Refactor streaming JSON to separate modules

firmware/src/json/error.rs

@@ -0,0 +1,42 @@
+use super::value::TryFromValueError;
+use core::fmt;
+
+/// JSON reader/writer error
+#[derive(Debug, PartialEq)]
+pub enum Error<E> {
+    Io(E),
+    Eof,
+    Unexpected(char),
+    NumberTooLarge,
+    InvalidType,
+}
+
+impl<E: embedded_io_async::Error> From<E> for Error<E> {
+    fn from(err: E) -> Self {
+        Self::Io(err)
+    }
+}
+
+impl<E> From<TryFromValueError> for Error<E> {
+    fn from(_err: TryFromValueError) -> Self {
+        Self::InvalidType
+    }
+}
+
+impl<E: fmt::Display> fmt::Display for Error<E> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Io(err) => write!(f, "I/O error: {err}"),
+            Self::Eof => write!(f, "Premature EOF"),
+            Self::Unexpected(ch) => write!(f, "Unexpected `{ch}`"),
+            Self::NumberTooLarge => write!(f, "Number too large"),
+            Self::InvalidType => write!(f, "Invalid type"),
+        }
+    }
+}
+
+impl<E> Error<E> {
+    pub fn unexpected(ch: u8) -> Self {
+        Self::Unexpected(char::from(ch))
+    }
+}

firmware/src/json/mod.rs

@@ -0,0 +1,13 @@
+#![allow(unused_imports)]
+
+mod error;
+pub use self::error::Error;
+
+mod reader;
+pub use self::reader::{FromJson, Reader};
+
+mod value;
+pub use self::value::{TryFromValueError, Value};
+
+mod writer;
+pub use self::writer::{ObjectWriter, ToJson, Writer};