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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 07 of 15] libxl: ocaml: support for KeyedUnion in the bindings generator
> # HG changeset patch
> # User Ian Campbell <ijc@xxxxxxxxxxxxxx> # Date 1353432141 0 # Node ID
> 0cf342afa9e6b506fad68346cb3a1207030372eb
> # Parent f618acdeea1bf60b3b68da4062de018d8162fe8c
> libxl: ocaml: support for KeyedUnion in the bindings generator.
>
> A KeyedUnion consists of two fields in the containing struct. First an enum
> field ("e") used as a descriminator and second a union ("u") containing
> potentially anonymous structs associated with each enum value.
>
> We map the anonymous structs to structs named after the descriminator
> field ("e") and the specific enum values. We then declare an ocaml variant
> type name e__union mapping each enum value to its associated struct.
>
> So given IDL:
>
> foo = Enumeration("foo",
> (0, "BAR"),
> (1, "BAZ"),
> s = Struct("s", [
> ("u", KeyedUnion(none, foo, "blargle", [
> ("bar", Struct(...xxx...)),
> ("baz", Struct(...yyy...)),
> ])),
> ])
>
> We generate C:
>
> enum { FOO, BAR } foo;
> struct s {
> enum foo blargle;
> union {
> struct { ...xxx... } bar;
> struct { ...yyy... } baz;
> } u;
> }
>
> and map this to ocaml
>
> type foo = BAR | BAZ;
>
> module s = Struct
>
> type blargle_bar = ...xxx...;
>
> type blargle_baz = ...yyy...;
>
> type blargle__union = Bar of blargle_bar | Baz of blargle_baz;
>
> type t =
> {
> blargle : blargle__union;
> }
>
> These type names are OK because they are already within the namespace
> associated with the struct "s".
I think this is a useful representation of KeyedUnion types in ocaml.
I'll play around a bit with this implementation.
Cheers,
Rob
> If the struct assiated with bar is empty then we don't bother iwht
> blargle_bar of "of blargle_bar".
>
> No actually change in the gnerated code since we don't generated any
> KeyedUnions yet.
>
> The actual implementation was inspired by http://www.linux-
> nantes.org/~fmonnier/ocaml/ocaml-wrapping-c.php#ref_constvrnt
>
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
>
> diff -r f618acdeea1b -r 0cf342afa9e6 tools/libxl/idl.py
> --- a/tools/libxl/idl.py Tue Nov 20 17:22:21 2012 +0000
> +++ b/tools/libxl/idl.py Tue Nov 20 17:22:21 2012 +0000
> @@ -216,6 +216,9 @@ class Struct(Aggregate):
> kwargs.setdefault('passby', PASS_BY_REFERENCE)
> Aggregate.__init__(self, "struct", name, fields, **kwargs)
>
> + def has_fields(self):
> + return len(self.fields) != 0
> +
> class Union(Aggregate):
> def __init__(self, name, fields, **kwargs):
> # Generally speaking some intelligence is required to free a diff -r
> f618acdeea1b -r 0cf342afa9e6 tools/ocaml/libs/xl/genwrap.py
> --- a/tools/ocaml/libs/xl/genwrap.py Tue Nov 20 17:22:21 2012 +0000
> +++ b/tools/ocaml/libs/xl/genwrap.py Tue Nov 20 17:22:21 2012 +0000
> @@ -65,6 +65,8 @@ def ocaml_type_of(ty):
> if not typename:
> raise NotImplementedError("No typename for Builtin %s (%s)" %
> (ty.typename, type(ty)))
> return typename
> + elif isinstance(ty,idl.KeyedUnion):
> + return ty.union_name
> elif isinstance(ty,idl.Aggregate):
> return ty.rawname.capitalize() + ".t"
> else:
> @@ -76,8 +78,67 @@ def munge_name(name):
> else:
> return name
>
> -def ocaml_instance_of(type, name):
