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common: improve documentation comments (#16701)

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This commit adds many comments and removes unused code.
It also removes the EmptyHash function, which had some uses
but was silly.
This commit is contained in:
kiel barry 2018-05-29 03:42:21 -07:00 committed by Felix Lange
parent 998f6564b2
commit 84f8c0cc1f
9 changed files with 84 additions and 138 deletions
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20
common/bytes.go
View File

@ -19,15 +19,20 @@ package common
import "encoding/hex"
// ToHex returns the hex representation of b, prefixed with '0x'.
// For empty slices, the return value is "0x0".
//
// Deprecated: use hexutil.Encode instead.
func ToHex(b []byte) string {
hex := Bytes2Hex(b)
// Prefer output of "0x0" instead of "0x"
if len(hex) == 0 {
hex = "0"
}
return "0x" + hex
}
// FromHex returns the bytes represented by the hexadecimal string s.
// s may be prefixed with "0x".
func FromHex(s string) []byte {
if len(s) > 1 {
if s[0:2] == "0x" || s[0:2] == "0X" {
@ -40,9 +45,7 @@ func FromHex(s string) []byte {
return Hex2Bytes(s)
}
// Copy bytes
//
// Returns an exact copy of the provided bytes
// CopyBytes returns an exact copy of the provided bytes.
func CopyBytes(b []byte) (copiedBytes []byte) {
if b == nil {
return nil
@ -53,14 +56,17 @@ func CopyBytes(b []byte) (copiedBytes []byte) {
return
}
// hasHexPrefix validates str begins with '0x' or '0X'.
func hasHexPrefix(str string) bool {
return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
}
// isHexCharacter returns bool of c being a valid hexadecimal.
func isHexCharacter(c byte) bool {
return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
}
// isHex validates whether each byte is valid hexadecimal string.
func isHex(str string) bool {
if len(str)%2 != 0 {
return false
@ -73,16 +79,18 @@ func isHex(str string) bool {
return true
}
// Bytes2Hex returns the hexadecimal encoding of d.
func Bytes2Hex(d []byte) string {
return hex.EncodeToString(d)
}
// Hex2Bytes returns the bytes represented by the hexadecimal string str.
func Hex2Bytes(str string) []byte {
h, _ := hex.DecodeString(str)
return h
}
// Hex2BytesFixed returns bytes of a specified fixed length flen.
func Hex2BytesFixed(str string, flen int) []byte {
h, _ := hex.DecodeString(str)
if len(h) == flen {
@ -96,6 +104,7 @@ func Hex2BytesFixed(str string, flen int) []byte {
return hh
}
// RightPadBytes zero-pads slice to the right up to length l.
func RightPadBytes(slice []byte, l int) []byte {
if l <= len(slice) {
return slice
@ -107,6 +116,7 @@ func RightPadBytes(slice []byte, l int) []byte {
return padded
}
// LeftPadBytes zero-pads slice to the left up to length l.
func LeftPadBytes(slice []byte, l int) []byte {
if l <= len(slice) {
return slice

5
common/math/big.go
View File

@ -78,7 +78,7 @@ func ParseBig256(s string) (*big.Int, bool) {
return bigint, ok
}
// MustParseBig parses s as a 256 bit big integer and panics if the string is invalid.
// MustParseBig256 parses s as a 256 bit big integer and panics if the string is invalid.
func MustParseBig256(s string) *big.Int {
v, ok := ParseBig256(s)
if !ok {
@ -186,9 +186,8 @@ func U256(x *big.Int) *big.Int {
func S256(x *big.Int) *big.Int {
if x.Cmp(tt255) < 0 {
return x
} else {
return new(big.Int).Sub(x, tt256)
}
return new(big.Int).Sub(x, tt256)
}
// Exp implements exponentiation by squaring.

