QemuOpts: add qemu_opt_get_*_del functions for replace work

Add qemu_opt_get_del, qemu_opt_get_bool_del, qemu_opt_get_number_del and
qemu_opt_get_size_del to replace the same handling of QEMUOptionParameter
(get and delete).

Several drivers are coded to parse a known subset of options, then
remove them from the list before handing all remaining options to a
second driver for further option processing.  get_*_del makes it easier
to retrieve a known option (or its default) and remove it from the list
all in one action.

Share common helper function:

For qemu_opt_get_bool/size/number, they and their get_*_del counterpart
could share most of the code except whether or not deleting the opt from
option list, so generate common helper functions.

For qemu_opt_get and qemu_opt_get_del, keep code duplication, since
1. qemu_opt_get_del returns malloc'd memory while qemu_opt_get returns
in-place memory
2. qemu_opt_get_del returns (char *), qemu_opt_get returns (const char *),
and could not change to (char *), since in one case, it will return
desc->def_value_str, which is (const char *).

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
Signed-off-by: Chunyan Liu <cyliu@suse.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

2 files changed, 110 insertions, 13 deletions

diff --git a/include/qemu/option.h b/include/qemu/option.h
index c3b0a917d9..6653e4300b 100644
--- a/include/qemu/option.h
+++ b/include/qemu/option.h
@@ -111,6 +111,7 @@ struct QemuOptsList {
 };
 
 const char *qemu_opt_get(QemuOpts *opts, const char *name);
+char *qemu_opt_get_del(QemuOpts *opts, const char *name);
 /**
  * qemu_opt_has_help_opt:
  * @opts: options to search for a help request
@@ -126,6 +127,11 @@ bool qemu_opt_has_help_opt(QemuOpts *opts);
 bool qemu_opt_get_bool(QemuOpts *opts, const char *name, bool defval);
 uint64_t qemu_opt_get_number(QemuOpts *opts, const char *name, uint64_t defval);
 uint64_t qemu_opt_get_size(QemuOpts *opts, const char *name, uint64_t defval);
+bool qemu_opt_get_bool_del(QemuOpts *opts, const char *name, bool defval);
+uint64_t qemu_opt_get_number_del(QemuOpts *opts, const char *name,
+                                 uint64_t defval);
+uint64_t qemu_opt_get_size_del(QemuOpts *opts, const char *name,
+                               uint64_t defval);
 int qemu_opt_unset(QemuOpts *opts, const char *name);
 int qemu_opt_set(QemuOpts *opts, const char *name, const char *value);
 void qemu_opt_set_err(QemuOpts *opts, const char *name, const char *value,
diff --git a/util/qemu-option.c b/util/qemu-option.c
index 71244836c3..a7330c6321 100644
--- a/util/qemu-option.c
+++ b/util/qemu-option.c
@@ -575,6 +575,20 @@ static void qemu_opt_del(QemuOpt *opt)
     g_free(opt);
 }
 
+/* qemu_opt_set allows many settings for the same option.
+ * This function deletes all settings for an option.
+ */
+static void qemu_opt_del_all(QemuOpts *opts, const char *name)
+{
+    QemuOpt *opt, *next_opt;
+
+    QTAILQ_FOREACH_SAFE(opt, &opts->head, next, next_opt) {
+        if (!strcmp(opt->name, name)) {
+            qemu_opt_del(opt);
+        }
+    }
+}
+
 const char *qemu_opt_get(QemuOpts *opts, const char *name)
 {
     QemuOpt *opt = qemu_opt_find(opts, name);
@@ -588,6 +602,34 @@ const char *qemu_opt_get(QemuOpts *opts, const char *name)
     return opt ? opt->str : NULL;
 }
 
+/* Get a known option (or its default) and remove it from the list
+ * all in one action. Return a malloced string of the option value.
+ * Result must be freed by caller with g_free().
+ */
+char *qemu_opt_get_del(QemuOpts *opts, const char *name)
+{
+    QemuOpt *opt;
+    const QemuOptDesc *desc;
+    char *str = NULL;
+
+    if (opts == NULL) {
+        return NULL;
+    }
+
+    opt = qemu_opt_find(opts, name);
+    if (!opt) {
+        desc = find_desc_by_name(opts->list->desc, name);
+        if (desc && desc->def_value_str) {
+            str = g_strdup(desc->def_value_str);
+        }
+        return str;
+    }
+    str = opt->str;
+    opt->str = NULL;
+    qemu_opt_del_all(opts, name);
+    return str;
+}
+
 bool qemu_opt_has_help_opt(QemuOpts *opts)
 {
     QemuOpt *opt;
@@ -600,50 +642,99 @@ bool qemu_opt_has_help_opt(QemuOpts *opts)
     return false;
 }
 
