Previously, function prototype prop_handler_t() in props.h is
just for setting and getting @value. However, it prints @value
directly instead of returns the value. It was difficult to get
@value by @name.
For code-reuse, here divide prop_handler_t into three handlers:
1) prop_setter_t: set @value as origin.
2) prop_getter_t:
if arg @value is NULL, return the length of result for
caller to allocate.
else copy result to memory space which arg @value points to.
3) prop_printer_t: just call correspond prop_getter_t and
prints result.
Notice:
Since C language has no feature like tpyeinfo in others.
After return of prop_getter_t(), the arg @value will point
to array of characters without null-terminated.
Signed-off-by: Su Yue <suy.f...@cn.fujitsu.com>
---
cmds-property.c | 7 +++++--
props.c | 11 +++++++----
props.h | 19 +++++++++++++++----
3 files changed, 27 insertions(+), 10 deletions(-)
diff --git a/cmds-property.c b/cmds-property.c
index 03bafa054701..6795d1795027 100644
--- a/cmds-property.c
+++ b/cmds-property.c
@@ -180,7 +180,7 @@ static int dump_prop(const struct prop_handler *prop,
if ((types & type) && (prop->types & type)) {
if (!name_and_help)
- ret = prop->handler(type, object, prop->name, NULL);
+ ret = prop->printer(type, object, prop->name);
else
printf("%-20s%s\n", prop->name, prop->desc);
}
@@ -244,7 +244,10 @@ static int setget_prop(int types, const char *object,
goto out;
}
- ret = prop->handler(types, object, name, value);
+ if (value)
+ ret = prop->setter(types, object, name, value);
+ else
+ ret = prop->printer(types, object, name);
if (ret < 0)
ret = 50;
diff --git a/props.c b/props.c
index cddbd9272fe4..d6249f53887d 100644
--- a/props.c
+++ b/props.c
@@ -188,10 +188,13 @@ out:
const struct prop_handler prop_handlers[] = {
{"ro", "Set/get read-only flag of subvolume.", 0, prop_object_subvol,
- prop_read_only},
+ NULL, NULL, NULL},
+
{"label", "Set/get label of device.", 0,
- prop_object_dev | prop_object_root, prop_label},
+ prop_object_dev | prop_object_root, NULL, NULL, NULL},
+
{"compression", "Set/get compression for a file or directory", 0,
- prop_object_inode, prop_compression},
- {NULL, NULL, 0, 0, NULL}
+ prop_object_inode, NULL, NULL, NULL},
+
+ {NULL, NULL, 0, 0, NULL, NULL, NULL}
};
diff --git a/props.h b/props.h
index a43cb2537f37..fd5796bff09d 100644
--- a/props.h
+++ b/props.h
@@ -17,6 +17,8 @@
#ifndef __BTRFS_PROPS_H__
#define __BTRFS_PROPS_H__
+#include <unistd.h>
+
enum prop_object_type {
prop_object_dev = (1 << 0),
prop_object_root = (1 << 1),
@@ -25,17 +27,26 @@ enum prop_object_type {
__prop_object_max,
};
-typedef int (*prop_handler_t)(enum prop_object_type type,
+typedef int (*prop_setter_t)(enum prop_object_type type,
+ const char *object,
+ const char *name,
+ const char *value);
+typedef ssize_t (*prop_getter_t)(enum prop_object_type type,
+ const char *object,
+ const char *name,
+ char *value);
+typedef int (*prop_printer_t)(enum prop_object_type type,
const char *object,
- const char *name,
- const char *value);
+ const char *name);
struct prop_handler {
const char *name;
const char *desc;
int read_only;
int types;
- prop_handler_t handler;
+ prop_setter_t setter;
+ prop_getter_t getter;
+ prop_printer_t printer;
};
extern const struct prop_handler prop_handlers[];
--
2.15.0
--
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