org.python.modules._io.PyFileIO Maven / Gradle / Ivy
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/* Copyright (c)2013 Jython Developers */
package org.python.modules._io;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import org.python.core.ArgParser;
import org.python.core.BuiltinDocs;
import org.python.core.Py;
import org.python.core.PyArray;
import org.python.core.PyBuffer;
import org.python.core.PyException;
import org.python.core.PyJavaType;
import org.python.core.PyLong;
import org.python.core.PyNewWrapper;
import org.python.core.PyObject;
import org.python.core.PyString;
import org.python.core.PyType;
import org.python.core.PyUnicode;
import org.python.core.Untraversable;
import org.python.core.io.FileIO;
import org.python.core.io.RawIOBase;
import org.python.core.io.StreamIO;
import org.python.expose.ExposedGet;
import org.python.expose.ExposedMethod;
import org.python.expose.ExposedNew;
import org.python.expose.ExposedSet;
import org.python.expose.ExposedType;
import jnr.constants.platform.Errno;
@Untraversable
@ExposedType(name = "_io.FileIO", base = PyRawIOBase.class)
public class PyFileIO extends PyRawIOBase {
public static final PyType TYPE = PyType.fromClass(PyFileIO.class);
/** The {@link FileIO} or {@link StreamIO} to which we delegate operations not complete locally. */
private RawIOBase ioDelegate;
/*
* Implementation note: CPython fileio does not use the base-class, possibly overridden,
* readable(), writable() and seekable(). Instead it sets local variables for readable and
* writable using the open mode, and returns these as readable() and writable(), while using
* them internally. The local variable seekable (and seekable()) is worked out from a one-time
* trial seek.
*/
/** Set true when stream must be readable = reading | updating */
private boolean readable;
/** Set true when stream must be writable = writing | updating | appending */
private boolean writable;
/** Set true when we have made the seekable test */
private boolean seekableKnown;
/** Set true when stream is seekable */
private boolean seekable;
/** Whether to close the underlying stream on closing this object. */
@ExposedGet(doc = "True if the file descriptor will be closed")
public final boolean closefd;
/** The mode as a PyString based on readable and writable */
@ExposedGet(doc = "String giving the file mode: 'rb', 'rb+', or 'wb'")
public final PyString mode;
@ExposedSet(name = "mode")
public final void mode_readonly(PyString value) {
readonlyAttributeError("mode");
}
private static final PyString defaultMode = new PyString("r");
/**
* Construct an open _io.FileIO starting with an object that may be a file name or
* a file descriptor (actually a {@link RawIOBase}). Only the relevant flags within the parsed
* mode object are consulted (so that flags meaningful to this sub-class need not be processed
* out).
*
* @param file path or descriptor on which this should be constructed
* @param mode type of access specified
* @param closefd if false, do not close fd on call to
* close()
*/
public PyFileIO(PyObject file, OpenMode mode, boolean closefd) {
this(TYPE, file, mode, closefd);
}
/**
* Construct an open _io.FileIO for a sub-class constructor starting with an object
* that may be a file name or a file descriptor (actually a {@link RawIOBase}). Only the
* relevant flags within the parsed mode object are consulted (so that flags meaningful to this
* sub-class need not be processed out).
*
* @param subtype for which construction is occurring
* @param file path or descriptor on which this should be constructed
* @param mode type of access specified
* @param closefd if false, do not close file on call to
* close()
*/
public PyFileIO(PyType subtype, PyObject file, OpenMode mode, boolean closefd) {
super(subtype);
// Establish the direction(s) of flow
readable = mode.reading | mode.updating;
writable = mode.writing | mode.updating | mode.appending;
// Assign a delegate according to the file argument
this.closefd = closefd;
setDelegate(file, mode);
// The mode string of a raw file always asserts it is binary: "rb", "rb+", or "wb".
if (readable) {
this.mode = new PyString(writable ? "rb+" : "rb");
} else {
this.mode = new PyString("wb");
}
}
/**
* Helper function that turns the arguments of the most general constructor, or
* __new__, into a {@link FileIO}, assigned to {@link #ioDelegate}. It enforces
* rules on {@link #closefd} and the type of object that may be a file descriptor, and assigns
* the name attribute to the string name or the file descriptor (see Python docs
* for io.FileIO.name). This places the logic of those several operations in one place.
*
* In many cases (such as construction from a file name, the FileIO is a newly-opened file. When
* the file object passed in is a file descriptor, the FileIO may be created to wrap that
* existing stream.
