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Unified Diff: device/base/synchronization/one_writer_seqlock.cc

Issue 2273703002: Force events to be non blocking if main thread is unresponsive. (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Nits Created 4 years ago
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Index: device/base/synchronization/one_writer_seqlock.cc
diff --git a/device/base/synchronization/one_writer_seqlock.cc b/device/base/synchronization/one_writer_seqlock.cc
index 7b855cfd1cb4c79c464527cd71436ae23c470bcb..044856d1a7dfdbd6406c166f65112ffe51304ee3 100644
--- a/device/base/synchronization/one_writer_seqlock.cc
+++ b/device/base/synchronization/one_writer_seqlock.cc
@@ -24,6 +24,17 @@ base::subtle::Atomic32 OneWriterSeqLock::ReadBegin() const {
return version;
}
+void OneWriterSeqLock::ReadOrFail(bool* can_read,
+ base::subtle::Atomic32* version) const {
+ DCHECK(can_read);
+ DCHECK(version);
+
+ *version = base::subtle::NoBarrier_Load(&sequence_);
+ // If the counter is even, then the associated data might be in a
+ // consistent state, so we can try to read.
+ *can_read = (*version & 1) == 0;
+}
+
bool OneWriterSeqLock::ReadRetry(base::subtle::Atomic32 version) const {
// If the sequence number was updated then a read should be re-attempted.
// -- Load fence, read membarrier

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