2020-10-08 11:17:36 +08:00
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# 遍历所有 KV
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本示例演示了如果遍历 KVDB 中的所有 KV ，用户可以在遍历 KV 时增加自己的处理动作。
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## 代码说明
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下面的示例代码中，首先初始化了 KVDB 的迭代器，然后使用迭代器 API ，将 KVDB 的所有 KV 逐一遍历出来。
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遍历出来的 KV 对象含有 KV 的一些属性，包括：key name, value saved addr, value length 等，用户通过 `fdb_blob_read` 配合 `fdb_kv_to_blob` 读取出来，做一些自己的业务处理。
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```C
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void kvdb_tarversal_sample(fdb_kvdb_t kvdb)
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{
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struct fdb_kv_iterator iterator;
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fdb_kv_t cur_kv;
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struct fdb_blob blob;
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size_t data_size;
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uint8_t *data_buf;
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2023-04-29 16:11:35 +08:00
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fdb_kv_iterator_init(kvdb, &iterator);
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2020-10-08 11:17:36 +08:00
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while (fdb_kv_iterate(kvdb, &iterator)) {
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cur_kv = &(iterator.curr_kv);
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data_size = (size_t) cur_kv->value_len;
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data_buf = (uint8_t *) malloc(data_size);
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if (data_buf == NULL) {
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FDB_INFO("Error: malloc failed.\n");
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break;
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}
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fdb_blob_read((fdb_db_t) kvdb, fdb_kv_to_blob(cur_kv, fdb_blob_make(&blob, data_buf, data_size)));
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/*
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* balabala do what ever you like with blob...
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*/
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free(data_buf);
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}
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}
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```
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