On 9/25/18 10:39 AM, John Arbuckle wrote:
Add the ability for the user to display help for a certain command.
Example: qemu-img create --help
What is printed is all the options available to this command and an example.
Signed-off-by: John Arbuckle <programmingk...@gmail.com>
---
v3 changes:
Fixed a bug that caused qemu-img to crash when running a command without
options.
Hmm, I just reviewed v2 without noticing that you had posted v3.
v2 changes:
Removed block of string comparison code for each command.
Added a help_func field to the img_cmd_t struct.
Made strings longer than 80 characters wide.
qemu-img.c | 660 +++++++++++++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 559 insertions(+), 101 deletions(-)
My v2 comment about splitting this into more reviewable portions still
applies.
+++ b/qemu-img.c
@@ -52,6 +52,7 @@
typedef struct img_cmd_t {
const char *name;
int (*handler)(int argc, char **argv);
+ void (*help_func)(void);
} img_cmd_t;
As does my complaint that you want to track the command synopses here in
this struct for reuse in multiple contexts later, rather than...
+static void help_amend(void)
+{
+ const char *msg =
+ "\n"
+ "usage: qemu-img amend [--object objectdef] [--image-opts] [-p] [-q] [-f
fmt]\n"
+ "[-t cache] -o options filename\n"
repeating things that are in qemu-img-cmds.h and risking them getting
out of sync.
-static const img_cmd_t img_cmds[] = {
+static img_cmd_t img_cmds[] = {
#define DEF(option, callback, arg_string) \
{ option, callback },
#include "qemu-img-cmds.h"
@@ -4894,6 +5334,12 @@ static const img_cmd_t img_cmds[] = {
{ NULL, NULL, },
};
+/* These functions will be added to the img_cmds array */
+void (*help_functions[])(void) = {help_amend, help_bench, help_check,\
+ help_commit, help_compare, help_convert, help_create, help_dd, help_info,\
+ help_map, help_measure, help_snapshot, help_rebase, help_resize};
And my biggest gripe, that this approach to initialization is dead
wrong, is still applicable.
Overall, I like the end result that you are trying to reach. (I'm not
always a fan of having to run 'command --help' followed by 'command
subcommand --help' to learn everything, but it sure beats a wall of
text, and we have at least 'git' and 'cvs' as examples of programs that
have used that approach, so we are not inventing something new). But
you'll need a v4, and preferably broken up into something easier to
review (one patch per command, rather than a wholesale rewrite in go),
if you want to get it in.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
