init

squashfs-root/usr/lib/python2.7/site-packages/xcbgen/expr.py

@@ -0,0 +1,175 @@
+'''
+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)
+    enum is the enum name this field refers to, if any.
+    '''
+    def __init__(self, type, field_type, field_name, visible, wire, auto, enum=None, isfd=False):
+        self.type = type
+        self.field_type = field_type
+        self.field_name = field_name
+        self.enum = enum
+        self.visible = visible
+        self.wire = wire
+        self.auto = auto
+        self.isfd = isfd
+        self.parent = None
+
+    def __str__(self):
+        field_string = "Field"
+        if self.field_name is None:
+            if self.field_type is not None:
+                field_string += " with type " + str(self.type)
+        else:
+            field_string += " \"" + self.field_name + "\""
+        if self.parent is not None:
+            field_string += " in " + str(self.parent)
+
+        return field_string
+
+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_parent = None
+        self.lenfield = None
+        self.lenwire = False
+        self.bitfield = False
+
+        self.op = None
+        self.lhs = None
+        self.rhs = None
+
+        self.contains_listelement_ref = False
+
+        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 == 'paramref':
+            self.lenfield_name = elt.text
+            self.lenfield_type = elt.get('type')
+
+        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 == 'unop':
+            # Op field.  Need to recurse.
+            self.op = elt.get('op')
+            self.rhs = Expression(list(elt)[0], parent)
+
+            self.lenfield_name = self.rhs.lenfield_name
+            
+        elif elt.tag == 'value':
+            # Constant expression
+            self.nmemb = int(elt.text, 0)
+
+        elif elt.tag == 'popcount':
+            self.op = 'popcount'
+            self.rhs = Expression(list(elt)[0], parent)
+            self.lenfield_name = self.rhs.lenfield_name
+            # xcb_popcount returns 'int' - handle the type in the language-specific part
+
+        elif elt.tag == 'enumref':
+            self.op = 'enumref'
+            self.lenfield_name = (elt.get('ref'), elt.text)
+            
+        elif elt.tag == 'sumof':
+            self.op = 'sumof'
+            self.lenfield_name = elt.get('ref')
+            subexpressions = list(elt)
+            if len(subexpressions) > 0:
+                # sumof with a nested expression which is to be evaluated
+                # for each list-element in the context of that list-element.
+                # sumof then returns the sum of the results of these evaluations
+                self.rhs = Expression(subexpressions[0], parent)
+
+        elif elt.tag == 'listelement-ref':
+            # current list element inside iterating expressions such as sumof
+            self.op = 'listelement-ref'
+            self.contains_listelement_ref = True
+
+        else:
+            # Notreached
+            raise Exception("undefined tag '%s'" % elt.tag)
+
+    def fixed_size(self):
+        return self.nmemb != None
+
+    def get_value(self):
+        return self.nmemb
+
+    # if the value of the expression is a guaranteed multiple of a number
+    # return this number, else return 1 (which is trivially guaranteed for integers)
+    def get_multiple(self):
+        multiple = 1
+        if self.op == '*':
+            if self.lhs.fixed_size():
+                multiple *= self.lhs.get_value()
+            if self.rhs.fixed_size():
+                multiple *= self.rhs.get_value()
+
+        return multiple
+
+    def recursive_resolve_tasks(self, module, parents):
+        for subexpr in (self.lhs, self.rhs):
+            if subexpr != None:
+                subexpr.recursive_resolve_tasks(module, parents)
+                self.contains_listelement_ref |= subexpr.contains_listelement_ref
+
+    def resolve(self, module, parents):
+        if self.op == 'enumref':
+            self.lenfield_type = module.get_type(self.lenfield_name[0])
+            self.lenfield_name = self.lenfield_name[1]
+        elif self.op == 'sumof':
+            # need to find the field with lenfield_name
+            for p in reversed(parents): 
+                fields = dict([(f.field_name, f) for f in p.fields])
+                if self.lenfield_name in fields.keys():
+                    if p.is_case_or_bitcase:
+                        # switch is the anchestor 
+                        self.lenfield_parent = p.parents[-1]
+                    else:
+                        self.lenfield_parent = p
+                    self.lenfield_type = fields[self.lenfield_name].field_type
+                    break
+
+        self.recursive_resolve_tasks(module, parents)
+