Refactor: Uses c++ init convention for time variables

This commit does following changes to time variables in net_processing.h:
- Used {} initialization.
- Uses universal initializer auto.
- Uses chrono::literals

The reason for these changes is to make code simpler, and easier to
understand and rationalize.

Author: shaavan

src/net_processing.cpp

@@ -64,7 +64,7 @@ static constexpr auto STALE_CHECK_INTERVAL{10min};
 /** How frequently to check for extra outbound peers and disconnect */
 static constexpr auto EXTRA_PEER_CHECK_INTERVAL{45s};
 /** Minimum time an outbound-peer-eviction candidate must be connected for, in order to evict */
-static constexpr std::chrono::seconds MINIMUM_CONNECT_TIME{30};
+static constexpr auto MINIMUM_CONNECT_TIME{30s};
 /** SHA256("main address relay")[0:8] */
 static constexpr uint64_t RANDOMIZER_ID_ADDRESS_RELAY = 0x3cac0035b5866b90ULL;
 /// Age after which a stale block will no longer be served if requested as
@@ -74,7 +74,7 @@ static constexpr int STALE_RELAY_AGE_LIMIT = 30 * 24 * 60 * 60;
 /// limiting block relay. Set to one week, denominated in seconds.
 static constexpr int HISTORICAL_BLOCK_AGE = 7 * 24 * 60 * 60;
 /** Time between pings automatically sent out for latency probing and keepalive */
-static constexpr std::chrono::minutes PING_INTERVAL{2};
+static constexpr auto PING_INTERVAL{2min};
 /** The maximum number of entries in a locator */
 static const unsigned int MAX_LOCATOR_SZ = 101;
 /** The maximum number of entries in an 'inv' protocol message */
@@ -88,19 +88,19 @@ static constexpr int32_t MAX_PEER_TX_REQUEST_IN_FLIGHT = 100;
  *  the actual transaction (from any peer) in response to requests for them. */
 static constexpr int32_t MAX_PEER_TX_ANNOUNCEMENTS = 5000;
 /** How long to delay requesting transactions via txids, if we have wtxid-relaying peers */
-static constexpr auto TXID_RELAY_DELAY = std::chrono::seconds{2};
+static constexpr auto TXID_RELAY_DELAY{2s};
 /** How long to delay requesting transactions from non-preferred peers */
-static constexpr auto NONPREF_PEER_TX_DELAY = std::chrono::seconds{2};
+static constexpr auto NONPREF_PEER_TX_DELAY{2s};
 /** How long to delay requesting transactions from overloaded peers (see MAX_PEER_TX_REQUEST_IN_FLIGHT). */
-static constexpr auto OVERLOADED_PEER_TX_DELAY = std::chrono::seconds{2};
-/** How long to wait (in microseconds) before downloading a transaction from an additional peer */
-static constexpr std::chrono::microseconds GETDATA_TX_INTERVAL{std::chrono::seconds{60}};
+static constexpr auto OVERLOADED_PEER_TX_DELAY{2s};
+/** How long to wait before downloading a transaction from an additional peer */
+static constexpr auto GETDATA_TX_INTERVAL{60s};
 /** Limit to avoid sending big packets. Not used in processing incoming GETDATA for compatibility */
 static const unsigned int MAX_GETDATA_SZ = 1000;
 /** Number of blocks that can be requested at any given time from a single peer. */
 static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 16;
 /** Time during which a peer must stall block download progress before being disconnected. */
-static constexpr auto BLOCK_STALLING_TIMEOUT = 2s;
+static constexpr auto BLOCK_STALLING_TIMEOUT{2s};
 /** Number of headers sent in one getheaders result. We rely on the assumption that if a peer sends
  *  less than this number, we reached its tip. Changing this value is a protocol upgrade. */
 static const unsigned int MAX_HEADERS_RESULTS = 2000;
@@ -125,16 +125,16 @@ static const int MAX_UNCONNECTING_HEADERS = 10;
