2 This module contains helper classes for structure fields and length expressions.
6 Represents a field of a structure.
8 type is the datatype object for the field.
9 field_type is the name of the type (string tuple)
10 field_name is the name of the structure field.
11 visible is true iff the field should be in the request API.
12 wire is true iff the field should be in the request structure.
13 auto is true iff the field is on the wire but not in the request API (e.g. opcode)
14 enum is the enum name this field refers to, if any.
16 def __init__(self, type, field_type, field_name, visible, wire, auto, enum=None, isfd=False):
18 self.field_type = field_type
19 self.field_name = field_name
21 self.visible = visible
28 class Expression(object):
30 Represents a mathematical expression for a list length or exprfield.
33 op is the operation (text +,*,/,<<,~) or None.
34 lhs and rhs are the sub-Expressions if op is set.
35 lenfield_name is the name of the length field, or None for request lists.
36 lenfield is the Field object for the length field, or None.
37 bitfield is True if the length field is a bitmask instead of a number.
38 nmemb is the fixed size (value)of the expression, or None
40 def __init__(self, elt, parent):
45 self.lenfield_name = None
46 self.lenfield_type = None
47 self.lenfield_parent = None
57 # List going into a request, which has no length field (inferred by server)
58 self.lenfield_name = elt.get('name') + '_len'
59 self.lenfield_type = 'CARD32'
61 elif elt.tag == 'fieldref':
62 # Standard list with a fieldref
63 self.lenfield_name = elt.text
65 elif elt.tag == 'valueparam':
66 # Value-mask. The length bitmask is described by attributes.
67 self.lenfield_name = elt.get('value-mask-name')
68 self.lenfield_type = elt.get('value-mask-type')
73 # Op field. Need to recurse.
74 self.op = elt.get('op')
75 self.lhs = Expression(list(elt)[0], parent)
76 self.rhs = Expression(list(elt)[1], parent)
78 # Hopefully we don't have two separate length fields...
79 self.lenfield_name = self.lhs.lenfield_name
80 if self.lenfield_name == None:
81 self.lenfield_name = self.rhs.lenfield_name
83 elif elt.tag == 'unop':
84 # Op field. Need to recurse.
85 self.op = elt.get('op')
86 self.rhs = Expression(list(elt)[0], parent)
88 self.lenfield_name = self.rhs.lenfield_name
90 elif elt.tag == 'value':
92 self.nmemb = int(elt.text, 0)
94 elif elt.tag == 'popcount':
96 self.rhs = Expression(list(elt)[0], parent)
97 self.lenfield_name = self.rhs.lenfield_name
98 # xcb_popcount returns 'int' - handle the type in the language-specific part
100 elif elt.tag == 'enumref':
102 self.lenfield_name = (elt.get('ref'), elt.text)
104 elif elt.tag == 'sumof':
106 self.lenfield_name = elt.get('ref')
107 subexpressions = list(elt)
108 if len(subexpressions) > 0:
109 # sumof with a nested expression which is to be evaluated
110 # for each list-element in the context of that list-element.
111 # sumof then returns the sum of the results of these evaluations
112 self.rhs = Expression(subexpressions[0], parent)
116 raise Exception("undefined tag '%s'" % elt.tag)
118 def fixed_size(self):
119 return self.nmemb != None
121 def resolve(self, module, parents):
122 if self.op == 'enumref':
123 self.lenfield_type = module.get_type(self.lenfield_name[0])
124 self.lenfield_name = self.lenfield_name[1]
125 elif self.op == 'sumof':
126 # need to find the field with lenfield_name
127 for p in reversed(parents):
128 fields = dict([(f.field_name, f) for f in p.fields])
129 if self.lenfield_name in fields.keys():
130 if p.is_case_or_bitcase:
131 # switch is the anchestor
132 self.lenfield_parent = p.parents[-1]
134 self.lenfield_parent = p
135 self.lenfield_type = fields[self.lenfield_name].field_type