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Re: [libvirt] [PATCH 1/3] virsh: add option aliases



On 03/07/2012 03:33 PM, Osier Yang wrote:
On 03/03/2012 09:02 AM, Eric Blake wrote:
In the past, we have created some virsh options with less-than-stellar
names. For back-compat reasons, those names must continue to parse,
but we don't want to document them in help output. This introduces
a new option type, an alias, which points to a canonical option name
later in the option list.

I'm actually quite impressed that our code has already been factored
to do all option parsing through common entry points, such that I
got this added in relatively few lines of code!

* tools/virsh.c (VSH_OT_ALIAS): New option type.
(opts_echo): Hook up an alias, for easy testing.
(vshCmddefOptParse, vshCmddefHelp, vshCmddefGetOption): Allow for
aliases.
* tests/virshtest.c (mymain): Test new feature.
---
tests/virshtest.c | 6 ++++++
tools/virsh.c | 28 ++++++++++++++++++++++++++--
2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/tests/virshtest.c b/tests/virshtest.c
index 6474c19..87b1336 100644
--- a/tests/virshtest.c
+++ b/tests/virshtest.c
@@ -386,6 +386,12 @@ mymain(void)
DO_TEST(30, "--shell a\n",
"echo \t '-'\"-\" \t --shell \t a");

+ /* Tests of alias handling. */
+ DO_TEST(31, "hello\n", "echo", "--string", "hello");
+ DO_TEST(32, "hello\n", "echo --string hello");
+ DO_TEST(33, "hello\n", "echo", "--str", "hello");
+ DO_TEST(34, "hello\n", "echo --str hello");
+
# undef DO_TEST

VIR_FREE(custom_uri);
diff --git a/tools/virsh.c b/tools/virsh.c
index aef050f..77cf4ac 100644
--- a/tools/virsh.c
+++ b/tools/virsh.c
@@ -138,7 +138,8 @@ typedef enum {
VSH_OT_STRING, /* optional string option */
VSH_OT_INT, /* optional or mandatory int option */
VSH_OT_DATA, /* string data (as non-option) */
- VSH_OT_ARGV /* remaining arguments */
+ VSH_OT_ARGV, /* remaining arguments */
+ VSH_OT_ALIAS, /* alternate spelling for a later argument */
} vshCmdOptType;

/*
@@ -190,7 +191,8 @@ typedef struct {
const char *name; /* the name of option, or NULL for list end */
vshCmdOptType type; /* option type */
unsigned int flags; /* flags */
- const char *help; /* non-NULL help string */
+ const char *help; /* non-NULL help string; or for VSH_OT_ALIAS
+ * the name of a later public option */
} vshCmdOptDef;

/*
@@ -15209,6 +15211,7 @@ static const vshCmdInfo info_echo[] = {
static const vshCmdOptDef opts_echo[] = {
{"shell", VSH_OT_BOOL, 0, N_("escape for shell use")},
{"xml", VSH_OT_BOOL, 0, N_("escape for XML use")},
+ {"str", VSH_OT_ALIAS, 0, "string"},
{"string", VSH_OT_ARGV, 0, N_("arguments to echo")},
{NULL, 0, 0, NULL}
};
@@ -17256,6 +17259,18 @@ vshCmddefOptParse(const vshCmdDef *cmd,
uint32_t *opts_need_arg,
return -1; /* bool options can't be mandatory */
continue;
}
+ if (opt->type == VSH_OT_ALIAS) {
+ int j;
+ if (opt->flags || !opt->help)
+ return -1; /* alias options are tracked by the original name */
+ for (j = i + 1; cmd->opts[j].name; j++) {
+ if (STREQ(opt->help, cmd->opts[j].name))
+ break;
+ }
+ if (!cmd->opts[j].name)
+ return -1; /* alias option must map to a later option name */
+ continue;
+ }
if (opt->flags& VSH_OFLAG_REQ_OPT) {
if (opt->flags& VSH_OFLAG_REQ)
*opts_required |= 1<< i;
@@ -17287,6 +17302,10 @@ vshCmddefGetOption(vshControl *ctl, const
vshCmdDef *cmd, const char *name,
const vshCmdOptDef *opt =&cmd->opts[i];

if (STREQ(opt->name, name)) {
+ if (opt->type == VSH_OT_ALIAS) {
+ name = opt->help;
+ continue;
+ }
if ((*opts_seen& (1<< i))&& opt->type != VSH_OT_ARGV) {
vshError(ctl, _("option --%s already seen"), name);
return NULL;
@@ -17465,6 +17484,9 @@ vshCmddefHelp(vshControl *ctl, const char
*cmdname)
: _("[<%s>]...");
}
break;
+ case VSH_OT_ALIAS:
+ /* aliases are intentionally undocumented */
+ continue;
default:
assert(0);
}
@@ -17506,6 +17528,8 @@ vshCmddefHelp(vshControl *ctl, const char
*cmdname)
shortopt ? _("[--%s]<string>") : _("<%s>"),
opt->name);
break;
+ case VSH_OT_ALIAS:
+ continue;
default:
assert(0);
}

Ah, I could recall we talked about this half year before, for
creating alias ("--config") for the options "--persistent" of
commands like "attach-device", then I forgot it to do it.


I created a patch which can be served as 4/4 of these series,
for the "--persistent" changes.

Osier


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