 /** Minimum blocks required to signal NODE_NETWORK_LIMITED */
 static const unsigned int NODE_NETWORK_LIMITED_MIN_BLOCKS = 288;
 /** Average delay between local address broadcasts */
-static constexpr auto AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL = 24h;
+static constexpr auto AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL{24h};
 /** Average delay between peer address broadcasts */
-static constexpr auto AVG_ADDRESS_BROADCAST_INTERVAL = 30s;
+static constexpr auto AVG_ADDRESS_BROADCAST_INTERVAL{30s};
 /** Average delay between trickled inventory transmissions for inbound peers.
  *  Blocks and peers with NetPermissionFlags::NoBan permission bypass this. */
-static constexpr auto INBOUND_INVENTORY_BROADCAST_INTERVAL = 5s;
+static constexpr auto INBOUND_INVENTORY_BROADCAST_INTERVAL{5s};
 /** Average delay between trickled inventory transmissions for outbound peers.
  *  Use a smaller delay as there is less privacy concern for them.
  *  Blocks and peers with NetPermissionFlags::NoBan permission bypass this. */
-static constexpr auto OUTBOUND_INVENTORY_BROADCAST_INTERVAL = 2s;
+static constexpr auto OUTBOUND_INVENTORY_BROADCAST_INTERVAL{2s};
 /** Maximum rate of inventory items to send per second.
  *  Limits the impact of low-fee transaction floods. */
 static constexpr unsigned int INVENTORY_BROADCAST_PER_SECOND = 7;
@@ -148,9 +148,9 @@ static constexpr unsigned int INVENTORY_MAX_RECENT_RELAY = 3500;
  *  peers, and random variations in the broadcast mechanism. */
 static_assert(INVENTORY_MAX_RECENT_RELAY >= INVENTORY_BROADCAST_PER_SECOND * UNCONDITIONAL_RELAY_DELAY / std::chrono::seconds{1}, "INVENTORY_RELAY_MAX too low");
 /** Average delay between feefilter broadcasts in seconds. */
-static constexpr auto AVG_FEEFILTER_BROADCAST_INTERVAL = 10min;
+static constexpr auto AVG_FEEFILTER_BROADCAST_INTERVAL{10min};
 /** Maximum feefilter broadcast delay after significant change. */
-static constexpr auto MAX_FEEFILTER_CHANGE_DELAY = 5min;
+static constexpr auto MAX_FEEFILTER_CHANGE_DELAY{5min};
 /** Maximum number of compact filters that may be requested with one getcfilters. See BIP 157. */
 static constexpr uint32_t MAX_GETCFILTERS_SIZE = 1000;
 /** Maximum number of cf hashes that may be requested with one getcfheaders. See BIP 157. */
@@ -727,7 +727,7 @@ struct CNodeState {
       *   - its chain tip has at least as much work as ours
       *
       * CHAIN_SYNC_TIMEOUT: if a peer's best known block has less work than our tip,
-      * set a timeout CHAIN_SYNC_TIMEOUT seconds in the future:
+      * set a timeout CHAIN_SYNC_TIMEOUT in the future:
       *   - If at timeout their best known block now has more work than our tip
       *     when the timeout was set, then either reset the timeout or clear it
       *     (after comparing against our current tip's work)
@@ -1137,7 +1137,7 @@ void PeerManagerImpl::AddTxAnnouncement(const CNode& node, const GenTxid& gtxid,
     //   - TXID_RELAY_DELAY for txid announcements while wtxid peers are available
     //   - OVERLOADED_PEER_TX_DELAY for announcements from peers which have at least
     //     MAX_PEER_TX_REQUEST_IN_FLIGHT requests in flight (and don't have NetPermissionFlags::Relay).
-    auto delay = std::chrono::microseconds{0};
+    auto delay{0us};
     const bool preferred = state->fPreferredDownload;
     if (!preferred) delay += NONPREF_PEER_TX_DELAY;
     if (!gtxid.IsWtxid() && m_wtxid_relay_peers > 0) delay += TXID_RELAY_DELAY;
@@ -1191,7 +1191,7 @@ void PeerManagerImpl::ReattemptInitialBroadcast(CScheduler& scheduler)
 
