Method walk

ZezeJava/ZezeJava/src/main/java/Zeze/Dbh2/Dbh2.java:348–387

(Binary exclusiveStartKey, int proposeLimit, boolean desc, Binary prefix,
						 Action2<Binary, RocksIterator> fill)

	}

	private boolean walk(Binary exclusiveStartKey, int proposeLimit, boolean desc, Binary prefix,
						 Action2<Binary, RocksIterator> fill) throws Exception {
		if (desc) {
			return walkDesc(exclusiveStartKey, proposeLimit, prefix, fill);
		}

		try (var it = stateMachine.getBucket().getData().iterator()) {
			if (exclusiveStartKey.size() > 0)
				it.seek(exclusiveStartKey.copyIf());
			else
				it.seekToFirst();

			if (it.isValid()) {
				var firstKey = it.key();
				//noinspection EqualsBetweenInconvertibleTypes
				if (exclusiveStartKey.size() > 0 && exclusiveStartKey.equals(firstKey))
					it.next(); // skip exclusive key if need.
			}

			var count = proposeLimit;
			var bucketEnd = false;
			var keyLast = stateMachine.getBucket().getBucketMeta().getKeyLast();
			for (; it.isValid() && count > 0; it.next(), count--) {
				var key = new Binary(it.key());
				if (keyLast.size() > 0 && key.compareTo(keyLast) >= 0) {
					// 分桶中刚完成时，数据可能超过Last，此时应该检查出来并结束walk。
					bucketEnd = true;
					break;
				}
				// 如果使用了prefix，那么发现了新的prefix时，也表示搜索结束。
				if (prefix.size() >= 0 && !key.startsWith(prefix)) {
					bucketEnd = true;
					break;
				}
				fill.run(key, it);
			}

			return bucketEnd || !it.isValid();
		}
	}

	@Override
	protected long ProcessWalkRequest(Walk r) throws Exception {