From 1467d2062a91a041661b0dff95f76a1537cbd9fc Mon Sep 17 00:00:00 2001
From: Andrew McKnight <andrew.mcknight@sentry.io>
Date: Mon, 17 Jul 2023 15:29:22 -0800
Subject: [PATCH] only store the count of tracers in bookkeeping, not a set of
 references

---
 .../SentryProfiledTracerConcurrency.mm        | 35 ++++++++-----------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/Sources/Sentry/Profiling/SentryProfiledTracerConcurrency.mm b/Sources/Sentry/Profiling/SentryProfiledTracerConcurrency.mm
index 70ec1a81271..44a41093f48 100644
--- a/Sources/Sentry/Profiling/SentryProfiledTracerConcurrency.mm
+++ b/Sources/Sentry/Profiling/SentryProfiledTracerConcurrency.mm
@@ -16,14 +16,14 @@
 #    endif // SENTRY_HAS_UIKIT
 
 /**
- * a mapping of profilers to the tracers that started them that are still in-flight and will need to
- * query them for their profiling data when they finish. this helps resolve the incongruity between
- * the different timeout durations between tracers (500s) and profilers (30s), where a transaction
- * may start a profiler that then times out, and then a new transaction starts a new profiler, and
- * we must keep the aborted one around until its associated transaction finishes.
+ * a mapping of profilers to the number of tracers that started them that are still in-flight and
+ * will need to query them for their profiling data when they finish. this helps resolve the
+ * incongruity between the different timeout durations between tracers (500s) and profilers (30s),
+ * where a transaction may start a profiler that then times out, and then a new transaction starts a
+ * new profiler, and we must keep the aborted one around until its associated transaction finishes.
  */
 static NSMutableDictionary</* SentryProfiler.profileId */ NSString *,
-    NSMutableSet<SentryTracer *> *> *_gProfilersToTracers;
+    /* number of in-flight tracers */ NSNumber *> *_gProfilersToTracers;
 
 /** provided for fast access to a profiler given a tracer */
 static NSMutableDictionary</* SentryTracer.tracerId */ NSString *, SentryProfiler *>
@@ -48,21 +48,14 @@
 
     if (_gProfilersToTracers == nil) {
         _gProfilersToTracers = [NSMutableDictionary</* SentryProfiler.profileId */ NSString *,
-            NSMutableSet<SentryTracer *> *> dictionaryWithObject:[NSMutableSet setWithObject:tracer]
-                                                          forKey:profilerKey];
+            /* number of in-flight tracers */ NSNumber *>
+            dictionary];
         _gTracersToProfilers =
             [NSMutableDictionary</* SentryTracer.tracerId */ NSString *, SentryProfiler *>
-                dictionaryWithObject:profiler
-                              forKey:tracerKey];
-        return;
-    }
-
-    if (_gProfilersToTracers[profilerKey] == nil) {
-        _gProfilersToTracers[profilerKey] = [NSMutableSet setWithObject:tracer];
-    } else {
-        [_gProfilersToTracers[profilerKey] addObject:tracer];
+                dictionary];
     }
 
+    _gProfilersToTracers[profilerKey] = @(_gProfilersToTracers[profilerKey].unsignedIntValue + 1);
     _gTracersToProfilers[tracerKey] = profiler;
 }
 
@@ -85,8 +78,8 @@
     const auto profilerKey = profiler.profileId.sentryIdString;
 
     [_gTracersToProfilers removeObjectForKey:tracerKey];
-    [_gProfilersToTracers[profilerKey] removeObject:tracer];
-    if ([_gProfilersToTracers[profilerKey] count] == 0) {
+    _gProfilersToTracers[profilerKey] = @(_gProfilersToTracers[profilerKey].unsignedIntValue - 1);
+    if ([_gProfilersToTracers[profilerKey] unsignedIntValue] == 0) {
         [_gProfilersToTracers removeObjectForKey:profilerKey];
         if ([profiler isRunning]) {
             [profiler stopForReason:SentryProfilerTruncationReasonNormal];
@@ -118,8 +111,8 @@
     const auto profilerKey = profiler.profileId.sentryIdString;
 
     [_gTracersToProfilers removeObjectForKey:tracerKey];
-    [_gProfilersToTracers[profilerKey] removeObject:tracer];
-    if ([_gProfilersToTracers[profilerKey] count] == 0) {
+    _gProfilersToTracers[profilerKey] = @(_gProfilersToTracers[profilerKey].unsignedIntValue - 1);
+    if ([_gProfilersToTracers[profilerKey] unsignedIntValue] == 0) {
         [_gProfilersToTracers removeObjectForKey:profilerKey];
         if ([profiler isRunning]) {
             [profiler stopForReason:SentryProfilerTruncationReasonNormal];