From 567d385fbd32e3bb35c534685a2bb30336824410 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Mon, 12 Aug 2024 16:11:16 -0700
Subject: [PATCH] WIP create child in getOrCreateChild

---
 ConflictSet.cpp       | 52 +++++++++++++++++++++++++++++--------------
 LongestCommonPrefix.h |  8 +++++++
 2 files changed, 43 insertions(+), 17 deletions(-)

diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index 499f1cf..b54593b 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -40,11 +40,13 @@ limitations under the License.
 #include <arm_neon.h>
 #endif
 
+#ifndef __SANITIZE_THREAD__
 #if defined(__has_feature)
 #if __has_feature(thread_sanitizer)
 #define __SANITIZE_THREAD__
 #endif
 #endif
+#endif
 
 #include <memcheck.h>
 
@@ -1126,9 +1128,12 @@ Node *getFirstChildExists(Node *self) {
 // Caller is responsible for assigning a non-null pointer to the returned
 // reference if null. Updates child's max version to `newMaxVersion` if child
 // exists but does not have a partial key.
-Node *&getOrCreateChild(Node *&self, uint8_t index,
+Node *&getOrCreateChild(Node *&self, std::span<const uint8_t> &key,
                         InternalVersionT newMaxVersion, WriteContext *tls) {
 
+  int index = key.front();
+  key = key.subspan(1, key.size() - 1);
+
   // Fast path for if it exists already
   switch (self->getType()) {
   case Type_Node0:
@@ -1181,6 +1186,14 @@ Node *&getOrCreateChild(Node *&self, uint8_t index,
     __builtin_unreachable(); // GCOVR_EXCL_LINE
   }
 
+  auto *newChild = tls->allocate<Node0>(key.size());
+  newChild->numChildren = 0;
+  newChild->entryPresent = false;
+  newChild->partialKeyLen = key.size();
+  newChild->parentsIndex = index;
+  memcpy(newChild->partialKey(), key.data(), key.size());
+  key = {};
+
   switch (self->getType()) {
   case Type_Node0: {
     auto *self0 = static_cast<Node0 *>(self);
@@ -1215,8 +1228,10 @@ Node *&getOrCreateChild(Node *&self, uint8_t index,
     }
     self3->index[i + 1] = index;
     auto &result = self3->children[i + 1];
-    result = nullptr;
+    self3->childMaxVersion[i + 1] = newMaxVersion;
+    result = newChild;
     ++self->numChildren;
+    newChild->parent = self;
     return result;
   }
   case Type_Node16: {
@@ -1243,8 +1258,10 @@ Node *&getOrCreateChild(Node *&self, uint8_t index,
     }
     self16->index[i + 1] = index;
     auto &result = self16->children[i + 1];
-    result = nullptr;
+    self16->childMaxVersion[i + 1] = newMaxVersion;
+    result = newChild;
     ++self->numChildren;
+    newChild->parent = self;
     return result;
   }
   case Type_Node48: {
@@ -1267,7 +1284,11 @@ Node *&getOrCreateChild(Node *&self, uint8_t index,
     self48->index[index] = nextFree;
     self48->reverseIndex[nextFree] = index;
     auto &result = self48->children[nextFree];
-    result = nullptr;
+    self48->childMaxVersion[nextFree] = newMaxVersion;
+    self48->maxOfMax[nextFree >> Node48::kMaxOfMaxShift] = std::max(
+        newMaxVersion, self48->maxOfMax[nextFree >> Node48::kMaxOfMaxShift]);
+    result = newChild;
+    newChild->parent = self;
     return result;
   }
   case Type_Node256: {
@@ -1276,7 +1297,13 @@ Node *&getOrCreateChild(Node *&self, uint8_t index,
     auto *self256 = static_cast<Node256 *>(self);
     ++self->numChildren;
     self256->bitSet.set(index);
-    return self256->children[index];
+    auto &result = self256->children[index];
+    self256->childMaxVersion[index] = newMaxVersion;
+    self256->maxOfMax[index >> Node256::kMaxOfMaxShift] = std::max(
+        newMaxVersion, self256->maxOfMax[index >> Node256::kMaxOfMaxShift]);
+    result = newChild;
+    newChild->parent = self;
+    return result;
   }
   default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE
@@ -2779,18 +2806,9 @@ Node **insert(Node **self, std::span<const uint8_t> key,
       return self;
     }
 
-    int index = key.front();
-    key = key.subspan(1, key.size() - 1);
-    auto &child = getOrCreateChild(*self, index, writeVersion, tls);
-    if (!child) {
-      child = tls->allocate<Node0>(key.size());
-      child->numChildren = 0;
-      child->entryPresent = false;
-      child->partialKeyLen = key.size();
-      child->parent = *self;
-      child->parentsIndex = index;
-      setMaxVersion(child, impl, writeVersion);
-      memcpy(child->partialKey(), key.data(), child->partialKeyLen);
+    bool existed = getChild(*self, key.front());
+    auto &child = getOrCreateChild(*self, key, writeVersion, tls);
+    if (!existed) {
       return &child;
     }
 
diff --git a/LongestCommonPrefix.h b/LongestCommonPrefix.h
index 2d1d3b9..da3c824 100644
--- a/LongestCommonPrefix.h
+++ b/LongestCommonPrefix.h
@@ -11,6 +11,14 @@
 #include <arm_neon.h>
 #endif
 
+#ifndef __SANITIZE_THREAD__
+#if defined(__has_feature)
+#if __has_feature(thread_sanitizer)
+#define __SANITIZE_THREAD__
+#endif
+#endif
+#endif
+
 #if defined(HAS_AVX) || defined(HAS_ARM_NEON)
 constexpr int kStride = 64;
 #else