Add public KVDB iterator api

inc/fdb_def.h

@@ -141,6 +141,15 @@ struct fdb_kv {
 };
 typedef struct fdb_kv *fdb_kv_t;
 
+struct fdb_kv_iterator {
+    struct fdb_kv curr_kv;                       /**< Current KV we get from the iterator */
+    uint32_t iterated_cnt;                       /**< How many KVs have we iterated already */
+    size_t iterated_obj_bytes;                   /**< Total storage size of KVs we have iterated. */
+    size_t iterated_value_bytes;                 /**< Total value size of KVs we have iterated. */
+    uint32_t sector_addr;                        /**< Current sector address we're iterating. DO NOT touch it. */
+};
+typedef struct fdb_kv_iterator *fdb_kv_iterator_t;
+
 /* time series log node object */
 struct fdb_tsl {
     fdb_tsl_status_t status;                     /**< node status, @see fdb_log_status_t */

inc/flashdb.h

@@ -46,6 +46,8 @@ fdb_kv_t   fdb_kv_get_obj    (fdb_kvdb_t db, const char *key, fdb_kv_t kv);
 fdb_blob_t        fdb_kv_to_blob      (fdb_kv_t   kv, fdb_blob_t blob);
 fdb_err_t         fdb_kv_set_default  (fdb_kvdb_t db);
 void              fdb_kv_print        (fdb_kvdb_t db);
+fdb_kv_iterator_t fdb_kv_iterator_init(fdb_kv_iterator_t itr);
+bool              fdb_kv_iterate      (fdb_kvdb_t db, fdb_kv_iterator_t itr);
 
 /* Time series log API like a TSDB */
 fdb_err_t  fdb_tsl_append      (fdb_tsdb_t db, fdb_blob_t blob);

src/fdb_kvdb.c

@@ -1612,4 +1612,66 @@ __exit:
     return result;
 }
 
+/**
+ * The KV database initialization.
+ *
+ * @param itr iterator structure to be initialized
+ *
+ * @return pointer to the iterator initialized.
+ */
+fdb_kv_iterator_t fdb_kv_iterator_init(fdb_kv_iterator_t itr)
+{
+    itr->curr_kv.addr.start = 0;
+
+    /* If iterator statistics is needed */
+    itr->iterated_cnt = 0;
+    itr->iterated_obj_bytes = 0;
+    itr->iterated_value_bytes = 0;
+    /* Start from sector head */
+    itr->sector_addr = 0;
+    return itr;
+}
+
+/**
+ * The KV database iterator.
+ *
+ * @param db database object
+ * @param itr the iterator structure
+ *
+ * @return false if iterate not ended, true if iterate ended.
+ */
+bool fdb_kv_iterate(fdb_kvdb_t db, fdb_kv_iterator_t itr)
+{
+    struct kvdb_sec_info sector;
+    fdb_kv_t kv = &(itr->curr_kv);
+    do {
+        if (read_sector_info(db, itr->sector_addr, &sector, false) != FDB_NO_ERR) {
+            continue;
+        }
+        else if (sector.status.store == FDB_SECTOR_STORE_USING || sector.status.store == FDB_SECTOR_STORE_FULL) {
+            if (kv->addr.start == 0) {
+                kv->addr.start = sector.addr + SECTOR_HDR_DATA_SIZE;
+            }
+            else if ((kv->addr.start = get_next_kv_addr(db, &sector, kv)) == FAILED_ADDR) {
+                kv->addr.start = 0;
+                continue;
+            }
+            /* If iterator statistics is needed */
+            itr->iterated_cnt++;
+            itr->iterated_obj_bytes += kv->len;
+            itr->iterated_value_bytes += kv->value_len;
+
+            /* We got a valid kv here. */
+            read_kv(db, kv);
+            return true;
+        }
+        /** Set kv->addr.start to 0 when we get into a new sector so that if we successfully get the next sector info,
+         *  the kv->addr.start is set to the new sector.addr + SECTOR_HDR_DATA_SIZE.
+        */
+        kv->addr.start == 0;
+    } while ((itr->sector_addr = get_next_sector_addr(db, &sector)) != FAILED_ADDR);
+    /* Finally we have iterated all the KVs. */
+    return false;
+}
+
 #endif /* defined(FDB_USING_KVDB) */