Add initial message to JSON serialization support

1 files changed, 80 insertions, 0 deletions

diff --git a/src/nimpb_buildpkg/plugin.nim b/src/nimpb_buildpkg/plugin.nim
index 7354fa8..abdad07 100644
--- a/src/nimpb_buildpkg/plugin.nim
+++ b/src/nimpb_buildpkg/plugin.nim
@@ -30,6 +30,7 @@ type
         mapEntry: Message
         defaultValue: string
         message: Message
+        jsonName: string
 
     Message = ref object
         names: Names
@@ -149,6 +150,11 @@ proc mapKeyType(field: Field): string =
         if f.name == "key":
             return f.nimTypeName
 
+proc mapValueField(field: Field): Field =
+    for f in field.mapEntry.fields:
+        if f.name == "value":
+            return f
+
 proc mapValueType(field: Field): string =
     for f in field.mapEntry.fields:
         if f.name == "value":
@@ -343,6 +349,9 @@ proc newField(file: ProtoFile, message: Message, desc: google_protobuf_FieldDesc
     if hasDefaultValue(desc):
         result.defaultValue = desc.default_value
 
+    if hasJsonName(desc):
+        result.jsonName = desc.jsonName
+
     log(&"newField {result.name} {$result.ftype} {result.typeName} PACKED={result.packed} SYNTAX={file.syntax}")
 
 proc newOneof(name: string): Oneof =
@@ -847,6 +856,69 @@ iterator genSizeOfMessageProc(msg: Message): string =
 
     yield ""
 
+proc shouldGenerateJsonProcs(typeName: string): bool =
+    const wktsHavingCustomProcs = [
+        "google_protobuf_Any",
+        "google_protobuf_BoolValue",
+        "google_protobuf_BytesValue",
+        "google_protobuf_DoubleValue",
+        "google_protobuf_Duration",
+        "google_protobuf_FieldMask",
+        "google_protobuf_FloatValue",
+        "google_protobuf_Int32Value",
+        "google_protobuf_Int64Value",
+        "google_protobuf_ListValue",
+        "google_protobuf_NullValue",
+        "google_protobuf_StringValue",
+        "google_protobuf_Struct",
+        "google_protobuf_Timestamp",
+        "google_protobuf_UInt32Value",
+        "google_protobuf_UInt64Value",
+        "google_protobuf_Value",
+    ]
+
+    return typeName notin wktsHavingCustomProcs
+
+iterator genMessageToJsonProc(msg: Message): string =
+    yield &"proc toJson*(message: {msg.names}): JsonNode ="
+    yield indent("result = newJObject()", 4)
+
+    proc fieldToJson(field: Field, v: string): string =
+        case field.ftype
+        of google_protobuf_FieldDescriptorProto_Type.TypeMessage,
+           google_protobuf_FieldDescriptorProto_Type.TypeInt64,
+           google_protobuf_FieldDescriptorProto_Type.TypeUInt64,
+           google_protobuf_FieldDescriptorProto_Type.TypeSFixed64,
+           google_protobuf_FieldDescriptorProto_Type.TypeFixed64,
+           google_protobuf_FieldDescriptorProto_Type.TypeDouble,
+           google_protobuf_FieldDescriptorProto_Type.TypeFloat:
+            result = &"toJson({v})"
+        of google_protobuf_FieldDescriptorProto_Type.TypeEnum:
+            result = &"%(${v})"
+        else:
+            result = &"%{v}"
+
+    for field in msg.fields:
+        yield indent(&"if has{field.name}(message):", 4)
+        if isMapEntry(field):
+            yield indent("let obj = newJObject()", 8)
+            yield indent(&"for key, value in message.{field.name}:", 8)
+            let f = mapValueField(field)
+            let j = fieldToJson(f, "value")
+            yield indent(&"obj[$key] = {j}", 12)
+            yield indent(&"result[\"{field.jsonName}\"] = obj", 8)
+        elif isRepeated(field):
+            yield indent(&"let arr = newJArray()", 8)
+            yield indent(&"for value in message.{field.name}:", 8)
+            let v = fieldToJson(field, "value")
+            yield indent(&"add(arr, {v})", 12)
+            yield indent(&"result[\"{field.jsonName}\"] = arr", 8)
+        else:
+            let v = fieldToJson(field, &"message.{field.name}")
+            yield indent(&"result[\"{field.jsonName}\"] = {v}", 8)
+
+    yield ""
+
 iterator genMessageProcForwards(msg: Message): string =
     # TODO: can we be more intelligent and only forward declare the minimum set
     # of procs?
@@ -856,6 +928,8 @@ iterator genMessageProcForwards(msg: Message): string =
         yield &"proc write{msg.names}*(stream: ProtobufStream, message: {msg.names})"
         yield &"proc read{msg.names}*(stream: ProtobufStream): {msg.names}"
         yield &"proc sizeOf{msg.names}*(message: {msg.names}): uint64"
+        if shouldGenerateJsonProcs($msg.names):
+            yield &"proc toJson*(message: {msg.names}): JsonNode"
     else:
         let
             key = mapKeyField(msg)
@@ -887,6 +961,9 @@ iterator genProcs(msg: Message): string =
         for line in genWriteMessageProc(msg): yield line
         for line in genReadMessageProc(msg): yield line
 
+        if shouldGenerateJsonProcs($msg.names):
+            for line in genMessageToJsonProc(msg): yield line
+
         yield &"proc serialize*(message: {msg.names}): string ="
         yield indent("let", 4)
         yield indent("ss = newStringStream()", 8)
@@ -928,12 +1005,15 @@ proc processFile(fdesc: google_protobuf_FileDescriptorProto,
 
     addLine(result.data, "# Generated by protoc_gen_nim. Do not edit!")
     addLine(result.data, "")
+    addLine(result.data, "import base64")
     addLine(result.data, "import intsets")
+    addLine(result.data, "import json")
     if hasMaps:
         addLine(result.data, "import tables")
         addLine(result.data, "export tables")
     addLine(result.data, "")
     addLine(result.data, "import nimpb/nimpb")
+    addLine(result.data, "import nimpb/json as nimpb_json")
     addLine(result.data, "")
 
     for dep in fdesc.dependency: