Re: [Qemu-devel] [PATCH v2 2/4] scripts: qmp-shell: Expand support for QMP expressions

[John Snow]

On 04/22/2015 12:21 PM, John Snow wrote:
> This includes support for [] expressions, single-quotes in
> QMP expressions (which is not strictly a part of JSON), and
> the ability to use "True" or "False" literals instead of
> JSON's lowercased 'true' and 'false' literals.
>
> qmp-shell currently allows you to describe values as
> JSON expressions:
> key={"key":{"key2":"val"}}
>
> But it does not currently support arrays, which are needed
> for serializing and deserializing transactions:
> key=[{"type":"drive-backup","data":{...}}]
>
> qmp-shell also only currently accepts doubly quoted strings
> as-per JSON spec, but QMP allows single quotes.
>
> Lastly, python allows you to utilize "True" or "False" as
> boolean literals, but JSON expects "true" or "false". Expand
> qmp-shell to allow the user to type either, converting to the
> correct type.
>
> As a consequence of the above, the key=val parsing is also improved
> to give better error messages if a key=val token is not provided.
>
> CAVEAT: The parser is still extremely rudimentary and does not
> expect to find spaces in {} nor [] expressions. This patch does
> not improve this functionality.
>
> Signed-off-by: John Snow <address@hidden>
> ---
>   scripts/qmp/qmp-shell | 44 ++++++++++++++++++++++++++++----------------
>   1 file changed, 28 insertions(+), 16 deletions(-)

Left a line dangling in my local tree by accident:

diff --git a/scripts/qmp/qmp-shell b/scripts/qmp/qmp-shell
index 4cdcb6c..e7b40eb 100755
--- a/scripts/qmp/qmp-shell
+++ b/scripts/qmp/qmp-shell
@@ -32,6 +32,7 @@

 import qmp
 import json
+import ast
 import readline
 import sys
 import pprint


> diff --git a/scripts/qmp/qmp-shell b/scripts/qmp/qmp-shell
> index a9632ec..4cdcb6c 100755
> --- a/scripts/qmp/qmp-shell
> +++ b/scripts/qmp/qmp-shell
> @@ -88,23 +88,35 @@ class QMPShell(qmp.QEMUMonitorProtocol):
>           # clearing everything as it doesn't seem to matter
>           readline.set_completer_delims('')
>
> +    def __parse_value(self, val):
> +        try:
> +            return int(val)
> +        except ValueError:
> +            pass
> +
> +        if val.lower() == 'true':
> +            return True
> +        if val.lower() == 'false':
> +            return False
> +        if val.startswith(('{', '[')):
> +            try:
> +                return json.loads(val)
> +            except ValueError:
> +                pass
> +            try:
> +                return ast.literal_eval(val)
> +            except SyntaxError:
> +                pass
> +        return val
> +
>       def __cli_expr(self, tokens, parent):
>           for arg in tokens:
> -            opt = arg.split('=')
> -            try:
> -                if(len(opt) > 2):
> -                    opt[1] = '='.join(opt[1:])
> -                value = int(opt[1])
> -            except ValueError:
> -                if opt[1] == 'true':
> -                    value = True
> -                elif opt[1] == 'false':
> -                    value = False
> -                elif opt[1].startswith('{'):
> -                    value = json.loads(opt[1])
> -                else:
> -                    value = opt[1]
> -            optpath = opt[0].split('.')
> +            (key, _, val) = arg.partition('=')
> +            if not val:
> +                raise QMPShellError("Expected a key=value pair, got '%s'" % 
> arg)
> +
> +            value = __parse_value(val)
> +            optpath = key.split('.')
>               curpath = []
>               for p in optpath[:-1]:
>                   curpath.append(p)
> @@ -117,7 +129,7 @@ class QMPShell(qmp.QEMUMonitorProtocol):
>                   if type(parent[optpath[-1]]) is dict:
>                       raise QMPShellError('Cannot use "%s" as both leaf and 
> non-leaf key' % '.'.join(curpath))
>                   else:
> -                    raise QMPShellError('Cannot set "%s" multiple times' % 
> opt[0])
> +                    raise QMPShellError('Cannot set "%s" multiple times' % key)
>               parent[optpath[-1]] = value
>
>       def __build_cmd(self, cmdline):