43
common/number/int.go
View File

@ -34,13 +34,12 @@ func limitUnsigned256(x *Number) *Number {
func limitSigned256(x *Number) *Number {
if x.num.Cmp(tt255) < 0 {
return x
} else {
x.num.Sub(x.num, tt256)
return x
}
x.num.Sub(x.num, tt256)
return x
}
// Number function
// Initialiser is a Number function
type Initialiser func(n int64) *Number
// A Number represents a generic integer with a bounding function limiter. Limit is called after each operations
@ -51,65 +50,65 @@ type Number struct {
limit func(n *Number) *Number
}
// Returns a new initialiser for a new *Number without having to expose certain fields
// NewInitialiser returns a new initialiser for a new *Number without having to expose certain fields
func NewInitialiser(limiter func(*Number) *Number) Initialiser {
return func(n int64) *Number {
return &Number{big.NewInt(n), limiter}
}
}
// Return a Number with a UNSIGNED limiter up to 256 bits
// Uint256 returns a Number with a UNSIGNED limiter up to 256 bits
func Uint256(n int64) *Number {
return &Number{big.NewInt(n), limitUnsigned256}
}
// Return a Number with a SIGNED limiter up to 256 bits
// Int256 returns Number with a SIGNED limiter up to 256 bits
func Int256(n int64) *Number {
return &Number{big.NewInt(n), limitSigned256}
}
// Returns a Number with a SIGNED unlimited size
// Big returns a Number with a SIGNED unlimited size
func Big(n int64) *Number {
return &Number{big.NewInt(n), func(x *Number) *Number { return x }}
}
// Sets i to sum of x+y
// Add sets i to sum of x+y
func (i *Number) Add(x, y *Number) *Number {
i.num.Add(x.num, y.num)
return i.limit(i)
}
// Sets i to difference of x-y
// Sub sets i to difference of x-y
func (i *Number) Sub(x, y *Number) *Number {
i.num.Sub(x.num, y.num)
return i.limit(i)
}
// Sets i to product of x*y
// Mul sets i to product of x*y
func (i *Number) Mul(x, y *Number) *Number {
i.num.Mul(x.num, y.num)
return i.limit(i)
}
// Sets i to the quotient prodject of x/y
// Div sets i to the quotient prodject of x/y
func (i *Number) Div(x, y *Number) *Number {
i.num.Div(x.num, y.num)
return i.limit(i)
}
// Sets i to x % y
// Mod sets i to x % y
func (i *Number) Mod(x, y *Number) *Number {
i.num.Mod(x.num, y.num)
return i.limit(i)
}
// Sets i to x << s
// Lsh sets i to x << s
func (i *Number) Lsh(x *Number, s uint) *Number {
i.num.Lsh(x.num, s)
return i.limit(i)
}
// Sets i to x^y
// Pow sets i to x^y
func (i *Number) Pow(x, y *Number) *Number {
i.num.Exp(x.num, y.num, big.NewInt(0))
return i.limit(i)
@ -117,13 +116,13 @@ func (i *Number) Pow(x, y *Number) *Number {
// Setters
// Set x to i
// Set sets x to i
func (i *Number) Set(x *Number) *Number {
i.num.Set(x.num)
return i.limit(i)
}
// Set x bytes to i
// SetBytes sets x bytes to i
func (i *Number) SetBytes(x []byte) *Number {
i.num.SetBytes(x)
return i.limit(i)
@ -140,12 +139,12 @@ func (i *Number) Cmp(x *Number) int {
// Getters
// Returns the string representation of i
// String returns the string representation of i
func (i *Number) String() string {
return i.num.String()
}
// Returns the byte representation of i
// Bytes returns the byte representation of i
func (i *Number) Bytes() []byte {
return i.num.Bytes()
}
@ -160,17 +159,17 @@ func (i *Number) Int64() int64 {
return i.num.Int64()
}
// Returns the signed version of i
// Int256 returns the signed version of i
func (i *Number) Int256() *Number {
return Int(0).Set(i)
}
// Returns the unsigned version of i
// Uint256 returns the unsigned version of i
func (i *Number) Uint256() *Number {
return Uint(0).Set(i)
}
// Returns the index of the first bit that's set to 1
// FirstBitSet returns the index of the first bit that's set to 1
func (i *Number) FirstBitSet() int {
for j := 0; j < i.num.BitLen(); j++ {
if i.num.Bit(j) > 0 {

6
common/path.go
View File

@ -30,6 +30,7 @@ func MakeName(name, version string) string {
return fmt.Sprintf("%s/v%s/%s/%s", name, version, runtime.GOOS, runtime.Version())
}
// FileExist checks if a file exists at filePath.
func FileExist(filePath string) bool {
_, err := os.Stat(filePath)
if err != nil && os.IsNotExist(err) {
@ -39,9 +40,10 @@ func FileExist(filePath string) bool {
return true
}
func AbsolutePath(Datadir string, filename string) string {
// AbsolutePath returns datadir + filename, or filename if it is absolute.
func AbsolutePath(datadir string, filename string) string {
if filepath.IsAbs(filename) {
return filename
}
return filepath.Join(Datadir, filename)
return filepath.Join(datadir, filename)
}

74
common/types.go
View File

@ -42,19 +42,30 @@ var (
// Hash represents the 32 byte Keccak256 hash of arbitrary data.
type Hash [HashLength]byte
// BytesToHash sets b to hash.
// If b is larger than len(h), b will be cropped from the left.
func BytesToHash(b []byte) Hash {
var h Hash
h.SetBytes(b)
return h
}
func BigToHash(b *big.Int) Hash { return BytesToHash(b.Bytes()) }
func HexToHash(s string) Hash { return BytesToHash(FromHex(s)) }
// Get the string representation of the underlying hash
func (h Hash) Str() string { return string(h[:]) }
// BigToHash sets byte representation of b to hash.
// If b is larger than len(h), b will be cropped from the left.
func BigToHash(b *big.Int) Hash { return BytesToHash(b.Bytes()) }
// HexToHash sets byte representation of s to hash.
// If b is larger than len(h), b will be cropped from the left.
func HexToHash(s string) Hash { return BytesToHash(FromHex(s)) }
// Bytes gets the byte representation of the underlying hash.
func (h Hash) Bytes() []byte { return h[:] }
// Big converts a hash to a big integer.
func (h Hash) Big() *big.Int { return new(big.Int).SetBytes(h[:]) }
func (h Hash) Hex() string { return hexutil.Encode(h[:]) }
// Hex converts a hash to a hex string.
func (h Hash) Hex() string { return hexutil.Encode(h[:]) }
// TerminalString implements log.TerminalStringer, formatting a string for console
// output during logging.
@ -89,7 +100,8 @@ func (h Hash) MarshalText() ([]byte, error) {
return hexutil.Bytes(h[:]).MarshalText()
}
// Sets the hash to the value of b. If b is larger than len(h), 'b' will be cropped (from the left).
// SetBytes sets the hash to the value of b.
// If b is larger than len(h), b will be cropped from the left.
func (h *Hash) SetBytes(b []byte) {
if len(b) > len(h) {
b = b[len(b)-HashLength:]
@ -98,16 +110,6 @@ func (h *Hash) SetBytes(b []byte) {
copy(h[HashLength-len(b):], b)
}
// Set string `s` to h. If s is larger than len(h) s will be cropped (from left) to fit.
func (h *Hash) SetString(s string) { h.SetBytes([]byte(s)) }
// Sets h to other
func (h *Hash) Set(other Hash) {
for i, v := range other {
h[i] = v
}
}
// Generate implements testing/quick.Generator.
func (h Hash) Generate(rand *rand.Rand, size int) reflect.Value {
m := rand.Intn(len(h))
@ -117,10 +119,6 @@ func (h Hash) Generate(rand *rand.Rand, size int) reflect.Value {
return reflect.ValueOf(h)
}
func EmptyHash(h Hash) bool {
return h == Hash{}
}
// UnprefixedHash allows marshaling a Hash without 0x prefix.
type UnprefixedHash Hash
@ -139,13 +137,21 @@ func (h UnprefixedHash) MarshalText() ([]byte, error) {
// Address represents the 20 byte address of an Ethereum account.
type Address [AddressLength]byte
// BytesToAddress returns Address with value b.
// If b is larger than len(h), b will be cropped from the left.
func BytesToAddress(b []byte) Address {
var a Address
a.SetBytes(b)
return a
}
// BigToAddress returns Address with byte values of b.
// If b is larger than len(h), b will be cropped from the left.
func BigToAddress(b *big.Int) Address { return BytesToAddress(b.Bytes()) }
func HexToAddress(s string) Address { return BytesToAddress(FromHex(s)) }
// HexToAddress returns Address with byte values of s.
// If s is larger than len(h), s will be cropped from the left.
func HexToAddress(s string) Address { return BytesToAddress(FromHex(s)) }
// IsHexAddress verifies whether a string can represent a valid hex-encoded
// Ethereum address or not.
@ -156,11 +162,14 @@ func IsHexAddress(s string) bool {
return len(s) == 2*AddressLength && isHex(s)
}
// Get the string representation of the underlying address
func (a Address) Str() string { return string(a[:]) }
// Bytes gets the string representation of the underlying address.
func (a Address) Bytes() []byte { return a[:] }
// Big converts an address to a big integer.
func (a Address) Big() *big.Int { return new(big.Int).SetBytes(a[:]) }
func (a Address) Hash() Hash { return BytesToHash(a[:]) }
// Hash converts an address to a hash by left-padding it with zeros.
func (a Address) Hash() Hash { return BytesToHash(a[:]) }
// Hex returns an EIP55-compliant hex string representation of the address.
func (a Address) Hex() string {
@ -184,7 +193,7 @@ func (a Address) Hex() string {
return "0x" + string(result)
}
// String implements the stringer interface and is used also by the logger.
// String implements fmt.Stringer.
func (a Address) String() string {
return a.Hex()
}
@ -195,7 +204,8 @@ func (a Address) Format(s fmt.State, c rune) {
fmt.Fprintf(s, "%"+string(c), a[:])
}
// Sets the address to the value of b. If b is larger than len(a) it will panic
// SetBytes sets the address to the value of b.
// If b is larger than len(a) it will panic.
func (a *Address) SetBytes(b []byte) {
if len(b) > len(a) {
b = b[len(b)-AddressLength:]
@ -203,16 +213,6 @@ func (a *Address) SetBytes(b []byte) {
copy(a[AddressLength-len(b):], b)
}
// Set string `s` to a. If s is larger than len(a) it will panic
func (a *Address) SetString(s string) { a.SetBytes([]byte(s)) }
// Sets a to other
func (a *Address) Set(other Address) {
for i, v := range other {
a[i] = v
}
}
// MarshalText returns the hex representation of a.
func (a Address) MarshalText() ([]byte, error) {
return hexutil.Bytes(a[:]).MarshalText()
@ -228,7 +228,7 @@ func (a *Address) UnmarshalJSON(input []byte) error {
return hexutil.UnmarshalFixedJSON(addressT, input, a[:])
}
// UnprefixedHash allows marshaling an Address without 0x prefix.
// UnprefixedAddress allows marshaling an Address without 0x prefix.
type UnprefixedAddress Address
// UnmarshalText decodes the address from hex. The 0x prefix is optional.

