github.hscsec.cn/juliankolbe/go-ethereum@v1.9.7/core/gaspool.go (about)

     1  // Copyright 2015 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package core
    18  
    19  import (
    20  	"fmt"
    21  	"math"
    22  )
    23  
    24  // GasPool tracks the amount of gas available during execution of the transactions
    25  // in a block. The zero value is a pool with zero gas available.
    26  type GasPool uint64
    27  
    28  // AddGas makes gas available for execution.
    29  func (gp *GasPool) AddGas(amount uint64) *GasPool {
    30  	if uint64(*gp) > math.MaxUint64-amount {
    31  		panic("gas pool pushed above uint64")
    32  	}
    33  	*(*uint64)(gp) += amount
    34  	return gp
    35  }
    36  
    37  // SubGas deducts the given amount from the pool if enough gas is
    38  // available and returns an error otherwise.
    39  func (gp *GasPool) SubGas(amount uint64) error {
    40  	if uint64(*gp) < amount {
    41  		return ErrGasLimitReached
    42  	}
    43  	*(*uint64)(gp) -= amount
    44  	return nil
    45  }
    46  
    47  // Gas returns the amount of gas remaining in the pool.
    48  func (gp *GasPool) Gas() uint64 {
    49  	return uint64(*gp)
    50  }
    51  
    52  func (gp *GasPool) String() string {
    53  	return fmt.Sprintf("%d", *gp)
    54  }