skia2/src/sksl/ir/SkSLStatement.h

/*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SKSL_STATEMENT
#define SKSL_STATEMENT

#include "src/sksl/ir/SkSLIRNode.h"
#include "src/sksl/ir/SkSLType.h"

namespace SkSL {

/**
 * Abstract supertype of all statements.
 */
struct Statement : public IRNode {
    enum Kind {
        kBlock_Kind,
        kBreak_Kind,
        kContinue_Kind,
        kDiscard_Kind,
        kDo_Kind,
        kExpression_Kind,
        kFor_Kind,
        kIf_Kind,
        kNop_Kind,
        kReturn_Kind,
        kSwitch_Kind,
        kVarDeclaration_Kind,
        kVarDeclarations_Kind,
        kWhile_Kind
    };

    Statement(int offset, Kind kind)
    : INHERITED(offset)
    , fKind(kind) {}

    /**
     *  Use is<T> to check the type of a statement.
     *  e.g. replace `s.fKind == Statement::kReturn_Kind` with `s.is<ReturnStatement>()`.
     */
    template <typename T>
    bool is() const {
        return this->fKind == T::kStatementKind;
    }

    /**
     *  Use as<T> to downcast statements.
     *  e.g. replace `(ReturnStatement&) s` with `s.as<ReturnStatement>()`.
     */
    template <typename T>
    const T& as() const {
        SkASSERT(this->is<T>());
        return static_cast<const T&>(*this);
    }

    template <typename T>
    T& as() {
        SkASSERT(this->is<T>());
        return static_cast<T&>(*this);
    }

    virtual bool isEmpty() const {
        return false;
    }

    virtual std::unique_ptr<Statement> clone() const = 0;

    const Kind fKind;

    using INHERITED = IRNode;
};

}  // namespace SkSL

#endif