From 1577b5fa6732ef55d51ace6fc930f27c78e095b6 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Thu, 4 Apr 2024 12:42:41 -0400
Subject: [PATCH] Make SQLite busy back-off logic portable

Use C++ standard library not Unix functions for sleeping and randomness.

Suggested by @edolstra in https://github.com/NixOS/nix/pull/8901#discussion_r1550416615
---
 src/libstore/sqlite.cc | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/libstore/sqlite.cc b/src/libstore/sqlite.cc
index 06abfb90b..3175c1978 100644
--- a/src/libstore/sqlite.cc
+++ b/src/libstore/sqlite.cc
@@ -7,6 +7,7 @@
 #include <sqlite3.h>
 
 #include <atomic>
+#include <thread>
 
 namespace nix {
 
@@ -256,10 +257,8 @@ void handleSQLiteBusy(const SQLiteBusy & e, time_t & nextWarning)
     /* Sleep for a while since retrying the transaction right away
        is likely to fail again. */
     checkInterrupt();
-    struct timespec t;
-    t.tv_sec = 0;
-    t.tv_nsec = (random() % 100) * 1000 * 1000; /* <= 0.1s */
-    nanosleep(&t, 0);
+    /* <= 0.1s */
+    std::this_thread::sleep_for(std::chrono::milliseconds { rand() % 100 });
 }
 
 }