net: move the constant maxWait out of InterruptibleRecv()

Move `maxWait` out of `InterruptibleRecv()` and rename it to
`MAX_WAIT_FOR_IO` so that it can be reused by other code.

Author: vasild

src/netbase.cpp

@@ -14,6 +14,7 @@
 #include <util/time.h>
 
 #include <atomic>
+#include <chrono>
 #include <cstdint>
 #include <functional>
 #include <limits>
@@ -360,9 +361,6 @@ static IntrRecvError InterruptibleRecv(uint8_t* data, size_t len, int timeout, c
 {
     int64_t curTime = GetTimeMillis();
     int64_t endTime = curTime + timeout;
-    // Maximum time to wait for I/O readiness. It will take up until this time
-    // (in millis) to break off in case of an interruption.
-    const int64_t maxWait = 1000;
     while (len > 0 && curTime < endTime) {
         ssize_t ret = sock.Recv(data, len, 0); // Optimistically try the recv first
         if (ret > 0) {
@@ -373,10 +371,11 @@ static IntrRecvError InterruptibleRecv(uint8_t* data, size_t len, int timeout, c
         } else { // Other error or blocking
             int nErr = WSAGetLastError();
             if (nErr == WSAEINPROGRESS || nErr == WSAEWOULDBLOCK || nErr == WSAEINVAL) {
-                // Only wait at most maxWait milliseconds at a time, unless
+                // Only wait at most MAX_WAIT_FOR_IO at a time, unless
                 // we're approaching the end of the specified total timeout
-                int timeout_ms = std::min(endTime - curTime, maxWait);
-                if (!sock.Wait(std::chrono::milliseconds{timeout_ms}, Sock::RECV)) {
+                const auto remaining = std::chrono::milliseconds{endTime - curTime};
+                const auto timeout = std::min(remaining, std::chrono::milliseconds{MAX_WAIT_FOR_IO});
+                if (!sock.Wait(timeout, Sock::RECV)) {
                     return IntrRecvError::NetworkError;
                 }
             } else {

src/util/sock.h

@@ -6,10 +6,17 @@
 #define BITCOIN_UTIL_SOCK_H
 
 #include <compat.h>
+#include <util/time.h>
 
 #include <chrono>
 #include <string>
 
+/**
+ * Maximum time to wait for I/O readiness.
+ * It will take up until this time to break off in case of an interruption.
+ */
+static constexpr auto MAX_WAIT_FOR_IO = 1s;
+
 /**
  * RAII helper class that manages a socket. Mimics `std::unique_ptr`, but instead of a pointer it
  * contains a socket and closes it automatically when it goes out of scope.