[Qemu-devel] [RFC 2/8] qapi: add QemuFileOutputVisitor

[Michael Roth <mdroth@linux.vnet.ibm.com>]

Visitor interface to write values to a QEMUFile.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 Makefile.objs                   |   16 +-
 qapi/qemu-file-output-visitor.c |  353 +++++++++++++++++++++++++++++++++++++++
 qapi/qemu-file-output-visitor.h |   26 +++
 3 files changed, 388 insertions(+), 7 deletions(-)
 create mode 100644 qapi/qemu-file-output-visitor.c
 create mode 100644 qapi/qemu-file-output-visitor.h

diff --git a/Makefile.objs b/Makefile.objs
index 62020d7..48fe0c4 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -20,6 +20,13 @@ coroutine-obj-$(CONFIG_POSIX) += coroutine-gthread.o
 endif
 coroutine-obj-$(CONFIG_WIN32) += coroutine-win32.o
 
+######################################################################
+# qapi
+
+qapi-nested-y = qapi-visit-core.o qmp-input-visitor.o qmp-output-visitor.o qapi-dealloc-visitor.o
+qapi-nested-y += qmp-registry.o qmp-dispatch.o
+qapi-obj-y = $(addprefix qapi/, $(qapi-nested-y))
+
 #######################################################################
 # block-obj-y is code used by both qemu system emulation and qemu-img
 
@@ -73,6 +80,8 @@ fsdev-obj-$(CONFIG_VIRTFS) += $(addprefix fsdev/, $(fsdev-nested-y))
 # CPUs and machines.
 
 common-obj-y = $(block-obj-y) blockdev.o
+common-obj-y += $(qapi-obj-y)
+common-obj-y += qapi/qemu-file-output-visitor.o
 common-obj-y += $(net-obj-y)
 common-obj-y += $(qobject-obj-y)
 common-obj-$(CONFIG_LINUX) += $(fsdev-obj-$(CONFIG_LINUX))
@@ -399,13 +408,6 @@ $(trace-obj-y): $(GENERATED_HEADERS)
 libcacard-y = cac.o event.o vcard.o vreader.o vcard_emul_nss.o vcard_emul_type.o card_7816.o
 
 ######################################################################
-# qapi
-
-qapi-nested-y = qapi-visit-core.o qmp-input-visitor.o qmp-output-visitor.o qapi-dealloc-visitor.o
-qapi-nested-y += qmp-registry.o qmp-dispatch.o
-qapi-obj-y = $(addprefix qapi/, $(qapi-nested-y))
-
-######################################################################
 # guest agent
 
