From: Luiz Capitulino <lcapitul...@redhat.com>
New error-handling framework that allows for exception-like error
propagation.
Signed-off-by: Luiz Capitulino <lcapitul...@redhat.com>
Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com>
---
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 90838f6..0f7bb52 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -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))
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 <aligu...@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;
+}
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 <aligu...@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
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 <aligu...@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
--
1.7.0.4
