First continuation for interleaved check range read

ConflictSet.cpp

@@ -3240,10 +3240,11 @@ struct CheckJob {
   }
 
   void init(const ConflictSet::ReadRange *read, ConflictSet::Result *result,
-            Node *root, int64_t oldestVersionFullPrecision, ReadContext *tls);
+            Node *root, int64_t oldestVersionFullPrecision);
 
   Node *n;
   std::span<const uint8_t> begin;
+  std::span<const uint8_t> end; // range read only
   InternalVersionT readVersion;
   ConflictSet::Result *result;
   Continuation continuation;
@@ -3290,7 +3291,7 @@ FLATTEN PRESERVE_NONE void complete(CheckJob *job, CheckContext *context) {
   } else {
     int temp = context->started++;
     job->init(context->queries + temp, context->results + temp, context->root,
-              context->oldestVersionFullPrecision, context->tls);
+              context->oldestVersionFullPrecision);
   }
   MUSTTAIL return keepGoing(job, context);
 }
@@ -3428,9 +3429,40 @@ void down_left_spine(CheckJob *job, CheckContext *context) {
 
 } // namespace check_point_read_state_machine
 
+namespace check_range_read_state_machine {
+FLATTEN PRESERVE_NONE void begin(CheckJob *, CheckContext *);
+
+FLATTEN PRESERVE_NONE void begin(CheckJob *job, CheckContext *context) {
+  int lcp = longestCommonPrefix(job->begin.data(), job->end.data(),
+                                std::min(job->begin.size(), job->end.size()));
+  if (lcp == int(job->begin.size()) &&
+      job->end.size() == job->begin.size() + 1 && job->end.back() == 0) {
+    job->continuation = check_point_read_state_machine::begin;
+    // Call directly since we have nothing to prefetch
+    MUSTTAIL return job->continuation(job, context);
+  }
+  if (lcp == int(job->begin.size() - 1) &&
+      job->end.size() == job->begin.size() &&
+      int(job->begin.back()) + 1 == int(job->end.back())) {
+    *job->result =
+        checkPrefixRead(job->n, job->begin, job->readVersion, context->tls)
+            ? ConflictSet::Commit
+            : ConflictSet::Conflict;
+    return complete(job, context);
+  }
+
+  *job->result = checkRangeRead(job->n, job->begin, job->end, job->readVersion,
+                                context->tls)
+                     ? ConflictSet::Commit
+                     : ConflictSet::Conflict;
+  return complete(job, context);
+}
+
+} // namespace check_range_read_state_machine
+
 void CheckJob::init(const ConflictSet::ReadRange *read,
                     ConflictSet::Result *result, Node *root,
-                    int64_t oldestVersionFullPrecision, ReadContext *tls) {
+                    int64_t oldestVersionFullPrecision) {
   auto begin = std::span<const uint8_t>(read->begin.p, read->begin.len);
   auto end = std::span<const uint8_t>(read->end.p, read->end.len);
   if (read->readVersion < oldestVersionFullPrecision) [[unlikely]] {
@@ -3443,11 +3475,12 @@ void CheckJob::init(const ConflictSet::ReadRange *read,
     this->result = result;
     continuation = check_point_read_state_machine::begin;
   } else {
-    *result = checkRangeRead(root, begin, end,
+    this->begin = begin;
-                             InternalVersionT(read->readVersion), tls)
+    this->end = end;
-                  ? ConflictSet::Commit
+    this->n = root;
-                  : ConflictSet::Conflict;
+    this->readVersion = InternalVersionT(read->readVersion);
-    continuation = complete;
+    this->result = result;
+    continuation = check_range_read_state_machine::begin;
   }
 }
 
@@ -3477,7 +3510,7 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
     context.started = started;
     for (int i = 0; i < started; i++) {
       inProgress[i].init(reads + i, result + i, root,
-                         oldestVersionFullPrecision, &tls);
+                         oldestVersionFullPrecision);
     }
     for (int i = 0; i < started - 1; i++) {
       inProgress[i].next = inProgress + i + 1;