Trace Redaction - Iterative timeline search
The timeline search can be simplified by converting the recursive
search to an iterative search.
Bug: 333740194
Change-Id: I14faa23dee0c37fc02991655c988f16e2ba03e1e
diff --git a/src/trace_redaction/process_thread_timeline.cc b/src/trace_redaction/process_thread_timeline.cc
index 71a7984..e27d46e 100644
--- a/src/trace_redaction/process_thread_timeline.cc
+++ b/src/trace_redaction/process_thread_timeline.cc
@@ -47,38 +47,33 @@
ProcessThreadTimeline::Slice ProcessThreadTimeline::Search(uint64_t ts,
int32_t pid) const {
- PERFETTO_CHECK(mode_ == Mode::kRead);
-
- auto e = Search(0, ts, pid);
-
- return {pid, e.type == Event::Type::kOpen ? e.uid : Event::kUnknownUid};
-}
-
-ProcessThreadTimeline::Event ProcessThreadTimeline::Search(size_t depth,
- uint64_t ts,
- int32_t pid) const {
PERFETTO_DCHECK(mode_ == Mode::kRead);
- if (depth >= kMaxSearchDepth) {
- return {};
- }
-
auto event = FindPreviousEvent(ts, pid);
- if (!TestEvent(event)) {
- return event;
+ for (size_t d = 0; d < kMaxSearchDepth; ++d) {
+ // The thread/process was freed. It won't exist until a new open event.
+ if (event.type != Event::Type::kOpen) {
+ return {pid, Event::kUnknownUid};
+ }
+
+ // System processes all have uids equal to zero, so everything eventually
+ // has a uid. This means that all threads should find a process and a uid.
+ // However, if a thread does not have a process (this should not happen)
+ // that thread will be treated as invalid.
+ if (event.uid != Event::kUnknownUid) {
+ return {pid, event.uid};
+ }
+
+ // If there is no parent, there is no reason to keep searching.
+ if (event.ppid == Event::kUnknownPid) {
+ return {pid, Event::kUnknownUid};
+ }
+
+ event = FindPreviousEvent(ts, event.ppid);
}
- if (event.uid != Event::kUnknownUid) {
- return event;
- }
-
- // If there is no parent, there is no reason to keep searching.
- if (event.ppid == Event::kUnknownPid) {
- return {};
- }
-
- return Search(depth + 1, ts, event.ppid);
+ return {pid, Event::kUnknownUid};
}
ProcessThreadTimeline::Event ProcessThreadTimeline::FindPreviousEvent(
@@ -141,17 +136,4 @@
: invalid;
}
-bool ProcessThreadTimeline::TestEvent(Event event) const {
- // The thread/process was freed. It won't exist until a new open event.
- if (event.type != Event::Type::kOpen) {
- return false;
- }
-
- // It is a rare case in production, but a common case in tests, the top-level
- // event will have no parent but will have the uid. So, to avoid make the
- // tests fragile and without taking on any risk, the uid should be checked
- // before the ppid.
- return event.uid != Event::kUnknownUid || event.ppid != Event::kUnknownPid;
-}
-
} // namespace perfetto::trace_redaction
diff --git a/src/trace_redaction/process_thread_timeline.h b/src/trace_redaction/process_thread_timeline.h
index 5e2d759..62aac05 100644
--- a/src/trace_redaction/process_thread_timeline.h
+++ b/src/trace_redaction/process_thread_timeline.h
@@ -129,10 +129,6 @@
// events_for(pid).before(ts).sort_by_time().last()
Event FindPreviousEvent(uint64_t ts, int32_t pid) const;
- Event Search(size_t depth, uint64_t ts, int32_t pid) const;
-
- bool TestEvent(Event event) const;
-
std::vector<Event> events_;
Mode mode_ = Mode::kRead;