     // Schedule next run for 10-15 minutes in the future.
     // We add randomness on every cycle to avoid the possibility of P2P fingerprinting.
-    const std::chrono::milliseconds delta = std::chrono::minutes{10} + GetRandMillis(std::chrono::minutes{5});
+    const std::chrono::milliseconds delta = 10min + GetRandMillis(5min);
     scheduler.scheduleFromNow([&] { ReattemptInitialBroadcast(scheduler); }, delta);
 }
 
@@ -1296,7 +1296,7 @@ bool PeerManagerImpl::GetNodeStateStats(NodeId nodeid, CNodeStateStats& stats) c
     // since pingtime does not update until the ping is complete, which might take a while.
     // So, if a ping is taking an unusually long time in flight,
     // the caller can immediately detect that this is happening.
-    std::chrono::microseconds ping_wait{0};
+    auto ping_wait{0us};
     if ((0 != peer->m_ping_nonce_sent) && (0 != peer->m_ping_start.load().count())) {
         ping_wait = GetTime<std::chrono::microseconds>() - peer->m_ping_start.load();
     }
@@ -1496,7 +1496,7 @@ void PeerManagerImpl::StartScheduledTasks(CScheduler& scheduler)
     scheduler.scheduleEvery([this] { this->CheckForStaleTipAndEvictPeers(); }, std::chrono::seconds{EXTRA_PEER_CHECK_INTERVAL});
 
     // schedule next run for 10-15 minutes in the future
-    const std::chrono::milliseconds delta = std::chrono::minutes{10} + GetRandMillis(std::chrono::minutes{5});
+    const std::chrono::milliseconds delta = 10min + GetRandMillis(5min);
     scheduler.scheduleFromNow([&] { ReattemptInitialBroadcast(scheduler); }, delta);
 }
 
@@ -1963,10 +1963,9 @@ void PeerManagerImpl::ProcessGetData(CNode& pfrom, Peer& peer, const std::atomic
     std::vector<CInv> vNotFound;
     const CNetMsgMaker msgMaker(pfrom.GetCommonVersion());
 
-    const std::chrono::seconds now = GetTime<std::chrono::seconds>();
+    const auto now{GetTime<std::chrono::seconds>()};
     // Get last mempool request time
-    const std::chrono::seconds mempool_req = pfrom.m_tx_relay != nullptr ? pfrom.m_tx_relay->m_last_mempool_req.load()
-                                                                          : std::chrono::seconds::min();
+    const auto mempool_req = pfrom.m_tx_relay != nullptr ? pfrom.m_tx_relay->m_last_mempool_req.load() : std::chrono::seconds::min();
 
     // Process as many TX items from the front of the getdata queue as
     // possible, since they're common and it's efficient to batch process
@@ -2890,7 +2889,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
         int64_t nSince = nNow - 10 * 60;
 
         // Update/increment addr rate limiting bucket.
-        const auto current_time = GetTime<std::chrono::microseconds>();
+        const auto current_time{GetTime<std::chrono::microseconds>()};
         if (peer->m_addr_token_bucket < MAX_ADDR_PROCESSING_TOKEN_BUCKET) {
             // Don't increment bucket if it's already full
             const auto time_diff = std::max(current_time - peer->m_addr_token_timestamp, 0us);
@@ -2976,7 +2975,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
 
         LOCK(cs_main);
 
-        const auto current_time = GetTime<std::chrono::microseconds>();
+        const auto current_time{GetTime<std::chrono::microseconds>()};
         uint256* best_block{nullptr};
 
         for (CInv& inv : vInv) {
@@ -3354,7 +3353,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
                 }
             }
             if (!fRejectedParents) {
-                const auto current_time = GetTime<std::chrono::microseconds>();
+                const auto current_time{GetTime<std::chrono::microseconds>()};
 
                 for (const uint256& parent_txid : unique_parents) {
                     // Here, we only have the txid (and not wtxid) of the
@@ -4571,7 +4570,7 @@ bool PeerManagerImpl::SendMessages(CNode* pto)
     // If we get here, the outgoing message serialization version is set and can't change.
     const CNetMsgMaker msgMaker(pto->GetCommonVersion());
 
-    const auto current_time = GetTime<std::chrono::microseconds>();
+    const auto current_time{GetTime<std::chrono::microseconds>()};
 
     if (pto->IsAddrFetchConn() && current_time - pto->m_connected > 10 * AVG_ADDRESS_BROADCAST_INTERVAL) {
         LogPrint(BCLog::NET, "addrfetch connection timeout; disconnecting peer=%d\n", pto->GetId());