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monitor: support sub command in help

Enterprise / Virtualization / QEMU - Wenchao Xia [linux.vnet.ibm.com] - 30 August 2013 06:41 UTC

The old code in help_cmd() uses global 'info_cmds' and treats it as a special case. Actually 'info_cmds' is a sub command group of 'mon_cmds', in order to avoid direct use of it, help_cmd() needs to change its work mechanism to support sub command and not treat it as a special case any more.

To support sub command, help_cmd() will first parse the input and then call help_cmd_dump(), which works as a reentrant function. When it meets a sub command, it simply enters the function again. Since help dumping needs to know whole input to printf full help message include prefix, for example, "help info block" need to printf prefix "info", so help_cmd_dump() takes all args from input and extra parameter arg_index to identify the progress. Another function help_cmd_dump_one() is introduced to printf the prefix and command's help message.

Now help supports sub command, so later if another sub command group is added in any depth, help will automatically work for it. Still "help info block" will show error since command parser reject additional parameter, which can be improved later. "log" is still treated as a special case.

6685549 monitor: support sub command in help
monitor.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 52 insertions(+), 10 deletions(-)

Upstream: git.qemu.org