/**
* 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;
}
/**
* Register a directory for changes as follows:
*
* <p>1. Open directory 2. Read its attributes (and check it really is a directory) 3. Assign
* completion key and associated handle with completion port 4. Call ReadDirectoryChangesW to
* start (async) read of changes 5. Create or return existing key representing registration
*/
@Override
Object implRegister(
Path obj, Set<? extends WatchEvent.Kind<?>> events, WatchEvent.Modifier... modifiers) {
WindowsPath dir = (WindowsPath) obj;
boolean watchSubtree = false;
// FILE_TREE modifier allowed
for (WatchEvent.Modifier modifier : modifiers) {
if (modifier == ExtendedWatchEventModifier.FILE_TREE) {
watchSubtree = true;
} else {
if (modifier == null) return new NullPointerException();
if (modifier instanceof com.sun.nio.file.SensitivityWatchEventModifier)
continue; // ignore
return new UnsupportedOperationException("Modifier not supported");
}
}
// open directory
long handle;
try {
handle =
CreateFile(
dir.getPathForWin32Calls(),
FILE_LIST_DIRECTORY,
(FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE),
OPEN_EXISTING,
FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED);
} catch (WindowsException x) {
return x.asIOException(dir);
}
boolean registered = false;
try {
// read attributes and check file is a directory
WindowsFileAttributes attrs;
try {
attrs = WindowsFileAttributes.readAttributes(handle);
} catch (WindowsException x) {
return x.asIOException(dir);
}
if (!attrs.isDirectory()) {
return new NotDirectoryException(dir.getPathForExceptionMessage());
}
// check if this directory is already registered
FileKey fk =
new FileKey(attrs.volSerialNumber(), attrs.fileIndexHigh(), attrs.fileIndexLow());
WindowsWatchKey existing = fk2key.get(fk);
// if already registered and we're not changing the subtree
// modifier then simply update the event and return the key.
if (existing != null && watchSubtree == existing.watchSubtree()) {
existing.setEvents(events);
return existing;
}
// Can overflow the int type capacity.
// Skip WAKEUP_COMPLETION_KEY value.
int completionKey = ++lastCompletionKey;
if (completionKey == WAKEUP_COMPLETION_KEY) completionKey = ++lastCompletionKey;
// associate handle with completion port
try {
CreateIoCompletionPort(handle, port, completionKey);
} catch (WindowsException x) {
return new IOException(x.getMessage());
}
// allocate memory for events, including space for other structures
// needed to do overlapped I/O
int size = CHANGES_BUFFER_SIZE + SIZEOF_DWORD + SIZEOF_OVERLAPPED;
NativeBuffer buffer = NativeBuffers.getNativeBuffer(size);
long bufferAddress = buffer.address();
long overlappedAddress = bufferAddress + size - SIZEOF_OVERLAPPED;
long countAddress = overlappedAddress - SIZEOF_DWORD;
// zero the overlapped structure
UNSAFE.setMemory(overlappedAddress, SIZEOF_OVERLAPPED, (byte) 0);
// start async read of changes to directory
try {
createAndAttachEvent(overlappedAddress);
ReadDirectoryChangesW(
handle,
bufferAddress,
CHANGES_BUFFER_SIZE,
watchSubtree,
ALL_FILE_NOTIFY_EVENTS,
countAddress,
overlappedAddress);
} catch (WindowsException x) {
closeAttachedEvent(overlappedAddress);
buffer.release();
return new IOException(x.getMessage());
}
WindowsWatchKey watchKey;
if (existing == null) {
// not registered so create new watch key
watchKey =
new WindowsWatchKey(dir, watcher, fk)
.init(
handle,
events,
watchSubtree,
buffer,
countAddress,
overlappedAddress,
completionKey);
// map file key to watch key
fk2key.put(fk, watchKey);
} else {
// directory already registered so need to:
// 1. remove mapping from old completion key to existing watch key
// 2. release existing key's resources (handle/buffer)
// 3. re-initialize key with new handle/buffer
ck2key.remove(existing.completionKey());
releaseResources(existing);
watchKey =
existing.init(
handle,
events,
watchSubtree,
buffer,
countAddress,
overlappedAddress,
completionKey);
}
// map completion map to watch key
ck2key.put(completionKey, watchKey);
registered = true;
return watchKey;
} finally {
if (!registered) CloseHandle(handle);
}
}
