bool copyOriginal)
{
CriticalFileToken tempToken = null;
DocumentStream result = null;
FileStream temporary = null;
bool isFileSource = (_xpsFileToken != null);
//----------------------------------------------------------------------
// Open File in Same Location (if possible)
if (isFileSource)
{
MakeTempFile(true, out temporary, out tempToken);
}
//----------------------------------------------------------------------
// Open File in System Generated Location
if (tempToken == null)
{
// TODO: Should we prompt user asking if it is okay in the case
// where the source is a local file, as it may mean degraded
// security? We could check if this would be the case by
// comparing ACLs & attributes before prompting
MakeTempFile(false, out temporary, out tempToken);
}
//----------------------------------------------------------------------
// File Was Opened
if ((temporary != null) && (tempToken != null))
{
//------------------------------------------------------------------
// Copy Data
if (copyOriginal)
{
// We use a native File.Copy if possible because this is
// most performant. This is only possible if the source is file
// based.
if (isFileSource)
{
string sourcePath = _xpsFileToken.Location.LocalPath;
string tempPath = tempToken.Location.LocalPath;
temporary.Close();
File.Copy(sourcePath, tempPath, true);
temporary = new FileStream(
tempPath,
FileMode.Open,
FileAccess.ReadWrite,
FileShare.None);
// we did the copy
copyOriginal = false;
Trace.SafeWrite(Trace.File, "Performed a file copy from source.");
}
else
{
StreamHelper.CopyStream(
this, temporary);
Trace.SafeWrite(Trace.File, "Performed a stream copy from source.");
}
}
//------------------------------------------------------------------
// Create the DocumentStream
result = new DocumentStream(
tempToken, temporary, this);
result.DeleteOnClose = true;
Trace.SafeWrite(Trace.File, "Created temporary file {0}.", tempToken.Location);
}
else
{
// rescind consent if any was given
tempToken = null;
Trace.SafeWrite(Trace.File, "Unable to create a temporary file. Caller is expected to disable edits.");
}
return(result);
}
//--------------------------------------------------------------------------
// Internal Methods
//--------------------------------------------------------------------------
/// <summary>
/// Will create an XpsDocument by copying this one to a target file and
/// returning a stream corresponding to the new file.
/// </summary>
/// <exception cref="System.ArgumentNullException"/>
/// <exception cref="System.IO.InvalidDataException"/>
/// <param name="copiesToken">The token for the target file.</param>
/// <returns>An DocumentStream.</returns>
internal DocumentStream Copy(CriticalFileToken copiesToken)
{
DocumentStream result;
FileStream target = null;
bool isFileSource = (_xpsFileToken != null);
Invariant.Assert(copiesToken != null, "No target file to which to copy.");
ThrowIfInvalidXpsFileForSave(copiesToken.Location);
string sourcePath = string.Empty;
string copiesPath = copiesToken.Location.LocalPath;
// if the source is a file, we need to release our lock on the source
// file and also assert for permissions to read the file
if (isFileSource)
{
Target.Close();
sourcePath = _xpsFileToken.Location.LocalPath;
}
try
{
// if the source is a file, file copy is the fastest
if (isFileSource)
{
File.Copy(sourcePath, copiesPath, true);
// If the original file was marked read-only, the copy will be read-only as
// well. However, the copy is done for the purpose of creating a new file,
// so it should not be marked read-only.
FileAttributes attrib = File.GetAttributes(copiesPath);
if ((attrib & FileAttributes.ReadOnly) == FileAttributes.ReadOnly)
{
File.SetAttributes(copiesPath, attrib ^ FileAttributes.ReadOnly);
}
// open the destination file that was just created by File.Copy
target = new FileStream(
copiesPath,
FileMode.Open,
FileAccess.ReadWrite,
FileShare.None);
}
else
{
// open the destination file for create; we will copy the
// source stream's data to the new stream outside the assert
target = new FileStream(
copiesPath,
FileMode.Create,
FileAccess.ReadWrite,
FileShare.None);
}
}
// Since we have already closed the original file, we need to reopen it if we
// fail to copy the file or open the new file. After doing so, we rethrow the
// original exception so it can be handled at a higher level.
#pragma warning suppress 56500 // suppress PreSharp Warning 56500: Avoid `swallowing errors by catching non-specific exceptions..
catch
{
if (isFileSource)
{
Trace.SafeWrite(
Trace.File,
"File copy failed -- reopening original file.");
try
{
Target = new FileStream(
sourcePath,
FileMode.Open,
FileAccess.Read,
FileShare.Read);
}
// If we fail to reopen the original file, rethrow an exception to
// indicate this specific error.
#pragma warning suppress 56500 // suppress PreSharp Warning 56500: Avoid `swallowing errors by catching non-specific exceptions..
catch (Exception e)
{
Trace.SafeWrite(
Trace.File,
"Unable to reopen original file.");
throw new UnauthorizedAccessException(
SR.Get(SRID.DocumentStreamCanNoLongerOpen), e);
}
}
throw;
}
if (isFileSource)
{
Trace.SafeWrite(Trace.File, "Performed a file copy from source.");
// reacquire our stream
ReOpenWriteable();
}
else
{
// if the source wasn't a file, we want to copy the stream now
StreamHelper.CopyStream(this, target);
Trace.SafeWrite(Trace.File, "Performed a stream copy from source.");
}
//----------------------------------------------------------------------
// Create the DocumentStream
result = new DocumentStream(copiesToken, target, this);
result.DeleteOnClose = false;
Trace.SafeWrite(Trace.File, "Created copy to file {0}.", copiesToken.Location);
return(result);
}
