Introduce the new error framework (d5ec4f27) · Commits · SUMMER2020 / students / proj-2021291

Makefile.objs

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		@@ -59,7 +59,7 @@ fsdev-obj-$(CONFIG_VIRTFS) += $(addprefix fsdev/, $(fsdev-nested-y))
		# system emulation, i.e. a single QEMU executable should support all
		# CPUs and machines.

		common-obj-y = $(block-obj-y) blockdev.o
		common-obj-y = $(block-obj-y) blockdev.o error.o
		common-obj-y += $(net-obj-y)
		common-obj-y += $(qobject-obj-y)
		common-obj-$(CONFIG_LINUX) += $(fsdev-obj-$(CONFIG_LINUX))

error.c

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		/*
		* QEMU Error Objects
		*
		* Copyright IBM, Corp. 2011
		*
		* Authors:
		* Anthony Liguori <aliguori@us.ibm.com>
		*
		* 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 <assert.h>

		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;
		}

error.h

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		/*
		* QEMU Error Objects
		*
		* Copyright IBM, Corp. 2011
		*
		* Authors:
		* Anthony Liguori <aliguori@us.ibm.com>
		*
		* 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 <stdbool.h>

		/**
		* 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

error_int.h

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		/*
		* QEMU Error Objects
		*
		* Copyright IBM, Corp. 2011
		*
		* Authors:
		* Anthony Liguori <aliguori@us.ibm.com>
		*
		* 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