add hash iterator

src/util/inc/hash.h

@@ -23,12 +23,13 @@ extern "C" {
 #include "hashfunc.h"
 
 #define HASH_MAX_CAPACITY (1024 * 1024 * 16)
-#define HASH_VALUE_IN_TRASH (-1)
 #define HASH_DEFAULT_LOAD_FACTOR (0.75)
 #define HASH_INDEX(v, c) ((v) & ((c)-1))
 
+typedef void (*_hash_free_fn_t)(void *param);
+
 typedef struct SHashNode {
-  char *key;  // null-terminated string
+  char *key;
   union {
     struct SHashNode * prev;
     struct SHashEntry *prev1;
@@ -50,6 +51,7 @@ typedef struct SHashObj {
   size_t          capacity;  // number of slots
   size_t          size;      // number of elements in hash table
   _hash_fn_t      hashFp;    // hash function
+  _hash_free_fn_t freeFp;    // hash node free callback function
 
 #if defined(LINUX)
   pthread_rwlock_t *lock;
@@ -58,6 +60,14 @@ typedef struct SHashObj {
 #endif
 } SHashObj;
 
+typedef struct SHashMutableIterator {
+  SHashObj * pHashObj;
+  int32_t    entryIndex;
+  SHashNode *pCur;
+  SHashNode *pNext;  // current node can be deleted for mutable iterator, so keep the next one before return current
+  int32_t    num;    // already check number of elements in hash table
+} SHashMutableIterator;
+
 /**
  * init the hash table
  *
@@ -110,6 +120,41 @@ void  taosHashRemove(SHashObj *pHashObj, const char *key, size_t keyLen);
  */
 void taosHashCleanup(SHashObj *pHashObj);
 
+/**
+ * Set the free callback function
+ * This function if set will be invoked right before freeing each hash node
+ * @param pHashObj
+ */
+void taosHashSetFreecb(SHashObj *pHashObj, _hash_free_fn_t freeFp);
+
+/**
+ *
+ * @param pHashObj
+ * @return
+ */
+SHashMutableIterator* taosHashCreateIter(SHashObj *pHashObj);
+
+/**
+ *
+ * @param iter
+ * @return
+ */
+bool taosHashIterNext(SHashMutableIterator *iter);
+
+/**
+ *
+ * @param iter
+ * @return
+ */
+void *taosHashIterGet(SHashMutableIterator *iter);
+
+/**
+ *
+ * @param iter
+ * @return
+ */
+void* taosHashDestroyIter(SHashMutableIterator* iter);
+
 /**
  *
  * @param pHashObj

src/util/src/hash.c

@@ -155,8 +155,8 @@ static void taosHashTableResize(SHashObj *pHashObj) {
 
   int32_t newSize = pHashObj->capacity << 1U;
   if (newSize > HASH_MAX_CAPACITY) {
-    pTrace("current capacity:%d, maximum capacity:%d, no resize applied due to limitation is reached", pHashObj->capacity,
-           HASH_MAX_CAPACITY);
+    pTrace("current capacity:%d, maximum capacity:%d, no resize applied due to limitation is reached",
+           pHashObj->capacity, HASH_MAX_CAPACITY);
     return;
   }
 
@@ -483,6 +483,10 @@ void taosHashCleanup(SHashObj *pHashObj) {
 
       while (pNode) {
         pNext = pNode->next;
+        if (pHashObj->freeFp) {
+          pHashObj->freeFp(pNode->data);
+        }
+
         free(pNode);
         pNode = pNext;
       }
@@ -496,10 +500,108 @@ void taosHashCleanup(SHashObj *pHashObj) {
   __unlock(pHashObj->lock);
   __lock_destroy(pHashObj->lock);
 
+  tfree(pHashObj->lock);
   memset(pHashObj, 0, sizeof(SHashObj));
   free(pHashObj);
 }
 
+void taosHashSetFreecb(SHashObj *pHashObj, _hash_free_fn_t freeFp) {
+  if (pHashObj == NULL || freeFp == NULL) {
+    return;
+  }
+
+  pHashObj->freeFp = freeFp;
+}
+
+SHashMutableIterator *taosHashCreateIter(SHashObj *pHashObj) {
+  SHashMutableIterator *pIter = calloc(1, sizeof(SHashMutableIterator));
+  if (pIter == NULL) {
+    return NULL;
+  }
+
+  pIter->pHashObj = pHashObj;
+}
+
+static SHashNode *getNextHashNode(SHashMutableIterator *pIter) {
+  assert(pIter != NULL);
+
+  while (pIter->entryIndex < pIter->pHashObj->capacity) {
+    SHashEntry *pEntry = pIter->pHashObj->hashList[pIter->entryIndex];
+    if (pEntry->next == NULL) {
+      pIter->entryIndex++;
+      continue;
+    }
+
+    return pEntry->next;
+  }
+
+  return NULL;
+}
+
+bool taosHashIterNext(SHashMutableIterator *pIter) {
+  if (pIter == NULL) {
+    return false;
+  }
+
+  size_t size = taosHashGetSize(pIter->pHashObj);
+  if (size == 0 || pIter->num >= size) {
+    return false;
+  }
+
+  // check the first one
+  if (pIter->num == 0) {
+    assert(pIter->pCur == NULL && pIter->pNext == NULL);
+
+    while (1) {
+      SHashEntry *pEntry = pIter->pHashObj->hashList[pIter->entryIndex];
+      if (pEntry->next == NULL) {
+        pIter->entryIndex++;
+        continue;
+      }
+
+      pIter->pCur = pEntry->next;
+
+      if (pIter->pCur->next) {
+        pIter->pNext = pIter->pCur->next;
+      } else {
+        pIter->pNext = getNextHashNode(pIter);
+      }
+
+      break;
+    }
+
+    pIter->num++;
+    return true;
+  } else {
+    assert(pIter->pCur != NULL);
+    if (pIter->pNext) {
+      pIter->pCur = pIter->pNext;
+    } else {  // no more data in the hash list
+      return false;
+    }
+
+    pIter->num++;
+
+    if (pIter->pCur->next) {
+      pIter->pNext = pIter->pCur->next;
+    } else {
+      pIter->pNext = getNextHashNode(pIter);
+    }
+
+    return true;
+  }
+}
+
+void *taosHashIterGet(SHashMutableIterator *iter) { return (iter == NULL) ? NULL : iter->pCur->data; }
+
+void *taosHashDestroyIter(SHashMutableIterator *iter) {
+  if (iter == NULL) {
+    return NULL;
+  }
+
+  free(iter);
+}
+
 // for profile only
 int32_t taosHashGetMaxOverflowLinkLength(const SHashObj *pHashObj) {
   if (pHashObj == NULL || pHashObj->size == 0) {