[Qemu-devel] [PATCH V10 1/4] add def_print_str and use it in qemu_opts_print.

[Dong Xu Wang <wdongxu@linux.vnet.ibm.com>]

qemu_opts_print has no user now, so can re-write the function safely.

qemu_opts_print will be used while using "qemu-img create", it will
produce the same output as previous code.

The behavior of this function has changed:

1. Print every possible option, whether a value has been set or not.
2. Option descriptors may provide a default value.
3. Print to stdout instead of stderr.

Previously the behavior was to print every option that has been set.
Options that have not been set would be skipped.

Signed-off-by: Dong Xu Wang <wdongxu@linux.vnet.ibm.com>
---
v7->v8:
1) print "elements => accept any params" while opts_accepts_any() ==
true.
2) since def_print_str is the default value if an option isn't set,
so rename it to def_value_str.

 include/qemu/option.h |    1 +
 qemu-option.c         |   31 ++++++++++++++++++++++++-------
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/include/qemu/option.h b/include/qemu/option.h
index ba197cd..394170a 100644
--- a/include/qemu/option.h
+++ b/include/qemu/option.h
@@ -96,6 +96,7 @@ typedef struct QemuOptDesc {
     const char *name;
     enum QemuOptType type;
     const char *help;
+    const char *def_value_str;
 } QemuOptDesc;
 
 struct QemuOptsList {
diff --git a/qemu-option.c b/qemu-option.c
index f532b76..6f19fd3 100644
--- a/qemu-option.c
+++ b/qemu-option.c
@@ -862,15 +862,32 @@ void qemu_opts_del(QemuOpts *opts)
 
 int qemu_opts_print(QemuOpts *opts, void *dummy)
 {
-    QemuOpt *opt;
+    QemuOptDesc *desc = opts->list->desc;
 
-    fprintf(stderr, "%s: %s:", opts->list->name,
-            opts->id ? opts->id : "<noid>");
-    QTAILQ_FOREACH(opt, &opts->head, next) {
-        fprintf(stderr, " %s=\"%s\"", opt->name, opt->str);
+    if (desc[0].name == NULL) {
+        printf("no elements => accept any params");
+        return 0;
     }
-    fprintf(stderr, "\n");
-    return 0;
+    for (; desc && desc->name; desc++) {
+        const char *value = desc->def_value_str;
+        QemuOpt *opt;
+
+        opt = qemu_opt_find(opts, desc->name);
+        if (opt) {
+            value = opt->str;
+        }
+
+        if (!value) {
+            continue;
+        }
+
+        if (desc->type == QEMU_OPT_STRING) {
+            printf("%s='%s' ", desc->name, value);
+        } else {
+            printf("%s=%s ", desc->name, value);
+        }
+    }
+     return 0;
 }
 
 static int opts_do_parse(QemuOpts *opts, const char *params,
-- 
1.7.1