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165 рядки
5.1 KiB
165 рядки
5.1 KiB
#include "fields.h"
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#include "util/coding.h"
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#include <iostream>
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#include <utility>
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namespace leveldb {
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/* 构造函数 */
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Fields::Fields(FieldArray fields)
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: fields_(std::move(fields)) {
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SortFields();
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}
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Fields::Fields(const Field& field)
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: fields_({field}) {}
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Fields::Fields(const std::vector<std::string>& field_names) {
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for (const auto& name : field_names) {
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fields_.emplace_back(name, "");
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}
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SortFields();
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}
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/* 根据 field_name 从小到大进行排序，减少通过 field_name 遍历 Fields 的耗时 */
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void Fields::SortFields() {
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std::sort(fields_.begin(), fields_.end(), [](const Field& a, const Field& b) {
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return a.first < b.first;
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});
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}
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/* 更新/插入单个字段值 */
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void Fields::UpdateField(const std::string& field_name, const std::string& field_value) {
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for (auto iter = fields_.begin(); iter != fields_.end(); iter++) {
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if ((*iter).first > field_name) {
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fields_.insert(iter, {field_name, field_value});
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return;
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}
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if ((*iter).first == field_name) {
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(*iter).second = field_value;
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return;
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}
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}
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fields_.emplace_back(field_name, field_value);
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}
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void Fields::UpdateField(const Field& field) {
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UpdateField(field.first, field.second);
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}
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/* 更新/插入多个字段值 */
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void Fields::UpdateFields(const std::vector<std::string>& field_names, const std::vector<std::string>& field_values) {
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if (field_names.size() != field_values.size()) {
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std::cerr << "UpdateFields Failed: field_name and field_values must have the same size." << std::endl;
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return;
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}
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for (size_t i = 0; i < field_names.size(); ++i) {
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UpdateField(field_names[i], field_values[i]);
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}
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}
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void Fields::UpdateFields(const FieldArray& fields) {
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for (const auto& field : fields) {
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UpdateField(field);
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}
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}
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/* 删除单个字段 */
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void Fields::DeleteField(const std::string& field_name) {
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for (auto iter = fields_.begin(); iter != fields_.end(); iter++) {
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if ((*iter).first > field_name) return;
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if ((*iter).first == field_name) {
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fields_.erase(iter);
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return;
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}
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}
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}
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/* 删除多个字段 */
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void Fields::DeleteFields(const std::vector<std::string>& field_names) {
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for (auto &name : field_names) {
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if (fields_.empty()) return;
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DeleteField(name);
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}
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}
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/* 序列化 Field 或 FieldArray 为 value 字符串 */
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std::string Fields::SerializeValue(const FieldArray& fields) {
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std::string value_str;
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for (const auto& field : fields) {
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std::string field_str = SerializeValue(field);
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value_str += field_str;
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}
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return value_str;
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}
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std::string Fields::SerializeValue(const Field& field) {
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std::string value_str;
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PutLengthPrefixedSlice(&value_str, Slice(field.first));
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PutLengthPrefixedSlice(&value_str, Slice(field.second));
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return value_str;
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}
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std::string Fields::SerializeValue() const {
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return SerializeValue(fields_);
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}
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/* 反序列化 value 字符串为 Fields */
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Fields Fields::ParseValue(const std::string& value_str) {
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Fields fields;
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Slice value_slice(value_str);
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while (!value_slice.empty()) {
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Slice field_name;
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Slice field_value;
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if (!GetLengthPrefixedSlice(&value_slice, &field_name)) break;
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if (!GetLengthPrefixedSlice(&value_slice, &field_value)) break;
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fields.UpdateField(field_name.ToString(), field_value.ToString());
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}
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return fields;
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}
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/* 获取字段 */
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Field Fields::GetField(const std::string& field_name) const {
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for (auto iter = fields_.begin(); iter != fields_.end(); iter++) {
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if ((*iter).first == field_name) return *iter;
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if ((*iter).first > field_name || iter == fields_.end() - 1) {
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std::cerr << "GetField Failed: field name [" + field_name + "] doesn't exist, return {}." << std::endl;
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return {};
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}
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}
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}
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/* 检查字段是否存在 */
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bool Fields::HasField(const std::string& field_name) const {
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for (auto iter = fields_.begin(); iter != fields_.end(); iter++) {
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if ((*iter).first == field_name) return true;
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if ((*iter).first > field_name || iter == fields_.end() - 1) return false;
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}
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}
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/* 重载运算符 [] 用于访问字段值 */
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std::string Fields::operator[](const std::string& field_name) const {
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for (auto iter = fields_.begin(); iter != fields_.end(); iter++) {
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if ((*iter).first == field_name) return (*iter).second;
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if ((*iter).first > field_name || iter == fields_.end() - 1) {
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static const std::string empty_str;
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std::cerr << "GetField Failed: field name [" + field_name + "] doesn't exist." << std::endl;
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return empty_str;
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}
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}
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}
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std::string& Fields::operator[](const std::string& field_name) {
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for (auto iter = fields_.begin(); iter != fields_.end(); iter++) {
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if ((*iter).first == field_name) return (*iter).second;
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if ((*iter).first > field_name) {
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return fields_.insert(iter, {field_name, ""})->second;
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}
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}
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fields_.emplace_back(field_name, "");
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return fields_.back().second;
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}
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} // namespace leveldb
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