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-rw-r--r--rpc/utils.go246
1 files changed, 246 insertions, 0 deletions
diff --git a/rpc/utils.go b/rpc/utils.go
new file mode 100644
index 000000000..25321c543
--- /dev/null
+++ b/rpc/utils.go
@@ -0,0 +1,246 @@
+// 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/>.
+
+package rpc
+
+import (
+ "crypto/rand"
+ "encoding/hex"
+ "errors"
+ "math/big"
+ "reflect"
+ "unicode"
+ "unicode/utf8"
+
+ "fmt"
+
+ "golang.org/x/net/context"
+)
+
+// Is this an exported - upper case - name?
+func isExported(name string) bool {
+ rune, _ := utf8.DecodeRuneInString(name)
+ return unicode.IsUpper(rune)
+}
+
+// Is this type exported or a builtin?
+func isExportedOrBuiltinType(t reflect.Type) bool {
+ for t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+ // PkgPath will be non-empty even for an exported type,
+ // so we need to check the type name as well.
+ return isExported(t.Name()) || t.PkgPath() == ""
+}
+
+var errorType = reflect.TypeOf((*error)(nil)).Elem()
+
+// Implements this type the error interface
+func isErrorType(t reflect.Type) bool {
+ for t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+ return t.Implements(errorType)
+}
+
+var subscriptionType = reflect.TypeOf((*Subscription)(nil)).Elem()
+
+func isSubscriptionType(t reflect.Type) bool {
+ for t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+ return t == subscriptionType
+}
+
+// isPubSub tests whether the given method return the pair (v2.Subscription, error)
+func isPubSub(methodType reflect.Type) bool {
+ if methodType.NumOut() != 2 {
+ return false
+ }
+ return isSubscriptionType(methodType.Out(0)) && isErrorType(methodType.Out(1))
+}
+
+// formatName will convert to first character to lower case
+func formatName(name string) string {
+ ret := []rune(name)
+ if len(ret) > 0 {
+ ret[0] = unicode.ToLower(ret[0])
+ }
+ return string(ret)
+}
+
+var bigIntType = reflect.TypeOf((*big.Int)(nil)).Elem()
+
+// Indication if this type should be serialized in hex
+func isHexNum(t reflect.Type) bool {
+ if t == nil {
+ return false
+ }
+ for t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+
+ return t == bigIntType
+}
+
+var blockNumberType = reflect.TypeOf((*BlockNumber)(nil)).Elem()
+
+// Indication if the given block is a BlockNumber
+func isBlockNumber(t reflect.Type) bool {
+ if t == nil {
+ return false
+ }
+
+ for t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+
+ return t == blockNumberType
+}
+
+var contextType = reflect.TypeOf(new(context.Context)).Elem()
+
+// suitableCallbacks iterates over the methods of the given type. It will determine if a method satisfies the criteria
+// for a RPC callback or a subscription callback and adds it to the collection of callbacks or subscriptions. See server
+// documentation for a summary of these criteria.
+func suitableCallbacks(rcvr reflect.Value, typ reflect.Type) (callbacks, subscriptions) {
+ callbacks := make(callbacks)
+ subscriptions := make(subscriptions)
+
+METHODS:
+ for m := 0; m < typ.NumMethod(); m++ {
+ method := typ.Method(m)
+ mtype := method.Type
+ mname := formatName(method.Name)
+ if method.PkgPath != "" { // method must be exported
+ continue
+ }
+
+ var h callback
+ h.isSubscribe = isPubSub(mtype)
+ h.rcvr = rcvr
+ h.method = method
+ h.errPos = -1
+
+ firstArg := 1
+ numIn := mtype.NumIn()
+ if numIn >= 2 && mtype.In(1) == contextType {
+ h.hasCtx = true
+ firstArg = 2
+ }
+
+ if h.isSubscribe {
+ h.argTypes = make([]reflect.Type, numIn-firstArg) // skip rcvr type
+ for i := firstArg; i < numIn; i++ {
+ argType := mtype.In(i)
+ if isExportedOrBuiltinType(argType) {
+ h.argTypes[i-firstArg] = argType
+ } else {
+ continue METHODS
+ }
+ }
+
+ subscriptions[mname] = &h
+ continue METHODS
+ }
+
+ // determine method arguments, ignore first arg since it's the receiver type
+ // Arguments must be exported or builtin types
+ h.argTypes = make([]reflect.Type, numIn-firstArg)
+ for i := firstArg; i < numIn; i++ {
+ argType := mtype.In(i)
+ if !isExportedOrBuiltinType(argType) {
+ continue METHODS
+ }
+ h.argTypes[i-firstArg] = argType
+ }
+
+ // check that all returned values are exported or builtin types
+ for i := 0; i < mtype.NumOut(); i++ {
+ if !isExportedOrBuiltinType(mtype.Out(i)) {
+ continue METHODS
+ }
+ }
+
+ // when a method returns an error it must be the last returned value
+ h.errPos = -1
+ for i := 0; i < mtype.NumOut(); i++ {
+ if isErrorType(mtype.Out(i)) {
+ h.errPos = i
+ break
+ }
+ }
+
+ if h.errPos >= 0 && h.errPos != mtype.NumOut()-1 {
+ continue METHODS
+ }
+
+ switch mtype.NumOut() {
+ case 0, 1:
+ break
+ case 2:
+ if h.errPos == -1 { // method must one return value and 1 error
+ continue METHODS
+ }
+ break
+ default:
+ continue METHODS
+ }
+
+ callbacks[mname] = &h
+ }
+
+ return callbacks, subscriptions
+}
+
+func newSubscriptionId() (string, error) {
+ var subid [16]byte
+ n, _ := rand.Read(subid[:])
+ if n != 16 {
+ return "", errors.New("Unable to generate subscription id")
+ }
+ return "0x" + hex.EncodeToString(subid[:]), nil
+}
+
+// SupportedModules returns the collection of API's that the RPC server offers
+// on which the given client connects.
+func SupportedModules(client Client) (map[string]string, error) {
+ req := map[string]interface{}{
+ "id": 1,
+ "method": "rpc_modules",
+ }
+
+ if err := client.Send(req); err != nil {
+ return nil, err
+ }
+
+ var response map[string]interface{}
+ if err := client.Recv(&response); err != nil {
+ return nil, err
+ }
+
+ if payload, ok := response["result"]; ok {
+ mods := make(map[string]string)
+ if modules, ok := payload.(map[string]interface{}); ok {
+ for m, v := range modules {
+ mods[m] = fmt.Sprintf("%s", v)
+ }
+ return mods, nil
+ }
+ }
+
+ return nil, fmt.Errorf("unable to retrieve modules")
+}