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generate_casts.py
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185 lines (159 loc) · 5.81 KB
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# Licensed to the .NET Foundation under one or more agreements.
# The .NET Foundation licenses this file to you under the Apache 2.0 License.
# See the LICENSE file in the project root for more information.
from generate import generate
Int32 = "Int32"
Double = "Double"
Boolean = "Boolean"
Int64 = "Int64"
Int16 = "Int16"
UInt32 = "UInt32"
UInt64 = "UInt64"
UInt16 = "UInt16"
SByte = "SByte"
Byte = "Byte"
Single = "Single"
Char = "Char"
Decimal = "Decimal"
Object = "Object"
types = [ Int32, Double, Boolean, Int64, Int16, UInt32, UInt64, UInt16, SByte, Byte, Single, Char, Decimal ]
additional_cached = [ Object ]
non_cls_types = [ UInt32, UInt64, UInt16, SByte ]
enum_types = [ Byte, SByte, Int16, UInt16, Int32, UInt32, Int64, UInt64 ]
# Invalid casts.
# This is reflective so only one direction is enough
invalid_casts = [
( Int32, Boolean ),
( Double, Boolean ),
( Int64, Boolean ),
( Int16, Boolean ),
( UInt32, Boolean ),
( UInt64, Boolean ),
( UInt16, Boolean ),
( SByte, Boolean ),
( Byte, Boolean ),
( Single, Boolean ),
( Char, Boolean ),
( Decimal, Boolean ),
]
# intermediate enum types to use for enum casts
# e.g. enum to Single will go via EnumToInt64 -> Single
enum_casts = {
Int32 : Int32,
Double : Int64,
Int64 : Int64,
Int16 : Int16,
UInt32 : UInt32,
UInt64 : UInt64,
UInt16 : UInt16,
SByte : SByte,
Byte : Byte,
Single : Int64,
Char : Int32,
Decimal : Int64,
}
def generate_nullable_instance(cw):
cw.enter_block("public static object NewNullableInstance(Type type)")
cond = cw.conditions()
for t in types:
cond.condition("if (type == %(type)sType)", type = t)
cw.write("return new Nullable<%(type)s>();", type = t)
cw.else_block()
cw.write("return NewNullableInstanceSlow(type);")
cw.exit_block()
cw.exit_block()
def valid_cast(f, t):
return not (f, t) in invalid_casts and not (t, f) in invalid_casts
def get_enum_type_for(t):
return enum_casts[t]
def mark_cls_compliance(cw, t):
if t in non_cls_types:
cw.write("[CLSCompliant(false)]")
def generate_type_cast(cw, t):
mark_cls_compliance(cw, t)
cw.enter_block("public static %(type)s ExplicitCastTo%(type)s(object o)", type = t)
cw.enter_block("if (o != null)")
cw.write("Type type = o.GetType();");
cond = cw.conditions()
# direct casts
for f in types:
if valid_cast(f, t):
cond.condition("if (type == %(from_t)sType)", from_t = f, to_t = t)
cw.write("return (%(to_t)s)(%(from_t)s)o;", from_t = f, to_t = t)
# enums (only if int cast is valid)
if valid_cast(Int32, t):
cond.condition("if (type.IsEnum)")
cw.write("return (%(to_t)s)ExplicitCastEnumTo%(enum)s(o);", to_t = t, enum = get_enum_type_for(t))
# nullables
for f in types:
if valid_cast(f, t):
cond.condition("if (type == Nullable%(from_t)sType)", from_t = f, to_t = t)
cw.write("return (%(to_t)s)(Nullable<%(from_t)s>)o;", from_t = f, to_t = t)
cond.close()
cw.exit_block()
cw.write("throw InvalidCast(o, \"%(type)s\");", type = t)
cw.exit_block()
def generate_nullable_type_cast(cw, t):
mark_cls_compliance(cw, t)
cw.enter_block("public static Nullable<%(type)s> ExplicitCastToNullable%(type)s(object o)", type = t)
cw.enter_block("if (o == null)")
cw.write("return new Nullable<%(type)s>();", type = t);
cw.exit_block()
cw.write("Type type = o.GetType();");
cond = cw.conditions()
# direct casts
for f in types:
if valid_cast(f, t):
cond.condition("if (type == %(from_t)sType)", from_t = f, to_t = t)
cw.write("return (Nullable<%(to_t)s>)(%(from_t)s)o;", from_t = f, to_t = t)
# enums (only if int cast is valid)
if valid_cast(Int32, t):
cond.condition("if (type.IsEnum)")
cw.write("return (Nullable<%(to_t)s>)ExplicitCastEnumTo%(enum)s(o);", to_t = t, enum = get_enum_type_for(t))
# nullables
for f in types:
if valid_cast(f, t):
cond.condition("if (type == Nullable%(from_t)sType)", from_t = f, to_t = t)
cw.write("return (Nullable<%(to_t)s>)(Nullable<%(from_t)s>)o;", from_t = f, to_t = t)
cond.close()
cw.write("throw InvalidCast(o, \"%(type)s\");", type = t)
cw.exit_block()
def generate_type_casts(cw):
for t in sorted(types):
generate_type_cast(cw, t)
cw.writeline()
for t in sorted(types):
generate_nullable_type_cast(cw, t)
cw.writeline()
def generate_type_cache(cw):
cache = list(types)
cache.extend(additional_cached)
# regulars
for t in sorted(cache):
cw.write("internal static readonly Type %(type)sType = typeof(%(type)s);", type = t)
cw.writeline()
for t in sorted(types):
cw.write("internal static readonly Type Nullable%(type)sType = typeof(Nullable<%(type)s>);", type = t)
def generate_enum_cast(cw, t):
cw.enter_block("internal static %(type)s ExplicitCastEnumTo%(type)s(object o)", type = t)
cw.write("Debug.Assert(o is Enum);")
cw.enter_block("switch (((Enum)o).GetTypeCode())")
for f in enum_types:
cw.case_label("case TypeCode.%(from_t)s: return (%(to_t)s)(%(from_t)s)o;", from_t = f, to_t = t)
cw.dedent()
cw.exit_block()
cw.write("throw new InvalidOperationException(\"Invalid enum\");")
cw.exit_block()
def generate_enum_casts(cw):
for t in enum_types:
generate_enum_cast(cw, t)
cw.writeline()
def main():
return generate(
("Nullable Instance", generate_nullable_instance),
("Type Cache", generate_type_cache),
("Type Casts", generate_type_casts),
("Enum Casts", generate_enum_casts),
)
if __name__ == "__main__":
main()