-bool qemu_opt_get_bool(QemuOpts *opts, const char *name, bool defval)
+static bool qemu_opt_get_bool_helper(QemuOpts *opts, const char *name,
+                                     bool defval, bool del)
 {
     QemuOpt *opt = qemu_opt_find(opts, name);
+    bool ret = defval;
 
     if (opt == NULL) {
         const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
         if (desc && desc->def_value_str) {
-            parse_option_bool(name, desc->def_value_str, &defval, &error_abort);
+            parse_option_bool(name, desc->def_value_str, &ret, &error_abort);
         }
-        return defval;
+        return ret;
     }
     assert(opt->desc && opt->desc->type == QEMU_OPT_BOOL);
-    return opt->value.boolean;
+    ret = opt->value.boolean;
+    if (del) {
+        qemu_opt_del_all(opts, name);
+    }
+    return ret;
 }
 
-uint64_t qemu_opt_get_number(QemuOpts *opts, const char *name, uint64_t defval)
+bool qemu_opt_get_bool(QemuOpts *opts, const char *name, bool defval)
+{
+    return qemu_opt_get_bool_helper(opts, name, defval, false);
+}
+
+bool qemu_opt_get_bool_del(QemuOpts *opts, const char *name, bool defval)
+{
+    return qemu_opt_get_bool_helper(opts, name, defval, true);
+}
+
+static uint64_t qemu_opt_get_number_helper(QemuOpts *opts, const char *name,
+                                           uint64_t defval, bool del)
 {
     QemuOpt *opt = qemu_opt_find(opts, name);
+    uint64_t ret = defval;
 
     if (opt == NULL) {
         const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
         if (desc && desc->def_value_str) {
-            parse_option_number(name, desc->def_value_str, &defval,
-                                &error_abort);
+            parse_option_number(name, desc->def_value_str, &ret, &error_abort);
         }
-        return defval;
+        return ret;
     }
     assert(opt->desc && opt->desc->type == QEMU_OPT_NUMBER);
-    return opt->value.uint;
+    ret = opt->value.uint;
+    if (del) {
+        qemu_opt_del_all(opts, name);
+    }
+    return ret;
 }
 
-uint64_t qemu_opt_get_size(QemuOpts *opts, const char *name, uint64_t defval)
+uint64_t qemu_opt_get_number(QemuOpts *opts, const char *name, uint64_t defval)
+{
+    return qemu_opt_get_number_helper(opts, name, defval, false);
+}
+
+uint64_t qemu_opt_get_number_del(QemuOpts *opts, const char *name,
+                                 uint64_t defval)
+{
+    return qemu_opt_get_number_helper(opts, name, defval, true);
+}
+
+static uint64_t qemu_opt_get_size_helper(QemuOpts *opts, const char *name,
+                                         uint64_t defval, bool del)
 {
     QemuOpt *opt = qemu_opt_find(opts, name);
+    uint64_t ret = defval;
 
     if (opt == NULL) {
         const QemuOptDesc *desc = find_desc_by_name(opts->list->desc, name);
         if (desc && desc->def_value_str) {
-            parse_option_size(name, desc->def_value_str, &defval, &error_abort);
+            parse_option_size(name, desc->def_value_str, &ret, &error_abort);
         }
-        return defval;
+        return ret;
     }
     assert(opt->desc && opt->desc->type == QEMU_OPT_SIZE);
-    return opt->value.uint;
+    ret = opt->value.uint;
+    if (del) {
+        qemu_opt_del_all(opts, name);
+    }
+    return ret;
+}
+
+uint64_t qemu_opt_get_size(QemuOpts *opts, const char *name, uint64_t defval)
+{
+    return qemu_opt_get_size_helper(opts, name, defval, false);
+}
+
+uint64_t qemu_opt_get_size_del(QemuOpts *opts, const char *name,
+                               uint64_t defval)
+{
+    return qemu_opt_get_size_helper(opts, name, defval, true);
 }
 
 static void qemu_opt_parse(QemuOpt *opt, Error **errp)