Moved dcb_hashtable_stats from hastable.c to dcb.c to break dependency between hashtable and the rest of the maxscale. Added check fields to hashtable structure.

server/core/dcb.c

@@ -688,3 +688,35 @@ dcb_isclient(DCB *dcb)
 
         return 0;
 }
+
+/**
+ * Print hash table statistics to a DCB
+ *
+ * @param dcb		The DCB to send the information to
+ * @param table		The hash table
+ */
+void dcb_hashtable_stats(
+        DCB*  dcb,
+        void* table)
+{
+        int total;
+        int longest;
+        int hashsize;
+        int i;
+        int j;
+
+        total = 0;
+	longest = 0;
+
+        hashtable_get_stats(table, &hashsize, &total, &longest);
+
+        dcb_printf(dcb,
+                   "Hashtable: %p, size %d\n",
+                   table,
+                   hashsize);
+        
+	dcb_printf(dcb, "\tNo. of entries:     	%d\n", total);
+	dcb_printf(dcb, "\tAverage chain length:	%.1f\n", (float)total / hashsize);
+	dcb_printf(dcb, "\tLongest chain length:	%d\n", longest);
+}
+

server/core/hashtable.c

@@ -90,6 +90,10 @@ HASHTABLE 	*rval;
 
 	if ((rval = malloc(sizeof(HASHTABLE))) == NULL)
 		return NULL;
+
+        rval->ht_chk_top = CHK_NUM_HASHTABLE;
+        rval->ht_chk_tail = CHK_NUM_HASHTABLE;
+
 	rval->hashsize = size;
 	rval->hashfn = hashfn;
 	rval->cmpfn = cmpfn;
@@ -321,41 +325,63 @@ HASHENTRIES	*entries;
 	printf("\tLongest chain length:	%d\n", longest);
 }
 
-/**
- * Print hash table statistics to a DCB
+/** 
+ * @node Produces stat output about hashtable 
+ *
+ * Parameters:
+ * @param table - <usage>
+ *          <description>
+ *
+ * @param hashsize - <usage>
+ *          <description>
+ *
+ * @param nelems - <usage>
+ *          <description>
+ *
+ * @param longest - <usage>
+ *          <description>
+ *
+ * @return void
+ *
+ * 
+ * @details (write detailed description here)
  *
- * @param dcb		The DCB to send the information to
- * @param table		The hash table
  */
-void
-dcb_hashtable_stats(DCB *dcb, HASHTABLE *table)
+void hashtable_get_stats(
+        void* table,
+        int*  hashsize,
+        int*  nelems,
+        int*  longest)
 {
-int		total, longest, i, j;
-HASHENTRIES	*entries;
+        HASHTABLE*   ht;
+        HASHENTRIES* entries;
+        int          i;
+        int          j;
 
-	dcb_printf(dcb, "Hashtable: %p, size %d\n", table, table->hashsize);
-	total = 0;
-	longest = 0;
-	hashtable_read_lock(table);
-	for (i = 0; i < table->hashsize; i++)
+        ht = (HASHTABLE *)table;
+        CHK_HASHTABLE(ht);
+        
+	hashtable_read_lock(ht);
+        
+	for (i = 0; i < ht->hashsize; i++)
 	{
 		j = 0;
-		entries = table->entries[i];
+		entries = ht->entries[i];
 		while (entries)
 		{
 			j++;
 			entries = entries->next;
 		}
-		total += j;
-		if (j > longest)
-			longest = j;
+		*nelems += j;
+		if (j > *longest) {
+			*longest = j;
+                }
 	}
-	hashtable_read_unlock(table);
-	dcb_printf(dcb, "\tNo. of entries:     	%d\n", total);
-	dcb_printf(dcb, "\tAverage chain length:	%.1f\n", (float)total / table->hashsize);
-	dcb_printf(dcb, "\tLongest chain length:	%d\n", longest);
+        *hashsize = ht->hashsize;
+	hashtable_read_unlock(ht);
 }
 
+
 /**
  * Take a read lock on the hashtable.
  *

server/include/dcb.h

@@ -185,5 +185,6 @@ extern void		dprintDCB(DCB *, DCB *);		/* Debug to print a DCB in the system */
 extern const char 	*gw_dcb_state2string(int);		/* DCB state to string */
 extern void		dcb_printf(DCB *, const char *, ...);	/* DCB version of printf */
 extern int		dcb_isclient(DCB *);			/* the DCB is the client of the session */
+extern void		dcb_hashtable_stats(DCB *, void *);	/**< Print statisitics */
 
 #endif

server/include/hashtable.h

@@ -31,6 +31,7 @@
  *
  * @endverbatim
  */
+#include <skygw_debug.h>
 #include <spinlock.h>
 #include <atomic.h>
 #include <dcb.h>
@@ -67,6 +68,7 @@ typedef void *(*HASHMEMORYFN)(void *);
  * The general purpose hashtable struct.
  */
 typedef struct hashtable {
+        skygw_chk_t     ht_chk_top;
 	int		hashsize;			/**< The number of HASHENTRIES */
 	HASHENTRIES	**entries;			/**< The entries themselves */
 	int		(*hashfn)(void *);		/**< The hash function */
@@ -76,6 +78,7 @@ typedef struct hashtable {
 	SPINLOCK	spin;				/**< Internal spinlock for the hashtable */
 	int		n_readers;			/**< Number of clients reading the table */
 	int		writelock;			/**< The table is locked by a writer */
+        skygw_chk_t     ht_chk_tail;
 } HASHTABLE;
 
 extern HASHTABLE	*hashtable_alloc(int, int (*hashfn)(), int (*cmpfn)());
@@ -91,7 +94,12 @@ extern int		hashtable_delete(HASHTABLE *, void *);
 extern void		*hashtable_fetch(HASHTABLE *, void *);
 				/**< Fetch the data for a given key */
 extern void		hashtable_stats(HASHTABLE *);			/**< Print statisitics */
-extern void		dcb_hashtable_stats(DCB *, HASHTABLE *);	/**< Print statisitics */
+void hashtable_get_stats(
+        void* hashtable,
+        int*  hashsize,
+        int*  nelems,
+        int*  longest);
+
 extern HASHITERATOR	*hashtable_iterator(HASHTABLE *);
 				/**< Allocate an iterator on the hashtable */
 extern void		*hashtable_next(HASHITERATOR *);

utils/skygw_debug.h

@@ -113,7 +113,8 @@ typedef enum skygw_chk_t {
     CHK_NUM_FNAMES,
     CHK_NUM_LOGMANAGER,
     CHK_NUM_FILE,
-    CHK_NUM_BLOCKBUF
+    CHK_NUM_BLOCKBUF,
+    CHK_NUM_HASHTABLE
 } skygw_chk_t;
 
 # define STRBOOL(b) ((b) ? "TRUE" : "FALSE")
@@ -319,4 +320,10 @@ typedef enum skygw_chk_t {
                             "Block buf under- or overflow");    \
     }
 
+#define CHK_HASHTABLE(t) {                                  \
+    ss_info_dassert(t->ht_chk_top == CHK_NUM_HASHTABLE &&   \
+                    t->ht_chk_tail == CHK_NUM_HASHTABLE,    \
+                    "Hashtable under- or overflow");        \
+    }
+
 #endif /* SKYGW_DEBUG_H */