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Jython is an implementation of the high-level, dynamic, object-oriented
language Python written in 100% Pure Java, and seamlessly integrated with
the Java platform. It thus allows you to run Python on any Java platform.
/* Copyright (c)2012 Jython Developers */
package org.python.modules._io;
import org.python.core.Py;
import org.python.core.PyBUF;
import org.python.core.PyBuffer;
import org.python.core.PyByteArray;
import org.python.core.PyList;
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.expose.ExposedMethod;
import org.python.expose.ExposedNew;
import org.python.expose.ExposedType;
/**
* An implementation of Python _io._RawIOBase mirroring the arrangement of methods in
* the CPython version.
*/
@ExposedType(name = "_io._RawIOBase", doc = PyRawIOBase.doc, base = PyIOBase.class)
public class PyRawIOBase extends PyIOBase {
public static final PyType TYPE = PyType.fromClass(PyRawIOBase.class);
public PyRawIOBase() {
this(TYPE);
}
public PyRawIOBase(PyType subtype) {
super(subtype);
}
@ExposedNew
static PyObject _RawIOBase__new__(PyNewWrapper new_, boolean init, PyType subtype,
PyObject[] args, String[] keywords) {
if (new_.for_type == subtype) {
// We only want an _io._RawIOBase, so the constructor does it all
return new PyRawIOBase();
} else {
// We want some sub-class of it (in which __init__ will be called by the caller)
return new PyRawIOBaseDerived(subtype);
}
}
/**
* The read() method is implemented by calling readinto(); derived classes that want to support
* read() only need to implement readinto() as a primitive operation. In general, readinto() can
* be more efficient than read().
*
* @param n number of bytes to read (if possible)
* @return a PyString holding the bytes read or Py.None (when a non-blocking source
* is not ready with further data)
*/
public PyObject read(int n) {
return _read(n);
}
/*
* CPython comment: (It would be tempting to also provide an implementation of readinto() in
* terms of read(), in case the latter is a more suitable primitive operation, but that would
* lead to nasty recursion in case a subclass doesn't implement either.)
*/
@ExposedMethod(defaults = "null", doc = read_doc)
final PyObject _RawIOBase_read(PyObject n) {
if (n == null || n == Py.None) {
return _read(-1);
} else if (n.isIndex()) {
return _read(n.asInt());
} else {
throw tailoredTypeError("integer", n);
}
}
/**
* Implementation of the read() method once the argument has been reduced to an int.
* @param n number of bytes to read (if possible)
* @return a PyString holding the bytes read or Py.None (when a non-blocking source
* is not ready with further data)
*/
private PyObject _read(int n) {
if (n < 0) {
// This is really a request to read the whole stream
return invoke("readall");
} else {
// Allocate a buffer big enough to satisfy the request
PyByteArray b = new PyByteArray(n);
// Read up to that much using the (possibly overridden) readinto() method
PyObject m = invoke("readinto", b);
if (m.isIndex()) {
// It returned the actual count of bytes read
int count = m.asIndex();
PyBuffer view = b.getBuffer(PyBUF.FULL_RO);
// We can forget view.release() as the bytearray b is garbage outside this method.
// Did we get all the bytes we expected?
if (count < n) {
// No, so swap the view for a slice of just the data we actually read.
view = view.getBufferSlice(PyBUF.FULL_RO, 0, count);
}
// Make a str from that view
return new PyString(view.toString());
} else {
// It must have returned None (signalling a vacuous read of non-blocking stream)
return m;
}
}
}
/**
* Read until end of file, using multiple read() operations on the underlying
* stream. If the first read() returns None (only possible in the case
* of a non-blocking stream), this method returns None.
*
* @return a PyString holding the bytes read or Py.None (when a non-blocking source
* is not ready with further data)
*/
public PyObject readall() {
return _RawIOBase_readall();
}
@ExposedMethod(doc = readall_doc)
final synchronized PyObject _RawIOBase_readall() {
// Get reference to the (possibly overridden) read() method
PyObject readMethod = __getattr__("read");
// Quite often, a single read operation will do the trick
PyObject prev = readMethod.__call__(_io.DEFAULT_BUFFER_SIZE);
if (!prev.__nonzero__()) {
// Nothing on the first read: that means we're done
return prev;
} else {
// Try a second read
PyObject curr = readMethod.__call__(_io.DEFAULT_BUFFER_SIZE);
if (!curr.__nonzero__()) {
// Nothing on the second read: the result is just the first one
return prev;
} else {
// Remembering more than one thing is hard: we're going to need a list
PyList list = new PyList();
list.add(prev);
// Accumulate the current read result and get another, until we run out of bytes.
do {
list.add(curr);
curr = readMethod.__call__(_io.DEFAULT_BUFFER_SIZE);
} while (curr.__nonzero__());
// Stitch it all together
return Py.EmptyString.join(list);
}
}
}
/**
* Read up to len(b) bytes into bytearray b and return the number of
* bytes read. If the object is in non-blocking mode and no bytes are available,
* None is returned.";
*
* @param b byte array to try to fill
* @return number of bytes actually read or Py.None (when a non-blocking source is
* not ready with further data)
*/
public PyObject readinto(PyObject b) {
return _RawIOBase_readinto(b);
}
@ExposedMethod(doc = readinto_doc)
final synchronized PyLong _RawIOBase_readinto(PyObject b) {
throw unsupported("readinto");
}
/**
* Write the given bytes or bytearray object to the underlying raw stream and return the number
* of bytes written.
*
* @param b buffer of bytes to be written
* @return
*/
public PyObject write(PyObject b) {
return _RawIOBase_write(b);
}
@ExposedMethod(doc = write_doc)
final PyLong _RawIOBase_write(PyObject b) {
throw unsupported("write");
}
/*
* Documentation strings: public where they might be useful to a subclass.
*/
public static final String read_doc = "Read up to n bytes from the object and return them.\n"
+ "As a convenience, if n is unspecified or -1, readall() is called.";
public static final String readall_doc =
"Read and return all the bytes from the stream until EOF, using multiple\n"
+ "calls to the stream if necessary.";
public static final String readinto_doc =
"Read up to len(b) bytes into bytearray b and return the number of bytes read.\n"
+ "If the object is in non-blocking mode and no bytes are available,\n"
+ "None is returned.";
public static final String write_doc =
"Write the given bytes or bytearray object, b, to the underlying raw\n"
+ "stream and return the number of bytes written.";
static final String doc = "Base class for raw binary I/O.";
}