Function krmDecodeRanges

fdbclient/KeyRangeMap.actor.cpp:39–90

}

RangeResult krmDecodeRanges(KeyRef mapPrefix, KeyRange keys, RangeResult kv, bool align) {
	ASSERT(!kv.more || kv.size() > 1);
	KeyRange withPrefix =
	    KeyRangeRef(mapPrefix.toString() + keys.begin.toString(), mapPrefix.toString() + keys.end.toString());

	RangeResult result;
	result.arena().dependsOn(kv.arena());
	result.arena().dependsOn(keys.arena());

	// Always push a kv pair <= keys.begin.
	KeyRef beginKey = keys.begin;
	if (!align && !kv.empty() && kv.front().key.startsWith(mapPrefix) && kv.front().key < withPrefix.begin) {
		beginKey = kv[0].key.removePrefix(mapPrefix);
	}
	ValueRef beginValue;
	if (!kv.empty() && kv.front().key.startsWith(mapPrefix) && kv.front().key <= withPrefix.begin) {
		beginValue = kv.front().value;
	}
	result.push_back(result.arena(), KeyValueRef(beginKey, beginValue));

	for (int i = 0; i < kv.size(); i++) {
		if (kv[i].key > withPrefix.begin && kv[i].key < withPrefix.end) {
			KeyRef k = kv[i].key.removePrefix(mapPrefix);
			result.push_back(result.arena(), KeyValueRef(k, kv[i].value));
		} else if (kv[i].key >= withPrefix.end) {
			kv.more = false;
			// There should be at most 1 value past mapPrefix + keys.end.
			ASSERT(i == kv.size() - 1);
			break;
		}
	}

	if (!kv.more) {
		KeyRef endKey = keys.end;
		if (!align && !kv.empty() && kv.back().key.startsWith(mapPrefix) && kv.back().key >= withPrefix.end) {
			endKey = kv.back().key.removePrefix(mapPrefix);
		}
		ValueRef endValue;
		if (!kv.empty()) {
			// In the aligned case, carry the last value to be the end value.
			if (align && kv.back().key.startsWith(mapPrefix) && kv.back().key > withPrefix.end) {
				endValue = result.back().value;
			} else {
				endValue = kv.back().value;
			}
		}
		result.push_back(result.arena(), KeyValueRef(endKey, endValue));
	}
	result.more = kv.more;

	return result;
}

// Returns keys.begin, all transitional points in keys, and keys.end, and their values
ACTOR Future<RangeResult> krmGetRanges(Transaction* tr, Key mapPrefix, KeyRange keys, int limit, int limitBytes) {