*
* @param file name or descriptor
* @param mode parsed file open mode
*/
private void setDelegate(PyObject file, OpenMode mode) {
if (file instanceof PyString) {
// Open a file by name
if (!closefd) {
throw Py.ValueError("Cannot use closefd=False with file name");
}
ioDelegate = new FileIO((PyString)file, mode.forFileIO());
} else {
/*
* Build an _io.FileIO from an existing "file descriptor", which we may or may not want
* closed at the end. A CPython file descriptor is an int, but this is not the natural
* choice in Jython, and file descriptors should be treated as opaque.
*/
Object fd = file.__tojava__(Object.class);
if (fd instanceof FileIO || fd instanceof StreamIO) {
/*
* It is the "Jython file descriptor", of a type suitable to be the ioDelegate. The
* allowed types are able to give us a non-null InputStream or OutputStream,
* according to direction.
*/
ioDelegate = (RawIOBase)fd;
}
}
// If we couldn't figure it out, ioDelegate will still be null
if (ioDelegate == null) {
// The file was a type we don't know how to use
throw Py.TypeError(String.format("invalid file: %s", file.__repr__().asString()));
} else {
if (ioDelegate.closed()) {
// A closed file descriptor is a "bad descriptor"
throw Py.OSError(Errno.EBADF);
}
if ((readable && !ioDelegate.readable()) || (writable && !ioDelegate.writable())) {
// Requested mode in conflict with underlying file or stream
throw tailoredValueError(readable ? "read" : "writ");
}
// The name is either the textual name or a file descriptor (see Python docs)
fastGetDict().__setitem__("name", file);
}
}
private static final String[] openArgs = {"file", "mode", "closefd"};
/**
* Create a {@link PyFileIO} and its FileIO delegate from the arguments.
*/
@ExposedNew
static PyObject FileIO___new__(PyNewWrapper new_, boolean init, PyType subtype,
PyObject[] args, String[] keywords) {
ArgParser ap = new ArgParser("FileIO", args, keywords, openArgs, 1);
PyObject file = ap.getPyObject(0);
PyObject m = ap.getPyObject(1, defaultMode);
boolean closefd = Py.py2boolean(ap.getPyObject(2, Py.True));
// Decode the mode string and check it
OpenMode mode = new OpenMode(m.asString()) {
{
invalid |= universal | text; // These other modes are invalid
}
};
mode.checkValid();
if (subtype == TYPE) {
return new PyFileIO(subtype, file, mode, closefd);
} else {
return new PyFileIODerived(subtype, file, mode, closefd);
}
}
/*
* ===========================================================================================
* Exposed methods in the order they appear in CPython's fileio.c method table
* ===========================================================================================
*/
// _RawIOBase.read is correct for us
// _RawIOBase.readall is correct for us
@Override
public PyObject readinto(PyObject buf) {
return FileIO_readinto(buf);
}
@ExposedMethod(doc = readinto_doc)
final PyLong FileIO_readinto(PyObject buf) {
int count;
if (!readable) { // ... (or closed)
throw tailoredValueError("read");
}
if (buf instanceof PyArray) {
// Special case: PyArray knows how to read into itself
PyArray a = (PyArray)buf;
try {
// The ioDelegate, if readable, can always provide an InputStream (see setDelegate)
InputStream is = ioDelegate.asInputStream();
count = a.fillFromStream(is);
count *= a.getItemsize();
} catch (IOException ioe) {
throw Py.IOError(ioe);
}
} else {
// Perform the operation through a buffer view on the object
try (PyBuffer pybuf = writablePyBuffer(buf)) {
ByteBuffer byteBuffer = pybuf.getNIOByteBuffer();
synchronized (ioDelegate) {
count = ioDelegate.readinto(byteBuffer);
}
}
}
return new PyLong(count);
}
@Override
public PyObject write(PyObject buf) {
return FileIO_write(buf);
}
@ExposedMethod(doc = write_doc)
final PyLong FileIO_write(PyObject buf) {
int count;
if (!writable) { // ... (or closed)
throw tailoredValueError("writ");
}
if (buf instanceof PyArray) {
// Special case: PyArray knows how to write itself
try {
// The ioDelegate, if writable, can always provide an OutputStream (see setDelegate)
OutputStream os = ioDelegate.asOutputStream();
count = ((PyArray)buf).toStream(os);
} catch (IOException ioe) {
throw Py.IOError(ioe);
}
} else {
// Get or synthesise a buffer API on the object to be written
try (PyBuffer pybuf = readablePyBuffer(buf)) {
// Access the data as a java.nio.ByteBuffer [pos:limit] within possibly larger array
ByteBuffer byteBuffer = pybuf.getNIOByteBuffer();
synchronized (ioDelegate) {
count = ioDelegate.write(byteBuffer);
}
}
}
return new PyLong(count);
}
@Override
public long seek(long pos, int whence) {
return FileIO_seek(pos, whence);
}
@ExposedMethod(defaults = "0", doc = seek_doc)
final long FileIO_seek(long pos, int whence) {
if (__closed) {
throw closedValueError();
}
synchronized (ioDelegate) {
return ioDelegate.seek(pos, whence);
}
}
// _IOBase.tell() is correct for us
@Override
public long truncate() {
return _truncate();
}
@Override
public long truncate(long size) {
return _truncate(size);
}
@ExposedMethod(defaults = "null", doc = truncate_doc)
final long FileIO_truncate(PyObject size) {
return (size != null) ? _truncate(size.asLong()) : _truncate();
}
/** Common to FileIO_truncate(null) and truncate(). */
private final long _truncate() {
if (!writable) { // ... (or closed)
throw tailoredValueError("writ");
}
synchronized (ioDelegate) {
return ioDelegate.truncate(ioDelegate.tell());
}
}
/** Common to FileIO_truncate(size) and truncate(size). */
private final long _truncate(long size) {
if (!writable) { // ... (or closed)
throw tailoredValueError("writ");
}
synchronized (ioDelegate) {
return ioDelegate.truncate(size);
}
}
/**
* Close the underlying ioDelegate only if closefd was specified as (or defaulted
* to) True.
