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1 /*
2  * Copyright 2016 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef SKSL_PREFIXEXPRESSION
9 #define SKSL_PREFIXEXPRESSION
10 
11 #ifdef SKSL_EXT
12 #include "src/sksl/SkSLLexerExt.h"
13 #else
14 #include "src/sksl/SkSLLexer.h"
15 #endif
16 #include "src/sksl/SkSLOperators.h"
17 #include "src/sksl/ir/SkSLExpression.h"
18 
19 #include <memory>
20 
21 namespace SkSL {
22 
23 /**
24  * An expression modified by a unary operator appearing before it, such as '!flag'.
25  */
26 class PrefixExpression final : public Expression {
27 public:
28     inline static constexpr Kind kExpressionKind = Kind::kPrefix;
29 
30     // Use PrefixExpression::Make to automatically simplify various prefix expression types.
PrefixExpression(Operator op,std::unique_ptr<Expression> operand)31     PrefixExpression(Operator op, std::unique_ptr<Expression> operand)
32         : INHERITED(operand->fLine, kExpressionKind, &operand->type())
33         , fOperator(op)
34         , fOperand(std::move(operand)) {}
35 
36     // Creates an SkSL prefix expression; uses the ErrorReporter to report errors.
37     static std::unique_ptr<Expression> Convert(const Context& context, Operator op,
38                                                std::unique_ptr<Expression> base);
39 
40     // Creates an SkSL prefix expression; reports errors via ASSERT.
41     static std::unique_ptr<Expression> Make(const Context& context, Operator op,
42                                             std::unique_ptr<Expression> base);
43 
getOperator()44     Operator getOperator() const {
45         return fOperator;
46     }
47 
operand()48     std::unique_ptr<Expression>& operand() {
49         return fOperand;
50     }
51 
operand()52     const std::unique_ptr<Expression>& operand() const {
53         return fOperand;
54     }
55 
hasProperty(Property property)56     bool hasProperty(Property property) const override {
57         if (property == Property::kSideEffects &&
58             (this->getOperator().kind() == Token::Kind::TK_PLUSPLUS ||
59              this->getOperator().kind() == Token::Kind::TK_MINUSMINUS)) {
60             return true;
61         }
62         return this->operand()->hasProperty(property);
63     }
64 
clone()65     std::unique_ptr<Expression> clone() const override {
66         return std::make_unique<PrefixExpression>(this->getOperator(), this->operand()->clone());
67     }
68 
description()69     String description() const override {
70         return this->getOperator().operatorName() + this->operand()->description();
71     }
72 
73 private:
74     Operator fOperator;
75     std::unique_ptr<Expression> fOperand;
76 
77     using INHERITED = Expression;
78 };
79 
80 }  // namespace SkSL
81 
82 #endif
83