/**
* Opens file based on parameters and options, returning a FileDescriptor encapsulating the handle
* to the open file.
*/
private static FileDescriptor open(
String pathForWindows, String pathToCheck, Flags flags, long pSecurityDescriptor)
throws WindowsException {
// set to true if file must be truncated after open
boolean truncateAfterOpen = false;
// map options
int dwDesiredAccess = 0;
if (flags.read) dwDesiredAccess |= GENERIC_READ;
if (flags.write) dwDesiredAccess |= GENERIC_WRITE;
int dwShareMode = 0;
if (flags.shareRead) dwShareMode |= FILE_SHARE_READ;
if (flags.shareWrite) dwShareMode |= FILE_SHARE_WRITE;
if (flags.shareDelete) dwShareMode |= FILE_SHARE_DELETE;
int dwFlagsAndAttributes = FILE_ATTRIBUTE_NORMAL;
int dwCreationDisposition = OPEN_EXISTING;
if (flags.write) {
if (flags.createNew) {
dwCreationDisposition = CREATE_NEW;
// force create to fail if file is orphaned reparse point
dwFlagsAndAttributes |= FILE_FLAG_OPEN_REPARSE_POINT;
} else {
if (flags.create) dwCreationDisposition = OPEN_ALWAYS;
if (flags.truncateExisting) {
// Windows doesn't have a creation disposition that exactly
// corresponds to CREATE + TRUNCATE_EXISTING so we use
// the OPEN_ALWAYS mode and then truncate the file.
if (dwCreationDisposition == OPEN_ALWAYS) {
truncateAfterOpen = true;
} else {
dwCreationDisposition = TRUNCATE_EXISTING;
}
}
}
}
if (flags.dsync || flags.sync) dwFlagsAndAttributes |= FILE_FLAG_WRITE_THROUGH;
if (flags.overlapped) dwFlagsAndAttributes |= FILE_FLAG_OVERLAPPED;
if (flags.deleteOnClose) dwFlagsAndAttributes |= FILE_FLAG_DELETE_ON_CLOSE;
// NOFOLLOW_LINKS and NOFOLLOW_REPARSEPOINT mean open reparse point
boolean okayToFollowLinks = true;
if (dwCreationDisposition != CREATE_NEW
&& (flags.noFollowLinks || flags.openReparsePoint || flags.deleteOnClose)) {
if (flags.noFollowLinks || flags.deleteOnClose) okayToFollowLinks = false;
dwFlagsAndAttributes |= FILE_FLAG_OPEN_REPARSE_POINT;
}
// permission check
if (pathToCheck != null) {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
if (flags.read) sm.checkRead(pathToCheck);
if (flags.write) sm.checkWrite(pathToCheck);
if (flags.deleteOnClose) sm.checkDelete(pathToCheck);
}
}
// open file
long handle =
CreateFile(
pathForWindows,
dwDesiredAccess,
dwShareMode,
pSecurityDescriptor,
dwCreationDisposition,
dwFlagsAndAttributes);
// make sure this isn't a symbolic link.
if (!okayToFollowLinks) {
try {
if (WindowsFileAttributes.readAttributes(handle).isSymbolicLink())
throw new WindowsException("File is symbolic link");
} catch (WindowsException x) {
CloseHandle(handle);
throw x;
}
}
// truncate file (for CREATE + TRUNCATE_EXISTING case)
if (truncateAfterOpen) {
try {
SetEndOfFile(handle);
} catch (WindowsException x) {
CloseHandle(handle);
throw x;
}
}
// make the file sparse if needed
if (dwCreationDisposition == CREATE_NEW && flags.sparse) {
try {
DeviceIoControlSetSparse(handle);
} catch (WindowsException x) {
// ignore as sparse option is hint
}
}
// create FileDescriptor and return
FileDescriptor fdObj = new FileDescriptor();
fdAccess.setHandle(fdObj, handle);
return fdObj;
}