*/
@Override
public void close() {
FileIO_close();
}
@ExposedMethod
final synchronized void FileIO_close() {
try {
// Close this object to further input (also calls flush)
super.close();
} finally {
// Now close downstream (if required to)
if (closefd) {
ioDelegate.close();
}
// This saves us doing two tests for each action (when the file is open)
readable = false;
writable = false;
}
}
@Override
public boolean seekable() {
return FileIO_seekable();
}
@ExposedMethod(doc = seekable_doc)
final boolean FileIO_seekable() {
if (__closed) {
throw closedValueError();
}
if (!seekableKnown) {
try {
ioDelegate.seek(0, 1); // Trial seek
seekable = true;
} catch (PyException exc) {
if (!exc.match(Py.IOError)) {
throw exc;
}
seekable = false;
}
seekableKnown = true;
}
return seekable;
}
@Override
public boolean readable() throws PyException {
return FileIO_readable();
}
@ExposedMethod(doc = readable_doc)
final boolean FileIO_readable() {
if (__closed) {
throw closedValueError();
}
return readable;
}
@Override
public boolean writable() throws PyException {
return FileIO_writable();
}
@ExposedMethod(doc = writable_doc)
final boolean FileIO_writable() {
if (__closed) {
throw closedValueError();
}
return writable;
}
@Override
public PyObject fileno() {
return FileIO_fileno();
}
@ExposedMethod(doc = fileno_doc)
final PyObject FileIO_fileno() {
return PyJavaType.wrapJavaObject(ioDelegate.fileno());
}
@Override
public boolean isatty() {
return FileIO_isatty();
}
@ExposedMethod(doc = isatty_doc)
final boolean FileIO_isatty() {
if (__closed) {
throw closedValueError();
}
return ioDelegate.isatty();
}
// fileio.c has no flush(), but why not, when there is fdflush()?
// And it is a no-op for Jython io.FileIO, but why when there is FileChannel.force()?
@Override
public void flush() {
FileIO_flush();
}
@ExposedMethod(doc = "Flush write buffers.")
final void FileIO_flush() {
if (writable()) {
// Check for *downstream* close. (Locally, closed means "closed to client actions".)
ioDelegate.checkClosed();
ioDelegate.flush();
}
}
@ExposedMethod(names = {"__str__", "__repr__"}, doc = BuiltinDocs.object___str___doc)
final String FileIO_toString() {
if (closed()) {
return "<_io.FileIO [closed]>";
} else {
PyObject name = fastGetDict().__finditem__("name");
if (name != null && (name instanceof PyString)) {
String xname = name.asString();
if (name instanceof PyUnicode) {
xname = PyString.encode_UnicodeEscape(xname, false);
}
return String.format("<_io.FileIO name='%s' mode='%s'>", xname, mode);
} else {
return String.format("<_io.FileIO fd=%s mode='%s'>", fileno(), mode);
}
}
}
@Override
public String toString() {
return FileIO_toString().toString();
}
/**
* Convenience method providing the exception when an method requires the file to be open, and
* it isn't.
*
* @return ValueError to throw
*/
private PyException closedValueError() {
return Py.ValueError("I/O operation on closed file");
}
/**
* Convenience method providing the exception when an method requires the file to be open,
* readable or writable, and it isn't. If the file is closed, return the message for that,
* otherwise, one about reading or writing.
*
* @param action type of operation not valid ("read" or "writ" in practice).
* @return ValueError to throw
*/
private PyException tailoredValueError(String action) {
if (action == null || __closed) {
return closedValueError();
} else {
return Py.ValueError("File not open for " + action + "ing");
}
}
}