From 0619b6325cf27e628d2047297ef922e58f95596a Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Fri, 22 Nov 2024 15:37:53 -0800
Subject: [PATCH] Convert checkPrefixRead to IteratorBase

---
 ConflictSet.cpp | 51 ++++++++++++++++++++++++++-----------------------
 1 file changed, 27 insertions(+), 24 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index a94e43d..2455faf 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -2037,6 +2037,8 @@ IteratorBase IteratorBase::getChildGeq(int index) {
   }
 }
 
+InternalVersionT IteratorBase::getMaxVersion() { return ::maxVersion(node); }
+
 bool IteratorBase::checkRangeVersionOfFirstGeq(InternalVersionT readVersion) {
   return ::checkRangeVersionOfFirstGeq(node, readVersion);
 }
@@ -4616,7 +4618,7 @@ bool checkPointRead(IteratorBase n, const TrivialSpan key,
 // Logically this is the same as performing firstGeq and then checking against
 // max version or range version if this prefix doesn't exist, but this version
 // short circuits as soon as it can prove that there's no conflict.
-bool checkPrefixRead(Node *n, const TrivialSpan key,
+bool checkPrefixRead(IteratorBase n, const TrivialSpan key,
                      InternalVersionT readVersion, ReadContext *readContext) {
   ++readContext->prefix_read_accum;
 #if DEBUG_VERBOSE && !defined(NDEBUG)
@@ -4626,54 +4628,55 @@ bool checkPrefixRead(Node *n, const TrivialSpan key,
   for (;; ++readContext->prefix_read_iterations_accum) {
     if (remaining.size() == 0) {
       // There's no way to encode a prefix read of "", so n is not the root
-      return maxVersion(n) <= readVersion;
+      return n.getMaxVersion() <= readVersion;
     }
 
-    auto [c, maxV] = getChildAndMaxVersion(n, remaining[0]);
-    Node *child = c;
-    if (child == nullptr) {
-      auto c = getChildGeq(n, remaining[0]);
-      if (c != nullptr) {
-        n = c;
-        return checkRangeVersionOfFirstGeq(n, readVersion);
+    auto [c, maxV] = n.getChildAndMaxVersion(remaining[0]);
+    IteratorBase child = c;
+    if (!child.valid()) {
+      auto c = n.getChildGeq(remaining[0]);
+      if (c.valid()) {
+        return c.checkRangeVersionOfFirstGeq(readVersion);
       } else {
-        n = nextSibling(n);
-        if (n == nullptr) {
+        n = n.nextSibling();
+        if (!n.valid()) {
           return true;
         }
-        return checkRangeVersionOfFirstGeq(n, readVersion);
+        return n.checkRangeVersionOfFirstGeq(readVersion);
       }
     }
 
     n = child;
     remaining = remaining.subspan(1, remaining.size() - 1);
 
-    if (n->partialKeyLen > 0) {
-      int commonLen = std::min<int>(n->partialKeyLen, remaining.size());
-      int i = longestCommonPrefix(n->partialKey(), remaining.data(), commonLen);
+    auto partialKey = n.partialKey();
+    if (partialKey.size() > 0) {
+      int commonLen = std::min<int>(partialKey.size(), remaining.size());
+      int i =
+          longestCommonPrefix(partialKey.data(), remaining.data(), commonLen);
       if (i < commonLen) {
-        auto c = n->partialKey()[i] <=> remaining[i];
+        auto c = partialKey[i] <=> remaining[i];
         if (c > 0) {
-          return checkRangeVersionOfFirstGeq(n, readVersion);
+          return n.checkRangeVersionOfFirstGeq(readVersion);
         } else {
-          n = nextSibling(n);
-          if (n == nullptr) {
+          n = n.nextSibling();
+          if (!n.valid()) {
             return true;
           }
-          return checkRangeVersionOfFirstGeq(n, readVersion);
+          return n.checkRangeVersionOfFirstGeq(readVersion);
         }
       }
-      if (commonLen == n->partialKeyLen) {
+      if (commonLen == partialKey.size()) {
         // partial key matches
         remaining = remaining.subspan(commonLen, remaining.size() - commonLen);
-      } else if (n->partialKeyLen > remaining.size()) {
+      } else if (partialKey.size() > remaining.size()) {
         // n is the first physical node greater than remaining, and there's no
         // eq node. All physical nodes that start with prefix are reachable from
         // n.
         if (maxV > readVersion) {
           return false;
         }
-        return checkRangeVersionOfFirstGeq(n, readVersion);
+        return n.checkRangeVersionOfFirstGeq(readVersion);
       }
     }
 
@@ -4866,7 +4869,7 @@ bool checkRangeRead(Node *n, TrivialSpan begin, TrivialSpan end,
   }
   if (lcp == begin.size() - 1 && end.size() == begin.size() &&
       begin.back() + 1 == end.back()) {
-    return checkPrefixRead(n, begin, readVersion, readContext);
+    return checkPrefixRead(IteratorBase{n}, begin, readVersion, readContext);
   }
 
   ++readContext->range_read_accum;