> - return "%s : %s" % (munge_name(name), ocaml_type_of(type))
> +def ocaml_instance_of_field(f):
> + if isinstance(f.type, idl.KeyedUnion):
> + name = f.type.keyvar.name
> + else:
> + name = f.name
> + return "%s : %s" % (munge_name(name), ocaml_type_of(f.type))
> +
> +def gen_struct(ty):
> + s = ""
> + for f in ty.fields:
> + if f.type.private:
> + continue
> + x = ocaml_instance_of_field(f)
> + x = x.replace("\n", "\n\t\t")
> + s += "\t\t" + x + ";\n"
> + return s
> +
> +def gen_ocaml_keyedunions(ty, interface, indent, parent = None):
> + s = ""
> +
> + if ty.rawname is not None:
> + # Non-anonymous types need no special handling
> + pass
> + elif isinstance(ty, idl.KeyedUnion):
> + if parent is None:
> + nparent = ty.keyvar.name
> + else:
> + nparent = parent + "_" + ty.keyvar.name
> +
> + for f in ty.fields:
> + if f.type is None: continue
> + if f.type.rawname is not None: continue
> + if isinstance(f.type, idl.Struct) and not f.type.has_fields():
> continue
> + s += "\ntype %s_%s =\n" % (nparent,f.name)
> + s += "{\n"
> + s += gen_struct(f.type)
> + s += "}\n"
> +
> + name = "%s__union" % ty.keyvar.name
> + s += "\n"
> + s += "type %s = " % name
> + u = []
> + for f in ty.fields:
> + if f.type is None:
> + u.append("%s" % (f.name.capitalize()))
> + elif isinstance(f.type, idl.Struct):
> + if f.type.rawname is not None:
> + u.append("%s of %s" % (f.name.capitalize(),
> f.type.rawname.capitalize()))
> + elif f.type.has_fields():
> + u.append("%s of %s_%s" % (f.name.capitalize(), nparent,
> f.name))
> + else:
> + u.append("%s" % (f.name.capitalize()))
> + else:
> + raise NotImplementedError("Cannot handle KeyedUnion
> + fields which are not Structs")
> +
> + s += " | ".join(u) + "\n"
> + ty.union_name = name
> +
> + if s == "":
> + return None
> + return s.replace("\n", "\n%s" % indent)
>
> def gen_ocaml_ml(ty, interface, indent=""):
>
> @@ -103,16 +164,17 @@ def gen_ocaml_ml(ty, interface, indent="
> s += "module %s : sig\n" % module_name
> else:
> s += "module %s = struct\n" % module_name
> - s += "\ttype t =\n"
> - s += "\t{\n"
> -
> +
> + # Handle KeyedUnions...
> for f in ty.fields:
> - if f.type.private:
> - continue
> - x = ocaml_instance_of(f.type, f.name)
> - x = x.replace("\n", "\n\t\t")
> - s += "\t\t" + x + ";\n"
> + ku = gen_ocaml_keyedunions(f.type, interface, "\t")
> + if ku is not None:
> + s += ku
> + s += "\n"
>
> + s += "\ttype t =\n"
> + s += "\t{\n"
> + s += gen_struct(ty)
> s += "\t}\n"
>
> if functions.has_key(ty.rawname):
> @@ -164,12 +226,43 @@ def c_val(ty, c, o, indent="", parent =
> n += 1
> s += " default: failwith_xl(\"cannot convert value to %s\", lg);
> break;\n" % ty.typename
> s += "}"
> - elif isinstance(ty, idl.Aggregate) and (parent is None):
> + elif isinstance(ty, idl.KeyedUnion):
> + s += "{\n"
> + s += "\tif(Is_long(%s)) {\n" % o
> + n = 0
> + s += "\t\tswitch(Int_val(%s)) {\n" % o
> + for f in ty.fields:
> + if f.type is None or not f.type.has_fields():
> + s += "\t\t case %d: %s = %s; break;\n" % (n,
> + parent + ty.keyvar.name,
> + f.enumname)
> + n += 1
> + s += "\t\t default: failwith_xl(\"variant handling bug %s%s
> (long)\",
> lg); break;\n" % (parent, ty.keyvar.name)
> + s += "\t\t}\n"
> + s += "\t} else {\n"
> + s += "\t\t/* Is block... */\n"
> + s += "\t\tswitch(Tag_val(%s)) {\n" % o
> + n = 0
> + for f in ty.fields:
