/*
Copyright (c) 2016, PyData Development Team
All rights reserved.

Distributed under the terms of the BSD Simplified License.

The full license is in the LICENSE file, distributed with this software.
*/

#include "io.h"

/*
  On-disk FILE, uncompressed
*/

void *new_rd_source(PyObject *obj) {
    rd_source *rds = (rd_source *)malloc(sizeof(rd_source));

    if (rds == NULL) {
        PyErr_NoMemory();
        return NULL;
    }
    /* hold on to this object */
    Py_INCREF(obj);
    rds->obj = obj;
    rds->buffer = NULL;
    rds->position = 0;

    return (void *)rds;
}

/*

  Cleanup callbacks

 */

int del_rd_source(void *rds) {
    Py_XDECREF(RDS(rds)->obj);
    Py_XDECREF(RDS(rds)->buffer);
    free(rds);

    return 0;
}

/*

  IO callbacks

 */

void *buffer_rd_bytes(void *source, size_t nbytes, size_t *bytes_read,
                      int *status, const char *encoding_errors) {
    PyGILState_STATE state;
    PyObject *result, *func, *args, *tmp;

    void *retval;

    size_t length;
    rd_source *src = RDS(source);
    state = PyGILState_Ensure();

    /* delete old object */
    Py_XDECREF(src->buffer);
    src->buffer = NULL;
    args = Py_BuildValue("(i)", nbytes);

    func = PyObject_GetAttrString(src->obj, "read");

    /* TODO: does this release the GIL? */
    result = PyObject_CallObject(func, args);
    Py_XDECREF(args);
    Py_XDECREF(func);

    if (result == NULL) {
        PyGILState_Release(state);
        *bytes_read = 0;
        *status = CALLING_READ_FAILED;
        return NULL;
    } else if (!PyBytes_Check(result)) {
        tmp = PyUnicode_AsEncodedString(result, "utf-8", encoding_errors);
        Py_DECREF(result);
        if (tmp == NULL) {
            PyGILState_Release(state);
            return NULL;
        }
        result = tmp;
    }

    length = PySequence_Length(result);

    if (length == 0)
        *status = REACHED_EOF;
    else
        *status = 0;

    /* hang on to the Python object */
    src->buffer = result;
    retval = (void *)PyBytes_AsString(result);

    PyGILState_Release(state);

    /* TODO: more error handling */
    *bytes_read = length;

    return retval;
}