@@ -94,3 +94,118 @@ impl<AbsoluteLocation: Get<MultiLocation>> Reserve
9494 } )
9595 }
9696}
97+
98+ // https://github.com/AstarNetwork/Astar/blob/2a8df8d098f6abc3fdf5aaf6514e94f615f9bdab/primitives/src/xcm/mod.rs#L276-L418
99+ // TODO: remove this after uplift to `polkadot-v0.9.44` or beyond, and replace it with code in XCM builder.
100+
101+ use codec:: { Compact , Encode } ;
102+ use sp_io:: hashing:: blake2_256;
103+ use sp_std:: prelude:: * ;
104+ use xcm_executor:: traits:: Convert as XcmConvert ;
105+
106+ /// Means of converting a location into a stable and unique descriptive identifier.
107+ pub trait DescribeLocation {
108+ /// Create a description of the given `location` if possible. No two locations should have the
109+ /// same descriptor.
110+ fn describe_location ( location : & MultiLocation ) -> Option < Vec < u8 > > ;
111+ }
112+
113+ #[ impl_trait_for_tuples:: impl_for_tuples( 30 ) ]
114+ impl DescribeLocation for Tuple {
115+ fn describe_location ( l : & MultiLocation ) -> Option < Vec < u8 > > {
116+ for_tuples ! ( #(
117+ match Tuple :: describe_location( l) {
118+ Some ( result) => return Some ( result) ,
119+ None => { } ,
120+ }
121+ ) * ) ;
122+ None
123+ }
124+ }
125+
126+ pub struct DescribeTerminus ;
127+ impl DescribeLocation for DescribeTerminus {
128+ fn describe_location ( l : & MultiLocation ) -> Option < Vec < u8 > > {
129+ match ( l. parents , & l. interior ) {
130+ ( 0 , Here ) => Some ( Vec :: new ( ) ) ,
131+ _ => return None ,
132+ }
133+ }
134+ }
135+
136+ pub struct DescribePalletTerminal ;
137+ impl DescribeLocation for DescribePalletTerminal {
138+ fn describe_location ( l : & MultiLocation ) -> Option < Vec < u8 > > {
139+ match ( l. parents , & l. interior ) {
140+ ( 0 , X1 ( PalletInstance ( i) ) ) =>
141+ Some ( ( b"Pallet" , Compact :: < u32 > :: from ( * i as u32 ) ) . encode ( ) ) ,
142+ _ => return None ,
143+ }
144+ }
145+ }
146+
147+ pub struct DescribeAccountId32Terminal ;
148+ impl DescribeLocation for DescribeAccountId32Terminal {
149+ fn describe_location ( l : & MultiLocation ) -> Option < Vec < u8 > > {
150+ match ( l. parents , & l. interior ) {
151+ ( 0 , X1 ( AccountId32 { id, .. } ) ) => Some ( ( b"AccountId32" , id) . encode ( ) ) ,
152+ _ => return None ,
153+ }
154+ }
155+ }
156+
157+ pub struct DescribeAccountKey20Terminal ;
158+ impl DescribeLocation for DescribeAccountKey20Terminal {
159+ fn describe_location ( l : & MultiLocation ) -> Option < Vec < u8 > > {
160+ match ( l. parents , & l. interior ) {
161+ ( 0 , X1 ( AccountKey20 { key, .. } ) ) => Some ( ( b"AccountKey20" , key) . encode ( ) ) ,
162+ _ => return None ,
163+ }
164+ }
165+ }
166+
167+ pub type DescribeAccountIdTerminal = ( DescribeAccountId32Terminal , DescribeAccountKey20Terminal ) ;
168+
169+ pub type DescribeAllTerminal = (
170+ DescribeTerminus ,
171+ DescribePalletTerminal ,
172+ DescribeAccountId32Terminal ,
173+ DescribeAccountKey20Terminal ,
174+ ) ;
175+
176+ pub struct DescribeFamily < DescribeInterior > ( PhantomData < DescribeInterior > ) ;
177+ impl < Suffix : DescribeLocation > DescribeLocation for DescribeFamily < Suffix > {
178+ fn describe_location ( l : & MultiLocation ) -> Option < Vec < u8 > > {
179+ match ( l. parents , l. interior . first ( ) ) {
180+ ( 0 , Some ( Parachain ( index) ) ) => {
181+ let tail = l. interior . split_first ( ) . 0 ;
182+ let interior = Suffix :: describe_location ( & tail. into ( ) ) ?;
183+ Some ( ( b"ChildChain" , Compact :: < u32 > :: from ( * index) , interior) . encode ( ) )
184+ } ,
185+ ( 1 , Some ( Parachain ( index) ) ) => {
186+ let tail = l. interior . split_first ( ) . 0 ;
187+ let interior = Suffix :: describe_location ( & tail. into ( ) ) ?;
188+ Some ( ( b"SiblingChain" , Compact :: < u32 > :: from ( * index) , interior) . encode ( ) )
189+ } ,
190+ ( 1 , _) => {
191+ let tail = l. interior . into ( ) ;
192+ let interior = Suffix :: describe_location ( & tail) ?;
193+ Some ( ( b"ParentChain" , interior) . encode ( ) )
194+ } ,
195+ _ => return None ,
196+ }
197+ }
198+ }
199+
200+ pub struct HashedDescription < AccountId , Describe > ( PhantomData < ( AccountId , Describe ) > ) ;
201+ impl < AccountId : From < [ u8 ; 32 ] > + Clone , Describe : DescribeLocation >
202+ XcmConvert < MultiLocation , AccountId > for HashedDescription < AccountId , Describe >
203+ {
204+ fn convert ( value : MultiLocation ) -> Result < AccountId , MultiLocation > {
205+ if let Some ( description) = Describe :: describe_location ( & value) {
206+ Ok ( blake2_256 ( & description) . into ( ) )
207+ } else {
208+ Err ( value)
209+ }
210+ }
211+ }
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