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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
#include "arrow/python/io.h"
#include <cstdint>
#include <cstdlib>
#include <memory>
#include <mutex>
#include <string>
#include "arrow/io/memory.h"
#include "arrow/memory_pool.h"
#include "arrow/status.h"
#include "arrow/util/logging.h"
#include "arrow/python/common.h"
namespace arrow {
namespace py {
// ----------------------------------------------------------------------
// Python file
// This is annoying: because C++11 does not allow implicit conversion of string
// literals to non-const char*, we need to go through some gymnastics to use
// PyObject_CallMethod without a lot of pain (its arguments are non-const
// char*)
template <typename... ArgTypes>
static inline PyObject* cpp_PyObject_CallMethod(PyObject* obj, const char* method_name,
const char* argspec, ArgTypes... args) {
return PyObject_CallMethod(obj, const_cast<char*>(method_name),
const_cast<char*>(argspec), args...);
}
// A common interface to a Python file-like object. Must acquire GIL before
// calling any methods
class PythonFile {
public:
explicit PythonFile(PyObject* file) : file_(file) { Py_INCREF(file_); }
~PythonFile() { Py_DECREF(file_); }
Status Close() {
// whence: 0 for relative to start of file, 2 for end of file
PyObject* result = cpp_PyObject_CallMethod(file_, "close", "()");
Py_XDECREF(result);
PY_RETURN_IF_ERROR(StatusCode::IOError);
return Status::OK();
}
Status Seek(int64_t position, int whence) {
// whence: 0 for relative to start of file, 2 for end of file
PyObject* result = cpp_PyObject_CallMethod(file_, "seek", "(ii)", position, whence);
Py_XDECREF(result);
PY_RETURN_IF_ERROR(StatusCode::IOError);
return Status::OK();
}
Status Read(int64_t nbytes, PyObject** out) {
PyObject* result = cpp_PyObject_CallMethod(file_, "read", "(i)", nbytes);
PY_RETURN_IF_ERROR(StatusCode::IOError);
*out = result;
return Status::OK();
}
Status Write(const void* data, int64_t nbytes) {
PyObject* py_data =
PyBytes_FromStringAndSize(reinterpret_cast<const char*>(data), nbytes);
PY_RETURN_IF_ERROR(StatusCode::IOError);
PyObject* result = cpp_PyObject_CallMethod(file_, "write", "(O)", py_data);
Py_XDECREF(py_data);
Py_XDECREF(result);
PY_RETURN_IF_ERROR(StatusCode::IOError);
return Status::OK();
}
Status Tell(int64_t* position) {
PyObject* result = cpp_PyObject_CallMethod(file_, "tell", "()");
PY_RETURN_IF_ERROR(StatusCode::IOError);
*position = PyLong_AsLongLong(result);
Py_DECREF(result);
// PyLong_AsLongLong can raise OverflowError
PY_RETURN_IF_ERROR(StatusCode::IOError);
return Status::OK();
}
std::mutex& lock() { return lock_; }
private:
std::mutex lock_;
PyObject* file_;
};
// ----------------------------------------------------------------------
// Seekable input stream
PyReadableFile::PyReadableFile(PyObject* file) { file_.reset(new PythonFile(file)); }
PyReadableFile::~PyReadableFile() {}
Status PyReadableFile::Close() {
PyAcquireGIL lock;
return file_->Close();
}
Status PyReadableFile::Seek(int64_t position) {
PyAcquireGIL lock;
return file_->Seek(position, 0);
}
Status PyReadableFile::Tell(int64_t* position) const {
PyAcquireGIL lock;
return file_->Tell(position);
}
Status PyReadableFile::Read(int64_t nbytes, int64_t* bytes_read, void* out) {
PyAcquireGIL lock;
PyObject* bytes_obj = NULL;
ARROW_RETURN_NOT_OK(file_->Read(nbytes, &bytes_obj));
DCHECK(bytes_obj != NULL);
*bytes_read = PyBytes_GET_SIZE(bytes_obj);
std::memcpy(out, PyBytes_AS_STRING(bytes_obj), *bytes_read);
Py_XDECREF(bytes_obj);
return Status::OK();
}
Status PyReadableFile::Read(int64_t nbytes, std::shared_ptr<Buffer>* out) {
PyAcquireGIL lock;
OwnedRef bytes_obj;
ARROW_RETURN_NOT_OK(file_->Read(nbytes, bytes_obj.ref()));
DCHECK(bytes_obj.obj() != NULL);
return PyBuffer::FromPyObject(bytes_obj.obj(), out);
}
Status PyReadableFile::ReadAt(int64_t position, int64_t nbytes, int64_t* bytes_read,
void* out) {
std::lock_guard<std::mutex> guard(file_->lock());
RETURN_NOT_OK(Seek(position));
return Read(nbytes, bytes_read, out);
}
Status PyReadableFile::ReadAt(int64_t position, int64_t nbytes,
std::shared_ptr<Buffer>* out) {
std::lock_guard<std::mutex> guard(file_->lock());
RETURN_NOT_OK(Seek(position));
return Read(nbytes, out);
}
Status PyReadableFile::GetSize(int64_t* size) {
PyAcquireGIL lock;
int64_t current_position = -1;
ARROW_RETURN_NOT_OK(file_->Tell(¤t_position));
ARROW_RETURN_NOT_OK(file_->Seek(0, 2));
int64_t file_size = -1;
ARROW_RETURN_NOT_OK(file_->Tell(&file_size));
// Restore previous file position
ARROW_RETURN_NOT_OK(file_->Seek(current_position, 0));
*size = file_size;
return Status::OK();
}
bool PyReadableFile::supports_zero_copy() const { return false; }
// ----------------------------------------------------------------------
// Output stream
PyOutputStream::PyOutputStream(PyObject* file) : position_(0) {
file_.reset(new PythonFile(file));
}
PyOutputStream::~PyOutputStream() {}
Status PyOutputStream::Close() {
PyAcquireGIL lock;
return file_->Close();
}
Status PyOutputStream::Tell(int64_t* position) const {
*position = position_;
return Status::OK();
}
Status PyOutputStream::Write(const void* data, int64_t nbytes) {
PyAcquireGIL lock;
position_ += nbytes;
return file_->Write(data, nbytes);
}
} // namespace py
} // namespace arrow