Add wrapper for char arrays to access str conveniently (#388)

* Add wrapper for char arrays to access str conveniently

This adds a wrapper around char arrays that allows
to access them either as slices or as strings. When
accessing the string representation, it will automatically
convert the char array to a string slice up to the first null byte.

* Implement RustDefault for CharArray

* Fix review comments

* Fix tests

* Fix formatting

* Fix ts annotation for CharArray

* Fix merge conflicts and change serialization

* Avoid unnecessary find

Author: azerupi

mavlink-bindgen/src/parser.rs

@@ -215,7 +215,7 @@ impl MavProfile {
             #[allow(unused_imports)]
             use bitflags::bitflags;
 
-            use mavlink_core::{MavlinkVersion, Message, MessageData, bytes::Bytes, bytes_mut::BytesMut};
+            use mavlink_core::{MavlinkVersion, Message, MessageData, bytes::Bytes, bytes_mut::BytesMut, types::CharArray};
 
             #[cfg(feature = "serde")]
             use serde::{Serialize, Deserialize};
@@ -710,23 +710,15 @@ impl MavMessage {
                     quote!()
                 };
 
-                let serde_with_attr = if let MavType::Array(_, size) = field.mavtype {
-                    if field.mavtype.primitive_type() == "char" {
-                        let format_serialize = format!("crate::nulstr::serialize::<_, {}>", size);
-                        let format_deserialize = format!("crate::nulstr::deserialize::<_, {}>", size);
-                        quote!(
-                            #[cfg_attr(feature = "serde", serde(
-                                serialize_with = #format_serialize,
-                                deserialize_with = #format_deserialize
-                            ))]
-                            #[cfg_attr(feature = "ts", ts(type = "string"))]
-                        )
-                    } else {
-                        quote!(
-                            #[cfg_attr(feature = "serde", serde(with = "serde_arrays"))]
-                            #[cfg_attr(feature = "ts", ts(type = "Array<number>"))]
-                        )
-                    }
+                let serde_with_attr = if matches!(field.mavtype, MavType::Array(_, _)) {
+                    quote!(
+                        #[cfg_attr(feature = "serde", serde(with = "serde_arrays"))]
+                        #[cfg_attr(feature = "ts", ts(type = "Array<number>"))]
+                    )
+                } else if matches!(field.mavtype, MavType::CharArray(_)) {
+                    quote!(
+                        #[cfg_attr(feature = "ts", ts(type = "string"))]
+                    )
                 } else {
                     quote!()
                 };
@@ -1113,6 +1105,7 @@ pub enum MavType {
     Char,
     Float,
     Double,
+    CharArray(usize),
     Array(Box<MavType>, usize),
 }
 
@@ -1133,16 +1126,18 @@ impl MavType {
             "float" => Some(Float),
             "Double" => Some(Double),
             "double" => Some(Double),
-            _ => {
-                if s.ends_with(']') {
-                    let start = s.find('[')?;
-                    let size = s[start + 1..(s.len() - 1)].parse::<usize>().ok()?;
-                    let mtype = Self::parse_type(&s[0..start])?;
-                    Some(Array(Box::new(mtype), size))
-                } else {
-                    None
-                }
+            _ if s.starts_with("char[") => {
+                let start = 4;
+                let size = s[start + 1..(s.len() - 1)].parse::<usize>().ok()?;
+                Some(CharArray(size))
             }
+            _ if s.ends_with(']') => {
+                let start = s.find('[')?;
+                let size = s[start + 1..(s.len() - 1)].parse::<usize>().ok()?;
+                let mtype = Self::parse_type(&s[0..start])?;
+                Some(Array(Box::new(mtype), size))
+            }
+            _ => None,
         }
     }
 
