From 049a7b8be2a42f4a115de63eb1a202dd667a6723 Mon Sep 17 00:00:00 2001
From: Bert Belder <bertbelder@gmail.com>
Date: Mon, 25 Sep 2017 17:53:11 +0200
Subject: [PATCH] reflock-tree: add mechanism for pointer-safe tree lookups

---
 src/reflock-tree.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++
 src/reflock-tree.h | 37 +++++++++++++++++++++++
 2 files changed, 111 insertions(+)
 create mode 100644 src/reflock-tree.c
 create mode 100644 src/reflock-tree.h

diff --git a/src/reflock-tree.c b/src/reflock-tree.c
new file mode 100644
index 0000000..05224f2
--- /dev/null
+++ b/src/reflock-tree.c
@@ -0,0 +1,74 @@
+#include <stdint.h>
+
+#include "reflock-tree.h"
+#include "reflock.h"
+#include "tree.h"
+#include "util.h"
+#include "win.h"
+
+void reflock_tree_init(reflock_tree_t* rlt) {
+  tree_init(&rlt->tree);
+  InitializeSRWLock(&rlt->lock);
+}
+
+void reflock_tree_node_init(reflock_tree_node_t* node) {
+  tree_node_init(&node->tree_node);
+  reflock_init(&node->reflock);
+}
+
+int reflock_tree_add(reflock_tree_t* rlt,
+                     reflock_tree_node_t* node,
+                     uintptr_t key) {
+  int r;
+
+  AcquireSRWLockExclusive(&rlt->lock);
+  r = tree_add(&rlt->tree, &node->tree_node, key);
+  ReleaseSRWLockExclusive(&rlt->lock);
+
+  return r;
+}
+
+reflock_tree_node_t* reflock_tree_del_and_ref(reflock_tree_t* rlt,
+                                              uintptr_t key) {
+  tree_node_t* tree_node;
+  reflock_tree_node_t* rlt_node;
+
+  AcquireSRWLockExclusive(&rlt->lock);
+
+  tree_node = tree_find(&rlt->tree, (uintptr_t) key);
+  rlt_node = safe_container_of(tree_node, reflock_tree_node_t, tree_node);
+
+  if (rlt_node != NULL) {
+    tree_del(&rlt->tree, tree_node);
+    reflock_ref(&rlt_node->reflock);
+  }
+
+  ReleaseSRWLockExclusive(&rlt->lock);
+
+  return rlt_node;
+}
+
+reflock_tree_node_t* reflock_tree_find_and_ref(reflock_tree_t* rlt,
+                                               uintptr_t key) {
+  tree_node_t* tree_node;
+  reflock_tree_node_t* rlt_node;
+
+  AcquireSRWLockShared(&rlt->lock);
+
+  tree_node = tree_find(&rlt->tree, (uintptr_t) key);
+  rlt_node = safe_container_of(tree_node, reflock_tree_node_t, tree_node);
+  if (rlt_node != NULL)
+    reflock_ref(&rlt_node->reflock);
+
+  ReleaseSRWLockShared(&rlt->lock);
+
+  return rlt_node;
+}
+
+void reflock_tree_node_unref(reflock_tree_node_t* node) {
+  reflock_unref(&node->reflock);
+}
+
+void reflock_tree_node_unref_and_destroy(reflock_tree_node_t* node) {
+  reflock_unref_and_destroy(&node->reflock);
+}
diff --git a/src/reflock-tree.h b/src/reflock-tree.h
new file mode 100644
index 0000000..64df2a3
--- /dev/null
+++ b/src/reflock-tree.h
@@ -0,0 +1,37 @@
+#ifndef REFLOCK_TREE_H_
+#define REFLOCK_TREE_H_
+
+#include <stdint.h>
+
+#include "internal.h"
+#include "reflock.h"
+#include "tree.h"
+#include "win.h"
+
+typedef struct reflock_tree {
+  tree_t tree;
+  SRWLOCK lock;
+} reflock_tree_t;
+
+typedef struct reflock_tree_node {
+  tree_node_t tree_node;
+  reflock_t reflock;
+} reflock_tree_node_t;
+
+EPOLL_INTERNAL void reflock_tree_init(reflock_tree_t* rtl);
+EPOLL_INTERNAL void reflock_tree_node_init(reflock_tree_node_t* node);
+
+EPOLL_INTERNAL int reflock_tree_add(reflock_tree_t* rlt,
+                                    reflock_tree_node_t* node,
+                                    uintptr_t key);
+
+EPOLL_INTERNAL reflock_tree_node_t* reflock_tree_del_and_ref(
+    reflock_tree_t* rlt, uintptr_t key);
+EPOLL_INTERNAL reflock_tree_node_t* reflock_tree_find_and_ref(
+    reflock_tree_t* rlt, uintptr_t key);
+
+EPOLL_INTERNAL void reflock_tree_node_unref(reflock_tree_node_t* node);
+EPOLL_INTERNAL void reflock_tree_node_unref_and_destroy(
+    reflock_tree_node_t* node);
+
+#endif /* REFLOCK_TREE_H_ */