Add block-centric Storage API (#774)

* blocks: Add storage method

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Add support for runtime API calls and expose it to the blocks API

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* storage: Add storage type for block centric API

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Adjust subxt to the new Storage interface

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

* Fix clippy

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

Signed-off-by: Alexandru Vasile <alexandru.vasile@parity.io>

examples/examples/concurrent_storage_requests.rs

@@ -32,8 +32,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     // For storage requests, we can join futures together to
     // await multiple futures concurrently:
-    let a_fut = api.storage().fetch(&staking_bonded, None);
-    let b_fut = api.storage().fetch(&staking_ledger, None);
+    let a_fut = api.storage().at(None).await?.fetch(&staking_bonded);
+    let b_fut = api.storage().at(None).await?.fetch(&staking_ledger);
     let (a, b) = join!(a_fut, b_fut);
 
     println!("{a:?}, {b:?}");

examples/examples/dynamic_queries.rs

@@ -66,7 +66,9 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     );
     let account = api
         .storage()
-        .fetch_or_default(&storage_address, None)
+        .at(None)
+        .await?
+        .fetch_or_default(&storage_address)
         .await?
         .to_value()?;
     println!("Bob's account details: {account}");
@@ -74,7 +76,12 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     // 4. Dynamic storage iteration (the dynamic equivalent to the fetch_all_accounts example).
 
     let storage_address = subxt::dynamic::storage_root("System", "Account");
-    let mut iter = api.storage().iter(storage_address, 10, None).await?;
+    let mut iter = api
+        .storage()
+        .at(None)
+        .await?
+        .iter(storage_address, 10)
+        .await?;
     while let Some((key, account)) = iter.next().await? {
         println!("{}: {}", hex::encode(key), account.to_value()?);
     }

examples/examples/fetch_all_accounts.rs

@@ -26,7 +26,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     let address = polkadot::storage().system().account_root();
 
-    let mut iter = api.storage().iter(address, 10, None).await?;
+    let mut iter = api.storage().at(None).await?.iter(address, 10).await?;
 
     while let Some((key, account)) = iter.next().await? {
         println!("{}: {}", hex::encode(key), account.data.free);

examples/examples/fetch_staking_details.rs

@@ -32,7 +32,13 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let api = OnlineClient::<PolkadotConfig>::new().await?;
 
     let active_era_addr = polkadot::storage().staking().active_era();
-    let era = api.storage().fetch(&active_era_addr, None).await?.unwrap();
+    let era = api
+        .storage()
+        .at(None)
+        .await?
+        .fetch(&active_era_addr)
+        .await?
+        .unwrap();
     println!(
         "Staking active era: index: {:?}, start: {:?}",
         era.index, era.start
@@ -52,13 +58,20 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let controller_acc_addr = polkadot::storage().staking().bonded(&alice_stash_id);
     let controller_acc = api
         .storage()
-        .fetch(&controller_acc_addr, None)
+        .at(None)
+        .await?
+        .fetch(&controller_acc_addr)
         .await?
         .unwrap();
     println!("    account controlled by: {:?}", controller_acc);
 
     let era_reward_addr = polkadot::storage().staking().eras_reward_points(era.index);
-    let era_result = api.storage().fetch(&era_reward_addr, None).await?;
+    let era_result = api
+        .storage()
+        .at(None)
+        .await?
+        .fetch(&era_reward_addr)
+        .await?;
     println!("Era reward points: {:?}", era_result);
 
     Ok(())

examples/examples/storage_iterating.rs

@@ -35,7 +35,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     {
         let key_addr = polkadot::storage().xcm_pallet().version_notifiers_root();
 
-        let mut iter = api.storage().iter(key_addr, 10, None).await?;
+        let mut iter = api.storage().at(None).await?.iter(key_addr, 10).await?;
 
         println!("\nExample 1. Obtained keys:");
         while let Some((key, value)) = iter.next().await? {
@@ -52,14 +52,18 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         // Fetch at most 10 keys from below the prefix XcmPallet' VersionNotifiers.
         let keys = api
             .storage()
-            .fetch_keys(&key_addr.to_root_bytes(), 10, None, None)
+            .at(None)
+            .await?
+            .fetch_keys(&key_addr.to_root_bytes(), 10, None)
             .await?;
 
         println!("Example 2. Obtained keys:");
         for key in keys.iter() {
             println!("Key: 0x{}", hex::encode(key));
 
-            if let Some(storage_data) = api.storage().fetch_raw(&key.0, None).await? {
+            if let Some(storage_data) =
+                api.storage().at(None).await?.fetch_raw(&key.0).await?
+            {
                 // We know the return value to be `QueryId` (`u64`) from inspecting either:
                 // - polkadot code
                 // - polkadot.rs generated file under `version_notifiers()` fn
@@ -86,13 +90,20 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         // `twox_128("XcmPallet") ++ twox_128("VersionNotifiers") ++ twox_64(2u32) ++ 2u32`
         println!("\nExample 3\nQuery key: 0x{}", hex::encode(&query_key));
 
-        let keys = api.storage().fetch_keys(&query_key, 10, None, None).await?;
+        let keys = api
+            .storage()
+            .at(None)
+            .await?
+            .fetch_keys(&query_key, 10, None)
+            .await?;
 
         println!("Obtained keys:");
         for key in keys.iter() {
             println!("Key: 0x{}", hex::encode(key));
 
-            if let Some(storage_data) = api.storage().fetch_raw(&key.0, None).await? {
+            if let Some(storage_data) =
+                api.storage().at(None).await?.fetch_raw(&key.0).await?
+            {
                 // We know the return value to be `QueryId` (`u64`) from inspecting either:
                 // - polkadot code
                 // - polkadot.rs generated file under `version_notifiers()` fn