@@ -1162,6 +1157,15 @@ impl MavType {
             Int64 => quote! {#val = #buf.get_i64_le();},
             Float => quote! {#val = #buf.get_f32_le();},
             Double => quote! {#val = #buf.get_f64_le();},
+            CharArray(size) => {
+                quote! {
+                    let mut tmp = [0_u8; #size];
+                    for v in &mut tmp {
+                        *v = #buf.get_u8();
+                    }
+                    #val = CharArray::new(tmp);
+                }
+            }
             Array(t, _) => {
                 let r = t.rust_reader(&quote!(let val), buf);
                 quote! {
@@ -1190,6 +1194,14 @@ impl MavType {
             UInt64 => quote! {#buf.put_u64_le(#val);},
             Int64 => quote! {#buf.put_i64_le(#val);},
             Double => quote! {#buf.put_f64_le(#val);},
+            CharArray(_) => {
+                let w = Char.rust_writer(&quote!(*val), buf);
+                quote! {
+                    for val in &#val {
+                        #w
+                    }
+                }
+            }
             Array(t, _size) => {
                 let w = t.rust_writer(&quote!(*val), buf);
                 quote! {
@@ -1209,6 +1221,7 @@ impl MavType {
             UInt16 | Int16 => 2,
             UInt32 | Int32 | Float => 4,
             UInt64 | Int64 | Double => 8,
+            CharArray(size) => *size,
             Array(t, size) => t.len() * size,
         }
     }
@@ -1217,7 +1230,7 @@ impl MavType {
     fn order_len(&self) -> usize {
         use self::MavType::*;
         match self {
-            UInt8MavlinkVersion | UInt8 | Int8 | Char => 1,
+            UInt8MavlinkVersion | UInt8 | Int8 | Char | CharArray(_) => 1,
             UInt16 | Int16 => 2,
             UInt32 | Int32 | Float => 4,
             UInt64 | Int64 | Double => 8,
@@ -1241,6 +1254,7 @@ impl MavType {
             UInt64 => "uint64_t".into(),
             Int64 => "int64_t".into(),
             Double => "double".into(),
+            CharArray(_) => "char".into(),
             Array(t, _) => t.primitive_type(),
         }
     }
@@ -1261,6 +1275,7 @@ impl MavType {
             UInt64 => "u64".into(),
             Int64 => "i64".into(),
             Double => "f64".into(),
+            CharArray(size) => format!("CharArray<{}>", size),
             Array(t, size) => format!("[{};{}]", t.rust_type(), size),
         }
     }
@@ -1286,6 +1301,7 @@ impl MavType {
             UInt64 => quote!(0_u64),
             Int64 => quote!(0_i64),
             Double => quote!(0.0_f64),
+            CharArray(size) => quote!(CharArray::new([0_u8; #size])),
             Array(ty, size) => {
                 let default_value = ty.emit_default_value(dialect_has_version);
                 quote!([#default_value; #size])
@@ -1866,7 +1882,7 @@ pub fn extra_crc(msg: &MavMessage) -> u8 {
             crc.digest(field.name.as_bytes());
         }
         crc.digest(b" ");
-        if let MavType::Array(_, size) = field.mavtype {
+        if let MavType::Array(_, size) | MavType::CharArray(size) = field.mavtype {
             crc.digest(&[size as u8]);
         }
     }

mavlink-bindgen/tests/snapshots/e2e_snapshots__deprecated.xml@deprecated.rs.snap

@@ -1,6 +1,5 @@
 ---
 source: mavlink-bindgen/tests/e2e_snapshots.rs
-assertion_line: 26
 expression: contents
 ---
 #![doc = "MAVLink deprecated dialect."]
@@ -11,7 +10,9 @@ expression: contents
 use arbitrary::Arbitrary;
 #[allow(unused_imports)]
 use bitflags::bitflags;
-use mavlink_core::{bytes::Bytes, bytes_mut::BytesMut, MavlinkVersion, Message, MessageData};
+use mavlink_core::{
+    bytes::Bytes, bytes_mut::BytesMut, types::CharArray, MavlinkVersion, Message, MessageData,
+};
 #[allow(unused_imports)]
 use num_derive::FromPrimitive;
 #[allow(unused_imports)]

mavlink-bindgen/tests/snapshots/e2e_snapshots__heartbeat.xml@heartbeat.rs.snap

@@ -11,7 +11,9 @@ expression: contents
 use arbitrary::Arbitrary;
 #[allow(unused_imports)]
 use bitflags::bitflags;
-use mavlink_core::{bytes::Bytes, bytes_mut::BytesMut, MavlinkVersion, Message, MessageData};
+use mavlink_core::{
+    bytes::Bytes, bytes_mut::BytesMut, types::CharArray, MavlinkVersion, Message, MessageData,
+};
 #[allow(unused_imports)]
 use num_derive::FromPrimitive;
 #[allow(unused_imports)]

mavlink-bindgen/tests/snapshots/e2e_snapshots__no_field_description.xml@no_field_description.rs.snap

