Merge pull request #113 from tdakkota/feature/gen/encode-zero-value

gen: automatic encoding of optional fields

bin/fields.go

@@ -7,6 +7,11 @@ import "strconv"
 // that fields "1", "5" and "10" were set.
 type Fields uint32
 
+// Zero returns true, if all bits are equal to zero.
+func (f Fields) Zero() bool {
+	return f == 0
+}
+
 // String implement fmt.Stringer
 func (f Fields) String() string {
 	return strconv.FormatUint(uint64(f), 2)

internal/gen/_template/handlers.tmpl

@@ -19,6 +19,7 @@ type UpdateContext struct {
 
     Users map[int]*User
     Chats map[int]*Chat
+    Channels map[int]*Channel
     init bool
 }
 
@@ -38,12 +39,14 @@ func (u *UpdateContext) lazyInitFromUpdates(updates *Updates) {
 	}
 
     u.Chats = make(map[int]*Chat, len(updates.Chats))
+    u.Channels = make(map[int]*Channel, len(updates.Chats))
 	for _, class := range updates.Chats {
-		chat, ok := class.(*Chat)
-		if !ok {
-			continue
-		}
-		u.Chats[chat.ID] = chat
+        switch chat := class.(type) {
+        case *Chat:
+            u.Chats[chat.ID] = chat
+        case *Channel:
+            u.Channels[chat.ID] = chat
+        }
 	}
 }
 

internal/gen/_template/main.tmpl

@@ -37,6 +37,7 @@ type {{ $s.Name }} struct {
 const {{ $s.Name }}TypeID = 0x{{ $s.HexID }};
 {{- end }}
 
+{{template "zero_derive" $s }}
 {{template "string_derive" $s }}
 
 // Encode implements bin.Encoder.
@@ -45,7 +46,14 @@ func ({{ $s.Receiver }} *{{ $s.Name }}) Encode({{ $s.BufArg }} *bin.Buffer) erro
         return fmt.Errorf("can't encode {{ $s.RawType }} as nil")
     }
 {{- if not $s.Vector }}
-{{ $s.BufArg }}.PutID({{ $s.Name }}TypeID)
+    {{ $s.BufArg }}.PutID({{ $s.Name }}TypeID)
+{{- end }}
+{{- range $f := $s.Fields }}
+    {{- if $f.Conditional }}
+    if !({{ $s.Receiver }}.{{template "compare_zero" $f}}) {
+        {{ $s.Receiver }}.{{ $f.ConditionalField }}.Set({{ $f.ConditionalIndex }})
+    }
+    {{- end }}
 {{- end }}
 {{- range $f := $s.Fields }}
     {{- if not $f.ConditionalBool }}
@@ -100,7 +108,7 @@ func ({{ $s.Receiver }} *{{ $s.Name }}) Encode({{ $s.BufArg }} *bin.Buffer) erro
 {{- range $f := $s.Fields }}
 {{ if $f.Conditional }}
 // Set{{ $f.Name }} sets value of {{ $f.Name }} conditional field.
-func ({{ $s.Receiver }} *{{ $s.Name }}) Set{{ $f.Name }}(value {{ if $f.DoubleSlice }}[][]{{ else if $f.Slice }}[]{{ end }} {{ $f.Type }}) {
+func ({{ $s.Receiver }} *{{ $s.Name }}) Set{{ $f.Name }}(value {{ template "print_type" $f }}) {
 {{- if $f.ConditionalBool }}
     if value {
         {{ $s.Receiver }}.{{ $f.ConditionalField }}.Set({{ $f.ConditionalIndex }})
@@ -311,7 +319,9 @@ type {{ $f.Name }} interface {
     bin.Encoder
     bin.Decoder
     construct() {{ $f.Name }}
+
     fmt.Stringer
+    Zero() bool
 }
 
 // Decode{{ $f.Func }} implements binary de-serialization for {{ $f.Name }}.

internal/gen/_template/zero.tmpl

@@ -0,0 +1,30 @@
+{{ define "zero_derive" }}{{ $s := . }}
+{{- /*gotype: github.com/gotd/td/internal/gen.structDef*/ -}}
+func ({{ $s.Receiver }} *{{ $s.Name }}) Zero() bool {
+    if {{ $s.Receiver }} == nil {
+        return true
+    }
+{{- /*gotype: github.com/gotd/td/internal/gen.fieldDef*/ -}}
+{{- range $f := $s.Fields }}{{- if ne ($f.Name) ($f.ConditionalField) }}
+    if !({{ $s.Receiver }}.{{template "compare_zero" $f}}) {
+        return false
+    }
+{{- end }}{{- end }}
+
+    return true
+}
+{{- end -}}
+
+{{ define "compare_zero" }}
+{{- /*gotype: github.com/gotd/td/internal/gen.fieldDef*/ -}}
+{{- .Name -}}
+{{- if or (.Slice) (.DoubleSlice) -}} == nil
+{{- else if eq (.Type) ("bin.Int128") -}} == bin.Int128{}
+{{- else if eq (.Type) ("bin.Int256") -}} == bin.Int256{}
+{{- else if or (hasPrefix (.Type) ("int")) (hasPrefix (.Type) ("float")) }} == 0
+{{- else if eq (.Type) ("string") -}} == ""
+{{- else if eq (.Type) ("bool") -}} == false
+{{- else if eq (.Type) ("bin.Object") }} == nil
+{{- else if hasSuffix (.Type) ("Class") }} == nil
+{{- else -}}.Zero()
+{{- end -}}{{- end }}