github.com/halybang/go-ethereum@v1.0.5-0.20180325041310-3b262bc1367c/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  	"math/big"
    21  
    22  	"github.com/wanchain/go-wanchain/log"
    23  )
    24  
    25  // GasPool tracks the amount of gas available during
    26  // execution of the transactions in a block.
    27  // The zero value is a pool with zero gas available.
    28  type GasPool big.Int
    29  
    30  // AddGas makes gas available for execution.
    31  func (gp *GasPool) AddGas(amount *big.Int) *GasPool {
    32  	i := (*big.Int)(gp)
    33  	i.Add(i, amount)
    34  	log.Trace("gas pool add gas", "amount", amount.Uint64(), "left", i.Uint64())
    35  	return gp
    36  }
    37  
    38  // SubGas deducts the given amount from the pool if enough gas is
    39  // available and returns an error otherwise.
    40  func (gp *GasPool) SubGas(amount *big.Int) error {
    41  	i := (*big.Int)(gp)
    42  	if i.Cmp(amount) < 0 {
    43  		return ErrGasLimitReached
    44  	}
    45  	i.Sub(i, amount)
    46  	log.Trace("gas pool sub gas", "amount", amount.Uint64(), "left", i.Uint64())
    47  	return nil
    48  }
    49  
    50  func (gp *GasPool) String() string {
    51  	return (*big.Int)(gp).String()
    52  }