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

1 files changed, 65 insertions, 0 deletions

diff --git a/vendor/github.com/naoina/toml/util.go b/vendor/github.com/naoina/toml/util.go
new file mode 100644
index 000000000..f882f4e5f
--- /dev/null
+++ b/vendor/github.com/naoina/toml/util.go
@@ -0,0 +1,65 @@
+package toml
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+const fieldTagName = "toml"
+
+// fieldCache maps normalized field names to their position in a struct.
+type fieldCache struct {
+	named map[string]fieldInfo // fields with an explicit name in tag
+	auto  map[string]fieldInfo // fields with auto-assigned normalized names
+}
+
+type fieldInfo struct {
+	index   []int
+	name    string
+	ignored bool
+}
+
+func makeFieldCache(cfg *Config, rt reflect.Type) fieldCache {
+	named, auto := make(map[string]fieldInfo), make(map[string]fieldInfo)
+	for i := 0; i < rt.NumField(); i++ {
+		ft := rt.Field(i)
+		// skip unexported fields
+		if ft.PkgPath != "" && !ft.Anonymous {
+			continue
+		}
+		col, _ := extractTag(ft.Tag.Get(fieldTagName))
+		info := fieldInfo{index: ft.Index, name: ft.Name, ignored: col == "-"}
+		if col == "" || col == "-" {
+			auto[cfg.NormFieldName(rt, ft.Name)] = info
+		} else {
+			named[col] = info
+		}
+	}
+	return fieldCache{named, auto}
+}
+
+func (fc fieldCache) findField(cfg *Config, rv reflect.Value, name string) (reflect.Value, string, error) {
+	info, found := fc.named[name]
+	if !found {
+		info, found = fc.auto[cfg.NormFieldName(rv.Type(), name)]
+	}
+	if !found {
+		if cfg.MissingField == nil {
+			return reflect.Value{}, "", fmt.Errorf("field corresponding to `%s' is not defined in %v", name, rv.Type())
+		} else {
+			return reflect.Value{}, "", cfg.MissingField(rv.Type(), name)
+		}
+	} else if info.ignored {
+		return reflect.Value{}, "", fmt.Errorf("field corresponding to `%s' in %v cannot be set through TOML", name, rv.Type())
+	}
+	return rv.FieldByIndex(info.index), info.name, nil
+}
+
+func extractTag(tag string) (col, rest string) {
+	tags := strings.SplitN(tag, ",", 2)
+	if len(tags) == 2 {
+		return strings.TrimSpace(tags[0]), strings.TrimSpace(tags[1])
+	}
+	return strings.TrimSpace(tags[0]), ""
+}