From 6ec1313aeb3e1033a2a4bf5c62b6f447bfba5b02 Mon Sep 17 00:00:00 2001 From: Luiz Capitulino Date: Mon, 5 Mar 2012 17:43:40 -0500 Subject: [PATCH 13/98] Introduce the new error framework New error-handling framework that allows for exception-like error propagation. Signed-off-by: Luiz Capitulino Signed-off-by: Michael Roth Signed-off-by: Anthony Liguori (cherry picked from commit d5ec4f27c387c3b3200abb8656343b2519ea3047) Conflicts: Makefile.objs Signed-off-by: Jeff Cody Signed-off-by: Michal Novotny --- Makefile.objs | 2 +- error.c | 140 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ error.h | 70 ++++++++++++++++++++++++++++ error_int.h | 29 ++++++++++++ 4 files changed, 240 insertions(+), 1 deletions(-) create mode 100644 error.c create mode 100644 error.h create mode 100644 error_int.h diff --git a/Makefile.objs b/Makefile.objs index 14db493..6d6244c 100644 --- a/Makefile.objs +++ b/Makefile.objs @@ -63,7 +63,7 @@ shared-obj-y = qemu-error.o $(block-obj-y) $(qobject-obj-y) common-obj-y = $(shared-obj-y) common-obj-y += qemu-thread.o -common-obj-y += blockdev.o +common-obj-y += blockdev.o error.o common-obj-y += $(net-obj-y) common-obj-y += readline.o console.o cursor.o diff --git a/error.c b/error.c new file mode 100644 index 0000000..867eec2 --- /dev/null +++ b/error.c @@ -0,0 +1,140 @@ +/* + * QEMU Error Objects + * + * Copyright IBM, Corp. 2011 + * + * Authors: + * Anthony Liguori + * + * This work is licensed under the terms of the GNU LGPL, version 2. See + * the COPYING.LIB file in the top-level directory. + */ +#include "error.h" +#include "error_int.h" +#include "qemu-objects.h" +#include "qerror.h" +#include + +struct Error +{ + QDict *obj; + const char *fmt; + char *msg; +}; + +void error_set(Error **errp, const char *fmt, ...) +{ + Error *err; + va_list ap; + + if (errp == NULL) { + return; + } + + err = qemu_mallocz(sizeof(*err)); + + va_start(ap, fmt); + err->obj = qobject_to_qdict(qobject_from_jsonv(fmt, &ap)); + va_end(ap); + err->fmt = fmt; + + *errp = err; +} + +bool error_is_set(Error **errp) +{ + return (errp && *errp); +} + +const char *error_get_pretty(Error *err) +{ + if (err->msg == NULL) { + QString *str; + str = qerror_format(err->fmt, err->obj); + err->msg = qemu_strdup(qstring_get_str(str)); + QDECREF(str); + } + + return err->msg; +} + +const char *error_get_field(Error *err, const char *field) +{ + if (strcmp(field, "class") == 0) { + return qdict_get_str(err->obj, field); + } else { + QDict *dict = qdict_get_qdict(err->obj, "data"); + return qdict_get_str(dict, field); + } +} + +QDict *error_get_data(Error *err) +{ + QDict *data = qdict_get_qdict(err->obj, "data"); + QINCREF(data); + return data; +} + +void error_set_field(Error *err, const char *field, const char *value) +{ + QDict *dict = qdict_get_qdict(err->obj, "data"); + return qdict_put(dict, field, qstring_from_str(value)); +} + +void error_free(Error *err) +{ + if (err) { + QDECREF(err->obj); + qemu_free(err->msg); + qemu_free(err); + } +} + +bool error_is_type(Error *err, const char *fmt) +{ + const char *error_class; + char *ptr; + char *end; + + ptr = strstr(fmt, "'class': '"); + assert(ptr != NULL); + ptr += strlen("'class': '"); + + end = strchr(ptr, '\''); + assert(end != NULL); + + error_class = error_get_field(err, "class"); + if (strlen(error_class) != end - ptr) { + return false; + } + + return strncmp(ptr, error_class, end - ptr) == 0; +} + +void error_propagate(Error **dst_err, Error *local_err) +{ + if (dst_err) { + *dst_err = local_err; + } else if (local_err) { + error_free(local_err); + } +} + +QObject *error_get_qobject(Error *err) +{ + QINCREF(err->obj); + return QOBJECT(err->obj); +} + +void error_set_qobject(Error **errp, QObject *obj) +{ + Error *err; + if (errp == NULL) { + return; + } + err = qemu_mallocz(sizeof(*err)); + err->obj = qobject_to_qdict(obj); + qobject_incref(obj); + + *errp = err; +} diff --git a/error.h b/error.h new file mode 100644 index 0000000..003c855 --- /dev/null +++ b/error.h @@ -0,0 +1,70 @@ +/* + * QEMU Error Objects + * + * Copyright IBM, Corp. 2011 + * + * Authors: + * Anthony Liguori + * + * This work is licensed under the terms of the GNU LGPL, version 2. See + * the COPYING.LIB file in the top-level directory. + */ +#ifndef ERROR_H +#define ERROR_H + +#include + +/** + * A class representing internal errors within QEMU. An error has a string + * typename and optionally a set of named string parameters. + */ +typedef struct Error Error; + +/** + * Set an indirect pointer to an error given a printf-style format parameter. + * Currently, qerror.h defines these error formats. This function is not + * meant to be used outside of QEMU. + */ +void error_set(Error **err, const char *fmt, ...) + __attribute__((format(printf, 2, 3))); + +/** + * Returns true if an indirect pointer to an error is pointing to a valid + * error object. + */ +bool error_is_set(Error **err); + +/** + * Get a human readable representation of an error object. + */ +const char *error_get_pretty(Error *err); + +/** + * Get an individual named error field. + */ +const char *error_get_field(Error *err, const char *field); + +/** + * Get an individual named error field. + */ +void error_set_field(Error *err, const char *field, const char *value); + +/** + * Propagate an error to an indirect pointer to an error. This function will + * always transfer ownership of the error reference and handles the case where + * dst_err is NULL correctly. + */ +void error_propagate(Error **dst_err, Error *local_err); + +/** + * Free an error object. + */ +void error_free(Error *err); + +/** + * Determine if an error is of a speific type (based on the qerror format). + * Non-QEMU users should get the `class' field to identify the error type. + */ +bool error_is_type(Error *err, const char *fmt); + +#endif diff --git a/error_int.h b/error_int.h new file mode 100644 index 0000000..5e39424 --- /dev/null +++ b/error_int.h @@ -0,0 +1,29 @@ +/* + * QEMU Error Objects + * + * Copyright IBM, Corp. 2011 + * + * Authors: + * Anthony Liguori + * + * This work is licensed under the terms of the GNU LGPL, version 2. See + * the COPYING.LIB file in the top-level directory. + */ +#ifndef QEMU_ERROR_INT_H +#define QEMU_ERROR_INT_H + +#include "qemu-common.h" +#include "qobject.h" +#include "qdict.h" +#include "error.h" + +/** + * Internal QEMU functions for working with Error. + * + * These are used to convert QErrors to Errors + */ +QDict *error_get_data(Error *err); +QObject *error_get_qobject(Error *err); +void error_set_qobject(Error **errp, QObject *obj); + +#endif -- 1.7.7.6