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    qapi: Swap visit_* arguments for consistent 'name' placement · 51e72bc1
    Eric Blake authored
    
    
    JSON uses "name":value, but many of our visitor interfaces were
    called with visit_type_FOO(v, &value, name, errp).  This can be
    a bit confusing to have to mentally swap the parameter order to
    match JSON order.  It's particularly bad for visit_start_struct(),
    where the 'name' parameter is smack in the middle of the
    otherwise-related group of 'obj, kind, size' parameters! It's
    time to do a global swap of the parameter ordering, so that the
    'name' parameter is always immediately after the Visitor argument.
    
    Additional reason in favor of the swap: the existing include/qjson.h
    prefers listing 'name' first in json_prop_*(), and I have plans to
    unify that file with the qapi visitors; listing 'name' first in
    qapi will minimize churn to the (admittedly few) qjson.h clients.
    
    Later patches will then fix docs, object.h, visitor-impl.h, and
    those clients to match.
    
    Done by first patching scripts/qapi*.py by hand to make generated
    files do what I want, then by running the following Coccinelle
    script to affect the rest of the code base:
     $ spatch --sp-file script `git grep -l '\bvisit_' -- '**/*.[ch]'`
    I then had to apply some touchups (Coccinelle insisted on TAB
    indentation in visitor.h, and botched the signature of
    visit_type_enum() by rewriting 'const char *const strings[]' to
    the syntactically invalid 'const char*const[] strings').  The
    movement of parameters is sufficient to provoke compiler errors
    if any callers were missed.
    
        // Part 1: Swap declaration order
        @@
        type TV, TErr, TObj, T1, T2;
        identifier OBJ, ARG1, ARG2;
        @@
         void visit_start_struct
        -(TV v, TObj OBJ, T1 ARG1, const char *name, T2 ARG2, TErr errp)
        +(TV v, const char *name, TObj OBJ, T1 ARG1, T2 ARG2, TErr errp)
         { ... }
    
        @@
        type bool, TV, T1;
        identifier ARG1;
        @@
         bool visit_optional
        -(TV v, T1 ARG1, const char *name)
        +(TV v, const char *name, T1 ARG1)
         { ... }
    
        @@
        type TV, TErr, TObj, T1;
        identifier OBJ, ARG1;
        @@
         void visit_get_next_type
        -(TV v, TObj OBJ, T1 ARG1, const char *name, TErr errp)
        +(TV v, const char *name, TObj OBJ, T1 ARG1, TErr errp)
         { ... }
    
        @@
        type TV, TErr, TObj, T1, T2;
        identifier OBJ, ARG1, ARG2;
        @@
         void visit_type_enum
        -(TV v, TObj OBJ, T1 ARG1, T2 ARG2, const char *name, TErr errp)
        +(TV v, const char *name, TObj OBJ, T1 ARG1, T2 ARG2, TErr errp)
         { ... }
    
        @@
        type TV, TErr, TObj;
        identifier OBJ;
        identifier VISIT_TYPE =~ "^visit_type_";
        @@
         void VISIT_TYPE
        -(TV v, TObj OBJ, const char *name, TErr errp)
        +(TV v, const char *name, TObj OBJ, TErr errp)
         { ... }
    
        // Part 2: swap caller order
        @@
        expression V, NAME, OBJ, ARG1, ARG2, ERR;
        identifier VISIT_TYPE =~ "^visit_type_";
        @@
        (
        -visit_start_struct(V, OBJ, ARG1, NAME, ARG2, ERR)
        +visit_start_struct(V, NAME, OBJ, ARG1, ARG2, ERR)
        |
        -visit_optional(V, ARG1, NAME)
        +visit_optional(V, NAME, ARG1)
        |
        -visit_get_next_type(V, OBJ, ARG1, NAME, ERR)
        +visit_get_next_type(V, NAME, OBJ, ARG1, ERR)
        |
        -visit_type_enum(V, OBJ, ARG1, ARG2, NAME, ERR)
        +visit_type_enum(V, NAME, OBJ, ARG1, ARG2, ERR)
        |
        -VISIT_TYPE(V, OBJ, NAME, ERR)
        +VISIT_TYPE(V, NAME, OBJ, ERR)
        )
    
    Signed-off-by: default avatarEric Blake <eblake@redhat.com>
    Reviewed-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
    Message-Id: <1454075341-13658-19-git-send-email-eblake@redhat.com>
    Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
    51e72bc1