 qga-nested-y = guest-agent-commands.o guest-agent-command-state.o
diff --git a/qapi/qemu-file-output-visitor.c b/qapi/qemu-file-output-visitor.c
new file mode 100644
index 0000000..c44b76c
--- /dev/null
+++ b/qapi/qemu-file-output-visitor.c
@@ -0,0 +1,353 @@
+/*
+ * QEMUFile Output Visitor
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Michael Roth   <mdroth@linux.vnet.ibm.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 "qemu-file-output-visitor.h"
+#include "qemu-queue.h"
+#include "qemu-common.h"
+#include "qemu-objects.h"
+#include "hw/hw.h"
+#include "qerror.h"
+
+typedef struct {
+    size_t elem_count;
+    size_t elem_size;
+    size_t pos;
+} ArrayInfo;
+
+typedef struct StackEntry
+{
+    enum {
+        QFOV_ARRAY,
+        QFOV_LIST,
+        QFOV_STRUCT,
+    } type;
+    ArrayInfo array_info;
+    bool is_list_head;
+    QTAILQ_ENTRY(StackEntry) node;
+} StackEntry;
+
+struct QemuFileOutputVisitor
+{
+    Visitor visitor;
+    QTAILQ_HEAD(, StackEntry) stack;
+    QEMUFile *file;
+};
+
+static QemuFileOutputVisitor *to_ov(Visitor *v)
+{
+    return container_of(v, QemuFileOutputVisitor, visitor);
+}
+
+static void qemu_file_output_push(QemuFileOutputVisitor *ov, StackEntry *e)
+{
+    QTAILQ_INSERT_HEAD(&ov->stack, e, node);
+}
+
+static void qemu_file_output_push_array(QemuFileOutputVisitor *ov, ArrayInfo ai)
+{
+    StackEntry *e = g_malloc0(sizeof(*e));
+    e->type = QFOV_ARRAY;
+    e->array_info = ai;
+    qemu_file_output_push(ov, e);
+}
+
+static void qemu_file_output_push_list(QemuFileOutputVisitor *ov)
+{
+    StackEntry *e = g_malloc0(sizeof(*e));
+    e->type = QFOV_LIST;
+    e->is_list_head = true;
+    qemu_file_output_push(ov, e);
+}
+
+static void qemu_file_output_push_struct(QemuFileOutputVisitor *ov)
+{
+    StackEntry *e = g_malloc0(sizeof(*e));
+    e->type = QFOV_STRUCT;
+    qemu_file_output_push(ov, e);
+}
+
+static StackEntry *qemu_file_output_pop(QemuFileOutputVisitor *ov)
+{
+    StackEntry *e = QTAILQ_FIRST(&ov->stack);
+    QTAILQ_REMOVE(&ov->stack, e, node);
+    return e;
+}
+
+static bool qemu_file_output_is_array(QemuFileOutputVisitor *ov)
+{
+    StackEntry *e = QTAILQ_FIRST(&ov->stack);
+    return e && e->type == QFOV_ARRAY;
+}
+
+static bool qemu_file_output_is_list(QemuFileOutputVisitor *ov)
+{
+    StackEntry *e = QTAILQ_FIRST(&ov->stack);
+    return e && e->type == QFOV_LIST;
+}
+
+static void qemu_file_output_start_struct(Visitor *v, void **obj,
+                                          const char *kind, const char *name,
+                                          size_t unused, Error **errp)
+{
+    QemuFileOutputVisitor *ov = to_ov(v);
+
+    if (!obj || *obj == NULL) {
+        error_set(errp, QERR_INVALID_PARAMETER, "obj");
+    }
+    qemu_file_output_push_struct(ov);
+}
+
+static void qemu_file_output_end_struct(Visitor *v, Error **errp)
+{
+    QemuFileOutputVisitor *ov = to_ov(v);
+    StackEntry *e = qemu_file_output_pop(ov);
+
+    if (!e || e->type != QFOV_STRUCT) {
+        error_set(errp, QERR_UNDEFINED_ERROR);
+        return;
+    }
+    g_free(e);
+}
+
+static void qemu_file_output_start_list(Visitor *v, const char *name,
+                                        Error **errp)
+{
+    QemuFileOutputVisitor *ov = to_ov(v);
+    qemu_file_output_push_list(ov);
+}
+
+static GenericList *qemu_file_output_next_list(Visitor *v, GenericList **list,
+                                           Error **errp)
+{
+    QemuFileOutputVisitor *ov = to_ov(v);
+    GenericList *entry = *list;
+    StackEntry *e = QTAILQ_FIRST(&ov->stack);
+
+    if (!entry || !qemu_file_output_is_list(ov)) {
+        error_set(errp, QERR_UNDEFINED_ERROR);
+    }
+
+    /* The way the list iterator is currently used unfortunately clobbers
+     * **list by subseqently assigning our return value to the same container.
+     * This can cause an infinite loop, but we can get around this by tracking
+     * a bit of state to note when we should pass back the next entry rather
+     * than the current one.
