From c5c1a028cdd3cf345046c46963fb0fdacfb2c33c Mon Sep 17 00:00:00 2001
From: Dean Scarff <deanscarff@google.com>
Date: Sat, 4 Apr 2020 12:48:25 +1100
Subject: [PATCH] Use deterministic assignments for unique_id
Fixes qpdf/qpdf#419
---
libqpdf/QPDF.cc | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/libqpdf/QPDF.cc b/libqpdf/QPDF.cc
index bbe8f31c..3177d38b 100644
--- a/libqpdf/QPDF.cc
+++ b/libqpdf/QPDF.cc
@@ -1,6 +1,7 @@
#include <qpdf/qpdf-config.h> // include first for large file support
#include <qpdf/QPDF.hh>
+#include <atomic>
#include <vector>
#include <map>
#include <algorithm>
@@ -172,9 +173,8 @@ QPDF::QPDF() :
// Generate a unique ID. It just has to be unique among all QPDF
// objects allocated throughout the lifetime of this running
// application.
- m->unique_id = static_cast<unsigned long>(QUtil::get_current_time());
- m->unique_id <<= 32;
- m->unique_id |= static_cast<unsigned long>(QUtil::random());
+ static std::atomic<unsigned long long> unique_id{0};
+ m->unique_id = unique_id.fetch_add(1ULL);
}
QPDF::~QPDF()