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-rw-r--r--libxcb/xcb-proto/xcbgen/expr.py88
1 files changed, 88 insertions, 0 deletions
diff --git a/libxcb/xcb-proto/xcbgen/expr.py b/libxcb/xcb-proto/xcbgen/expr.py
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+++ b/libxcb/xcb-proto/xcbgen/expr.py
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+'''
+This module contains helper classes for structure fields and length expressions.
+'''
+class Field(object):
+ '''
+ Represents a field of a structure.
+
+ type is the datatype object for the field.
+ field_type is the name of the type (string tuple)
+ field_name is the name of the structure field.
+ visible is true iff the field should be in the request API.
+ wire is true iff the field should be in the request structure.
+ auto is true iff the field is on the wire but not in the request API (e.g. opcode)
+ '''
+ def __init__(self, type, field_type, field_name, visible, wire, auto):
+ self.type = type
+ self.field_type = field_type
+ self.field_name = field_name
+ self.visible = visible
+ self.wire = wire
+ self.auto = auto
+
+
+class Expression(object):
+ '''
+ Represents a mathematical expression for a list length or exprfield.
+
+ Public fields:
+ op is the operation (text +,*,/,<<) or None.
+ lhs and rhs are the sub-Expressions if op is set.
+ lenfield_name is the name of the length field, or None for request lists.
+ lenfield is the Field object for the length field, or None.
+ bitfield is True if the length field is a bitmask instead of a number.
+ nmemb is the fixed size (value)of the expression, or None
+ '''
+ def __init__(self, elt, parent):
+ self.parent = parent
+
+ self.nmemb = None
+
+ self.lenfield_name = None
+ self.lenfield_type = None
+ self.lenfield = None
+ self.lenwire = False
+ self.bitfield = False
+
+ self.op = None
+ self.lhs = None
+ self.rhs = None
+
+ if elt.tag == 'list':
+ # List going into a request, which has no length field (inferred by server)
+ self.lenfield_name = elt.get('name') + '_len'
+ self.lenfield_type = 'CARD32'
+
+ elif elt.tag == 'fieldref':
+ # Standard list with a fieldref
+ self.lenfield_name = elt.text
+
+ elif elt.tag == 'valueparam':
+ # Value-mask. The length bitmask is described by attributes.
+ self.lenfield_name = elt.get('value-mask-name')
+ self.lenfield_type = elt.get('value-mask-type')
+ self.lenwire = True
+ self.bitfield = True
+
+ elif elt.tag == 'op':
+ # Op field. Need to recurse.
+ self.op = elt.get('op')
+ self.lhs = Expression(list(elt)[0], parent)
+ self.rhs = Expression(list(elt)[1], parent)
+
+ # Hopefully we don't have two separate length fields...
+ self.lenfield_name = self.lhs.lenfield_name
+ if self.lenfield_name == None:
+ self.lenfield_name = self.rhs.lenfield_name
+
+ elif elt.tag == 'value':
+ # Constant expression
+ self.nmemb = int(elt.text)
+
+ else:
+ # Notreached
+ raise Exception('XXX')
+
+
+ def fixed_size(self):
+ return self.nmemb != None