+     */
+    if (e->is_list_head) {
+        e->is_list_head = false;
+        return entry;
+    }
+
+    *list = entry->next;
+    return entry->next;
+}
+
+static void qemu_file_output_end_list(Visitor *v, Error **errp)
+{
+    QemuFileOutputVisitor *ov = to_ov(v);
+    StackEntry *e = qemu_file_output_pop(ov);
+    if (!e || e->type != QFOV_LIST) {
+        error_set(errp, QERR_UNDEFINED_ERROR);
+    }
+    g_free(e);
+}
+
+static void qemu_file_output_start_array(Visitor *v, void **obj,
+                                         const char *name,
+                                         size_t elem_count,
+                                         size_t elem_size, Error **errp)
+{
+    QemuFileOutputVisitor *ov = to_ov(v);
+    ArrayInfo ai = {
+        .elem_count = elem_count,
+        .elem_size = elem_size,
+        .pos = 0
+    };
+    qemu_file_output_push_array(ov, ai);
+}
+
+static void qemu_file_output_next_array(Visitor *v, Error **errp)
+{
+    QemuFileOutputVisitor *ov = to_ov(v);
+    StackEntry *e = QTAILQ_FIRST(&ov->stack);
+    if (!qemu_file_output_is_array(ov) ||
+        e->array_info.pos >= e->array_info.elem_count) {
+        error_set(errp, QERR_UNDEFINED_ERROR);
+    }
+
+    e->array_info.pos++;
+}
+
+static void qemu_file_output_end_array(Visitor *v, Error **errp)
+{
+    QemuFileOutputVisitor *ov = to_ov(v);
+    StackEntry *e = qemu_file_output_pop(ov);
+    if (!e || e->type != QFOV_ARRAY) {
+        error_set(errp, QERR_UNDEFINED_ERROR);
+        return;
+    }
+    g_free(e);
+}
+
+static void qemu_file_output_type_str(Visitor *v, char **obj, const char *name,
+                                      Error **errp)
+{
+    if (obj) {
+        g_free(*obj);
+    }
+}
+
+static void qemu_file_output_type_uint8_t(Visitor *v, uint8_t *obj,
+                                          const char *name,
+                                          Error **errp)
+{
+    QemuFileOutputVisitor *ov = container_of(v, QemuFileOutputVisitor, visitor);
+    qemu_put_byte(ov->file, *obj);
+}
+
+static void qemu_file_output_type_uint16_t(Visitor *v, uint16_t *obj,
+                                           const char *name, Error **errp)
+{
+    QemuFileOutputVisitor *ov = container_of(v, QemuFileOutputVisitor, visitor);
+    qemu_put_byte(ov->file, *obj >> 8);
+    qemu_put_byte(ov->file, *obj);
+}
+
+static void qemu_file_output_type_uint32_t(Visitor *v, uint32_t *obj,
+                                           const char *name, Error **errp)
+{
+    QemuFileOutputVisitor *ov = container_of(v, QemuFileOutputVisitor, visitor);
+    qemu_put_byte(ov->file, *obj >> 24);
+    qemu_put_byte(ov->file, *obj >> 16);
+    qemu_put_byte(ov->file, *obj >> 8);
+    qemu_put_byte(ov->file, *obj);
+}
+
+static void qemu_file_output_type_uint64_t(Visitor *v, uint64_t *obj,
+                                           const char *name, Error **errp)
+{
+    QemuFileOutputVisitor *ov = container_of(v, QemuFileOutputVisitor, visitor);
+    qemu_put_byte(ov->file, *obj >> 56);
+    qemu_put_byte(ov->file, *obj >> 48);
+    qemu_put_byte(ov->file, *obj >> 40);
+    qemu_put_byte(ov->file, *obj >> 32);
+    qemu_put_byte(ov->file, *obj >> 24);
+    qemu_put_byte(ov->file, *obj >> 16);
+    qemu_put_byte(ov->file, *obj >> 8);
+    qemu_put_byte(ov->file, *obj);
+}
+
+static void qemu_file_output_type_int8_t(Visitor *v, int8_t *obj,
+                                         const char *name, Error **errp)
+{
+    QemuFileOutputVisitor *ov = container_of(v, QemuFileOutputVisitor, visitor);
+    qemu_put_sbyte(ov->file, *obj);
+}
+
+static void qemu_file_output_type_int16_t(Visitor *v, int16_t *obj,
+                                          const char *name, Error **errp)
+{
+    QemuFileOutputVisitor *ov = container_of(v, QemuFileOutputVisitor, visitor);
+    qemu_put_sbyte(ov->file, *obj >> 8);
+    qemu_put_sbyte(ov->file, *obj);
+}
+
+static void qemu_file_output_type_int32_t(Visitor *v, int32_t *obj,
