Make subxt-core ready for publishing (#1508)

* Move Extrinsic decoding things to subxt_core and various tidy-ups

* A couple more fixes and fmt

* first pass moving tx logic to subxt_core

* cargo fmt

* fix wasm example

* clippy

* more clippy

* WIP Adding examples and such

* Move storage functionality more fully to subxt_core and nice examples for storage and txs

* Add example for events

* consistify how addresses/payloads are exposed in subxt-core and add runtime API fns

* Add runtime API core example

* fmt

* remove scale-info patch

* Add a little to the top level docs

* swap args around

* clippy

* cargo fmt and fix wasm-example

* doc fixes

* no-std-ise new subxt-core additions

* alloc, not core

* more no-std fixes

* A couple more fixes

* Add back extrinsic decode test

core/src/error.rs

@@ -1,15 +1,24 @@
+// Copyright 2019-2024 Parity Technologies (UK) Ltd.
+// This file is dual-licensed as Apache-2.0 or GPL-3.0.
+// see LICENSE for license details.
+
+//! The errors that can be emitted in this crate.
+
 use alloc::boxed::Box;
 use alloc::string::String;
 use derive_more::{Display, From};
 use subxt_metadata::StorageHasher;
 
+/// The error emitted when something goes wrong.
 #[derive(Debug, Display, From)]
 pub enum Error {
     /// Codec error.
     #[display(fmt = "Scale codec error: {_0}")]
     Codec(codec::Error),
+    /// Metadata error.
     #[display(fmt = "Metadata Error: {_0}")]
     Metadata(MetadataError),
+    /// Storage address error.
     #[display(fmt = "Storage Error: {_0}")]
     StorageAddress(StorageAddressError),
     /// Error decoding to a [`crate::dynamic::Value`].
@@ -21,16 +30,39 @@ pub enum Error {
     /// Error constructing the appropriate extrinsic params.
     #[display(fmt = "Extrinsic params error: {_0}")]
     ExtrinsicParams(ExtrinsicParamsError),
+    /// Block body error.
+    #[display(fmt = "Error working with block body: {_0}")]
+    Block(BlockError),
 }
 
+#[cfg(feature = "std")]
+impl std::error::Error for Error {}
+
 impl From<scale_decode::visitor::DecodeError> for Error {
     fn from(value: scale_decode::visitor::DecodeError) -> Self {
         Error::Decode(value.into())
     }
 }
 
+/// Block error
+#[derive(Clone, Debug, Display, Eq, PartialEq)]
+pub enum BlockError {
+    /// Extrinsic type ID cannot be resolved with the provided metadata.
+    #[display(
+        fmt = "Extrinsic type ID cannot be resolved with the provided metadata. Make sure this is a valid metadata"
+    )]
+    MissingType,
+    /// Unsupported signature.
+    #[display(fmt = "Unsupported extrinsic version, only version 4 is supported currently")]
+    /// The extrinsic has an unsupported version.
+    UnsupportedVersion(u8),
+    /// Decoding error.
+    #[display(fmt = "Cannot decode extrinsic: {_0}")]
+    DecodingError(codec::Error),
+}
+
 #[cfg(feature = "std")]
-impl std::error::Error for Error {}
+impl std::error::Error for BlockError {}
 
 /// Something went wrong trying to access details in the metadata.
 #[derive(Clone, Debug, PartialEq, Display)]