Add print_message_fields_in_index_order to text-format (#140)

prost-reflect-tests/src/test.proto

@@ -107,3 +107,9 @@ enum EnumWithAlias {
 message MessageWithAliasedEnum {
   EnumWithAlias aliased = 1;
 }
+
+message IndexOrder {
+  int32 a = 3;
+  int32 b = 2;
+  int32 c = 1;
+}

prost-reflect-tests/src/text_format.rs

@@ -10,8 +10,8 @@ use prost_reflect::{text_format::FormatOptions, DynamicMessage, ReflectMessage,
 
 use crate::{
     proto::{
-        contains_group, ComplexType, ContainsGroup, MessageWithAliasedEnum, Point, ScalarArrays,
-        Scalars, WellKnownTypes,
+        contains_group, ComplexType, ContainsGroup, IndexOrder, MessageWithAliasedEnum, Point,
+        ScalarArrays, Scalars, WellKnownTypes,
     },
     test_file_descriptor,
 };
@@ -353,6 +353,23 @@ fn fmt_group() {
     );
 }
 
+#[test]
+fn fmt_index_order() {
+    let value = IndexOrder { a: 1, b: 2, c: 3 }.transcode_to_dynamic();
+    assert_eq!(
+        value.to_text_format_with_options(
+            &FormatOptions::new().print_message_fields_in_index_order(true)
+        ),
+        "a:1,b:2,c:3"
+    );
+    assert_eq!(
+        value.to_text_format_with_options(
+            &FormatOptions::new().print_message_fields_in_index_order(false)
+        ),
+        "c:3,b:2,a:1"
+    );
+}
+
 #[test]
 fn parse_group() {
     let value = ContainsGroup {

prost-reflect/src/descriptor/api.rs

@@ -756,6 +756,19 @@ impl MessageDescriptor {
             })
     }
 
+    pub(crate) fn fields_in_index_order(
+        &self,
+    ) -> impl ExactSizeIterator<Item = FieldDescriptor> + '_ {
+        self.inner()
+            .fields
+            .iter()
+            .enumerate()
+            .map(|(index, _)| FieldDescriptor {
+                message: self.clone(),
+                index: index as u32,
+            })
+    }
+
     /// Gets an iterator yielding a [`OneofDescriptor`] for each oneof field defined in this message.
     pub fn oneofs(&self) -> impl ExactSizeIterator<Item = OneofDescriptor> + '_ {
         indices(&self.inner().oneofs).map(|index| OneofDescriptor {

prost-reflect/src/dynamic/fields.rs

@@ -9,7 +9,10 @@ use crate::{
     ExtensionDescriptor, FieldDescriptor, Kind, MessageDescriptor, OneofDescriptor, Value,
 };
 
-use super::unknown::{UnknownField, UnknownFieldSet};
+use super::{
+    unknown::{UnknownField, UnknownFieldSet},
+    Either,
+};
 
 pub(crate) trait FieldDescriptorLike: fmt::Debug {
     #[cfg(feature = "text-format")]
@@ -143,68 +146,55 @@ impl DynamicMessageFieldSet {
         }
     }
 
+    /// Iterates over the fields in the message.
+    ///
+    /// If `include_default` is `true`, fields with their default value will be included.
+    /// If `index_order` is `true`, fields will be iterated in the order they were defined in the source code. Otherwise, they will be iterated in field number order.
     pub(crate) fn iter<'a>(
         &'a self,
         message: &'a MessageDescriptor,
+        include_default: bool,
+        index_order: bool,
     ) -> impl Iterator<Item = ValueAndDescriptor<'a>> + 'a {
-        self.fields
-            .iter()
-            .filter_map(move |(&number, value)| match value {
-                ValueOrUnknown::Value(value) => {
-                    if let Some(field) = message.get_field(number) {
-                        if field.has(value) {
-                            Some(ValueAndDescriptor::Field(Cow::Borrowed(value), field))
-                        } else {
-                            None
-                        }
-                    } else if let Some(extension) = message.get_extension(number) {
-                        if extension.has(value) {
-                            Some(ValueAndDescriptor::Extension(
-                                Cow::Borrowed(value),
-                                extension,
-                            ))
-                        } else {
-                            None
-                        }
-                    } else {
-                        panic!("no field found with number {}", number)
-                    }
+        let field_descriptors = if index_order {
+            Either::Left(message.fields_in_index_order())
+        } else {
+            Either::Right(message.fields())
+        };
+
+        let fields = field_descriptors
+            .filter(move |f| {
+                if include_default {
+                    !f.supports_presence() || self.has(f)
+                } else {
+                    self.has(f)
                 }
-                ValueOrUnknown::Unknown(unknown) => Some(ValueAndDescriptor::Unknown(unknown)),
-                ValueOrUnknown::Taken => None,
             })
-    }
-
-    pub(crate) fn iter_include_default<'a>(
-        &'a self,
-        message: &'a MessageDescriptor,
-    ) -> impl Iterator<Item = ValueAndDescriptor<'a>> + 'a {
-        let fields = message
-            .fields()
-            .filter(move |f| !f.supports_presence() || self.has(f))
-            .map(move |f| ValueAndDescriptor::Field(self.get(&f), f));
-        let others = self
-            .fields
-            .iter()
-            .filter_map(move |(&number, value)| match value {
-                ValueOrUnknown::Value(value) => {
-                    if let Some(extension) = message.get_extension(number) {
-                        if extension.has(value) {
-                            Some(ValueAndDescriptor::Extension(
-                                Cow::Borrowed(value),
-                                extension,
-                            ))
+            .map(|f| ValueAndDescriptor::Field(self.get(&f), f));
+
+        let extensions_unknowns =
+            self.fields
+                .iter()
+                .filter_map(move |(&number, value)| match value {
+                    ValueOrUnknown::Value(value) => {
+                        if let Some(extension) = message.get_extension(number) {
+                            if extension.has(value) {
+                                Some(ValueAndDescriptor::Extension(
+                                    Cow::Borrowed(value),
+                                    extension,
+                                ))
+                            } else {
+                                None
+                            }
                         } else {
                             None
                         }
-                    } else {
-                        None
                     }
-                }
-                ValueOrUnknown::Unknown(unknown) => Some(ValueAndDescriptor::Unknown(unknown)),
-                ValueOrUnknown::Taken => None,
-            });
-        fields.chain(others)
+                    ValueOrUnknown::Unknown(unknown) => Some(ValueAndDescriptor::Unknown(unknown)),
+                    ValueOrUnknown::Taken => None,
+                });
+
+        fields.chain(extensions_unknowns)
     }
 
