cmd/geth: add --config file flag (#13875)

* p2p/discover, p2p/discv5: add marshaling methods to Node

* p2p/netutil: make Netlist decodable from TOML

* common/math: encode nil HexOrDecimal256 as 0x0

* cmd/geth: add --config file flag

* cmd/geth: add missing license header

* eth: prettify Config again, fix tests

* eth: use gasprice.Config instead of duplicating its fields

* eth/gasprice: hide nil default from dumpconfig output

* cmd/geth: hide genesis block in dumpconfig output

* node: make tests compile

* console: fix tests

* cmd/geth: make TOML keys look exactly like Go struct fields

* p2p: use discovery by default

This makes the zero Config slightly more useful. It also fixes package
node tests because Node detects reuse of the datadir through the
NodeDatabase.

* cmd/geth: make ethstats URL settable through config file

* cmd/faucet: fix configuration

* cmd/geth: dedup attach tests

* eth: add comment for DefaultConfig

* eth: pass downloader.SyncMode in Config

This removes the FastSync, LightSync flags in favour of a more
general SyncMode flag.

* cmd/utils: remove jitvm flags

* cmd/utils: make mutually exclusive flag error prettier

It now reads:

   Fatal: flags --dev, --testnet can't be used at the same time

* p2p: fix typo

* node: add DefaultConfig, use it for geth

* mobile: add missing NoDiscovery option

* cmd/utils: drop MakeNode

This exposed a couple of places that needed to be updated to use
node.DefaultConfig.

* node: fix typo

* eth: make fast sync the default mode

* cmd/utils: remove IPCApiFlag (unused)

* node: remove default IPC path

Set it in the frontends instead.

* cmd/geth: add --syncmode

* cmd/utils: make --ipcdisable and --ipcpath mutually exclusive

* cmd/utils: don't enable WS, HTTP when setting addr

* cmd/utils: fix --identity

vendor/github.com/naoina/toml/ast/ast.go

@@ -0,0 +1,192 @@
+package ast
+
+import (
+	"strconv"
+	"strings"
+	"time"
+)
+
+type Position struct {
+	Begin int
+	End   int
+}
+
+type Value interface {
+	Pos() int
+	End() int
+	Source() string
+}
+
+type String struct {
+	Position Position
+	Value    string
+	Data     []rune
+}
+
+func (s *String) Pos() int {
+	return s.Position.Begin
+}
+
+func (s *String) End() int {
+	return s.Position.End
+}
+
+func (s *String) Source() string {
+	return string(s.Data)
+}
+
+type Integer struct {
+	Position Position
+	Value    string
+	Data     []rune
+}
+
+func (i *Integer) Pos() int {
+	return i.Position.Begin
+}
+
+func (i *Integer) End() int {
+	return i.Position.End
+}
+
+func (i *Integer) Source() string {
+	return string(i.Data)
+}
+
+func (i *Integer) Int() (int64, error) {
+	return strconv.ParseInt(i.Value, 10, 64)
+}
+
+type Float struct {
+	Position Position
+	Value    string
+	Data     []rune
+}
+
+func (f *Float) Pos() int {
+	return f.Position.Begin
+}
+
+func (f *Float) End() int {
+	return f.Position.End
+}
+
+func (f *Float) Source() string {
+	return string(f.Data)
+}
+
+func (f *Float) Float() (float64, error) {
+	return strconv.ParseFloat(f.Value, 64)
+}
+
+type Boolean struct {
+	Position Position
+	Value    string
+	Data     []rune
+}
+
+func (b *Boolean) Pos() int {
+	return b.Position.Begin
+}
+
+func (b *Boolean) End() int {
+	return b.Position.End
+}
+
+func (b *Boolean) Source() string {
+	return string(b.Data)
+}
+
+func (b *Boolean) Boolean() (bool, error) {
+	return strconv.ParseBool(b.Value)
+}
+
+type Datetime struct {
+	Position Position
+	Value    string
+	Data     []rune
+}
+
+func (d *Datetime) Pos() int {
+	return d.Position.Begin
+}
+
+func (d *Datetime) End() int {
+	return d.Position.End
+}
+
+func (d *Datetime) Source() string {
+	return string(d.Data)
+}
+
+func (d *Datetime) Time() (time.Time, error) {
+	switch {
+	case !strings.Contains(d.Value, ":"):
+		return time.Parse("2006-01-02", d.Value)
+	case !strings.Contains(d.Value, "-"):
+		return time.Parse("15:04:05.999999999", d.Value)
+	default:
+		return time.Parse(time.RFC3339Nano, d.Value)
+	}
+}
+
+type Array struct {
+	Position Position
+	Value    []Value
+	Data     []rune
+}
+
+func (a *Array) Pos() int {
+	return a.Position.Begin
+}
+
+func (a *Array) End() int {
+	return a.Position.End
+}
+
+func (a *Array) Source() string {
+	return string(a.Data)
+}
+
+type TableType uint8
+
+const (
+	TableTypeNormal TableType = iota
+	TableTypeArray
+)
+
+var tableTypes = [...]string{
+	"normal",
+	"array",
+}
+
+func (t TableType) String() string {
+	return tableTypes[t]
+}
+
+type Table struct {
+	Position Position
+	Line     int
+	Name     string
+	Fields   map[string]interface{}
+	Type     TableType
+	Data     []rune
+}
+
+func (t *Table) Pos() int {
+	return t.Position.Begin
+}
+
+func (t *Table) End() int {
+	return t.Position.End
+}
+
+func (t *Table) Source() string {
+	return string(t.Data)
+}
+
+type KeyValue struct {
+	Key   string
+	Value Value
+	Line  int
+}