@@ -1,6 +1,5 @@
 ---
 source: mavlink-bindgen/tests/e2e_snapshots.rs
-assertion_line: 26
 expression: contents
 ---
 #![doc = "MAVLink no_field_description dialect."]
@@ -11,7 +10,9 @@ expression: contents
 use arbitrary::Arbitrary;
 #[allow(unused_imports)]
 use bitflags::bitflags;
-use mavlink_core::{bytes::Bytes, bytes_mut::BytesMut, MavlinkVersion, Message, MessageData};
+use mavlink_core::{
+    bytes::Bytes, bytes_mut::BytesMut, types::CharArray, MavlinkVersion, Message, MessageData,
+};
 #[allow(unused_imports)]
 use num_derive::FromPrimitive;
 #[allow(unused_imports)]

mavlink-bindgen/tests/snapshots/e2e_snapshots__parameters.xml@parameters.rs.snap

@@ -1,6 +1,5 @@
 ---
 source: mavlink-bindgen/tests/e2e_snapshots.rs
-assertion_line: 26
 expression: contents
 ---
 #![doc = "MAVLink parameters dialect."]
@@ -11,7 +10,9 @@ expression: contents
 use arbitrary::Arbitrary;
 #[allow(unused_imports)]
 use bitflags::bitflags;
-use mavlink_core::{bytes::Bytes, bytes_mut::BytesMut, MavlinkVersion, Message, MessageData};
+use mavlink_core::{
+    bytes::Bytes, bytes_mut::BytesMut, types::CharArray, MavlinkVersion, Message, MessageData,
+};
 #[allow(unused_imports)]
 use num_derive::FromPrimitive;
 #[allow(unused_imports)]
@@ -156,23 +157,16 @@ pub struct PARAM_REQUEST_READ_DATA {
     #[doc = "Component ID"]
     pub target_component: u8,
     #[doc = "Onboard parameter id, terminated by NULL if the                 length is less than 16 human-readable chars and WITHOUT null termination (NULL) byte                 if                 the length is exactly 16 chars - applications have to provide 16+1 bytes storage if                 the                 ID is stored as string"]
-    #[cfg_attr(
-        feature = "serde",
-        serde(
-            serialize_with = "crate::nulstr::serialize::<_, 16>",
-            deserialize_with = "crate::nulstr::deserialize::<_, 16>"
-        )
-    )]
     #[cfg_attr(feature = "ts", ts(type = "string"))]
-    pub param_id: [u8; 16],
+    pub param_id: CharArray<16>,
 }
 impl PARAM_REQUEST_READ_DATA {
     pub const ENCODED_LEN: usize = 20usize;
     pub const DEFAULT: Self = Self {
         param_index: 0_i16,
         target_system: 0_u8,
         target_component: 0_u8,
-        param_id: [0_u8; 16usize],
+        param_id: CharArray::new([0_u8; 16usize]),
     };
     #[cfg(feature = "arbitrary")]
     pub fn random<R: rand::RngCore>(rng: &mut R) -> Self {
@@ -210,10 +204,11 @@ impl MessageData for PARAM_REQUEST_READ_DATA {
         __struct.param_index = buf.get_i16_le();
         __struct.target_system = buf.get_u8();
         __struct.target_component = buf.get_u8();
-        for v in &mut __struct.param_id {
-            let val = buf.get_u8();
-            *v = val;
+        let mut tmp = [0_u8; 16usize];
+        for v in &mut tmp {
+            *v = buf.get_u8();
         }
+        __struct.param_id = CharArray::new(tmp);
         Ok(__struct)
     }
     fn ser(&self, version: MavlinkVersion, bytes: &mut [u8]) -> usize {
@@ -257,15 +252,8 @@ pub struct PARAM_SET_DATA {
     #[doc = "Component ID"]
     pub target_component: u8,
     #[doc = "Onboard parameter id, terminated by NULL if the                 length is less than 16 human-readable chars and WITHOUT null termination (NULL) byte                 if                 the length is exactly 16 chars - applications have to provide 16+1 bytes storage if                 the                 ID is stored as string"]
