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[Qemu-devel] [PATCH 2/7] Introduce QError
From: |
Luiz Capitulino |
Subject: |
[Qemu-devel] [PATCH 2/7] Introduce QError |
Date: |
Thu, 29 Oct 2009 16:42:25 -0200 |
QError is a high-level data type that can be used to store the
following error information:
o Error data: Any kind of data generated at error time can be stored
(if turned into a QObject)
o Description: A string description, which may contain error data
o Error location: file name and line number of where the error was
triggered
Before using it functions usually have to register a new error type,
this is done by adding a new entry in the qerror_type[] table with
the following error information:
1. Code, which should be added to enum QErrorCode first
2. Description, which is a printf-like string
QError exports the following functions:
- qerror_new(): Create a new 'empty' QError
- qerror_from_va(): Create a new QError from the specified va_list
- qerror_print(): Print the specified QError
Signed-off-by: Luiz Capitulino <address@hidden>
---
Makefile | 2 +-
qerror.c | 240 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
qerror.h | 48 ++++++++++++
qobject.h | 1 +
4 files changed, 290 insertions(+), 1 deletions(-)
create mode 100644 qerror.c
create mode 100644 qerror.h
diff --git a/Makefile b/Makefile
index 813bd0a..325e583 100644
--- a/Makefile
+++ b/Makefile
@@ -125,7 +125,7 @@ obj-y += net.o net-queue.o
obj-y += qemu-char.o aio.o net-checksum.o savevm.o
obj-y += msmouse.o ps2.o
obj-y += qdev.o qdev-properties.o
-obj-y += qint.o qstring.o qdict.o qlist.o qfloat.o qbool.o qjson.o
+obj-y += qint.o qstring.o qdict.o qlist.o qfloat.o qbool.o qjson.o qerror.o
obj-y += qemu-config.o
obj-$(CONFIG_BRLAPI) += baum.o
diff --git a/qerror.c b/qerror.c
new file mode 100644
index 0000000..0359d65
--- /dev/null
+++ b/qerror.c
@@ -0,0 +1,240 @@
+/*
+ * QError: QEMU Error data-type.
+ *
+ * Copyright (C) 2009 Red Hat Inc.
+ *
+ * Authors:
+ * Luiz Capitulino <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+#include "qint.h"
+#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' member is a printf-like string, the format of the format
+ * string is:
+ *
+ * %(KEY)TYPE
+ *
+ * Where KEY is a QDict key and TYPE is the type of its value, KEY and
+ * its value must be passed to qerror_from_info().
+ *
+ * Example:
+ *
+ * "foo error on device: %(device)s slot: %(slot_nr)s"
+ *
+ * A single percent sign can be printed if followed by a second one,
+ * for example:
+ *
+ * "running out of foo: %(foo)d%%"
+ *
+ * Valid types are:
+ *
+ * s (string)
+ * d (integer)
+ */
+static QErrorTable qerror_table[] = {
+ {
+ .code = QERR_UNKNOWN,
+ .desc = "unknown error",
+ },
+};
+
+/**
+ * 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;
+}
+
+/**
+ * qerror_from_info(): Create a new QError from error information
+ *
+ * The information consists of:
+ *
+ * - code: error code
+ * - file: the file of where the error happend
+ * - linenr: the line number of where the error happend
+ * - fmt: JSON printf-like format
+ * - va: va_list of all arguments
+ *
+ * Return strong reference.
+ */
+QError *qerror_from_info(QErrorCode code, const char *file, int linenr,
+ const char *fmt, va_list *va)
+{
+ QError *qerr;
+
+ assert((code > 0) && (code < QERR_MAX));
+
+ qerr = qerror_new();
+ qerr->entry = &qerror_table[code];
+ qerr->file = file;
+ qerr->linenr = linenr;
+ if (fmt) {
+ qerr->data = qobject_from_json_va(fmt, va);
+ assert(qerr->data != NULL);
+ }
+
+ return qerr;
+}
+
+static char *get_substr(const char *start, const char *end)
+{
+ char *str;
+ size_t length;
+
+ length = end - start + 1;
+ str = qemu_malloc(length + 1);
+ memcpy(str, start, length);
+ str[length] = '\0';
+
+ return str;
+}
+
+static void qerror_abort(const QError *qerror)
+{
+ fprintf(stderr, " in '%s'\n", qerror->entry->desc);
+ abort();
+}
+
+#define ERROR_PREFIX "\n\nqerror: "
+
+static void type_error(const QError *qerror, int c)
+{
+ fprintf(stderr, ERROR_PREFIX "invalid type '%c'", c);
+ qerror_abort(qerror);
+}
+
+static void key_error(const QError *qerror, const char *key)
+{
+ fprintf(stderr, ERROR_PREFIX "key '%s' not found in QDict ", key);
+ fprintf(stderr, "check call at %s:%d\n", qerror->file, qerror->linenr);
+ abort();
+}
+
+static void parse_error(const QError *qerror, int c)
+{
+ fprintf(stderr, ERROR_PREFIX "expected '%c'", c);
+ qerror_abort(qerror);
+}
+
+static const char *print_field(const QError *qerror, const char *start)
+{
+ int type;
+ QDict *qdict;
+ char *name;
+ const char *end;
+
+ if (*start != '%')
+ parse_error(qerror, '%');
+ start++;
+ if (*start != '(')
+ parse_error(qerror, '(');
+ start++;
+
+ end = strchr(start, ')');
+ if (!end)
+ parse_error(qerror, ')');
+
+ name = get_substr(start, end - 1);
+ qdict = qobject_to_qdict(qerror->data);
+
+ if (!qdict_haskey(qdict, name)) {
+ key_error(qerror, name);
+ }
+
+ type = *++end;
+ switch (type) {
+ case 's':
+ qemu_error("%s", qdict_get_str(qdict, name));
+ break;
+ case 'd':
+ qemu_error("%" PRId64, qdict_get_int(qdict, name));
+ break;
+ default:
+ type_error(qerror, type);
+ }
+
+ qemu_free(name);
+ 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 ou Monitor's device).
