Archipelago » qemu

/*

 * QError: QEMU Error data-type.

 *

 * Copyright (C) 2009 Red Hat Inc.

 *

 * Authors:

 *  Luiz Capitulino <lcapitulino@redhat.com>

 *

 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.

 * See the COPYING.LIB file in the top-level directory.

 */

#include "qjson.h"

#include "qerror.h"

#include "qstring.h"

#include "sysemu.h"

#include "qemu-common.h"

static void qerror_destroy_obj(QObject *obj);

static const QType qerror_type = {

    .code = QTYPE_QERROR,

    .destroy = qerror_destroy_obj,

};

/**

 * The 'desc' parameter is a printf-like string, the format of the format

 * string is:

 *

 * %(KEY)

 *

 * Where KEY is a QDict key, which has to be passed to qerror_from_info().

 *

 * Example:

 *

 * "foo error on device: %(device) slot: %(slot_nr)"

 *

 * A single percent sign can be printed if followed by a second one,

 * for example:

 *

 * "running out of foo: %(foo)%%"

 */

const QErrorStringTable qerror_table[] = {

    {}

};

/**

 * qerror_new(): Create a new QError

 *

 * Return strong reference.

 */

QError *qerror_new(void)

{

    QError *qerr;

    qerr = qemu_mallocz(sizeof(*qerr));

    QOBJECT_INIT(qerr, &qerror_type);

    return qerr;

}

static void qerror_abort(const QError *qerr, const char *fmt, ...)

{

    va_list ap;

    fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);

    fprintf(stderr, "qerror: -> ");

    va_start(ap, fmt);

    vfprintf(stderr, fmt, ap);

    va_end(ap);

    fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);

    abort();

}

static void qerror_set_data(QError *qerr, const char *fmt, va_list *va)

{

    QObject *obj;

    obj = qobject_from_jsonv(fmt, va);

    if (!obj) {

        qerror_abort(qerr, "invalid format '%s'", fmt);

    }

    if (qobject_type(obj) != QTYPE_QDICT) {

        qerror_abort(qerr, "error format is not a QDict '%s'", fmt);

    }

    qerr->error = qobject_to_qdict(obj);

    obj = qdict_get(qerr->error, "class");

    if (!obj) {

        qerror_abort(qerr, "missing 'class' key in '%s'", fmt);

    }

    if (qobject_type(obj) != QTYPE_QSTRING) {

        qerror_abort(qerr, "'class' key value should be a QString");

    }

    obj = qdict_get(qerr->error, "data");

    if (!obj) {

        qerror_abort(qerr, "missing 'data' key in '%s'", fmt);

    }

    if (qobject_type(obj) != QTYPE_QDICT) {

        qerror_abort(qerr, "'data' key value should be a QDICT");

    }

}

static void qerror_set_desc(QError *qerr, const char *fmt)

{

    int i;

    // FIXME: inefficient loop

    for (i = 0; qerror_table[i].error_fmt; i++) {

        if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {

            qerr->entry = &qerror_table[i];

            return;

        }

    }

    qerror_abort(qerr, "error format '%s' not found", fmt);

}

/**

 * qerror_from_info(): Create a new QError from error information

 *

 * The information consists of:

 *

 * - file   the file name of where the error occurred

 * - linenr the line number of where the error occurred

 * - func   the function name of where the error occurred

 * - fmt    JSON printf-like dictionary, there must exist keys 'class' and

 *          'data'

 * - va     va_list of all arguments specified by fmt

 *

 * Return strong reference.

 */

QError *qerror_from_info(const char *file, int linenr, const char *func,

                         const char *fmt, va_list *va)

{

    QError *qerr;

    qerr = qerror_new();

    qerr->linenr = linenr;

    qerr->file = file;

    qerr->func = func;

    if (!fmt) {

        qerror_abort(qerr, "QDict not specified");

    }

    qerror_set_data(qerr, fmt, va);

    qerror_set_desc(qerr, fmt);

    return qerr;

}

static void parse_error(const QError *qerror, int c)

{

    qerror_abort(qerror, "expected '%c' in '%s'", c, qerror->entry->desc);

}

static const char *append_field(QString *outstr, const QError *qerror,

                                const char *start)

{

    QObject *obj;

    QDict *qdict;

    QString *key_qs;

    const char *end, *key;

    if (*start != '%')

        parse_error(qerror, '%');

    start++;

    if (*start != '(')

        parse_error(qerror, '(');

    start++;

    end = strchr(start, ')');

    if (!end)

        parse_error(qerror, ')');

    key_qs = qstring_from_substr(start, 0, end - start - 1);

    key = qstring_get_str(key_qs);

    qdict = qobject_to_qdict(qdict_get(qerror->error, "data"));

    obj = qdict_get(qdict, key);

    if (!obj) {

        qerror_abort(qerror, "key '%s' not found in QDict", key);

    }

    switch (qobject_type(obj)) {

        case QTYPE_QSTRING:

            qstring_append(outstr, qdict_get_str(qdict, key));

            break;

        case QTYPE_QINT:

            qstring_append_int(outstr, qdict_get_int(qdict, key));

            break;

        default:

            qerror_abort(qerror, "invalid type '%c'", qobject_type(obj));

    }

    QDECREF(key_qs);

    return ++end;

}

/**

 * qerror_print(): Print QError data

 *

 * This function will print the member 'desc' of the specified QError object,

 * it uses qemu_error() for this, so that the output is routed to the right

 * place (ie. stderr or Monitor's device).

 */

void qerror_print(const QError *qerror)

{

    const char *p;

    QString *qstring;

    assert(qerror->entry != NULL);

    qstring = qstring_new();

    for (p = qerror->entry->desc; *p != '\0';) {

        if (*p != '%') {

            qstring_append_chr(qstring, *p++);

        } else if (*(p + 1) == '%') {

            qstring_append_chr(qstring, '%');

            p += 2;

        } else {

            p = append_field(qstring, qerror, p);

        }

    }

    qemu_error("%s\n", qstring_get_str(qstring));

    QDECREF(qstring);

}

/**

 * qobject_to_qerror(): Convert a QObject into a QError

 */

QError *qobject_to_qerror(const QObject *obj)

{

    if (qobject_type(obj) != QTYPE_QERROR) {

        return NULL;

    }

    return container_of(obj, QError, base);

}

/**

 * qerror_destroy_obj(): Free all memory allocated by a QError

 */

static void qerror_destroy_obj(QObject *obj)

{

    QError *qerr;

    assert(obj != NULL);

    qerr = qobject_to_qerror(obj);

    QDECREF(qerr->error);

    qemu_free(qerr);

}