/*

 * Copyright 2022 Google LLC

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#ifndef SKSL_PROGRAMUSAGE

#define SKSL_PROGRAMUSAGE

#include "include/core/SkTypes.h"

#include "src/core/SkTHash.h"

namespace SkSL {

class Expression;

class FunctionDeclaration;

class ProgramElement;

class Statement;

class Symbol;

class Variable;

/**

 * Side-car class holding mutable information about a Program's IR

 */

class ProgramUsage {

public:

    struct VariableCounts {

        int fVarExists = 0;  // if this is zero, the Variable might have already been deleted

        int fRead = 0;

        int fWrite = 0;

    };

    VariableCounts get(const Variable&) const;

    bool isDead(const Variable&) const;

    int get(const FunctionDeclaration&) const;

    void add(const Expression* expr);

    void add(const Statement* stmt);

    void add(const ProgramElement& element);

    void remove(const Expression* expr);

    void remove(const Statement* stmt);

    void remove(const ProgramElement& element);

    bool operator==(const ProgramUsage& that) const;

    bool operator!=(const ProgramUsage& that) const { return !(*this == that); }

    // All Symbol* objects in fStructCounts must be StructType*.

    skia_private::THashMap<const Symbol*, int> fStructCounts;

    // All Symbol* objects in fCallCounts must be FunctionDeclaration*.

    skia_private::THashMap<const Symbol*, int> fCallCounts;

    skia_private::THashMap<const Variable*, VariableCounts> fVariableCounts;

};

}  // namespace SkSL

#endif