     pub(crate) fn iter_fields<'a>(

prost-reflect/src/dynamic/message.rs

@@ -19,7 +19,7 @@ impl Message for DynamicMessage {
     where
         Self: Sized,
     {
-        for field in self.fields.iter(&self.desc) {
+        for field in self.fields.iter(&self.desc, false, false) {
             match field {
                 ValueAndDescriptor::Field(value, field_desc) => {
                     value.encode_field(&field_desc, buf)
@@ -61,7 +61,7 @@ impl Message for DynamicMessage {
 
     fn encoded_len(&self) -> usize {
         let mut len = 0;
-        for field in self.fields.iter(&self.desc) {
+        for field in self.fields.iter(&self.desc, false, false) {
             match field {
                 ValueAndDescriptor::Field(value, field_desc) => {
                     len += value.encoded_len(&field_desc);

prost-reflect/src/dynamic/serde/ser/mod.rs

@@ -54,11 +54,9 @@ fn serialize_dynamic_message_fields<S>(
 where
     S: SerializeMap,
 {
-    let fields = if options.skip_default_fields {
-        crate::dynamic::Either::Left(value.fields.iter(&value.desc))
-    } else {
-        crate::dynamic::Either::Right(value.fields.iter_include_default(&value.desc))
-    };
+    let fields = value
+        .fields
+        .iter(&value.desc, !options.skip_default_fields, false);
 
     for field in fields {
         let (name, value, ref kind) = match field {

prost-reflect/src/dynamic/text_format/format.rs

@@ -42,11 +42,11 @@ where
             }
         }
 
-        let fields = if self.options.skip_default_fields {
-            crate::dynamic::Either::Left(message.fields.iter(&message.desc))
-        } else {
-            crate::dynamic::Either::Right(message.fields.iter_include_default(&message.desc))
-        };
+        let fields = message.fields.iter(
+            &message.desc,
+            !self.options.skip_default_fields,
+            self.options.print_message_fields_in_index_order,
+        );
 
         if self.options.skip_unknown_fields {
             self.fmt_delimited(
@@ -90,13 +90,11 @@ where
                 write!(self.f, "{}", value)
             }
             Value::Message(message) => {
-                let mut fields = if self.options.skip_default_fields {
-                    crate::dynamic::Either::Left(message.fields.iter(&message.desc))
-                } else {
-                    crate::dynamic::Either::Right(
-                        message.fields.iter_include_default(&message.desc),
-                    )
-                };
+                let mut fields = message.fields.iter(
+                    &message.desc,
+                    !self.options.skip_default_fields,
+                    self.options.print_message_fields_in_index_order,
+                );
 
                 if fields.all(|f| {
                     self.options.skip_unknown_fields && matches!(f, ValueAndDescriptor::Unknown(..))

prost-reflect/src/dynamic/text_format/mod.rs

@@ -19,6 +19,7 @@ pub struct FormatOptions {
     skip_unknown_fields: bool,
     expand_any: bool,
     skip_default_fields: bool,
+    print_message_fields_in_index_order: bool,
 }
 
 #[cfg(feature = "text-format")]
@@ -158,6 +159,18 @@ impl FormatOptions {
         self
     }
 
+    /// Whether to print message fields in the order they were defined in source code.
+    ///
+    /// If set to `true`, message fields will be printed in the order they were defined in the source code.
+    /// Otherwise, they will be printed in field number order.
+    ///
+    /// The default value is `false`.
+    #[cfg(feature = "text-format")]
+    pub fn print_message_fields_in_index_order(mut self, yes: bool) -> Self {
+        self.print_message_fields_in_index_order = yes;
+        self
+    }
+
     /// Whether to use the expanded form of the `google.protobuf.Any` type.
     ///
     /// If set to `true`, `Any` fields will use an expanded form:
@@ -207,6 +220,7 @@ impl Default for FormatOptions {
             skip_unknown_fields: true,
             expand_any: true,
             skip_default_fields: true,
+            print_message_fields_in_index_order: false,
         }
     }
 }