Add account-decoder utilities (#10846)

* Fix comment and make less pub

* Add account-decoder crate and use to decode vote and system (nonce) accounts

* Update docs

* Rename RpcAccount struct

* s/Rpc/Display

* Call it jsonParsed and update docs

* Revert "s/Rpc/Display"

This reverts commit 6e7149f503.

* s/Rpc/Ui

* Add tests

* Ui more things

* Comments

account-decoder/src/lib.rs

@@ -0,0 +1,80 @@
+#[macro_use]
+extern crate lazy_static;
+#[macro_use]
+extern crate serde_derive;
+
+pub mod parse_account_data;
+pub mod parse_nonce;
+pub mod parse_vote;
+
+use crate::parse_account_data::parse_account_data;
+use serde_json::Value;
+use solana_sdk::{account::Account, clock::Epoch, pubkey::Pubkey};
+use std::str::FromStr;
+
+/// A duplicate representation of an Account for pretty JSON serialization
+#[derive(Serialize, Deserialize, Clone, Debug)]
+#[serde(rename_all = "camelCase")]
+pub struct UiAccount {
+    pub lamports: u64,
+    pub data: UiAccountData,
+    pub owner: String,
+    pub executable: bool,
+    pub rent_epoch: Epoch,
+}
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase", untagged)]
+pub enum UiAccountData {
+    Binary(String),
+    Json(Value),
+}
+
+impl From<Vec<u8>> for UiAccountData {
+    fn from(data: Vec<u8>) -> Self {
+        Self::Binary(bs58::encode(data).into_string())
+    }
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub enum UiAccountEncoding {
+    Binary,
+    JsonParsed,
+}
+
+impl UiAccount {
+    pub fn encode(account: Account, encoding: UiAccountEncoding) -> Self {
+        let data = match encoding {
+            UiAccountEncoding::Binary => account.data.into(),
+            UiAccountEncoding::JsonParsed => {
+                if let Ok(parsed_data) = parse_account_data(&account.owner, &account.data) {
+                    UiAccountData::Json(parsed_data)
+                } else {
+                    account.data.into()
+                }
+            }
+        };
+        UiAccount {
+            lamports: account.lamports,
+            data,
+            owner: account.owner.to_string(),
+            executable: account.executable,
+            rent_epoch: account.rent_epoch,
+        }
+    }
+
+    pub fn decode(&self) -> Option<Account> {
+        let data = match &self.data {
+            UiAccountData::Json(_) => None,
+            UiAccountData::Binary(blob) => bs58::decode(blob).into_vec().ok(),
+        }?;
+        Some(Account {
+            lamports: self.lamports,
+            data,
+            owner: Pubkey::from_str(&self.owner).ok()?,
+            executable: self.executable,
+            rent_epoch: self.rent_epoch,
+        })
+    }
+}