+                                          const char *name, Error **errp)
+{
+    QemuFileOutputVisitor *ov = container_of(v, QemuFileOutputVisitor, visitor);
+    qemu_put_sbyte(ov->file, *obj >> 24);
+    qemu_put_sbyte(ov->file, *obj >> 16);
+    qemu_put_sbyte(ov->file, *obj >> 8);
+    qemu_put_sbyte(ov->file, *obj);
+}
+
+static void qemu_file_output_type_int64_t(Visitor *v, int64_t *obj,
+                                          const char *name, Error **errp)
+{
+    QemuFileOutputVisitor *ov = container_of(v, QemuFileOutputVisitor, visitor);
+    qemu_put_sbyte(ov->file, *obj >> 56);
+    qemu_put_sbyte(ov->file, *obj >> 48);
+    qemu_put_sbyte(ov->file, *obj >> 40);
+    qemu_put_sbyte(ov->file, *obj >> 32);
+    qemu_put_sbyte(ov->file, *obj >> 24);
+    qemu_put_sbyte(ov->file, *obj >> 16);
+    qemu_put_sbyte(ov->file, *obj >> 8);
+    qemu_put_sbyte(ov->file, *obj);
+}
+
+static void qemu_file_output_type_bool(Visitor *v, bool *obj, const char *name,
+                                   Error **errp)
+{
+    uint8_t val = *obj;
+    qemu_file_output_type_uint8_t(v, &val, name, errp);
+}
+
+static void qemu_file_output_type_number(Visitor *v, double *obj,
+                                         const char *name, Error **errp)
+{
+    uint64_t *val = (uint64_t *)obj;
+    qemu_file_output_type_uint64_t(v, val, name, errp);
+}
+
+static void qemu_file_output_type_enum(Visitor *v, int *obj,
+                                       const char *strings[],
+                                       const char *kind, const char *name,
+                                       Error **errp)
+{
+}
+
+Visitor *qemu_file_output_get_visitor(QemuFileOutputVisitor *v)
+{
+    return &v->visitor;
+}
+
+void qemu_file_output_visitor_cleanup(QemuFileOutputVisitor *ov)
+{
+    g_free(ov);
+}
+
+QemuFileOutputVisitor *qemu_file_output_visitor_new(QEMUFile *f)
+{
+    QemuFileOutputVisitor *v;
+
+    v = g_malloc0(sizeof(*v));
+
+    v->file = f;
+
+    v->visitor.start_struct = qemu_file_output_start_struct;
+    v->visitor.end_struct = qemu_file_output_end_struct;
+    v->visitor.start_list = qemu_file_output_start_list;
+    v->visitor.next_list = qemu_file_output_next_list;
+    v->visitor.end_list = qemu_file_output_end_list;
+    v->visitor.start_array = qemu_file_output_start_array;
+    v->visitor.next_array = qemu_file_output_next_array;
+    v->visitor.end_array = qemu_file_output_end_array;
+    v->visitor.type_enum = qemu_file_output_type_enum;
+    v->visitor.type_int = qemu_file_output_type_int64_t;
+    v->visitor.type_uint8_t = qemu_file_output_type_uint8_t;
+    v->visitor.type_uint16_t = qemu_file_output_type_uint16_t;
+    v->visitor.type_uint32_t = qemu_file_output_type_uint32_t;
+    v->visitor.type_uint64_t = qemu_file_output_type_uint64_t;
+    v->visitor.type_int8_t = qemu_file_output_type_int8_t;
+    v->visitor.type_int16_t = qemu_file_output_type_int16_t;
+    v->visitor.type_int32_t = qemu_file_output_type_int32_t;
+    v->visitor.type_int64_t = qemu_file_output_type_int64_t;
+    v->visitor.type_bool = qemu_file_output_type_bool;
+    v->visitor.type_str = qemu_file_output_type_str;
+    v->visitor.type_number = qemu_file_output_type_number;
+
+    QTAILQ_INIT(&v->stack);
+
+    return v;
+}
diff --git a/qapi/qemu-file-output-visitor.h b/qapi/qemu-file-output-visitor.h
new file mode 100644
index 0000000..e446f08
--- /dev/null
+++ b/qapi/qemu-file-output-visitor.h
@@ -0,0 +1,26 @@
+/*
+ * QEMUFile Visitor
+ *
+ * Copyright IBM, Corp. 2011
+ *
+ * Authors:
+ *  Michael Roth   <mdroth@linux.vnet.ibm.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.
+ *
+ */
+
+#ifndef QEMU_FILE_OUTPUT_VISITOR_H
+#define QEMU_FILE_OUTPUT_VISITOR_H
+
+#include "qapi-visit-core.h"
+
+typedef struct QemuFileOutputVisitor QemuFileOutputVisitor;
+
+QemuFileOutputVisitor *qemu_file_output_visitor_new(QEMUFile *f);
+void qemu_file_output_visitor_cleanup(QemuFileOutputVisitor *d);
+
+Visitor *qemu_file_output_get_visitor(QemuFileOutputVisitor *v);
+
+#endif
-- 
1.7.0.4