-    #[cfg_attr(
-        feature = "serde",
-        serde(
-            serialize_with = "crate::nulstr::serialize::<_, 16>",
-            deserialize_with = "crate::nulstr::deserialize::<_, 16>"
-        )
-    )]
     #[cfg_attr(feature = "ts", ts(type = "string"))]
-    pub param_id: [u8; 16],
+    pub param_id: CharArray<16>,
     #[doc = "Onboard parameter type."]
     pub param_type: MavParamType,
 }
@@ -275,7 +263,7 @@ impl PARAM_SET_DATA {
         param_value: 0.0_f32,
         target_system: 0_u8,
         target_component: 0_u8,
-        param_id: [0_u8; 16usize],
+        param_id: CharArray::new([0_u8; 16usize]),
         param_type: MavParamType::DEFAULT,
     };
     #[cfg(feature = "arbitrary")]
@@ -314,10 +302,11 @@ impl MessageData for PARAM_SET_DATA {
         __struct.param_value = buf.get_f32_le();
         __struct.target_system = buf.get_u8();
         __struct.target_component = buf.get_u8();
-        for v in &mut __struct.param_id {
-            let val = buf.get_u8();
-            *v = val;
+        let mut tmp = [0_u8; 16usize];
+        for v in &mut tmp {
+            *v = buf.get_u8();
         }
+        __struct.param_id = CharArray::new(tmp);
         let tmp = buf.get_u8();
         __struct.param_type =
             FromPrimitive::from_u8(tmp).ok_or(::mavlink_core::error::ParserError::InvalidEnum {
@@ -368,15 +357,8 @@ pub struct PARAM_VALUE_DATA {
     #[doc = "Index of this onboard parameter"]
     pub param_index: u16,
     #[doc = "Onboard parameter id, terminated by NULL if the                 length is less than 16 human-readable chars and WITHOUT null termination (NULL) byte                 if                 the length is exactly 16 chars - applications have to provide 16+1 bytes storage if                 the                 ID is stored as string"]
-    #[cfg_attr(
-        feature = "serde",
-        serde(
-            serialize_with = "crate::nulstr::serialize::<_, 16>",
-            deserialize_with = "crate::nulstr::deserialize::<_, 16>"
-        )
-    )]
     #[cfg_attr(feature = "ts", ts(type = "string"))]
-    pub param_id: [u8; 16],
+    pub param_id: CharArray<16>,
     #[doc = "Onboard parameter type."]
     pub param_type: MavParamType,
 }
@@ -386,7 +368,7 @@ impl PARAM_VALUE_DATA {
         param_value: 0.0_f32,
         param_count: 0_u16,
         param_index: 0_u16,
-        param_id: [0_u8; 16usize],
+        param_id: CharArray::new([0_u8; 16usize]),
         param_type: MavParamType::DEFAULT,
     };
     #[cfg(feature = "arbitrary")]
@@ -425,10 +407,11 @@ impl MessageData for PARAM_VALUE_DATA {
         __struct.param_value = buf.get_f32_le();
         __struct.param_count = buf.get_u16_le();
         __struct.param_index = buf.get_u16_le();
-        for v in &mut __struct.param_id {
-            let val = buf.get_u8();
-            *v = val;
+        let mut tmp = [0_u8; 16usize];
+        for v in &mut tmp {
+            *v = buf.get_u8();
         }
+        __struct.param_id = CharArray::new(tmp);
         let tmp = buf.get_u8();
         __struct.param_type =
             FromPrimitive::from_u8(tmp).ok_or(::mavlink_core::error::ParserError::InvalidEnum {

mavlink-core/src/lib.rs

@@ -113,6 +113,7 @@ pub mod bytes_mut;
 #[cfg(feature = "std")]
 mod connection;
 pub mod error;
+pub mod types;
 #[cfg(feature = "std")]
 pub use self::connection::{connect, Connectable, MavConnection};