64
common/types_template.go
View File

@ -1,64 +0,0 @@
// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// +build none
//sed -e 's/_N_/Hash/g' -e 's/_S_/32/g' -e '1d' types_template.go | gofmt -w hash.go
package common
import "math/big"
type _N_ [_S_]byte
func BytesTo_N_(b []byte) _N_ {
var h _N_
h.SetBytes(b)
return h
}
func StringTo_N_(s string) _N_ { return BytesTo_N_([]byte(s)) }
func BigTo_N_(b *big.Int) _N_ { return BytesTo_N_(b.Bytes()) }
func HexTo_N_(s string) _N_ { return BytesTo_N_(FromHex(s)) }
// Don't use the default 'String' method in case we want to overwrite
// Get the string representation of the underlying hash
func (h _N_) Str() string { return string(h[:]) }
func (h _N_) Bytes() []byte { return h[:] }
func (h _N_) Big() *big.Int { return new(big.Int).SetBytes(h[:]) }
func (h _N_) Hex() string { return "0x" + Bytes2Hex(h[:]) }
// Sets the hash to the value of b. If b is larger than len(h) it will panic
func (h *_N_) SetBytes(b []byte) {
// Use the right most bytes
if len(b) > len(h) {
b = b[len(b)-_S_:]
}
// Reverse the loop
for i := len(b) - 1; i >= 0; i-- {
h[_S_-len(b)+i] = b[i]
}
}
// Set string `s` to h. If s is larger than len(h) it will panic
func (h *_N_) SetString(s string) { h.SetBytes([]byte(s)) }
// Sets h to other
func (h *_N_) Set(other _N_) {
for i, v := range other {
h[i] = v
}
}

2
core/state/state_test.go
View File

@ -99,7 +99,7 @@ func (s *StateSuite) TestNull(c *checker.C) {
s.state.SetState(address, common.Hash{}, value)
s.state.Commit(false)
value = s.state.GetState(address, common.Hash{})
if !common.EmptyHash(value) {
if value != (common.Hash{}) {
c.Errorf("expected empty hash. got %x", value)
}
}

6
core/vm/gas_table.go
View File

@ -124,12 +124,12 @@ func gasSStore(gt params.GasTable, evm *EVM, contract *Contract, stack *Stack, m
// 1. From a zero-value address to a non-zero value (NEW VALUE)
// 2. From a non-zero value address to a zero-value address (DELETE)
// 3. From a non-zero to a non-zero (CHANGE)
if common.EmptyHash(val) && !common.EmptyHash(common.BigToHash(y)) {
if val == (common.Hash{}) && y.Sign() != 0 {
// 0 => non 0
return params.SstoreSetGas, nil
} else if !common.EmptyHash(val) && common.EmptyHash(common.BigToHash(y)) {
} else if val != (common.Hash{}) && y.Sign() == 0 {
// non 0 => 0
evm.StateDB.AddRefund(params.SstoreRefundGas)
return params.SstoreClearGas, nil
} else {
// non 0 => non 0 (or 0 => 0)

2
eth/downloader/downloader.go
View File

@ -680,7 +680,7 @@ func (d *Downloader) findAncestor(p *peerConnection, height uint64) (uint64, err
}
}
// If the head fetch already found an ancestor, return
if !common.EmptyHash(hash) {
if hash != (common.Hash{}) {
if int64(number) <= floor {
p.log.Warn("Ancestor below allowance", "number", number, "hash", hash, "allowance", floor)
return 0, errInvalidAncestor