From 84d9c14a17e864058527981e3388cef148827c11 Mon Sep 17 00:00:00 2001
From: Yigit Sever
Date: Wed, 7 Apr 2021 04:33:45 +0300
Subject: Implement Block GET/PUT with new schema

- `Arc`+`Mutex` is replaced by `parking_lot::RwLock,` decoupled
  Read+Write and ability to upgrade read locks into write locks if
  needed
- Schema has changed, `Db` is now a struct that implements `new()` to
  return a new instance of itself, pros/cons listed in code but tl;dr
  blockchain and pending transactions are separate now
- `custom_filters` now supports extracting Block json and Transaction
  json in separate functions too
- /block GET and PUT implemented, `Blocks` currently have one check
  (transactions appear in pending transaction)
- debug is working after something, dunno how I fixed it
---
 src/handlers.rs | 94 +++++++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 71 insertions(+), 23 deletions(-)

(limited to 'src/handlers.rs')

diff --git a/src/handlers.rs b/src/handlers.rs
index 51c7b63..ecf5a92 100644
--- a/src/handlers.rs
+++ b/src/handlers.rs
@@ -1,45 +1,93 @@
-// API handlers, the ends of each filter chain
-
-use log::debug;
+/// API handlers, the ends of each filter chain
+use log::debug; // this is more useful than debug! learn how to use this
+use parking_lot::RwLockUpgradableReadGuard;
 use std::convert::Infallible;
 use warp::{http::StatusCode, reply};
 
-use crate::schema::{Db, Transaction}; // `Block` coming later
+use crate::schema::{Block, Db, Transaction};
+
+/// GET /transaction
+/// Returns JSON array of transactions
+/// Cannot fail
+pub async fn list_transactions(db: Db) -> Result<impl warp::Reply, Infallible> {
+    debug!("list all transactions");
+    let mut result = Vec::new();
+
+    let transactions = db.pending_transactions.read();
+    // let transactions = transactions.clone().into_iter().collect();
+
+    for (_, value) in transactions.iter() {
+        result.push(value)
+    }
+
+    Ok(reply::with_status(reply::json(&result), StatusCode::OK))
+}
+
+/// GET /block
+/// Returns JSON array of blocks
+/// Cannot fail
+/// Mostly around for debug purposes
+pub async fn list_blocks(db: Db) -> Result<impl warp::Reply, Infallible> {
+    debug!("list all blocks");
+
+    let mut result = Vec::new();
+    let blocks = db.blockchain.read();
+
+    for block in blocks.iter() {
+        result.push(block);
+    }
 
-// PROPOSE Transaction
-// POST /transaction
+    Ok(reply::with_status(reply::json(&result), StatusCode::OK))
+}
+
+/// POST /transaction
+/// Pushes a new transaction for pending transaction pool
+/// Can reject the transaction proposal
+/// TODO: when is a new transaction rejected <07-04-21, yigit> //
 pub async fn propose_transaction(
     new_transaction: Transaction,
     db: Db,
 ) -> Result<impl warp::Reply, warp::Rejection> {
     debug!("new transaction request {:?}", new_transaction);
 
-    let mut transactions = db.lock().await;
+    // let mut transactions = db.lock().await;
+    let mut transactions = db.pending_transactions.write();
 
-    transactions.push(new_transaction);
+    transactions.insert(new_transaction.source.to_owned(), new_transaction);
 
     Ok(StatusCode::CREATED)
 }
 
-// GET Transaction List
-// GET /transaction
-// Returns JSON array of transactions
-// Cannot fail?
-pub async fn list_transactions(db: Db) -> Result<impl warp::Reply, Infallible> {
-    debug!("list all transactions");
+/// POST /block
+/// Proposes a new block for the next round
+/// Can reject the block
+pub async fn propose_block(new_block: Block, db: Db) -> Result<impl warp::Reply, warp::Rejection> {
+    debug!("new block request {:?}", new_block);
 
-    let transactions = db.lock().await;
+    // https://blog.logrocket.com/create-an-async-crud-web-service-in-rust-with-warp/ (this has
+    // error.rs, error struct, looks very clean)
 
-    let transactions: Vec<Transaction> = transactions.clone().into_iter().collect();
+    let pending_transactions = db.pending_transactions.upgradable_read();
+    let blockchain = db.blockchain.upgradable_read();
 
-    Ok(reply::with_status(
-        reply::json(&transactions),
-        StatusCode::OK,
-    ))
-}
+    // TODO: check 1, new_block.transaction_list from pending_transactions pool? <07-04-21, yigit> //
+    for transaction_hash in new_block.transaction_list.iter() {
+        if !pending_transactions.contains_key(transaction_hash) {
+            return Ok(StatusCode::BAD_REQUEST);
+        }
+    }
 
-// PROPOSE Block
-// POST /block
+    // TODO: check 2, block hash (\w nonce) asserts $hash_condition? <07-04-21, yigit> //
+    // assume it is for now
+
+    let mut blockchain = RwLockUpgradableReadGuard::upgrade(blockchain);
+    blockchain.push(new_block);
+
+    let mut pending_transactions = RwLockUpgradableReadGuard::upgrade(pending_transactions);
+    pending_transactions.clear();
+
+    Ok(StatusCode::CREATED)
+}
 
 // `GET /games`
 // Returns JSON array of todos
-- 
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