build: Expose from_str_name for generated enums (#774)

prost-build/src/code_generator.rs

@@ -700,6 +700,38 @@ impl<'a> CodeGenerator<'a> {
         self.push_indent();
         self.buf.push_str("}\n"); // End of as_str_name()
 
+        self.push_indent();
+        self.buf
+            .push_str("/// Creates an enum from field names used in the ProtoBuf definition.\n");
+
+        self.push_indent();
+        self.buf
+            .push_str("pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {\n");
+        self.depth += 1;
+
+        self.push_indent();
+        self.buf.push_str("match value {\n");
+        self.depth += 1;
+
+        for variant in variant_mappings.iter() {
+            self.push_indent();
+            self.buf.push_str("\"");
+            self.buf.push_str(variant.proto_name);
+            self.buf.push_str("\" => Some(Self::");
+            self.buf.push_str(&variant.generated_variant_name);
+            self.buf.push_str("),\n");
+        }
+        self.push_indent();
+        self.buf.push_str("_ => None,\n");
+
+        self.depth -= 1;
+        self.push_indent();
+        self.buf.push_str("}\n"); // End of match
+
+        self.depth -= 1;
+        self.push_indent();
+        self.buf.push_str("}\n"); // End of from_str_name()
+
         self.path.pop();
         self.depth -= 1;
         self.push_indent();

prost-types/src/compiler.rs

@@ -161,5 +161,13 @@ pub mod code_generator_response {
                 Feature::Proto3Optional => "FEATURE_PROTO3_OPTIONAL",
             }
         }
+        /// Creates an enum from field names used in the ProtoBuf definition.
+        pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+            match value {
+                "FEATURE_NONE" => Some(Self::None),
+                "FEATURE_PROTO3_OPTIONAL" => Some(Self::Proto3Optional),
+                _ => None,
+            }
+        }
     }
 }

