Bot: Added package infer for getting IDs from unknown structs

bot/ctx_call.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"github.com/diamondburned/arikawa/api"
+	"github.com/diamondburned/arikawa/bot/extras/infer"
 	"github.com/diamondburned/arikawa/discord"
 	"github.com/diamondburned/arikawa/gateway"
 	"github.com/pkg/errors"
@@ -441,12 +442,12 @@ func (ctx *Context) eventIsAdmin(ev interface{}, is **bool) bool {
 		return **is
 	}
 
-	var channelID = reflectChannelID(ev)
+	var channelID = infer.ChannelID(ev)
 	if !channelID.Valid() {
 		return false
 	}
 
-	var userID = reflectUserID(ev)
+	var userID = infer.UserID(ev)
 	if !userID.Valid() {
 		return false
 	}
@@ -467,7 +468,7 @@ func (ctx *Context) eventIsGuild(ev interface{}, is **bool) bool {
 		return **is
 	}
 
-	var channelID = reflectChannelID(ev)
+	var channelID = infer.ChannelID(ev)
 	if !channelID.Valid() {
 		return false
 	}
@@ -524,68 +525,3 @@ func errorReturns(returns []reflect.Value) (interface{}, error) {
 	// Treat the last return as an error.
 	return nil, v.(error)
 }
-
-func reflectChannelID(_struct interface{}) discord.Snowflake {
-	return _reflectID(reflect.ValueOf(_struct), "Channel")
-}
-
-func reflectGuildID(_struct interface{}) discord.Snowflake {
-	return _reflectID(reflect.ValueOf(_struct), "Guild")
-}
-
-func reflectUserID(_struct interface{}) discord.Snowflake {
-	return _reflectID(reflect.ValueOf(_struct), "User")
-}
-
-func _reflectID(v reflect.Value, thing string) discord.Snowflake {
-	if !v.IsValid() {
-		return 0
-	}
-
-	t := v.Type()
-
-	if t.Kind() == reflect.Ptr {
-		v = v.Elem()
-
-		// Recheck after dereferring
-		if !v.IsValid() {
-			return 0
-		}
-
-		t = v.Type()
-	}
-
-	if t.Kind() != reflect.Struct {
-		return 0
-	}
-
-	numFields := t.NumField()
-
-	for i := 0; i < numFields; i++ {
-		field := t.Field(i)
-		fType := field.Type
-
-		if fType.Kind() == reflect.Ptr {
-			fType = fType.Elem()
-		}
-
-		switch fType.Kind() {
-		case reflect.Struct:
-			if chID := _reflectID(v.Field(i), thing); chID.Valid() {
-				return chID
-			}
-		case reflect.Int64:
-			if field.Name == thing+"ID" {
-				// grab value real quick
-				return discord.Snowflake(v.Field(i).Int())
-			}
-
-			// Special case where the struct name has Channel in it
-			if field.Name == "ID" && strings.Contains(t.Name(), thing) {
-				return discord.Snowflake(v.Field(i).Int())
-			}
-		}
-	}
-
-	return 0
-}

bot/ctx_test.go

@@ -342,79 +342,3 @@ func BenchmarkHelp(b *testing.B) {
 		_ = ctx.Help()
 	}
 }
-
-type hasID struct {
-	ChannelID discord.Snowflake
-}
-
-type embedsID struct {
-	*hasID
-	*embedsID
-}
-
-type hasChannelInName struct {
-	ID discord.Snowflake
-}
-
-func TestReflectChannelID(t *testing.T) {
-	var s = &hasID{
-		ChannelID: 69420,
-	}
-
-	t.Run("hasID", func(t *testing.T) {
-		if id := reflectChannelID(s); id != 69420 {
-			t.Fatal("unexpected channelID:", id)
-		}
-	})
-
-	t.Run("embedsID", func(t *testing.T) {
-		var e = &embedsID{
-			hasID: s,
-		}
-
-		if id := reflectChannelID(e); id != 69420 {
-			t.Fatal("unexpected channelID:", id)
-		}
-	})
-
-	t.Run("hasChannelInName", func(t *testing.T) {
-		var s = &hasChannelInName{
-			ID: 69420,
-		}
-
-		if id := reflectChannelID(s); id != 69420 {
-			t.Fatal("unexpected channelID:", id)
-		}
-	})
-}
-
-func BenchmarkReflectChannelID_1Level(b *testing.B) {
-	var s = &hasID{
-		ChannelID: 69420,
-	}
-
-	for i := 0; i < b.N; i++ {
-		_ = reflectChannelID(s)
-	}
-}
-
-func BenchmarkReflectChannelID_5Level(b *testing.B) {
-	var s = &embedsID{
-		nil,
-		&embedsID{
-			nil,
-			&embedsID{
-				nil,
-				&embedsID{
-					hasID: &hasID{
-						ChannelID: 69420,
-					},
-				},
-			},
-		},
-	}
-
-	for i := 0; i < b.N; i++ {
-		_ = reflectChannelID(s)
-	}
-}