+ */
+void qerror_print(const QError *qerror)
+{
+ const char *p;
+
+ for (p = qerror->entry->desc; *p != '\0'; p++) {
+ if (*p == '%') {
+ if (*(p + 1) == '%') {
+ p++;
+ } else {
+ p = print_field(qerror, p);
+ if (*p == '\0') {
+ break;
+ }
+ }
+ }
+
+ /*
+ * FIXME: This is inefficient, qemu_error() likes strings
+ */
+ qemu_error("%c", *p);
+ }
+
+ qemu_error("\n");
+}
+
+/**
+ * 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);
+
+ qobject_decref(qerr->data);
+ qemu_free(qerr);
+}
diff --git a/qerror.h b/qerror.h
new file mode 100644
index 0000000..2fd0d58
--- /dev/null
+++ b/qerror.h
@@ -0,0 +1,48 @@
+/*
+ * QError header file.
+ *
+ * Copyright (C) 2009 Red Hat Inc.
+ *
+ * Authors:
+ * Luiz Capitulino <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+#ifndef QERROR_H
+#define QERROR_H
+
+#include <stdarg.h>
+#include "qobject.h"
+
+/*
+ * IMPORTANT: errors numbers must not change after they have been
+ * added here.
+ */
+typedef enum QErrorCode {
+ QERR_UNKNOWN,
+ QERR_MAX,
+} QErrorCode;
+
+struct QError;
+
+typedef struct QErrorTable {
+ QErrorCode code;
+ const char *desc;
+} QErrorTable;
+
+typedef struct QError {
+ QObject_HEAD;
+ int linenr; /* error line number */
+ const char *file; /* error file */
+ QObject *data; /* error specific data */
+ const QErrorTable *entry;
+} QError;
+
+QError *qerror_new(void);
+QError *qerror_from_info(QErrorCode code, const char *file, int linenr,
+ const char *fmt, va_list *va);
+void qerror_print(const QError *qerror);
+QError *qobject_to_qerror(const QObject *obj);
+
+#endif /* QERROR_H */
diff --git a/qobject.h b/qobject.h
index 167b607..838dddc 100644
--- a/qobject.h
+++ b/qobject.h
@@ -43,6 +43,7 @@ typedef enum {
QTYPE_QLIST,
QTYPE_QFLOAT,
QTYPE_QBOOL,
+ QTYPE_QERROR,
} qtype_code;
struct QObject;
--
1.6.5.2.74.g610f9
- [Qemu-devel] [RFC 0/7] QError v1, Luiz Capitulino, 2009/10/29
- [Qemu-devel] [PATCH 1/7] QJSon: Introduce qobject_from_json_va(), Luiz Capitulino, 2009/10/29
- [Qemu-devel] [PATCH 2/7] Introduce QError,
Luiz Capitulino <=
- [Qemu-devel] Re: [PATCH 2/7] Introduce QError, Anthony Liguori, 2009/10/29
- [Qemu-devel] Re: [PATCH 2/7] Introduce QError, Luiz Capitulino, 2009/10/29
- [Qemu-devel] Re: [PATCH 2/7] Introduce QError, Paolo Bonzini, 2009/10/29
- Re: [Qemu-devel] Re: [PATCH 2/7] Introduce QError, Jamie Lokier, 2009/10/29
- [Qemu-devel] Re: [PATCH 2/7] Introduce QError, Anthony Liguori, 2009/10/30
- [Qemu-devel] Re: [PATCH 2/7] Introduce QError, Luiz Capitulino, 2009/10/30
[Qemu-devel] [PATCH 3/7] monitor: QError support, Luiz Capitulino, 2009/10/29
[Qemu-devel] [PATCH 4/7] QError: Add QERR_DEV_NFOUND, Luiz Capitulino, 2009/10/29
[Qemu-devel] [PATCH 5/7] qdev: Use QError for not found error, Luiz Capitulino, 2009/10/29
[Qemu-devel] [PATCH 6/7] QError: Add do_info_balloon() errors, Luiz Capitulino, 2009/10/29