prost-types/src/protobuf.rs

@@ -253,6 +253,30 @@ pub mod field_descriptor_proto {
                 Type::Sint64 => "TYPE_SINT64",
             }
         }
+        /// Creates an enum from field names used in the ProtoBuf definition.
+        pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+            match value {
+                "TYPE_DOUBLE" => Some(Self::Double),
+                "TYPE_FLOAT" => Some(Self::Float),
+                "TYPE_INT64" => Some(Self::Int64),
+                "TYPE_UINT64" => Some(Self::Uint64),
+                "TYPE_INT32" => Some(Self::Int32),
+                "TYPE_FIXED64" => Some(Self::Fixed64),
+                "TYPE_FIXED32" => Some(Self::Fixed32),
+                "TYPE_BOOL" => Some(Self::Bool),
+                "TYPE_STRING" => Some(Self::String),
+                "TYPE_GROUP" => Some(Self::Group),
+                "TYPE_MESSAGE" => Some(Self::Message),
+                "TYPE_BYTES" => Some(Self::Bytes),
+                "TYPE_UINT32" => Some(Self::Uint32),
+                "TYPE_ENUM" => Some(Self::Enum),
+                "TYPE_SFIXED32" => Some(Self::Sfixed32),
+                "TYPE_SFIXED64" => Some(Self::Sfixed64),
+                "TYPE_SINT32" => Some(Self::Sint32),
+                "TYPE_SINT64" => Some(Self::Sint64),
+                _ => None,
+            }
+        }
     }
     #[derive(
         Clone,
@@ -284,6 +308,15 @@ pub mod field_descriptor_proto {
                 Label::Repeated => "LABEL_REPEATED",
             }
         }
+        /// Creates an enum from field names used in the ProtoBuf definition.
+        pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+            match value {
+                "LABEL_OPTIONAL" => Some(Self::Optional),
+                "LABEL_REQUIRED" => Some(Self::Required),
+                "LABEL_REPEATED" => Some(Self::Repeated),
+                _ => None,
+            }
+        }
     }
 }
 /// Describes a oneof.
@@ -561,6 +594,15 @@ pub mod file_options {
                 OptimizeMode::LiteRuntime => "LITE_RUNTIME",
             }
         }
+        /// Creates an enum from field names used in the ProtoBuf definition.
+        pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+            match value {
+                "SPEED" => Some(Self::Speed),
+                "CODE_SIZE" => Some(Self::CodeSize),
+                "LITE_RUNTIME" => Some(Self::LiteRuntime),
+                _ => None,
+            }
+        }
     }
 }
 #[allow(clippy::derive_partial_eq_without_eq)]
@@ -737,6 +779,15 @@ pub mod field_options {
                 CType::StringPiece => "STRING_PIECE",
             }
         }
+        /// Creates an enum from field names used in the ProtoBuf definition.
+        pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+            match value {
+                "STRING" => Some(Self::String),
+                "CORD" => Some(Self::Cord),
+                "STRING_PIECE" => Some(Self::StringPiece),
+                _ => None,
+            }
+        }
     }
     #[derive(
         Clone,
@@ -770,6 +821,15 @@ pub mod field_options {
                 JsType::JsNumber => "JS_NUMBER",
             }
         }
+        /// Creates an enum from field names used in the ProtoBuf definition.
+        pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+            match value {
+                "JS_NORMAL" => Some(Self::JsNormal),
+                "JS_STRING" => Some(Self::JsString),
+                "JS_NUMBER" => Some(Self::JsNumber),
+                _ => None,
+            }
+        }
     }
 }
 #[allow(clippy::derive_partial_eq_without_eq)]
@@ -878,6 +938,15 @@ pub mod method_options {
                 IdempotencyLevel::Idempotent => "IDEMPOTENT",
             }
         }
+        /// Creates an enum from field names used in the ProtoBuf definition.
+        pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+            match value {
+                "IDEMPOTENCY_UNKNOWN" => Some(Self::IdempotencyUnknown),
+                "NO_SIDE_EFFECTS" => Some(Self::NoSideEffects),
+                "IDEMPOTENT" => Some(Self::Idempotent),
+                _ => None,
+            }
+        }
     }
 }
 /// A message representing a option the parser does not recognize. This only
@@ -1384,6 +1453,31 @@ pub mod field {
                 Kind::TypeSint64 => "TYPE_SINT64",
             }
         }
+        /// Creates an enum from field names used in the ProtoBuf definition.
+        pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+            match value {
+                "TYPE_UNKNOWN" => Some(Self::TypeUnknown),
+                "TYPE_DOUBLE" => Some(Self::TypeDouble),
+                "TYPE_FLOAT" => Some(Self::TypeFloat),
+                "TYPE_INT64" => Some(Self::TypeInt64),
+                "TYPE_UINT64" => Some(Self::TypeUint64),
+                "TYPE_INT32" => Some(Self::TypeInt32),
+                "TYPE_FIXED64" => Some(Self::TypeFixed64),
+                "TYPE_FIXED32" => Some(Self::TypeFixed32),
+                "TYPE_BOOL" => Some(Self::TypeBool),
+                "TYPE_STRING" => Some(Self::TypeString),
+                "TYPE_GROUP" => Some(Self::TypeGroup),
+                "TYPE_MESSAGE" => Some(Self::TypeMessage),
+                "TYPE_BYTES" => Some(Self::TypeBytes),
+                "TYPE_UINT32" => Some(Self::TypeUint32),
+                "TYPE_ENUM" => Some(Self::TypeEnum),
+                "TYPE_SFIXED32" => Some(Self::TypeSfixed32),
+                "TYPE_SFIXED64" => Some(Self::TypeSfixed64),
+                "TYPE_SINT32" => Some(Self::TypeSint32),
+                "TYPE_SINT64" => Some(Self::TypeSint64),
+                _ => None,
+            }
+        }
     }
     /// Whether a field is optional, required, or repeated.
     #[derive(
@@ -1421,6 +1515,16 @@ pub mod field {
                 Cardinality::Repeated => "CARDINALITY_REPEATED",
             }
         }
+        /// Creates an enum from field names used in the ProtoBuf definition.
+        pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+            match value {
+                "CARDINALITY_UNKNOWN" => Some(Self::Unknown),
+                "CARDINALITY_OPTIONAL" => Some(Self::Optional),
+                "CARDINALITY_REQUIRED" => Some(Self::Required),
+                "CARDINALITY_REPEATED" => Some(Self::Repeated),
+                _ => None,
+            }
+        }
     }
 }
 /// Enum type definition.
@@ -1495,6 +1599,14 @@ impl Syntax {
             Syntax::Proto3 => "SYNTAX_PROTO3",
         }
     }
+    /// Creates an enum from field names used in the ProtoBuf definition.
+    pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+        match value {
+            "SYNTAX_PROTO2" => Some(Self::Proto2),
+            "SYNTAX_PROTO3" => Some(Self::Proto3),
+            _ => None,
+        }
+    }
 }
 /// Api is a light-weight descriptor for an API Interface.
 ///
@@ -2072,6 +2184,13 @@ impl NullValue {
             NullValue::NullValue => "NULL_VALUE",
         }
     }
+    /// Creates an enum from field names used in the ProtoBuf definition.
+    pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+        match value {
+            "NULL_VALUE" => Some(Self::NullValue),
+            _ => None,
+        }
+    }
 }
 /// A Timestamp represents a point in time independent of any time zone or local
 /// calendar, encoded as a count of seconds and fractions of seconds at

tests/src/lib.rs

@@ -550,6 +550,34 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_enum_from_string() {
+        use default_enum_value::{ERemoteClientBroadcastMsg, PrivacyLevel};
+
+        assert_eq!(
+            Some(PrivacyLevel::One),
+            PrivacyLevel::from_str_name("PRIVACY_LEVEL_ONE")
+        );
+        assert_eq!(
+            Some(PrivacyLevel::Two),
+            PrivacyLevel::from_str_name("PRIVACY_LEVEL_TWO")
+        );
+        assert_eq!(
+            Some(PrivacyLevel::PrivacyLevelThree),
+            PrivacyLevel::from_str_name("PRIVACY_LEVEL_PRIVACY_LEVEL_THREE")
+        );
+        assert_eq!(
+            Some(PrivacyLevel::PrivacyLevelprivacyLevelFour),
+            PrivacyLevel::from_str_name("PRIVACY_LEVELPRIVACY_LEVEL_FOUR")
+        );
+        assert_eq!(None, PrivacyLevel::from_str_name("PRIVACY_LEVEL_FIVE"));
+
+        assert_eq!(
+            Some(ERemoteClientBroadcastMsg::KERemoteClientBroadcastMsgDiscovery),
+            ERemoteClientBroadcastMsg::from_str_name("k_ERemoteClientBroadcastMsgDiscovery")
+        );
+    }
+
     #[test]
     fn test_default_string_escape() {
         let msg = default_string_escape::Person::default();