bot/extras/infer/infer.go

@@ -0,0 +1,82 @@
+// Package infer implements reflect functions that package bot uses.
+//
+// Functions in this package may run recursively forever. This shouldn't happen
+// with Arikawa's structures, but use these functions with care.
+package infer
+
+import (
+	"reflect"
+	"strings"
+
+	"github.com/diamondburned/arikawa/discord"
+)
+
+// ChannelID looks for fields with name ChannelID, Channel, or in some special
+// cases, ID.
+func ChannelID(event interface{}) discord.Snowflake {
+	return reflectID(reflect.ValueOf(event), "Channel")
+}
+
+// GuildID looks for fields with name GuildID, Guild, or in some special cases,
+// ID.
+func GuildID(event interface{}) discord.Snowflake {
+	return reflectID(reflect.ValueOf(event), "Guild")
+}
+
+// UserID looks for fields with name UserID, User, or in some special cases, ID.
+func UserID(event interface{}) discord.Snowflake {
+	return reflectID(reflect.ValueOf(event), "User")
+}
+
+func reflectID(v reflect.Value, thing string) discord.Snowflake {
+	if !v.IsValid() {
+		return 0
+	}
+
+	t := v.Type()
+
+	if t.Kind() == reflect.Ptr {
+		v = v.Elem()
+
+		// Recheck after dereferring
+		if !v.IsValid() {
+			return 0
+		}
+
+		t = v.Type()
+	}
+
+	if t.Kind() != reflect.Struct {
+		return 0
+	}
+
+	numFields := t.NumField()
+
+	for i := 0; i < numFields; i++ {
+		field := t.Field(i)
+		fType := field.Type
+
+		if fType.Kind() == reflect.Ptr {
+			fType = fType.Elem()
+		}
+
+		switch fType.Kind() {
+		case reflect.Struct:
+			if chID := reflectID(v.Field(i), thing); chID.Valid() {
+				return chID
+			}
+		case reflect.Int64:
+			if field.Name == thing+"ID" {
+				// grab value real quick
+				return discord.Snowflake(v.Field(i).Int())
+			}
+
+			// Special case where the struct name has Channel in it
+			if field.Name == "ID" && strings.Contains(t.Name(), thing) {
+				return discord.Snowflake(v.Field(i).Int())
+			}
+		}
+	}
+
+	return 0
+}

bot/extras/infer/infer_test.go

@@ -0,0 +1,85 @@
+package infer
+
+import (
+	"testing"
+
+	"github.com/diamondburned/arikawa/discord"
+)
+
+type hasID struct {
+	ChannelID discord.Snowflake
+}
+
+type embedsID struct {
+	*hasID
+	*embedsID
+}
+
+type hasChannelInName struct {
+	ID discord.Snowflake
+}
+
+func TestReflectChannelID(t *testing.T) {
+	var s = &hasID{
+		ChannelID: 69420,
+	}
+
+	t.Run("hasID", func(t *testing.T) {
+		if id := ChannelID(s); id != 69420 {
+			t.Fatal("unexpected channelID:", id)
+		}
+	})
+
+	t.Run("embedsID", func(t *testing.T) {
+		var e = &embedsID{
+			hasID: s,
+		}
+
+		if id := ChannelID(e); id != 69420 {
+			t.Fatal("unexpected channelID:", id)
+		}
+	})
+
+	t.Run("hasChannelInName", func(t *testing.T) {
+		var s = &hasChannelInName{
+			ID: 69420,
+		}
+
+		if id := ChannelID(s); id != 69420 {
+			t.Fatal("unexpected channelID:", id)
+		}
+	})
+}
+
+var id discord.Snowflake
+
+func BenchmarkReflectChannelID_1Level(b *testing.B) {
+	var s = &hasID{
+		ChannelID: 69420,
+	}
+
+	for i := 0; i < b.N; i++ {
+		id = ChannelID(s)
+	}
+}
+
+func BenchmarkReflectChannelID_5Level(b *testing.B) {
+	var s = &embedsID{
+		nil,
+		&embedsID{
+			nil,
+			&embedsID{
+				nil,
+				&embedsID{
+					hasID: &hasID{
+						ChannelID: 69420,
+					},
+				},
+			},
+		},
+	}
+
+	for i := 0; i < b.N; i++ {
+		id = ChannelID(s)
+	}
+}

bot/nameflag.go

@@ -13,7 +13,7 @@ const None NameFlag = 0
 // These flags are applied to all events, if possible. The defined behavior
 // is to search for "ChannelID" fields or "ID" fields in structs with
 // "Channel" in its name. It doesn't handle individual events, as such, will
-// not be able to guarantee it will always work.
+// not be able to guarantee it will always work. Refer to package infer.
 
 // R - Raw, which tells the library to use the method name as-is (flags will
 // still be stripped). For example, if a method is called Reset its