> + if f.type is not None and f.type.has_fields():
> + if f.type.private:
> + continue
> + s += "\t\t case %d:\n" % (n)
> + s += "\t\t %s = %s;\n" % (parent + ty.keyvar.name,
> f.enumname)
> + (nparent,fexpr) = ty.member(c, f, False)
> + s += "%s" % c_val(f.type, fexpr, o, indent=indent+"\t\t
> ")
> + s += "break;\n"
> + n += 1
> + s += "\t\t default: failwith_xl(\"variant handling bug %s%s
> (block)\",
> lg); break;\n" % (parent, ty.keyvar.name)
> + s += "\t\t}\n"
> + s += "\t}\n"
> + s += "}"
> + elif isinstance(ty, idl.Aggregate) and (parent is None or ty.rawname is
> None):
> n = 0
> for f in ty.fields:
> if f.type.private:
> continue
> - (nparent,fexpr) = ty.member(c, f, parent is None)
> + (nparent,fexpr) = ty.member(c, f, ty.rawname is not None)
> s += "%s\n" % c_val(f.type, fexpr, "Field(%s, %d)" % (o,n),
> parent=nparent)
> n = n + 1
> else:
> @@ -191,8 +284,8 @@ def gen_c_val(ty, indent=""):
> s += "}\n"
>
> return s.replace("\n", "\n%s" % indent)
> -
> -def ocaml_Val(ty, o, c, indent="", parent = None):
> +
> +def ocaml_Val(ty, o, c, indent="", parent = None, struct_tag = None):
> s = indent
> if isinstance(ty,idl.UInt):
> if ty.width in [8, 16]:
> @@ -231,11 +324,39 @@ def ocaml_Val(ty, o, c, indent="", paren
> n += 1
> s += " default: failwith_xl(\"cannot convert value from %s\", lg);
> break;\n" % ty.typename
> s += "}"
> - elif isinstance(ty,idl.Aggregate) and (parent is None):
> + elif isinstance(ty, idl.KeyedUnion):
> + n = 0
> + s += "switch(%s) {\n" % (parent + ty.keyvar.name)
> + for f in ty.fields:
> + s += "\t case %s:\n" % f.enumname
> + if f.type is None:
> + s += "\t /* %d: None */\n" % n
> + s += "\t %s = Val_long(%d);\n" % (o,n)
> + elif not f.type.has_fields():
> + s += "\t /* %d: Long */\n" % n
> + s += "\t %s = Val_long(%d);\n" % (o,n)
> + else:
> + s += "\t /* %d: Block */\n" % n
> + (nparent,fexpr) = ty.member(c, f, parent is None)
> + s += ocaml_Val(f.type, o, fexpr, struct_tag = n, indent="\t
> ",
> parent=nparent)
> + s += "\n"
> + #s += "\t %s = caml_alloc(%d,%d);\n" %
> (o,len(f.type.fields),n)
> + s += "\t break;\n"
> + n += 1
> + s += "\t default: failwith_xl(\"cannot convert value from %s\",
> lg);
> break;\n" % ty.typename
> + s += "\t}"
> + elif isinstance(ty,idl.Aggregate) and (parent is None or ty.rawname is
> None):
> s += "{\n"
> - s += "\tvalue %s_field;\n" % ty.rawname
> + if ty.rawname is None:
> + fn = "anon_field"
> + else:
> + fn = "%s_field" % ty.rawname
> + s += "\tvalue %s;\n" % fn
> s += "\n"
> - s += "\t%s = caml_alloc_tuple(%d);\n" % (o, len(ty.fields))
> + if struct_tag is not None:
> + s += "\t%s = caml_alloc(%d,%d);\n" % (o, len(ty.fields),
> struct_tag)
> + else:
> + s += "\t%s = caml_alloc_tuple(%d);\n" % (o, len(ty.fields))
>
> n = 0
> for f in ty.fields:
> @@ -245,8 +366,8 @@ def ocaml_Val(ty, o, c, indent="", paren
> (nparent,fexpr) = ty.member(c, f, parent is None)
>
> s += "\n"
> - s += "\t%s\n" % ocaml_Val(f.type, "%s_field" % ty.rawname,
> ty.pass_arg(fexpr, c), parent=nparent)
> - s += "\tStore_field(%s, %d, %s);\n" % (o, n, "%s_field" %
> ty.rawname)
> + s += "\t%s\n" % ocaml_Val(f.type, fn, ty.pass_arg(fexpr, c),
> parent=nparent)
> + s += "\tStore_field(%s, %d, %s);\n" % (o, n, fn)
> n = n + 1
> s += "}"
> else:
>
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